@article {3672, title = {Impact of maternal diet during late gestation and pre-weaning milk allowance on heifer growth and first lactation milk yield}, journal = {New Zealand Journal of Animal Science and Production}, volume = {82}, year = {2022}, month = {01/2022}, pages = {99-103}, address = {Online}, abstract = {A total of 60 Friesian x Jersey heifer calves were allocated to a 2{\texttimes}2 factorial design to investigate early life nutrition on growth and production. The first factor was the maternal treatments where dams were offered a low crude protein (7.8\% LCP) or moderate crude protein (13.6\% MCP) diet for the last 50 days of gestation. The second factor was the calf milk replacer (CMR) allowance to heifer offspring, which was either restricted (RES) or high allowance (HA) allowance (15 or 25\% of initial live weight, respectively). All calves were given colostrum for 4 days then, warmed CMR (150 g/L) in two equal feeds between days 5 and 39, after which all calves received the same 15\% allowance. Milk intake, liveweight gain and fecal score were recorded for 5 weeks. Calves were weaned off milk at 8 weeks of age. The HA treatment improved weaning weight (88 vs 79{\textpm}1.4 kg; P<0.001) and overall ADG pre-weaning (0.9 vs 0.8{\textpm}0.02 kg/day; P<0.001) compared to RES. There was no effect of maternal diet on pre-weaning growth or fecal score. There was limited statistical evidence of a long-term effect of early life nutrition on milk yield, though maternal nutrition appeared to be more important than pre-weaning nutrition on future milk production.}, issn = {1176-5283}, author = {Moonsan Y and Thomas C and McCoard SA and Hammond KJ and Edwards GR and Bryant RH} } @article {3672, title = {The effects of substituting autumn nitrogen fertiliser with gibberellic acid on feed supply and milk production}, journal = {New Zealand Journal of Animal Science and Production}, volume = {81}, year = {2021}, month = {01/2022}, pages = {190-195}, address = {Online}, abstract = {The aim of this study was to investigate the use of gibberellic acid (GA) to improve feed supply and milk yield in late lactation. A grazing study at Lincoln used 36 lactating, mixed-age, Friesian-Jersey cross dairy cows balanced over three un-replicated treatments of perennial-ryegrass and white-clover pasture treated with nitrogen (N) fertiliser as urea (50 kg N/ha), GA as ProGibb{\textregistered} SG (8 g GA/ha) or untreated (Control). Treatments were applied in late March 2014 and grazed over 12 days in May. There was no effect of treatment on herbage pre-grazing pasture mass (2058{\textpm}6.9 kg DM/ha, P=0.20), clover (3.6{\textpm}0.86\%, P=0.53), ryegrass (88.0{\textpm}2.33\%, P=0.24) or crude protein (CP) content (17.8{\textpm}1.60\%, P=0.31). All milk yield components: 14.6{\textpm}0.40 L/day, 1.4{\textpm}0.09 kg MS/cow/day, 5.4{\textpm}0.33\% fat and 4.4{\textpm}0.21\% protein were similar among treatment groups (P=0.71, 0.14, 0.16 and 0.06, respectively). Although faecal-N content of cows on GA pasture (3.72\% N) was higher (P<0.001) than cows on N-fertilised pasture (3.45\% N) there was no treatment effect (P>0.05) on urinary-N content (0.4 {\textpm} 0.02\% N) or N excretion in milk (101{\textpm}4.4 g N/cow/d). The lack of response to GA or N fertiliser highlights the importance of timing of growth promotants for late lactation. Keywords: perennial ryegrass; white clover; urea; growth promotants; dairy cow; milk production}, issn = {1176-5283}, author = {Miller ME and Edwards GR and Hague H and Bryant RH} } @article {3672, title = {Liveweight gain and urinary nitrogen excretion of lambs grazing diverse (plantain, Italian ryegrass and red clover) or ryegrass-white clover pasture in autumn}, journal = {New Zealand Journal of Animal Science and Production}, volume = {80}, year = {2020}, month = {09/2020}, pages = {70-75}, address = {Online}, abstract = {The objective of this study was to investigate the effect of grazing a diverse pasture of plantain, Italian ryegrass, and red clover versus a ryegrass-white clover pasture on the liveweight gain (LWG) and urinary nitrogen (N) excretion of ram lambs over an 82- day experimental period in autumn. Eighty Coopworth ram lambs (8 months old) were allocated to two replicates of two pasture treatments (n = 20), a diverse pasture containing plantain, Italian ryegrass, and red clover (Diverse) and conventional ryegrass-white clover pasture (RGWC). Unfasted live weight (LWT) of lambs was recorded on seven occasions during the autumn experimental period. Apparent dry matter intake (DMI) was estimated as the difference between pre- and post-grazing herbage mass plus daily herbage growth. On two occasions, urine and blood samples were collected from each lamb to determine concentration of urinary N and plasma urea N (PUN). Liveweight gain (P=0.008) and feed conversion efficiency (P=0.022) were greater in Diverse than RGWC treatment (240 vs 160 g/day and 111 vs 86 g LWT per kg DMI, respectively). Urinary N and PUN concentration were similar between treatments; however, when urinary N excretion (g/d) was estimated as a function of PUN, lambs grazing Diverse pasture excreted less (P=0.003) urinary N per 100 g LWG than those grazing RGWC pasture. The proportion of N intake retained in LWG was greater (P=0.008) for lambs grazing Diverse (11.0\%) than those grazing RGWC (9.0\%). The results indicate that there is a potential to achieve target LWT of lambs in a shorter time and with less N loss to the environment by using a diverse mix containing plantain, Italian ryegrass and red clover in comparison to ryegrass-white clover mix in autumn. Keywords: Growing lambs; liveweight gain; urinary nitrogen; diverse pasture; ryegrass}, issn = {1176-5283}, author = {Al-marashdeh O and Cook GA and Anderson FC and Meyer JPH and Logan CM and Edwards GR and Maxwell TMR} } @article {3672, title = {BRIEF COMMUNICATION: Urinary nitrogen excretion and water balance of dairy heifers fed cut plantain or perennial-ryegrass pastures}, journal = {New Zealand Journal of Animal Science and Production}, volume = {79}, year = {2019}, month = {07/2019}, pages = {171-173}, address = {Palmerston North}, abstract = {Loline, an alkaloid produced by Neotyphodium endophytes in pastoral grass species with potential antimicrobial properties, has several known derivatives; N-formyl loline (NFL), N-acetyl loline (NAL), N-acetyl norloline (NANL), N-methyl loline (NML), and loline base, though the availability and form during rumen fermentation and digestion is unclear. Festuca pratensis seeds either with (LOL) or without (NIL) lolines (150-200 {\textmu}g/mL) were incubated in either sterile or viable rumen fluid or in either HCL/pepsin (pH 2) or water (pH 7). At 72 hours LOL in sterile rumen fluid had 23\%, 26\%, and 45\% more NFL (P=0.05), NANL (P=0.04), and loline base (P=0.01) respectively, with 27\% more total loline present (P=0.06), and 65\% more NML (P=0.09) compared with LOL in viable rumen fluid. Loline tended to alter the fermentation pattern as NIL produced 11\% more ammonia (P=0.07), and 5\% less propionate (P=0.06) than LOL. In HCL/pepsin there were 38\%, 49\%, and 39\% more total lolines (P=0.05), NANL (P=0.02), and NFL (P=0.04) respectively, compared with water. Rumen and abomasal digestion appear to have a small effect on loline{\textquoteright}s form and concentration with only slight alteration to the rumen fermentation pattern. Presence of lolines had little evidence of an antimicrobial effect.