@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}
}
