Premier Sires
It has long been known that there are extra production benefits to be obtained from crossbreeding, This tendency of a crossbred individual to show qualities superior to those of both parents is called heterosis, or hybrid vigour.
Many farmers expressed an interest in crossbred bulls, so when the introduction of Animal Evaluation in 1996 made it possible to compare different breeds more accurately, LIC decided to find out just how good crossbred animals were.
The results were good.
In 2005 LIC launched KiwiCross™, making New Zealand the first country in the world to offer a team of crossbred bulls.
As a result of this initiative, the industry now has access to a larger gene pool and can use top cows that could otherwise not have been used as bull mothers.
KiwiCross is a breed of its own and is sold separately from the Holstein-Friesian and Jersey breeds. Farmers who choose to use KiwiCross bulls across their cows and yearlings will maintain approximately half of the hybrid vigour experienced in a first cross animal.
PRODUCTION GAINS
The table below gives estimates of the hybrid vigour benefits associated with crossbreeding, based on New Zealand research. Figures given are the extra performance achieved from first cross animals, relative to the performance you would expect to see based on the average of the crossbred animals parents. Benefits are given as absolute yield, as well as a percentage difference from the average of the parents.
Estimated hybrid vigour in first cross animals, from New Zealand Research
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Holstein-Friesian x Jersey |
Holstein-Friesian x Ayrshire
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Jersey x Ayrshire |
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Milk Volume
Harris et al.
Lopez-Villalobos et al.
Ahlborn-Breier et al. |
129 (l)
181 (l) (6%)
171 (l) (6%) |
64 (l)
106 (l) (4%) |
146 (l)
172 (l) |
Milkfat (kg)
Harris et al.
Lopez-Villalobos et al.
Ahlborn-Breier et al.
Ahlborn-Breier
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6.8
10.4 (7%)
10.3kg (7%)
4.5-7.0kg (3-5%)
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2.7
9.0kg |
7.6
9.4kg (6.4%) |
Milkfat (kg)
Harris et al.
Lopez-Villalobos et al.
Ahlborn-Breier |
5.0kg
7.3kg (6%)
2.5kg (2%) |
2.4kg
3.6kg (3%) |
5.5kg
7.0kg (6%) |
Milkfat (kg)
Harris et al. |
7.2kg |
3.8kg |
12.5kg |
Ahlborn-Breier,1989.Crossbreeding – an opportunity to increase farm income. Dairyfarming Annual 41:23-43. Ahlborn-Breier et al,1991. Additive and nonadditive genetic effects on milk production in dairy cattle: evidence for major individual heterosis. Journal of Dairy Science 74:592-602. Harris et al,1994. Evaluating animals for breeding. Ruakura Farmers Conference 46:60-63. Lopez-Villalobos et al,1996. Profitability of rotational crossbreeding programmes in commercial dairy herds. Proceedings of the New Zealand Society of Animal Production 56:216-220.
REPRODUCTION GAINS
In addition to heterosis for milk production,crossbred dams exhibit heterosis for fertility – about 1.5% higher non return rate and 3.7% better calving rate.
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