Teagasc Dairy breeding policy for 2021 breeding season

The Irish dairy industry has benefited enormously from the increase in the EBI of the Irish dairy herd since its establishment in 2001. However, there are still significant benefits to be obtained by further increasing the EBI of the national dairy herd. Teagasc’s Next Generation Herd. clearly demonstrates this. Dairy farmers should select a team of high EBI AI bulls taking cognisance of relatedness, reliability, herd size and suitability to their farm system.

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Summary

It’s important to start planning now for the 2021 breeding season, and it is important that dairy farmers have a clear breeding policy as it will have a significant influence on their farm profitability, farm sustainability and animal welfare performance:

1. Use high EBI AI genetics to generate the required number of replacement heifers and in tandem increase the EBI of your herd. Target your heifers and highest EBI cows to generate replacements.
2. A balanced team of dairy AI sires should be used across the heifers and cows selected for breeding replacements. This will increase the reliability of the sire team as a whole. The optimum number of AI bulls to be used will vary with herd size; your Teagasc adviser will help you calculate this and to correctly match cows to AI sires.      
3. Incorporate a proportion of sexed semen into your AI strategy (if using Jersey or Jersey crossbreed genetics, use only sexed semen) while taking into account the considerations and guidelines outlined below - discuss with your Teagasc advisor.
4. Using the Dairy Beef Index (DBI) to select suitable beef AI sires, use beef sires on your lowest EBI/ late calving cows and once satisfied you have achieved sufficient dairy pregnancies to generate your targeted number of replacements.
5. Dairy ‘sweeper’ bulls should not be used. Use easy calving short gestation length beef bulls with a high Dairy Beef Index should be used. An alternative to beef stock bulls is the use of vasectomised bulls in conjunction with beef AI.

Background

The Irish dairy industry has benefited enormously from the increase in the EBI of the Irish dairy herd since its establishment in 2001. However, there are still significant benefits to be obtained by further increasing the EBI of the national dairy herd. This is clearly demonstrated by Teagasc’s Next Generation Herd. Therefore, dairy farmers should select a team of high EBI AI bulls taking cognisance of relatedness, reliability, herd size and suitability to their farm system.

Dairy cow numbers have increased significantly over the last 10 years. This was facilitated by greater use of dairy AI genetics on dairy farms. This rapid increase in dairy cow numbers has now slowed down, and replacement rates on dairy farms have also reduced due to better fertility and longevity in the dairy herd. Therefore dairy farmers that are not focused on expansion will require only 3 to 5 weeks of dairy AI to generate enough dairy replacements depending on use of sexed semen and herd fertility. ICBF launched the Dairy Beef Index (DBI) in 2018 with the objective of identifying beef bulls that are suitable for use on dairy herds. It is necessary to minimise the number of low value dairy calves within the dairy industry. All dairy farmers should first calculate the number of replacement heifers they want, and then calculate the number of dairy AI straws needed to generate that number of replacements. Beef AI bulls and beef stock bulls should be used to sire the remaining calves. Sexed semen can also play an important role in reducing the number of low value male dairy calves.  Dairy farmers who want to use Jersey or Jersey crossbred genetics should only use sexed semen. For dairy farmers that wish to use sexed Holstein-Friesian (HF) semen, the number of bulls available and their EBI is increasing as demand increases.  It is important to note that if you use sexed semen, conception rates will likely be less than with conventional semen (see Appendix 1 Guidelines for Sexed Semen Usage in Dairy Herds PDF). 

Many dairy farmers use AI for a period, followed by the use of natural service/stock bull. In order to minimise the number of low value male calves generated annually it is important that all natural service stock bulls used are of a beef breed, easy calving and short gestation; ideally the bull should be genomically tested to provide a higher reliability estimate of his dairy beef genetic merit (DBI is available for all beef bulls, including beef stock bulls). Where beef bulls are to be purchased, consideration (and run-in time) must be given to acclimatisation, suitable health status (via diagnosis) and appropriate vaccination protocol, ideally in advance of purchase but certainly in advance of use on your farm. An alternative to a beef stock bull is the use of vasectomised teaser bulls in conjunction with beef AI.

In recent years, there has been a trend to use less beef stock bulls and use more AI; this is preferable due to greater reliability and reduced biosecurity and safety risks.

In Teagasc herds, the breeding policy for 2021 is as follows:

• The use of high EBI HF genetics to include a combination of sex-sorted and conventional semen.
• Where Jersey or crossbreed Jersey genetics is to be used, it will be with sex-sorted AI only.
• The number of low value dairy calves will be reduced in the 2022 calving season by using suitable beef semen. Beef semen will be selected using the DBI with particular emphasis on easy calving, short gestation length bulls with good beef merit.
• No dairy ‘sweeper’ bulls will be used; in the limited situation where stock bulls will be used, it will be high DBI beef bred.