}, issn = {1176-5283}, author = {Al-marashdeh O and Judson HG and Schetelat S and Pawsey A and Edwards GR} } @article {3672, title = {BRIEF COMMUNICATION: Effect of maternal diet in late gestation on development of dairy calves}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {186-188}, address = {Lincoln}, abstract = {To investigate whether feeding strategies to reduce urinary N excretion would have negative effects on calf development, two feeding systems were compared. A total of 190 pregnant, Friesian {\texttimes} Jersey dairy cows were randomly allocated to one of two groups and offered either a low crude protein diet of maize silage and fodder beet (LCP) or a moderate CP diet of lucerne silage and fodder beet (MCP) for eight weeks prior to calving. Apparent metabolisable energy (ME) intake of dams was similar (110 MJME/cow/day) but CP concentration was greater for MCP than LCP (13.4 vs 7.5\% of the DM). There was no effect of maternal diet on calf birth weight (33.0{\textpm}0.5 kgLW) or morphometric measurements; heart girth (72.8{\textpm}0.5) spine length (54.4{\textpm}0.4) or hip height (73.1{\textpm}0.4 cm). These results suggest that dietary protein restriction in late gestation does not have any immediate negative effects on in utero calf development.}, issn = {1176-5283}, author = {Moonsan Y and Thomas C and Bryant RH and Edwards GR} } @article {3672, title = {BRIEF COMMUNICATION: Effect of timing of maize silage supplementation on grazing behaviour of dairy cows during a short grazing session on a ryegrass-based herbage}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {31-34}, address = {Lincoln}, abstract = {The objective of this experiment was to compare rumen degradation characteristics of ryegrass (Lolium perenne), white clover (Trifolium repens) or plantain (Plantago lanceolata) harvested either in the morning (0700) or afternoon (1600). Fresh herbage material from each treatment was weighed into duplicate nylon bags and incubated in four lactating Jersey {\texttimes} Friesian dairy cows with rumen fistula. Differences in nutritive value between forage types was greater than effect of harvest time as was the effect on rumen degradation characteristics. Plantain had faster (P<0.001) DM disappearance rates than perennial ryegrass-white clover (12.2 vs 8.80 \%/hr). The soluble fraction was greater (P=0.001) for forages harvested in the afternoon (25.2\% of DM) than those in the morning (15.4\% of DM) regardless of forage type. Nitrogen degradation was almost complete (>95\% of N) and similar for all treatments (P>0.05). An interaction for effective degradability revealed there was no effect of harvest time on DM and OM for plantain. However, perennial ryegrass-white clover harvested in the afternoon has a greater effective degradability of DM and OM than that harvested in the morning. This suggested there is a larger influence of harvest time on some degradation characteristics of perennial ryegrass-white clover compared with plantain.}, issn = {1176-5283}, author = {Al-marashdeh O and Gregorini P and Edwards GR} } @article {3672, title = {In sacco digestion kinetics of plantain and ryegrass-white clover harvested in the morning and afternoon}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {34-39}, address = {Lincoln}, issn = {1176-5283}, author = {Box LA and Edwards GR and Bryant RH} } @article {3672, title = {Milk production and milk fatty acid composition of grazing dairy cows supplemented with fodder beet}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {6-10}, address = {Lincoln}, abstract = {A study was conducted to evaluate the effect of supplementing a perennial ryegrass-based diet with fodder beet on milk production and milk fatty acid (FA) composition, of dairy cows in early lactation. Sixty Friesian {\texttimes} Jersey cows, were blocked into six groups of 10 cows, and groups randomly allocated to three replicates fed either 18 kg DM/day of ryegrass herbage (H), or 14.4 kg DM/ day of ryegrass herbage + 4 kg DM of harvested FB bulbs (FBB). Dry matter intake (DMI) was similar between H and FBB (15.0{\textpm}0.77 and 14.2{\textpm}0.48 kg DM/day respectively). Although milk yield tended to be greater for H than FBB (20.0 and 18.9 kg/ day respectively; P=0.09); milk solids production was not affected by treatment (P=0.89). Supplementation with FBB increased the saturated (80.6 versus 73.2{\textpm}0.39 g/100g FA; P<0.001) and medium chain milk FA (66.7 versus 56.2{\textpm}0.783; P<0.001) content, compared with H. Under the conditions of the present study, our results suggest that, supplementing grazing dairy cows with FBB in early lactation, may not improve milk production and increases the saturated FA content of milk.}, issn = {1176-5283}, author = {Fleming AE and Edwards GR and Bryant RH and Dalley DE and Gregorini P} } @article {3672, title = {Plantain: It is not only the dietary content, but also how we graze it{\textellipsis}}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {151-156}, address = {Lincoln}, abstract = {A mechanistic and dynamic model of a grazing ruminant, MINDY, was used to explore the effect of both the proportion dietary inclusion of plantain (PL) and its grazing management, compared with ryegrass (RG), on urinary N (UN) excretion of dairy cows. The treatment tested were: 1) frequency of allocation and 2) dietary proportion of PL. Frequency of allocation was set by stripgrazing (24 hrs. pasture breaks) PL or RG monocultures for 1, 5 or 10 consecutive days, allocated either after the morning (AM) or afternoon (PM) milking. The proportion of dietary PL was set by offering either 25 or 50\% of the diet as PL monocultures allocated either AM or PM. MINDY had greater intake of PL-containing diets than RG alone, resulting in increased N intake. However, with the exception of the {\textquoteleft}frequency{\textquoteright} treatments, daily urinary N excretion (UN) was reduced by including PL compared with RG alone. Plantain monocultures led to similar or lower urine volume compared with RG. Grazing RG and PL every 1 or 5 days increased urine volume, frequency and UN compared with RG or continuous PL. Offering PL or RG in the AM compared with PM reduced UN but reduced milk yield. This modelling exercise suggests that including PL in cattle{\textquoteright}s diet reduces UN and UN concentration, and that the frequency and timing of its allocation help to reduce environmental impact further while maintaining or increasing MS.}, issn = {1176-5283}, author = {Gregorini P and Bryant RH and Beck MR and Edwards GR} } @article {3672, title = {Whole-farm modelling using different grazing-management strategies with diverse pastures within an irrigated dairy-farm system}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {1-5}, address = {Lincoln}, abstract = {The objective of this study was to assess the effect of diverse pasture mixtures and grazing management on profitability of Canterbury dairy farms using a commercial modelling tool, Farmax Dairy Pro. Two years of pasture growth and quality data were obtained from irrigated plots sown with a pasture mixture consisting of perennial ryegrass, white clover, red clover, chicory and plantain (diverse) or the same pasture mixture plus Italian ryegrass (diverse-Italian). Pastures were subjected to one of three grazing management regimes: (1) conventional grazing (grazed to a compressed height of 3.5 cm all year); (2) spring lenient grazing; and (3) autumn lenient grazing. The data were fitted to a base model farm (average of North Canterbury region) using Farmax Dairy Pro to produce six different farm scenarios. Farm scenarios were ranked and compared by profit expressed as earnings before tax. Pastures managed by autumn lenient grazing resulted in the lowest DM production, more supplement purchased, and hence, lowest profit compared with conventional or spring lenient grazing management. The diverse pasture managed by spring lenient grazing resulted in the greatest profit ($2,658/ha) compared with other scenarios (average $2,261/ha). This greater profit was driven by greater annual DM production per hectare and, hence, less supplement purchased. When diverse pasture is considered, spring lenient grazing is a potential management option for irrigated Canterbury dairy farm systems to increase DM production and thereby profitability.