Page 27 - NZ Herefords Magazine 2018

Industry Focus
EBVs prove

their worth

– update on the dairy

beef progeny test

WORDS REBECCA HICKSON AND LUCY COLEMAN, ABOVE: The 2017 calving again showed that selection of
MASSEY UNIVERSITY appropriate beef bulls resulted in a hassle-free calving and a shed-
PHOTOGRAPHS SUPPLIED full of attractive dairy-beef calves.

THE 2017 CALVING at Limestone Downs again showed that required assistance in either year.
selection of appropriate beef bulls resulted in a hassle-free Table 2 shows the mean birth weight and weaning age, and
calving and a shed-full of attractive dairy-beef calves. the percentage of heifers assisted for heifers mated to Angus,
Over two seasons of the Beef + Lamb NZ Genetics Dairy Hereford or Jersey sires.
Beef Progeny Test, a total of 992 calves resulted from 65 bulls
being mated via artificial insemination to the milking herd at TABLE 2
Limestone Downs. The research demonstrated convincingly JERSEY 1 ANGUS HEREFORD
that the calving EBVs are a good indicator of actual calving
performance: there was a clear relationship between sire EBV BIRTH WEIGHT (KG) 30.1±0.6 a 34.4±0.5 b 35.9±0.6 b
and progeny performance for gestation length, birth weight and WEANING AGE (DAYS) -- 82.7±1.3 81.8±1.4
weaning age (indicated by 200d weight EBV). CALVING DIFFICULTY (%) 0% 1.6% 3.3%
Table 1 shows the expected performance of calves from an
average unrecorded bull, a 20 percentile bull and a 10 percentile ABOVE: - Jersey calves were not reared, so no weaning age
th
th
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bull for the Hereford breed. Similar results were seen for the Angus comparison. a, b - Jerseys were lighter than Angus and Hereford,
breed. Fewer than 1% of cows were assisted at calving. which were not significantly different from each other
The first cohort of progeny is on track, with the first mobs
TABLE 1 ready for processing in autumn if the rain keeps coming. The
mean live weight at 400 days was 289 kg.
BIRTH GESTATION WEANING
1
WEIGHT LENGTH AGE
(KG) (DAYS) (DAYS) BELOW, TOP TO BOTTOM: Over two seasons of the Beef + Lamb
HEREFORD NZ Genetics Dairy Beef Progeny Test, 992 calves resulted from 65
bulls being mated via artificial insemination to the milking herd at
AVERAGE UNRECORDED BULL 38.6 283.8 81.6 Limestone Downs; The research demonstrated convincingly that
TOP 20% RECORDED BULL 37.7 283.1 80.4 calving EBVs are a good indicator of actual calving performance.
TOP 10% RECORDED BULL 37.2 282.5 80.2

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ABOVE: - Calves were assessed on weaning age rather than
weaning weight because they were weaned at a threshold weight of
85 kg. Calves that were weaned younger were growing faster. Bulls
were ranked on 200d weight EBV for this trait.

Careful selection of bulls to mate first-calving heifers also
paid dividends, with 306 calves born to first-calving dairy heifers
in the project. This included 123 Angus, 113 Hereford and 70
Jersey-sired calves.
As expected, birth weight was greater in the beef-sired
calves than the Jersey-sired calves, but calving date was similar
(indicating similar gestation length). In year one, Hereford bulls
in the top 15% of the breed were used, and the heifers were
below target weight, which resulted in 12% assisted calving for
the heifers bred to Hereford bulls. In year two, bulls were top
5% for birth weight. This resulted in only two (4%) of heifers
mated to Herefords assisted. No heifers mated to Jersey bulls
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