@conference {41508,
	title = {Hogget mating in New Zealand - a survey},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {217-222},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Currently less than 30\% of all hoggets are presented for mating in New Zealand. This would suggest that there are a number of disadvantages to this management practise. However to date it has not been accurately established what farmers perceive as the disadvantages of hogget mating and the relative importance of each of these disadvantages. A questionnaire was sent to New Zealand sheep farmers which asked a series of questions regarding farm type, size, farm class, flock type, flock size and the intended use of hogget mating in 2002 and its use in the past. Those farmers who were not intending to mate hoggets in 2002 were also asked to indicate the importance, on a scale of 1.4, of 11 stated reasons for not hogget mating. A total of 1981 questionnaires were returned and used in the present study from a total of 14,000 sent to farmers. Descriptive analysis indicated negative effects on two-tooth performance and lack of additional feed were the two main reasons for not mating hoggets. The least important variables were lack of experience and the need for extra rams/teasers. The intended use of hogget mating differed based on farm class, farm size, ewe flock size and farm and flock type. Farmers were more than twice as likely to mate hoggets in 2002 if they had a mixed-bred flock in comparison to a straight-bred flock and more than twenty times more likely to mate hoggets in 2002 if they had mated hoggets in previous years. This study indicates that farmers perceive impaired two-tooth performance as a major reason for not hogget mating, even though research to date would indicate this is not that case. Therefore either improved technology transfer is required or the effects of hogget mating on two-tooth performance need to be re-visited. },
	issn = {1176-5283},
	author = {Kenyon PR and Morris ST and Perkins NR and West DM}
}
@conference {41045,
	title = {Pregnancy diagnosis of twinning beef cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {259-261},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Technology now exists to make beef cows twin-pregnant. Accurate detection of pregnancy status is a prerequisite for differential management of twin and single-bearing cows. Calving outcome for about 50 beef cows was compared with predicted outcome by foetal counting using transrectal ultrasonography at day 50-70 of pregnancy, and veterinary palpation to confirm pregnancy at day 111-156. The trial ran for 4 annual calvings, and different combinations of scanning operator and equipment were used in each year. Overall accuracy of prediction of calving outcome ranged from 74-94\%, and did not differ for cows carrying singles or twins. Prediction accuracy was highest in the 2 years where scanning equipment provided a high degree of visual detail, and the operator was experienced in distinguishing foetal abnormalities. It was concluded that the combination of early foetal counting using ultrasound, and later determination of wet/dry status by palpation, could lead to levels of accuracy close to those being achieved by competent commercial scanning operators for sheep. },
	issn = {1176-5283},
	author = {Lambert MG and Perkins NR and Devantier BP and Knight TW and Betteridge K}
}
@conference {40941,
	title = {Non-invasive pregnancy determination in mares by enzymeimmunoassay of estrone sulphate concentrations in faeces.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {234-236},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Measurement of faecal estrone sulphate by enzymeimmunoassay was evaluated as a non-invasive means of monitoring pregnancy status in mares. Faecal samples from non-pregnant mares had a mean {\textpm} s.e.m. estrone sulphate concentration of 23 {\textpm} 0.9 ng/g (N=242). In pregnant mares, mean faecal estrone sulphate concentrations increased progressively during the first half of gestation. The values rose from a mean {\textpm} s.e.m. of 49 {\textpm} 4 ng/g (N=121) for samples collected <80 days post-mating, to 122 {\textpm} 9 ng/g (N=30) for samples collected 161 to 180 days post-mating. Thereafter, faecal estrone sulphate concentrations remained relatively constant for the remainder of pregnancy. From 150 days post-mating onwards, <2\% of faecal samples from pregnant mares had an estrone sulphate concentration below 66 ng/g which was the value 3 standard deviations above the mean value found for non-pregnant mares. Following foaling or foetal death, faecal estrone sulphate concentrations returned quickly to non-pregnant levels. Using this estrone sulphate enzymeimmunoassay, mares may be confirmed pregnant once faecal estrone sulphate concentrations rise above the 66 ng/g cut-off value. Those mares in which faecal estrone sulphate concentrations have not risen above 66 ng/g by 150 days post-mating may be considered to be non-pregnant. Measurement of faecal estrone sulphate thus offers a convenient, non-invasive means of monitoring pregnancy status. },
	issn = {1176-5283},
	author = {Henderson KM and Perkins NR and Wards RL and Stewart JI}
}
