Journal Articles

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    Sire Effects on Birth Weight, Gestation Length, and Pre-Weaning Growth of Beef-Cross-Dairy Calves: A Case Study in New Zealand
    (MDPI (Basel, Switzerland), 2021-09-01) Coleman L; Back P; Blair H; López-Villalobos N; Hickson R; Meyer U
    Production of beef-cross-dairy calves from dairy cows increases the value of non-replacement calves born to the dairy herd. The use of beef-breed sires may impact on calf birth weight, gestation length and pre-weaning growth rate of calves, which in turn influences the profitability of the dairy farm. The aim of this case study was to compare the birth weight, gestation length, and pre-weaning growth of progeny born to mixed-aged dairy cows on a single farm which were artificially bred to a selection of Angus and Hereford bulls, typical of those used over dairy herds in New Zealand. The birth weight, gestation length and pre-weaning growth of 980 calves sired by 65 sires were compared. Mean progeny birth weight (range 33.3–41.4 kg), gestation length (range 276.1–288.6 days), age at weaning (range 70.3–88.3 days) and pre-weaning ADG (range 0.63–0.76 kg/d) differed among sires (p < 0.001). There was a negative genetic correlation (−0.31) and positive phenotypic correlation (0.36) between gestation length and birth weight. Age at weaning was negatively correlated with birth weight (genetic: −0.56, phenotypic: −0.57). Bulls used in this study, and other bulls with similar genetic merit for birth weight and gestation length would be suitable for mating mixed-aged dairy cows in New Zealand.
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    Estimated Breeding Values of Beef Sires Can Predict Performance of Beef-Cross-Dairy Progeny
    (Frontiers Media S.A., 2021-09-30) Martín N; Coleman L; Lopez-Villalobos N; Schreurs N; Morris S; Blair H; McDade J; Back P; Hickson R
    On average, half of the animal’s estimated breeding value (EBV) is passed on to their progeny. However, it is not known how the performance of beef-cross-dairy cattle relates to the EBV of their beef sire. Such information is required to determine the genetic potential of beef sires selected based on existing EBV to be used on dairy cows in New Zealand. This study evaluated the relationship between the EBV of 30 Angus and 34 Hereford sires and the performance of their progeny for birth, growth, and carcass traits, via progeny testing of 975 beef-cross-dairy offspring born to dairy cows and grown on hill country pasture. Overall, BREEDPLAN EBV did predict progeny performance of the beef-cross-dairy cattle from this study. Gestation length and birthweight increased with increasing sire EBV (mean 0.37–0.62days and 0.52–0.64kg, respectively, p<0.05). Age at weaning decreased with increasing sire EBV for liveweight at 200days (0.17–0.21days per extra kilo of sire EBV, p<0.05) but sire EBV for liveweight at 200days had no effect on the liveweight of the progeny at 200days for either breed (p>0.05). Liveweight increased with sire EBV for liveweight at 400, 600, and 800days, by a similar amount for both breeds (between 0.23 and 0.42kg increase in progeny liveweight per extra kilo of sire EBV, p<0.05). The relationships were more inconsistent for carcass traits. For Hereford, carcass weight and eye muscle area increased with increasing sire EBV (0.27kg and 0.70cm2, respectively, p<0.05). For Angus, marble score increased by 0.10 with 1% extra in sire EBV for intramuscular fat (p<0.05). Rib fat depth tended to increase with sire EBV for both breeds (p<0.1). EBV derived from beef-breed data work in dairy-beef systems but maybe slightly less than the expected 0.5units of performance per unit of EBV. New Zealand farmers should consider BREEDPLAN EBV when selecting sires to mate dairy cows or when buying beef-cross-dairy calves for beef production, to ensure the resulting calves are born safely and on time and then grow well to produce carcasses of suitable meat and fat composition.