The right tools for the job
A fruitful collaboration between researchers at Teagasc and the Irish Cattle Breeding Federation has led to the development of three interdependent tools to support beef-on-dairy breeding, mating and trading.
Beef-on-dairy breeding – the mating of beef bulls with dairy females – increases the value of calves born. This is because such calves typically benefit from the quality genetics found in beef bulls, which often results in superior carcasses compared to calves born of purebred dairy cattle.
Dairy producers are most interested in producing dairy-bred females in order to preserve the mature herd; unless genetically elite, their male dairy-bred contemporaries have a low market value as calves.
In recent years, there has been increasing interest in the use of beef bulls mating in dairy herds. This is due to the fact that fewer dairy females need to conceive to dairy bulls, thanks to a reducing requirement for replacement dairy females on farms, coupled with the availability of laboratory-sorted semen that produces almost exclusively female calves.
A gap in knowledge and tools on how to best facilitate such a breeding policy has been filled by researchers at Teagasc and the Irish Cattle Breeding Federation, who have successfully developed and deployed a trilogy of tools to help guide the shift. The tools are as follows:
- Dairy Beef Index – to establish and deliver year-on-year improvements in beef bulls suitable for mating to dairy females.
- Dairy Sire Advice web service – to recommend optimal individual male-female matings.
- Commercial Beef Value tool – to forecast the likely profit that would result from a calf destined for beef production.
1. Dairy Beef Index
Strong interdependencies exist between the researchers’ tools. The Dairy Sire Advice web service leans heavily on the components of the Dairy Beef Index. The Commercial Beef Value tool is founded on the index, the only real difference being that it does not include the calving performance traits.
Crucially, the data underpinning all three tools originate from a single point of truth managed by the Irish Cattle Breeding Federation, who have no conflict of interest in the individual values given to the animals. Values get updated as data accumulates, and additional modules that contribute to profit or public good values can be added.
A successful beef-on-dairy sector requires germplasm (living genetic resources maintained for the purpose of animal breeding) that produce a valuable calf for the beef producer, without negatively affecting the performance of the dairy cow that gave birth to the calf.
Breeding indexes have been used for decades to rank animals on an arrangement of different credentials, many of which are often antagonistically correlated (when a favourable value for one trait is associated with an unfavourable value for another). In 2019, a Dairy Beef Index was launched in Ireland with the goal of ranking beef bulls for suitability to both dairy and beef producers.
The index comprises traits of importance to both producers – the dairy and beef components of which are antagonistically correlated. Coupled with a well-structured breeding scheme, the index can help producers to deliver bulls that excel in both characteristics.
Concurrent selection for antagonistically correlated traits is possible – the best known example in cattle is the simultaneous improvement in milk production and reproductive performance in dairy cows.
Breeders of beef bulls can use the Dairy Beef Index to identify candidate sires and dams of the next generation of genetically elite beef bulls for mating to dairy females. In turn, dairy producers can use it to rank all available beef bulls on suitability for each dairy herd.
The publicly available index values are generated by the Irish Cattle Breeding Federation for both artificial insemination bulls and natural mating bulls, and are regularly updated as information on the descendants of the bulls is collected.
2. Dairy Sire Advice web service
Once the dairy producer selects an appropriate team of beef bulls, the next stage in the breeding programme is to decide which bulls should be mated to which cows – known as sire mating advice. Here, producers must consider the cow’s susceptibility to a difficult birth, including the size of the calf and the pelvic width of the cow herself.
While no actual measures of these characteristics exist, approximations are made through deep statistical analyses of millions of data points from Irish cattle. Dairy females that are more susceptible to a difficult birth should be mated to beef bulls that are less likely to produce calves that require assistance at birth.
Similarly, all else being equal, dairy females that are likely to produce carcasses with poor conformation (flesh coverage and overall shape) should be mated to a bull who, on average, has been proven to generate good conformation carcasses. It’s worth nothing, however, that all these combinations become unwieldy in large dairy herds.
The dairy-beef sire advice tool uses sophisticated statistical techniques to evaluate every such combination within the confines of certain criteria. The outcome from the web service is a list of dairy females in the herd with a recommended beef bull for mating.
3. Commercial Beef Value Tool
Revenue from beef-on-dairy cattle is predominantly determined by carcass value, which itself is determined by carcass weight and conformation, on average, many months or years post-birth. Predicting the carcass weight and conformation from visual inspection of a young calf can be challenging, even to the experienced eye. However, approximately half of the variation in both carcass weight and conformation in cattle is attributable to genetic differences.
The genes of an animal at slaughter are the same genes the animal was born with. Therefore, genetic merit estimates of carcass weight and conformation, along with information like calf gender and dam characteristics, can be used to predict animal performance. This approach has been taken in the Commercial Beef Value tool, available for all cattle.
Contributors
Donagh Berry
Senior Principal Research Officer
Dairy Production Research Centre, Teagasc, Moorepark, Co. Cork.
donagh.berry@teagasc.ie
Siobhán Ring
Senior Geneticist
Irish Cattle Breeding Federation, Cork, Co. Cork.