}, issn = {1176-5283}, author = {Cun, GS and Al-marashdeh O and Edwards GR} } @conference {3672, title = {Brief Communication: In vitro fermentation characteristics of ryegrass-white clover sward containing differnt proportions of chicory}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {77}, year = {2017}, month = {06/2017}, pages = {82-84}, address = {Rotorua}, abstract = {Chicory (Cichorum intybus) is a deep-rooted grazeable forage used to overcome production and nutritive value shortfalls of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) swards during summer drought periods in New Zealand (Waugh et al. 1998; Chapman et al. 2012). However, there is little and contrasting data on the proportion of chicory to be used in mixed swards to influence livestock production. For example, Golding et al. (2011) showed that feeding chicory in a mixed sward at 18{\textendash}40\% of total dry matter, increased lamb post-weaning liveweight gain (LWG) compared with a traditional ryegrass sward. On the other hand, Cheng et al. (2017) reported similar daily LWG for heifers offered a mixed sward of 50\% chicory and 50\% ryegrass-white clover or 100\% perennial ryegrass-white clover. These contrasting results justify more research on the chicory proportion in mixed swards and its effect on animal performance...}, issn = {1176-5283}, author = {Al-marashdeh O and Cheng L and Gregorini P and Edwards GR} } @conference {3672, title = {Growth curves of New Zealand Holstein-Friesian, Jersey and Holstein-Friesian-Jersey crossbred heifers}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {77}, year = {2017}, month = {06/2017}, pages = {64-68}, address = {Rotorua}, abstract = {There are differences in the proportion of target live weight (LWT) achieved between the main breeds of dairy heifers in New Zealand, suggesting a potential difference in growth pattern. The objectives of this study were to model growth curves of dairy heifers through random regression of Legendre polynomials, and to compare growth curves of the main breeds. Data comprised of 1,653,214 LWT records obtained from 189,936 dairy heifers in 1,547 herds. The fourth-order Legendre polynomial was the best at predicting LWT, with a relative prediction error (RPE) of less than 4\% for the whole dataset and for Holstein-Friesian, Jersey and Holstein-Friesian-Jersey crossbred (F{\texttimes}J) heifers. The regression coefficients of the growth curve differed among breeds for the intercept (α0; P<0.001), linear effect (α1; P<0.001), quadratic effect (α2; P<0.001), cubic effect (α3; P<0.001) and quartic effect (α4; P<0.001). At all ages Holstein-Friesian heifers were heavier than F{\texttimes}J which were heavier than Jersey heifers (P<0.001). The percentage difference among the breeds varied throughout the growth curve, indicating that the main breeds of dairy heifers in New Zealand exhibited different growth patterns that were non-linear. The different growth patterns for each breed should be considered when formulating target LWTs and growth rates.}, issn = {1176-5283}, author = {Handcock RC and Lopez-Villalobos N and McNaughton LR and Edwards GR and Hickson RE} } @conference {3672, title = {Stand-off pad wintering system: effect of surface types on cow comfort and urination behaviour}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {77}, year = {2017}, month = {06/2017}, pages = {137-142}, address = {Rotorua}, abstract = {Two consecutive experiments were conducted over four weeks during winter to investigate the effect of different stand-off pad surface types on dairy cow lying behaviour, cleanness and lameness scores, and urination frequency. In experiment one, 350 Frie-sian {\texttimes} Jersey, pregnant non-lactating dairy cows were blocked and assigned to five treatments for two weeks: fodder beet grazed in situ with no stand-off (control); fodder beet grazed in situ and cows spent 17 hours on a woodchip stand-off (WCG); harvested fodder beet bulb fed in paddock and cows spent 17 hours on a woodchip stand-off (WCH); fodder beet grazed in situ and cows spent 17 hours on a 70 mm round-stone stand-off (S70); fodder beet grazed in situ and cows spent 17 hours on a 50 mm round-stone stand-off (S50). In experiment two, 156 Friesian {\texttimes} Jersey, pregnant non-lactating dairy cows were blocked and assigned to three treatments for two weeks: control and WCG as described in experiment one, and a third geotextile {\textquoteleft}carpet{\textquoteright} stand-off for 17 hours (GC). In experiment one, surface type had no effect on lying time (average 10.1 hours), cleanness and lameness score, or urination behaviour. In experiment two, lying hours were greater (P=0.01) for cows on carpet (11.6) than for cows on woodchip (10.8). While current results showed a negligible effect of surface type on cow comfort and urination behaviour during winter, a longer study, covering the whole winter season, is required to confirm these results. }, issn = {1176-5283}, author = {Al-marashdeh O and Cameron KC and Bryant RH and Box L and Arends A and Coveney A and Crystal J and Edwards GR} } @conference {3672, title = {Dietary preference of dairy cows for perennial ryegrass cultivars growing with and without white clover}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {76}, year = {2016}, month = {07/2016}, pages = {81-86}, address = {Adelaide}, abstract = {Dietary preference of dairy cows for eight perennial ryegrass cultivars (AberMagic, Alto, Base, Bealey, Commando, Kamo, One50 and Prospect) growing with and without white clover was examined at two vegetative stages (May and October) and one reproductive stage (November). Groups of dairy cows (n = 8) were offered free choice among cultivars growing with or without white clover for 6 to 8 hours. Preference was defined as the relative decreasing rate in sward surface height. Preference was higher for the tetraploid cultivars, Base and Bealey and the high-sugar diploid cultivar, AberMagic (preference ranged from 1.02 to 1.45). Preference was negatively correlated with herbage mass (r = -0.179, P = 0.013), proportion of dead material (r = -0.301, P < 0.001) and neutral detergent fibre (r = -0.287, P < 0.001), and positively correlated with sward surface height (r = 0.386, P < 0.001), ryegrass lamina length (r = 0.233, P = 0.001), tiller mass (r = 0.338, P < 0.001), water-soluble carbohydrate concentration (r = 0.143, P = 0.049) and organic matter digestibility in dry matter (r = 0.312, P < 0.001). Although the proportion of white clover was low (< 7\% DM) in all three experiments, the interactions between perennial ryegrass cultivar and the presence of white clover were significant (P = 0.004 at pre-heading stage, P = 0.046 at reproductive stage and P = 0.038 at post-heading stage), with differences among preference for perennial ryegrass cultivars reduced when white clover was present}, issn = {1176-5283}, author = {Chen A and Bryant RH and Edwards GR} } @conference {3672, title = {Does mowing before grazing increase dry matter intake and milk yield?