Overall aim of deconstructing the choices that are open to the farmer and explaining how genomic breeding is particularly relevant. Using input from Low input Breeds and Sustainable Organic Low-input Dairying (SOLID) projects.
Gillian Butler (NEFG): Chair
Session summary
Conrad Ferris from AFBI spoke about research which had been carried out in Northern Ireland on breed substitution (comparing Norwegian Red cows with Holsteins) and cross breeding (comparing Holsteins with first cross Jersey crossbred cattle, and Holsteins with three-way crossbred dairy cattle (Swedish Red x Jersey x Holstein)). The comparisons included consideration of milk yield, milk fat and protein, health, longevity and fertility. The results are available on the agrisearch website (booklets 22 and 24). He emphasised that when crossing cattle the farmer should use good quality bulls from the breed he is introducing to his herd.
Gillian Butler of NEFG talked about work that had been done as part of the low input breeds project on genomic breeding for low input farming. This can result in a bull’s potential value being identified at an earlier stage rather than having to wait until his daughters start producing milk. It was suggested that as the genomic value is approximately 65% reliable, if selecting bulls based on their genomic value then a pool of four bulls should be used by the farmer to offset the slightly lower reliability. The reliability then increases as the bulls father offspring and their daughters’ performance can then be factored into their value.
Gordon Tweddle of Acorn Dairy then talked about his own experience with cross breeding. He had started cross-breeding for marketing reasons as he was direct-selling to consumers and wanted cows that would appeal to consumers. He also wanted them to be able to eat grass, clover and forage, have good health, longevity and fertility, somatic cell counts below 150,000, produce 6500 litres of milk per year and have a less than 20% replacement rate. He showed several photos of his cows and spoke about them with great enthusiasm. He confirmed that he is now hitting his targets.
The discussion after the talks included a question about whether the advances in genomics meant that cross breeding might not be required in the future. However, it was suggested that genomics could be used within cross-breeding: New Zealand has gone down the genomic breeding route but still carries out cross breeding.
There was also some discussion about whether a central database recording data from vet visits – antibiotic use, mastitis and lameness incidence – could provide accurate breeding information and would be useful to implement in the UK. It was pointed out that Norway and Sweden have such systems but that their milk markets are largely controlled by one co-operative and that their legislation is tighter with regard to antibiotic use. It was generally felt that such a system would have huge potential and could allow more progress in breeding but that it was difficult to see it happening in practice. It was questioned whether such an approach would lead to quicker culling of cows that needed e.g. antibiotic treatment more frequently. It was then asked whether that would be a bad thing and was suggested by some that more ruthless decisions could improve breeds.
Key conclusions
The discussion that followed the presentations brought out the following points:
- It is important to use good quality bulls when cross-breeding as well as when using one breed of cattle.
- When using genomic value to select bulls a pool of four bulls should be used to offset the 65% reliability of the breeding value.
- Genomic breeding can be used within cross breeding.
- A central database recording health data from vet visits could have huge potential and allow more progress in breeding but it is difficult to see it happening in practice in the UK.
Individual speaker presentations and abstracts
Conrad Ferris (AFBI): Alternative breeds and crossbreeding – their role in organic and low input systems (3.22mb pdf file)
Historical selection programmes within the Holstein breed focused mainly on milk production, while largely ignoring functional traits. The subsequent decline in these functional traits within the Holstein population, especially fertility and health, has now been well documented. The use of alternative breeds (breed substitu-tion) and crossbreeding have been suggested as strategies by which some of these problems may be overcome.
The potential of these two approaches have been examined in a number of studies undertaken at AFBI-Hillsborough, and on commercial dairy farms in Northern Ireland, with these studies conducted under predomi-nantly low input management scenarios. Breed substitution studies have involved comparisons of Holstein and Norwegian Red cattle, while crossbreeding studies have involved comparisons of Holstein with first cross Jersey crossbred cattle, and Holstein with three-way crossbred dairy cattle (Swedish Red x Jersey x Holstein). These studies have compared milk production and composition, fertility, health, longevity and profitability of the different breeds and genotypes.
Gillian Butler (NEFG): What has genomic breeding got to offer low-input and organic dairy cows? (1.23mb pdf file)
It has always been challenging to select breeding stock to ‘improve’ traits they do not express themselves. The classic case must be our inability to select bulls based on their milk yield; we need to rely on their mother’s, sisters’ and daughters’ performance to suggest how future offspring might shape-up. This traditional approach, relying on progeny testing means a bull is typically 5-6 years old before his daughters are milking and his ability is confirmed with any confidence. Another test, perhaps more pertinent to low-input or organic dairy production, is identifying robust breeding animals who’s offspring can cope with varying inputs and disease challenges, without resorting to drug treatment. We don’t want to expose our breeding animals to pathogens to see how they cope before selecting them as AI studs. Genomic breeding could offer solutions to both these dilemmas, allowing us to assess potential breeding stock from the time they are born, as well as their likely ability to stay healthy, despite diseases they or their offspring might encounter. This presentation will explain the principles of genomic breeding in the dairy sector and outline how is has been evaluated to improve functional traits in organic dairy cows, under the recent EU LowInputBreeds project.