Greg Hamill, LIC genetics business manager, provides an overview of why many dairy farmers find crossbreeding an attractive proposition, before detailing LIC’s market response to an increasing desire among farmers for a bigger, blacker, cow.
The primary goal of dairy cattle breeding is to make efficiency gains in milksolids production. In New Zealand, crossbreeding is considered the fastest method of achieving this efficiency.
In 2004, in response to growing demand for crossbred genetics, LIC launched KiwiCross bulls to the market.
Since then, the number of crossbred cows in the national herd has dramatically increased. Crossbreds have quickly earned their reputation as ‘easier care’ cows.
Various studies point to the advantages of crossbreeding, including improvements to:
The major implications of the above are two-fold:
Improvements through crossbreeding are a result of heterosis, also referred to as hybrid vigour.
When animals of different breeds are crossed, the performance of the crossbred animal (on average) can be greater than what would be expected from the average of two parents. Heterosis is the measure of superior performance.
Heterosis is strongest in the first cross between pure breeds.
Its effect is diminishes, although is still significant, in subsequent crossing. For example, a first cross cow (F8J8), mated to a F8J8 sire will retain 50% hybrid vigour, together with associated benefits (listed above).
The same F8J8 cow mated back to either parent breed (F16 or J16) also retains 50% hybrid vigour.
The first cross animal from purebred parents tends to be fairly uniform in physical appearance.
A Friesian-Jersey first cross animal almost always possesses a solid black coat colour.
However when a first cross animal is mated to another first cross animal, genes are further mixed up – resulting in greater variation in the progeny, including: a greater range of coat colours; a range in size, and; variation in milk production characteristics. For example, the progeny may appear as small black-and-white animals, or larger Jersey-coloured animals.
Farmer feedback (through surveys) reveals the preferred crossbred cow for the majority of LIC’s KiwiCross farmers tends to be an animal around the F10- to F12- cross.
This higher-Friesian cross animal reduces the phenotypic (physical appearance) variation, providing farmers with more uniformity in the resulting progeny.
New criteria for LIC KiwiCross Premier Sires
In response to market demand, LIC’s genetics team will – when confirming the 2016 Premier Sires KiwiCross team – ensure all appointed bulls meet specific breed-split criteria (in addition to meeting usual benchmarks for selection to Premier Sires).
This year, for the first time, the KiwiCross Premier Sires team will be predominantly made up of sires possessing a breed mix of F8 and greater.
A J9-F7 bull may be selected if it meets a ‘liveweight threshold‘, indicating it would throw progeny that are more characteristic of Friesians.
However, all J10 and J11 sires will be excluded from the KiwiCross Premier Sires Daughter Proven team.
A higher Jersey content team will be available through Alpha as a ‘no-choice pack’, at a reduced price from the standard Classic packs (ie. for farmers seeking KiwiCross bulls that are more dominant in Jersey).
By placing more emphasis on the breed split of our Premier Sires KiwiCross team, LIC expects to be able to narrow the variation in progeny – delivering a consistent cohort of calves each year to filter through the herd and helping farmers achieve the uniformity they are seeking.
LIC has seen the kind of uniformity that can delivered on-farm when a F10 breeding goal is worked toward.
Having worked with Lincoln University’s Dairy Farm (LUDF) for a number of years, LIC principal advisor Jack Hooper has helped deliver the farm’s breeding goal – which was to breed a herd of cows that were between F10 and F12 in breed split.
The size of the cow is consistent (as indicated in the adjacent photo). LUDF is reaping heterosis benefits, and this year the aim is to achieve at least 500kg of milksolids per cow (from a predominantly pasture based system).
For more information on results LUDF is achieving with its crossbreeding programme, visit www.siddc.org.nz
Article first published in The Bulletin, Autumn 2016 edition. For more stories, see The Bulletin webpage.