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {76}, year = {2016}, month = {07/2016}, pages = {73-77}, address = {Adelaide}, abstract = {Mowing pasture before allocation of herbage to dairy cows is one management strategy suggested to improve feed quality, increase herbage dry matter (DM) intake and increase milk solids yield. To test these hypotheses, pasture at either a three or four week regrowth interval was offered to dairy cows 3 hours after pasture had been mown or as standing pasture. Forty-eight late lactation, Friesian x Jersey dairy cows were blocked into four groups and randomly allocated to each treatment. There was no effect of mowing or regrowth interval on botanical composition of the pasture on offer. Composition of herbage above 3.5 cm varied in DM content which was increased by mowing (13.2 versus 18.4\% DM, P<0.05). For pastures with a three week regrowth interval, crude protein content was higher in the mown compared with standing herbage. At a similar herbage allocation, apparent DM intake was lower in mown (14.9 kg DM/cow/day) than in standing (15.5 kg DM/cow/day) treatments (P<0.05). This resulted in lower milk solids yield (P<0.05) in mown (1.24 MS/cow/day) compared with standing pasture (1.40 kg MS/cow/day). There was no apparent advantage in mowing ryegrass pastures in late lactation to improve herbage utilisation, DM intake or milk yield.}, issn = {1176-5283}, author = {Bryant RH and Kingsbury LA and Edwards GR} } @conference {3672, title = {Effect of grazing system on nitrogen partitioning in lactating dairy cows grazing irrigated pastures in Canterbury, New Zealand}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {76}, year = {2016}, month = {07/2016}, pages = {94-99}, address = {Adelaide}, abstract = {Regulations currently being developed by Regional Councils throughout New Zealand to manage freshwater quality may require substantial reductions in nitrate leaching from dairy farms in many regions. The objective of this study was to quantify nitrogen intake, partitioning, and excretion in two irrigated farming systems in Canterbury, comparing different possible pathways for future industry development. A {\textquoteleft}higher input{\textquoteright} system (HI, n = 34 cows) was characterised by a stocking rate of 5 cows per/ha, ~300 kg/ha/year fertiliser N and ~1t DM/cow/year purchased supplement fed on the milking platform. The {\textquoteleft}lower input{\textquoteright} system (LI, n = 29 cows) used a stocking rate of 3.5 cows/ha, 150 kg/ha/year fertiliser N, and minimal purchased supplement. Urine, faeces, plasma, and milk samples were collected for N determination at consecutive afternoon and morning milkings once per month for four years. Estimated N intake did not differ between HI and LI (537 g N/cow/day and 557 g N/cow/day respectively, P = 0.29). No differences were recorded for N parameters and estimated milk and urine N output/cow was not affected by farm system. When scaled to per hectare, urinary N excretion was 33\% greater for HI compared with LI (1.1 kg/ha/day and 0.8 kg/ha/day, respectively, P = 0.02).}, issn = {1176-5283}, author = {Clement AR and Dalley DE and Chapman DF and Edwards GR and Bryant RH} } @conference {3672, title = {Milk production and urinary nitrogen excretion of dairy cows grazing perennial ryegrass-white clover and pure plantain pastures}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {76}, year = {2016}, month = {07/2016}, pages = {18-21}, address = {Adelaide}, abstract = {Milk production and urinary nitrogen (N) concentration were measured in late lactation dairy cows grazing a perennial ryegrass- white clover pasture, pure plantain and an area that is comprised of 50\% perennial ryegrass-white clover and 50\% pure plantain by ground area (50-50 pasture-plantain), (n=12). Milksolids production was greater (P=0.01) for cows grazing plantain (1.67 kg MS/cow/d) than those grazing pasture (1.50 kg MS/cow/d), with cows grazing 50-50 pasture-plantain intermediate (1.60 kg MS/cow/d). Urine-N concentration was 56\% lower (P<0.001) for plantain (2.4 g N/L) and 33\% lower for 50-50 pasture-plantain (3.6 g N/L) than pasture (5.4 g N/L). Plantain may offer environmental benefits to dairy systems by reducing the urinary N concentration deposited on the soil from grazing cows in late lactation.}, issn = {1176-5283}, author = {Box LA and Edwards GR and Bryant RH} } @conference {3672, title = {Relationship between social dominance and milk production of dairy cows grazing pasture}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {76}, year = {2016}, month = {07/2016}, pages = {69-72}, address = {Adelaide}, abstract = {The objectives of this experiment were to study factors determining social dominance of grazing dairy cows and the relationship between social dominance and milk production under grazing systems. A total of 252 spring calving Friesian x Jersey dairy cows in three groups differing in stocking rate and herd size grazing perennial ryegrass and white clover pasture were observed for three months in early lactation to determine their dominance value. All cows ranged in age from 2 to 11 years and live weight (LW) ranged from 340 kg to 648 kg. Dominance values were determined by social interactions indicating dominance and submission between cows. Social interactions were recorded on a win and loss basis. In all three groups, the dominance value was positively correlated (P<0.05) with age (r = 0.42 to 0.65), live weight (r = 0.33 to 0.47) and milk production (r = 0.32 to 0.42), but no relationship with body condition score was found. In conclusion, older cows with higher live weight were more dominant and tended to have higher milk production.}, issn = {1176-5283}, author = {Hussein AN and Al-marashdeh O and Bryant RH and Edwards GR} } @conference {3672, title = {Urine volume of non-lactating dairy cows in late gestation fed forage based diets in winter}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {76}, year = {2016}, month = {07/2016}, pages = {22-25}, address = {Adelaide}, abstract = {Quantitative information on urine volume of dairy cows fed winter forages is required to accurately evaluate nitrate leaching risks on these diets. Thirty-two Friesian x Jersey non-lactating, pregnant dairy cows were fed either 10 kg DM of fodder beet with 5.6 kg DM of ryegrass baleage or 16.4 kg DM of kale with 6.4 kg of oat silage. Cows were fitted with a urine meter for 24 to 72 hours to record the frequency and volume of urine events. Daily urine volume (28 {\textpm} 3 L/cow/day), frequency (9 {\textpm} 0.89 events/cow/day), and event volume (3.2 {\textpm} 0.3 L/event) were not significantly different between fodder beet and kale treatments. This was despite respective differences in total apparent water (51 vs. 70 L/cow/day, {\textpm} 2, P<0.001) and nitrogen (N) intake (231 vs. 488 g N/cow/ day, {\textpm} 9.4, P<0.001). In this study, water consumption and N intake did not appear to be linked with urine volume of dairy cows when two different forage diets were compared.