@article {3672,
	title = {BRIEF COMMUNICATION: Impacts of live weight of ewe lambs at mating on their reproductive performance},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {87-90},
	address = {Palmerston North},
	abstract = {This experiment investigated the impacts of heavier live weight of twin-born ewe lambs at mating on reproductive performance. Romney ewe lambs (n=270) were allocated to one of two groups: {\textquoteleft}Heavy{\textquoteright} (48.0{\textpm}3.8 kg), had been preferentially fed from weaning to breeding, or {\textquoteleft}Control{\textquoteright} (44.8{\textpm}3.5 kg). Both groups were exposed to crayon-harnessed vasectomised rams for 68 days before breeding, and then were bred to entire Romney rams for 34 days. Crayon marks were recorded every 17 days. Heavy ewe lambs were more likely to be mated in the first 17 days of breeding (69.9\% vs. 54.8\%, P<0.05), mated in the entire breeding period (85.1\% vs. 69.4\%, P<0.01) and had a greater litter size (0.99 vs. 0.65; P<0.01) than did Control ewe lambs. Heavier live weight at mating improved reproductive performance of ewe lambs. These results emphasise the importance of an adequate live weight at breeding for reproductive success in ewe lambs.},
	issn = {1176-5283},
	author = {Haslin E and Corner-Thomas RA and Kenyon PR and Morris ST and Pettigrew EJ and Hickson RE and Blair HT}
}
@article {3672,
	title = {Can bone measures of the bovine metacarpus predict humeral bone structure?},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {8-12},
	address = {Palmerston North},
	abstract = {Peak bone mass in cattle is influenced by factors prior to puberty and insufficient peak bone mass prior to the first lactation predisposes heifers to the risk of spontaneous humeral fractures. At post-mortem examination, affected heifers present with osteoporosis (reduced periosteal circumference and reduced cortical wall thickness). Due to its location, there is no cost-effective way to scan the humerus in the live animal. However, the metacarpal bones (MC3/MC4) are straightforward to scan in a live anaesthetised animal. The aim of this experiment was to determine if the metacarpal could be used to predict bone mass and material properties of the humerus. The left humerus and metacarpal bones were obtained from 57 cattle aged six weeks to eight years. Bones were scanned at the mid-diaphysis using peripheral quantitative computed tomography (pQCT), to obtain measures of bone mass and material properties (strength). Strong positive relationships were observed (R2=0.89 - 0.98, P<0.0001) for pQCT measurements of bone mass and strength. Thus, the metacarpus is a good predictor of bone content and material properties of the humerus across cattle of differing age and maturity. },
	issn = {1176-5283},
	author = {Gibson MJ and Rogers CW and Dittmer K and Hickson RE and Pettigrew EJ and Back PJ}
}
@article {3672,
	title = {Differences in birth weight and neonatal survival rate of lambs born to ewe hoggets or mature ewes},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {16-20},
	address = {Lincoln},
	abstract = {This experiment investigated differences in birth weights and survival in lambs born to hogget and mature ewes. It included 1082 mature ewes with a scanning rate of 1.87 fetuses per ewe joined and 1026 hoggets with a scanning rate of 0.80 fetuses per hogget joined, that were bred together, and lambed separately, under commercial farming conditions. At lambing, birth weight, lamb vigour score, and ewe maternal behaviour score were recorded. Lambs born to hoggets were lighter and less vigorous than lambs born to mature ewes (P<0.05). Single-born lambs were heavier at birth (P<0.05), and had greater survival at birth (P<0.05) than did twin-born lambs. Twin-born lambs were heavier (P<0.05) at birth, and had greater survival at birth (P<0.05) than triplets. There was an interaction of dam age and birth rank on lamb survival to weaning (P<0.01). At all birth ranks lambs born to hoggets had lower survival to weaning than lambs born to mature ewes, and the difference in survival increased with increasing birth rank. Lambs that had a vigour score of 1 had lower survival (83.5\%; P<0.05) than lambs that had a vigour score of either 2 or 3 (88.6- and 91.4\%, respectively). Maternal behaviour score did not affect lamb survival (P>0.05). Lambs born to hoggets are at greater risk of mortality, so farmers need to prioritise their time and resources towards hoggets at lambing time.},
	issn = {1176-5283},
	author = {Pettigrew EJ and Hickson RE and Blair HT and Griffiths KJ and Ridler AL and Morris ST and Kenyon PR}
}
