No horns an ideal breeding aim - welfare watchdog

“Given the welfare impacts and the financial costs of disbudding and dehorning, we would want convincing that the potential compromises outweigh what we would see as a means to significantly improve animal welfare,” NAWAC says in a new report on selective breeding practices.

The committee understands it is not a priority due to “the compromises in genetic gain elsewhere that would occur if there was more of a focus on polled genetics”.

“The committee supports efforts by companies (such as CRV Ambreed) who are working to have high indexing polled genetics available.”

NAWAC overall says the dairy industry has good standards and practices for selective breeding but it raises several issues.

“The link between use of indoor systems and higher production could have implications for cow longevity.

“The strengthening of traits such as udder conformation, particularly in relation to the suspensory ligament, as well as feet, legs and somatic cell counts, should be considered for higher weighting under animal evaluation.

“As varied environments are introduced (for example, indoor housing) it should continue to be emphasised that animal genotype is appropriate for its environment.

“A high producing cow may do well in an intensive indoor environment, but suffer from poor welfare (for example, a lower body condition score) if raised in a low input pastoral system.”

The use of early calve/easy calve bulls may lead to smaller animals being born and possibly more onfarm euthanasia of the smaller calves if they take longer to be big enough for processing or are undesirable for onward rearing.

“Their benefit is however tied directly into reducing gestation length and these bulls are a useful tool now that there is no induction option as a general farming practice,” the report says.

More emphasis is being put on the use of beef bulls as they are being pushed as an option to increase saleability of surplus calves.

“Some of this cross-breeding can lead to problems at calving if the wrong bull has been selected, or if the cows are not of an age to handle having a bigger calf. Care should be taken to ensure that easy calve bulls are used when they are to be crossed with dairy animals, especially over maiden heifers.”

The NZ Veterinary Association has warned of the potential negative outcomes from extensive use of popular sires of selection. A recent example was the birth of about 1500 calves in 2012 which were particularly hairy, all sired by a genetic mutation from a single bull.

Apart from these concerns, the selective breeding approach the dairy industry is following is appropriate for the welfare of the cows and the industry’s needs at present, the report says.

Dairy cattle must be pregnant to produce milk, and excess calves, usually male, are often euthanased.

Sexed semen would reduce the need to euthanase male calves (although would presumably result in an excess of female calves).

NAWAC encourages such technology if it can be used alongside changes in animal management and selection to result in fewer calves being born, only to be euthanased shortly afterwards.

NAWAC supports DairyNZ’s focus on all animals having a use, for example, having excess dairy calves raised for beef.

The report says more comprehensive and accurate phenotypic recording has enabled better identification of the genetics underlying animal health and welfare traits in the dairy industry.

In the dairy report it says deep phenotyping has become more commonplace in recent years. This is the precise and comprehensive analysis of phenotypic abnormalities in which the individual components of the phenotype are observed and described. This has enabled more precise matching of genetics and phenotype related to health and welfare traits.

The report says the dairy industry also notes emerging technology that has the potential to allow estimation of breeding values for lameness, mastitis and facial eczema tolerance.

“The possibility of genetically improving dairy cattle for these traits is being explored.

Key drivers for the future include the desire to reduce culling rates in the industry, thus improving cow longevity. To do this, cows need to produce well, have reduced susceptibility to common diseases such as mastitis and lameness, and be fertile.”

An MBIE funded project lifetime productivity is underway.

Ethical approach

DairyNZ sees as ethical an approach to selective breeding whereby animals are “fit for purpose”, NAWAC concludes in its report.

Such animals would be profitable, well adapted to New Zealand farming conditions and productive without having health problems.

“This means taking account of not only productive capacity when selecting animals to breed from, but also directly traits such as fertility, somatic cell score and residual survival, which includes traits other than production such as temperament, udder quality and resistance to lameness and mastitis,” NAWAC explains.

“Focusing only on production as a trait led to a reduction in cow fertility in the 1990s, when a lot of Holstein type genetics were introduced. The industry now knows that a multi-trait, balanced selection process produces animals that are better overall for the farming system.”

DairyNZ also finds it important that all animals bred in the farming system have a use, the NAWAC report says.

“It is claimed that there is very little slaughter, and disposal with no return, of animals in the dairy industry, with the number of bobby calves killed onfarm estimated at less than 0.5% of the total.”

DairyNZ, through its subsidiary NZ Animal Evaluation Ltd, is responsible for setting the national breeding objective (NBO) for dairy cattle. The NBO is expressed via breeding worth (net farm income per 5 tonnes of dry matter) which includes seven traits (milk volume, milk protein, milk fat, fertility, somatic cell score, liveweight and residual survival) known to influence the profitability of dairy cattle.

The use of the breeding worth (BW) index has resulted in dairy cattle that are more productive and live longer: on average, cows are staying in the herd for 207 days more now than in 1984 (LIC via Nita Harding, Dairy NZ personal communication).

“The 2002 introduction of fertility into BW has helped – along with an improvement in bull fertility – arrest a decline in fertility in the national herd.

“In respect of mitigating any negative effects of selective breeding, the dairy industry uses a balanced selection index that includes not only production factors, but also aspects of animal health and welfare, to ensure that fit-for-purpose animals are being bred for the industry.

“For example, the addition of body condition score as a trait for BW has been approved and this began in February 2016.

“DairyNZ also provides results of gene tests for individual bulls, such as small calf syndrome, so these genetic variants can be considered in mating.”

A research project is underway with a range of industry partners to identify the reasons for the early exit of young stock and dairy cattle from dairy herds so that more targeted genetics and management solutions can be provided for the industry.

“In-breeding is monitored and actively managed during mating via the use of alerts that warn of father-daughter mating: cow numbers are entered into database by the AI technician before insemination. An alternative bull can then be used instead of the bull rostered for use that day.”

Useful technology is seen as including genomics, in enabling the identification of genetic variants that can have negative effects on animal health and welfare. This is widely used in the industry.