}, issn = {1176-5283}, author = {Farrell LJ and Bryant RH and Hague H and Edwards GR} } @conference {3672, title = {The effects of feeding maize silage at different times prior to a herbage meal on dry matter intake, milksolids production and nitrogen excretion in late-lactation dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {75}, year = {2015}, month = {07/2015}, pages = {140-144}, address = {Dunedin}, abstract = { The objective of this study was to determine the effect of feeding maize silage at different times before the herbage meal on dry matter (DM) intake, milksolids (MS) production and nitrogen (N) excretion of late lactation dairy cows. In an indoor study, nine Friesian {\texttimes} Jersey dairy cows were assigned to three treatments: (1) herbage only (control); (2) supplemented with 3 kg DM of maize silage after morning milking approximately nine hours before the herbage meal (9BH); and (3) supplemented with 3 kg DM of maize silage after afternoon milking approximately one hour before the herbage meal (1BH). Cows were offered ad libitum cut herbage (perennial ryegrass-white clover) for five hours from 1530 to 2030 h. Herbage DM intake was greater (P=0.03) for control than 1BH cows, but did not differ between control and 9BH or between 1BH and 9BH cows (13.71, 11.96 and 12.74 kg DM/cow/ day for control, 1BH and 9BH, respectively). The substitution of herbage by maize silage was greater (P=0.05) for 1BH than 9BH cows (0.56 vs 0.31 kg DM herbage per kg DM maize silage, respectively). Milksolids production did not differ between treatments (overall mean 1.33 kg MS/cow/day). Nitrogen concentration in faeces and estimated urinary-N excretion (g/day) were lower in supplemented than control cows. Under herbage restriction, it is important to consider time of maize silage supplementation relative to the herbage meal for managing substitution rate and urinary-N excretion.}, issn = {1176-5283}, author = {Al-marashdeh O and Greenwood SL and Hodge S and Edwards GR} } @conference {3672, title = {Milk production and urination behaviour of dairy cows grazing diverse and simple pasture}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {75}, year = {2015}, month = {07/2015}, pages = {79-83}, address = {Dunedin}, abstract = { Milk production and urination patterns were measured for mid-lactation dairy cows grazing a simple perennial ryegrass-white clover pasture (n = 15) and a more diverse pasture (n = 15) containing herb (chicory and plantain) and legume (lucerne) species in addition to the perennial ryegrass and white clover. Milksolids production was similar for simple (2.09 kg MS/cow/d) and diverse (1.94 kg MS/cow/d) pasture. Urination volume and frequency were similar for simple (2.0 L/urination, 11.6 urinations/cow/d) and diverse (2.2 L/urination, 15.0 urinations/cow/d) pasture. Urine-nitrogen (N) concentration was 20\% lower for diverse (4.9 g N/L) than simple (6.1 g N/L) pasture. Diverse pastures may offer benefits for reducing the environmental impact of dairy farming by reducing the N loading of urine patches.}, issn = {1176-5283}, author = {Edwards GR and Bryant RH and Smith N and Hague H and Ferris A and Farell L} } @conference {3672, title = {Nitrogen partitioning in sheep offered three perennial ryegrass cultivars at two allowances in spring and autumn}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {75}, year = {2015}, month = {07/2015}, pages = {74-78}, address = {Dunedin}, abstract = { }, issn = {1176-5283}, author = {Jonker A and Cheng L and Edwards GR and Molano G and Taylor PS and Sonoval E and Cosgrove GP} } @conference {3672, title = {Ryegrass staggers and liveweight gain of ewe lambs and hoggets grazing four combinations of perennial ryegrass and strains of endophyte}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {75}, year = {2015}, month = {07/2015}, pages = {175-178}, address = {Dunedin}, abstract = { Ryegrass staggers and live weight gain of Coopworth ewe lambs or hoggets were assessed over four eight week trials (two summer, two autumn) for four combinations of perennial ryegrass and strains of endophyte: Arrow with standard (SE, wild type) endophyte, Trojan with NEA3 endophyte, Trojan with a mixture of NEA2 and NEA3 endophytes, and Rohan with a mixture of NEA2 and NEA6 endophytes. In each trial, three replicates of 10 to 12 sheep were assigned to 0.3 ha plots of each cultivar x endophyte strain combination, with herbage mass reduced from 3-4000 kg DM/ha to 1500 kg DM during the eight weeks. Severe ryegrass staggers occurred in all four trials in Arrow SE, with a mean ryegrass staggers score ranging between 1.65 to 2.8 (0 to 5 scale). Minor ryegrass staggers occurred in Trojan NEA3, Trojan NEA2/3, Rohan NEA2/6 in two of the four trials, but only with a low mean score (<0.4). Live weight gain was lower in Arrow SE than the other cultivars in three of the four trials. Trojan NEA3 had live weight gain that was different from Trojan NEA2/3 (+27 g/head/day higher in Trojan NEA2/3) on one trial only. The perennial ryegrass cultivar x novel endophyte strain combinations Trojan NEA3, Trojan NEA2/3 and Rohan NEA2/6 showed liveweight gain that was similar or greater than the standard endophyte control, and caused minimal ryegrass staggers in {\textquoteleft}worstcase scenario{\textquoteright} conditions designed to induce this.}, issn = {1176-5283}, author = {Logan CM and Edwards GR and Kerr GA and Williams S} } @conference {3672, title = {Urinary nitrogen excretion, grazing and urination behaviour of dairy heifers grazing pasture, chicory and plantain in autumn}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {75}, year = {2015}, month = {07/2015}, pages = {70-73}, address = {Dunedin}, abstract = { The objective of this study was to investigate urinary nitrogen (N) excretion, grazing and urination behaviour of dairy heifers grazing pasture, chicory and plantain. A 35-day trial was conducted with 56 Friesian x Jersey heifers aged 9-10 months. Heifers were blocked into five treatments balanced for their live weight and breeding worth: 100\% ryegrass/white-clover pasture (PA; n = 12); 100\% chicory (CH; n = 10); 100\% plantain (PL; n = 12); 50\% pasture + 50\% chicory (PA+CH; n = 10); and 50\% pasture + 50\% plantain (PA+PL; n = 12). Feed was offered every three days with allowance calculated according to feed requirement for maintenance plus live weight gain of 0.8 kg/day. Measured urinary-N concentration, estimated daily urinary-N excretion (UN) and urinary output were similar among treatments. During the first six hours after feed allocation, heifers spent more time idling and less time ruminating on CH and PL than on PA. The CH and PA+CH groups urinated more frequently than other groups. Data from this study indicate that heifers grazed chicory urinated more frequently without increasing daily UN and may potentially reduce N loading from soil. Future study is needed to take account of urinary N excretion diurnal variation.}, issn = {1176-5283}, author = {Cheng L and McCormick J and Hussein AN and Fraslin C and Moonsan Y and Moonsan P and Logan C and Grabot J and Edwards GR} } @conference {3672, title = {Use of a urine meter to detect variation in urination behaviour of dairy cows on winter crops}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {75}, year = {2015}, month = {07/2015}, pages = {84-88}, address = {Dunedin}, abstract = { Nitrate leaching loss from urine patches is predicted using a number of variables including urine N concentration, number of urine patches produced, and urine patch size however, there is a lack of quantitative data on the variability of urination events. A study was conducted using two wintering systems at Ashley Dene, Lincoln, between June and July 2014. Wintering systems were either kale (KA) fed at an allowance of 14 kg DM/cow/day plus barley straw (3 kg DM/cow/day) (n=5), or fodder beet (FB) fed at an allowance of 8 kg DM/cow/day, plus ryegrass baleage (6 kg DM/cow/day) (n=7). Twelve pregnant, non-lactating Holstein- Friesian x Jersey cows were fitted with calibrated urine meters which measured volume and frequency of urination events. The meters were worn for 24-hour periods. A calibration equation was used to calculate urine patch coverage from measured urine patch areas in the field and urine volumes. There was large variation between animals for urination behaviour. Average urination volume was similar for KA and FB (2.37 L/event; P>0.1 SEM=0.29), however urination frequency (12 vs. 8 events/day; P<0.1 SEM=2.25) and daily total urine volume (30 vs. 18 litres; P<0.03, SEM=4.56) were greater for KA. Average urine patch area was also 1.8 times larger on KA than on FB (0.47 vs. 0.25 m2). This information will be used to help predict nitrate leaching losses from grazing systems.}, issn = {1176-5283}, author = {Ravera BL and Bryant RH and Cameron KC and Di HJ and Edwards GR and Smith N} } @conference {3672, title = {Grazing behaviour, dry matter intake and urination patterns of dairy cows offered kale or fodder beet in winter}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {74}, year = {2014}, month = {06/2014}, pages = {23-28}, address = {Napier}, abstract = {The opportunity to reduce nitrogen (N) losses to the environment from wintering systems for dairy cows may arise from a combination of restricted grazing systems and feeding low N diets to reduce N intake. Lack of information on urination behaviour and grazing intake during restricted grazing makes it difficult to predict animal and environmental responses. Three winter forage systems were simulated and pregnant, non-lactating Friesian x Jersey dairy cows were offered diets which varied in crop allowance and supplement: early sown-kale (EK) comprising 14 and 3 kg DM/cow/d of kale and barley straw; late-sown kale (LK) comprising 11 and 5 kg DM/cow/d of kale and green-chop oat silage; and fodder beet (FB) comprising 8 and 6 kg DM/cow/d fodder beet and grass baleage. Grazing behaviour, DM intake, DM utilisation and urination and faecal frequency, were recorded for six hours following morning crop allocation. After six hours, utilisation of EK, LK and FB crops were 82, 76 and 90\%, corresponding to respective DM intake rates of 1.9, 1.4 and 1.2 kg DM/cow/hr. Average urination frequency (2.7 urinations/cow) and duration (9.1 seconds/urination) during the six hour grazing bout was similar for all treatments, and urine N concentration was also similar for each treatment (2.22 g N/L). As cows consumed a high proportion (> 75\%) of their daily intake within six hours, and few urination events occurred during this period, the results indicate suitability for use of these systems in a restricted grazing regime combined with a standoff pad in order to mitigate losses of N to environment.}, issn = {1176-5283}, author = {Jenkinson BAB and Edwards GR and Bryant RH} } @conference {3678, title = {Plants for dairy grazing systems operating under nitrate leaching limits}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {74}, year = {2014}, month = {06/2014}, pages = {102-107}, address = {Napier}, abstract = {Regulations that place a limit on the amount of nitrate-nitrogen leaching from agricultural land are currently being developed by Regional Councils throughout New Zealand. These regulations may require substantial reductions in nitrate leaching from current typical dairy farm levels. Notions of the pasture plant {\textquoteleft}ideotype{\textquoteright}, which have previously emphasised pasture growth and the intake of digestible nutrients, should now also include characteristics which can reduce the nitrogen surplus in the animal, and, therefore, the amount of nitrogen (N) excreted in urine. Information on the critical external or internal N requirements of candidate pasture species could be used to develop hypotheses regarding future grazed forage systems; currently, there are few data available for this purpose. Recent empirical evidence indicates that diverse pastures incorporating forage herbs such as chicory and plantain can reduce total urinary N load while maintaining similar levels of herbage accumulation to ryegrass-white clover pasture. However, insufficient information is available to identify the mechanisms through which the urinary N reductions occur. This specific knowledge gap needs to be filled. In addition, more information is needed on the general nitrogen nutrition physiology of candidate pasture species for future forage systems.}, issn = {1176-5283}, author = {Chapman DF and Edwards GR and Pinxterhuis JB} } @conference {89253, title = {Can milk urea nitrogen differentiate nitrogen use efficiency of lactating cow groups raised on New Zealand pasture}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {73}, year = {2013}, month = {Jan}, pages = {199-201}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {

Improving nitrogen use efficiency (NUE) (g of milk nitrogen output/g of nitrogen intake) of dairy cows helps to maximise profitability and minimise nitrogen losses on farm. However, the traditional nitrogen balance technique used indoors to measure dry matter intake (DMI) and NUE is labour intensive, costly and unsuited to pasture-based grazing systems. In The Netherlands, milk urea nitrogen (MUN) has been used as a non-invasive and easy-to-conduct test to differentiate NUE of dairy cow groups (Kuipers et al. 1999). Generally, higher values of MUN are associated with a lower NUE. However, the usefulness of MUN in New Zealand pasture-based grazing systems is uncertain for numerous reasons. Firstly, MUN excretion reaches a maximum when dietary crude protein (CP) exceeds 20\% of feed dry matter (DM), reducing the sensitivity of MUN to differentiate NUE in high dietary CP systems (Reynolds \& Kristensen 2008). Secondly, water intake has been identified as one of the factors influencing the concentration of MUN, but it is not normally quantified in grazing systems (De Campeneere et al. 2006). Lastly, when individual cow samples are used, MUN may be subject to diurnal variation (Cheng et al. 2010).

}, issn = {1176-5283}, author = {Aizimu W and Hodge S and Edwards GR and Dewhurst RJ and Cheng L} } @conference {89255, title = {Effect of post grazing residual and concentrate feeding on milk production in early lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {73}, year = {2013}, month = {Jan}, pages = {205-210}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {

Two strategies to increase nutrient supply to early lactation dairy cows were compared and the cumulative effects on pasture quality and milk production were investigated. In a farmlet experiment the effect of feeding pasture only, or pasture plus concentrate (4kg/cow/day) at low (3.5 cm) or high (5.0 cm) post-grazing pasture residual (PGPR) was determined using a 2 x 2 factorial combination. Milk production for four groups of eight Friesian x Jersey dairy cows was measured within three consecutive grazing rotations during the first 12 weeks of lactation. PGPR for the low and high treatments remained constant throughout the 12 week period at 3.7 and 4.5 cm respectively. Mean milk solids production in the first, second and third rotation were 1.99 {\textpm} 0.12, 2.14 {\textpm} 0.10 and 2.01 {\textpm} 0.09 kg MS/cow/day respectively. Increasing PGPR from 3.7 to 4.5 cm did not affect pasture quality, milk production or milk composition. Concentrate feeding increased milk solids yield by 0.30 kg (P \< 0.05) in the third rotation. Concentrate feeding also increased milk protein yield by 68 g (P \<0.05), 104 g (P \<0.05) and 167 g (P \<0.001) in the first, second and third rotation respectively. When pasture quality is not altered by PGPR, feeding a concentrate is more effective at increasing nutrient supply than raising grazing height.

}, issn = {1176-5283}, author = {Bryant RH and Harkin C and Vazathara T and Edwards GR} } @conference {89231, title = {Estimation of protein utilization efficiency and metabolisable protein efficiency in lactating cows grouped by breeding worth}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {73}, year = {2013}, month = {Jan}, pages = {100-102}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {

The efficiency of conversion of feed protein to milk protein (protein use efficiency (PUE)) is important in ruminants as protein is the most valuable component of milk (Ryan et al. 2011). It is also essential to reduce nutrient and resource costs when the efficiency of nutrient use is low (Roberts, 2008). In ruminants, dietary protein has three main routes of metabolism, namely microbial fermentation in the rumen, absorption in the small intestine, and catabolism and excretion of excess digestible protein into faeces and urine nitrogen (Agricultural Research Council 1980). This makes PUE difficult to explain and predict because of the interaction of these pathways. Rumen degradable protein (RDP) and metabolisable protein (MP) are the two main protein pools for milk protein production.

}, issn = {1176-5283}, author = {Wheadon NW and Cheng L and Dewhurst RJ and Edwards GR} } @conference {89229, title = {Milksolids production of dairy cows grazing lucerne and perennial ryegrass in spring}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {73}, year = {2013}, month = {Jan}, pages = {93-95}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {

The potential of New Zealand grazing systems is dependant on the dry matter (DM) yield, nutritive characteristics, and utilisation of pasture. The most common pasture is a mixture of ryegrass and white clover, which is tolerant of a wide range of environments and management (Kemp et al. 1999). However species such as these with shallow root systems and poor growth in high temperatures will have reduced herbage accumulation and quality during dry summer periods (Hoglund \& White 1985). As demand for irrigation has increased to alleviate these problems, it has also raised questions about water allocation impacts on dairy farm production and profit (Thorrold et al. 2004). For Canterbury, which experiences hot, dry summers, lucerne is a potential source of high quality feed due to its active warm season growth and greater water use efficiency (Mills \& Moot 2010).

}, issn = {1176-5283}, author = {Smith G and Bryant RH and Edwards GR} } @conference {78976, title = {Dry matter intake and nitrogen losses of pregnant, non-lactating dairy cows fed kale with a range of supplements in winter}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {72}, year = {2012}, month = {Jan}, pages = {8-13}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {

An outdoor winter-feeding study conducted over 14 days using 40 Friesian-Jersey cross dairy cows measured dry matter (DM) intake and nitrogen (N) excretion of cows fed kale with either barley straw (S), whole crop barley silage (WCBS) and Lotus pedunculatus silage (LS) fed with (LS+PEG) or without polyethylene glycol (LS-PEG). Treatment groups did not differ in DM utilisation of kale (80\%) or apparent intake of kale (11.6 kg DM/cow/d). Total daily intake of N was lowest for S, intermediate for WCBS and highest for LS+PEG and LS-PEG (280, 323, 350 and 352 g N/cow/d, respectively). Urinary N excretion was lower (P \< 0.05) on kale diets supplemented with either S or WCBS (202 and 186 g N/cow/d respectively) compared with LS+PEG and LS-PEG (227 and 239 g N/cow/d respectively). Supplement treatment did not affect total faecal N excretion but faecal N\% was higher (P \< 0.05) in LS treatment groups (3.05\% in LS+PEG and 3.28\% in LS-PEG), compared with WCBS (2.74\%) and S (2.43\%). This study indicates that the current commonly used feeding system of kale, supplemented with straw, is a feeding system that has a low urinary N excretion compared with alternatives.

}, issn = {1176-5283}, author = {Miller ME and Bryant RH and Edwards GR} } @conference {78996, title = {Grazing behaviour of dairy cows on simple and diverse swards in summer and autumn}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {72}, year = {2012}, month = {Jan}, pages = {106-110}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Increasing the proportion of dicotyledonous species such as herbs and legumes in dairy pastures may increase herbage dry matter intakes through ease of prehension. Simple swards consisting of either standard perennial ryegrass, high sugar ryegrass or tall fescue cultivars with white clover were established at the Lincoln University research dairy farm. Diverse swards were created by adding chicory and plantain to all mixtures, plus prairie grass and red clover to the perennial ryegrass, and praire grass and lucerne to the tall fescue. Grazing behaviour of cows during a two hour grazing session was monitored in summer and autumn. In summer, Diverse swards had a greater compressed sward surface height, lower mass and bulk density. Cows grazing Simple swards achieved a greater bite rate (49.3 vs 43.8 bites/min respectively (P < 0.05)). In autumn, all pasture swards had lower mass and contained a higher proportion of grass species than in summer. Bite rate was greater on Diverse compared with Simple swards (60.3 vs 54.3 bites/min respectively (P < 0.05)). Lower bite rate on Simple swards was compensated for by increasing grazing duration (P < 0.001). Sward type influenced bite rate adaptations.}, issn = {1176-5283}, author = {Bryant RH and Miller ME and Edwards GR} } @conference {75867, title = {BRIEF COMMUNICATION: Comparison of the performance of dairy cows offered energy supplements prior to drying off and kale at high and low allowance during the dry period in winter}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {33-36}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {Forage availability and body condition score (BCS) of the dairy cow are important aspects of dairy livestock management during the dry and peripartum period. New Zealand guidelines recommend a target BCS of 5.0 at calving (1-10 scale where 1 = Emaciated and 10 = Obese, Roche et al., 2009). Providing adequate forage to meet... Continued}, issn = {1176-5283}, author = {Greenwood SL and Dalley DE and Purdie NG and Rugoho I and Bryant RH and Edwards GR} } @conference {75882, title = {Flexibility and climate risk management in high stocking rate dryland sheep farming systems}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {96-102}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {A trial unit of 87.8 ha with conventional grass-based pastures and one of 85.1 ha with high legume-content pastures were used to investigate the impact of climate-risk management strategies on production and profitability of dryland sheep farming systems. The target stocking rate of both units was 14 stock units (SU)/ha, which is markedly higher than the regional monitor farm at 8.8 SU/ha. Information on the feed supply and animal feed requirement of the two units for 2008/09 and 2009/10 are presented, along with differences in weather patterns, soils moisture, climate-risk responses used, and stock sales between the two years. Results from the grass-based unit indicated that the flexible livestock policies used and climate-risk management responses imposed were able to increase farm profitability and reduce its variability between years in comparison to the local Ministry of Agriculture and Forestry monitor farm model. However, the same was not true for the high legume-content unit, which encountered a number of problems with high lamb deaths and poor lamb finishing in 2008/09. Soil moisture level in the top 25 cm proved to be a simple, inexpensive and effective indicator for making appropriate farm management decisions in response to changes in the climate.}, issn = {1176-5283}, author = {Bywater AC and Logan CM and Edwards GR} } @conference {75883, title = {Pasture growth and quality, and lamb growth rates in high stocking rate dryland sheep farming systems}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {103-108}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {Pasture growth and quality, and lamb growth rates were measured on a conventional grass based trial unit of 87.8 ha and a high legume unit of 85.1 ha, established to investigate climate-risk management strategies within high stocking rate dryland sheep farming systems. There was no difference between the units in total pasture production with a pasture utilization of 71.7\% and 74.3\% on the grass and legume units, respectively. Metabolisable energy values remained close to, or above, the target values throughout the growing season. Preweaning lamb growth rates averaged 304 g/day on both units. There were significant differences between singles (342 g/day), twins (300 g/day) and triplets (254 g/day) and between lambs from first cycle (294 g/day) and main mob ewes (315 g/day). There were some differences in lamb growth rates between different pastures types but these were not consistent between years. Post-weaning growth rates averaged 137 g/day with significant differences attributable to litter size, mob and year. Growth from birth to sale averaged 295 g/day, slightly less than the target of 300 g/day. Thus high lamb growth rates are possible on a range of pasture types on dryland at low pasture covers of high quality.}, issn = {1176-5283}, author = {Bywater AC and Logan CM and Edwards GR and Sedcole JR} } @conference {75877, title = {Why is clover better than ryegrass?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {71-78}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {This review quantitatively compares the nutritive value of ryegrass and clover. It confirms that the animal performance on clover is on average 40\% higher than on ryegrass. It establishes that although the digestibility of clover is less affected by stage of vegetative growth than ryegrass, the digestibility and metabolisable content of the two species is little different when compared at a young vegetative stage. Although the crude protein content of clover is often higher than that of grass the ratio of metabolisable protein to metabolisable energy supply is similar from the two forages. Despite a similar metabolisable energy content, the utilisation of metabolosable energy for growth is higher for clover than ryegrass. This may be due to a greater proportion of energy digestion in the small intestine. Most of the elements of ingestive behaviour, bite size, biting rate and intake rate are greater for clover than ryegrass and consequently the total gazing time and thus cost of harvesting clover are lower. The review concludes by estimating the relative contribution of increased efficiency of utilisation, reduced costs of ingestion and increased intake to the higher animal performance from clover.}, issn = {1176-5283}, author = {Nicol AM and Edwards GR} } @conference {69472, title = {Investigation of N isotopic fractionation in dairy cows using milk samples collected at the morning and afternoon milkings}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {65-66}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Conversion of feed protein into milk protein is a basis of sustainable dairy production systems from both economic and environmental perspectives. This project addresses the need for rapid screening tools to support nutritional and breeding strategies to improve the efficiency of converting feed into milk protein. The approach is based on the phenomenon of N isotopic fractionation, whereby N sinks become relatively enriched or depleted in 15N, as a result of differential incorporation during various biochemical reactions. Macko et al. (1986) showed that N isotopic fractionation was related to the deamination and transamination of amino acids. Sick et al. (1997) conducted a feeding experiment with rats and found that plasma protein was enriched and plasma urea was depleted in 15N relative to the diet. Furthermore, Robbins et al}, issn = {1176-5283}, author = {Cheng L and Dewhurst RJ and Larkin J and Buckley F and Thackaberry C and Nicol AM and Edwards GR} } @conference {60933, title = {Effect of water soluble carbohydrate concentration of ryegrass on the partial preference of sheep for clover}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {69}, year = {2009}, month = {Jun}, pages = {20-23}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {A trial was carried out to determine whether grass cultivar or water soluble carbohydrate (WSC) concentration would influence the partial preference of sheep for clover and ryegrass. Six mixed age Coopworth ewes were housed in individual pens and once a day offered swardlet monocultures of white clover adjacent to one of three perennial ryegrass cultivars. One swardlet of each grass cultivar was shaded and the other left un-shaded in order to create differences in WSC concentration. WSC concentration did not differ among ryegrass cultivars but was lower in shaded (210 g/kg dry matter (DM)) than non-shaded (230 g/kg DM) ryegrasses. Neutral detergent fibre was significantly higher in the un-shaded (439 g/kg DM) than non-shaded (422 g/kg DM) ryegrass (P <0.01). The total number of bites from clover swardlets fed adjacent to shaded grass swardlets was 21\% greater (P = 0.026) than when fed adjacent to non-shaded grass swardlets. Sheep took a significantly lower proportion of bites from clover when paired with un-shaded (44\%) than shaded (55\%) ryegrass (P = 0.03). There were no significant effects of ryegrass cultivar on any aspect of the preference tests. The results of this work support the hypothesis that partial preference for clover can be manipulated by altering the WSC concentration of companion ryegrass by shading but not, in this case, by ryegrass cultivar. }, issn = {1176-5283}, author = {Allsop ARC and Nicol AM and Edwards GR} } @conference {41742, title = {Comparison of the effect of simultaneous grazing of sheep or cattle with hinds during fawning}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {67}, year = {2007}, month = {Jan}, pages = {280-284}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Wanaka}, abstract = {Groups (4) of aged, pregnant red deer hinds (n = 7 or 12) were set-stocked pre-fawning with similar liveweight per ha of either dry ewes or yearling heifers in one of two paddocks equally divided in area (2 replicates). Cattle and sheep were progressively withdrawn from each area independently so that the average pasture height did not fall below 6 cm. The liveweight of the hinds and fawns was recorded and pasture samples taken for botanical and chemical analysis. There was no significant effect of sheep vs. cattle on the liveweight change of hinds or their fawns. All groups of hinds lost condition over lactation even though pasture height was maintained around 6-8 cm. However the liveweight gain of the fawns (from mid January to early March) was close to 350 g/day. Overall, there was no significant difference in composition or quality between the pastures grazed by the two stock combinations. We conclude from this study that under the conditions of this trial, in which the pasture was kept under tight control (6-8 cm) over the whole of lactation, there was no difference in the effect of the co-grazing species (sheep or cattle) on the performance of lactating hinds and their fawns.}, issn = {1176-5283}, author = {Nicol AM and Edwards GR and Ridgway MJ and Griffiths WM} } @conference {41710, title = {Integrated livestock management ... challenges and opportunities of farming deer with other livestock}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {67}, year = {2007}, month = {Jan}, pages = {107-116}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Wanaka}, abstract = {A recent survey indicated that approximately 67\% of deer farmers integrate sheepand/or cattle on their deer unit to better match feed demand with the seasonal pattern of pasture growth, maintain pasture quality, particularly during lactation and to control weeds. Integrated stock policies also allow for improved financial risk management and provide flexibility to adjust stock numbers in response to market signals and feed supply. There is evidence from the sheep and beef industries that productivity can be increased from the integration of sheep and cattle compared to a single species system. There is limited information for the integration of sheep and cattle with deer so an assessment of the {\textquoteleft}challenges and opportunities for co-grazing deer with other livestock{\textquoteright} must inevitably rely on extrapolation of knowledge from the co-grazing of sheep, cattle and goats of which there is an extensive literature. This paper identifies the key knowledge needed to meet the challengesand identify the opportunities of grazing deer withother livestock.}, issn = {1176-5283}, author = {Nicol AM and Griffiths WM and Edwards GR} }