Planning for the breeding season is now underway on many dairy farms, meaning it is now time to determine how many heifer calves will be needed in 2025.
Once you have determined how many replacement heifers are required, you then need to determine how many straws will be needed to generate these heifers.
The number of straws required will vary, depending on whether you are using sexed semen, conventional semen or a mix of both.
Goals
The breeding goal of an individual herd will vary depending on the system being operated and the cow type on the farm.
What is important, is that you set a goal for your herd and work towards achieving this through breeding.
No matter the cow type or system being operated, there should be two main focuses for your breeding plan.
Firstly, you need to focus on improving the milk solids produced and sold from the herd. The quickest way to achieve this is by increasing the percentages.
Select bulls that are going to drive percentages and breed them to the best cows in your herd.
Secondly, a continued focus on fertility is important, having a cow that will calf down every year is important.
Another area to focus on is health. This can be particularly important in herds where bovine-TB or somatic cell counts (SCC) are an issue.
Breeding
Reducing the number of cows bred to dairy sires should be a aim of every dairy herd to decrease the number of low value calves entering the beef sector.
You can then replace what would have been dairy straws with high value dairy beef genetics, that will give you a hopefully high value dairy-beef calf.
Teagasc have outlined a example using a 100-cow herd where there is a requirement for 22 replacements heifers.
In this example all dairy straws used are female sexed semen, and all are used in the first three weeks of breeding.
It is also important to note that the conception rates used this example should be adjusted to reflect your herds past performance.
This example assumes a 100% submission rate with the maiden heifers and 90% with the milking herd in the first three weeks of breeding.
From this example 11 heifer calves are produced from the maiden heifers, with 22 straws used.
Assuming a 50% conception rate to dairy sexed semen on the cows, 25 cows must be bred to produce a further 11 heifers.
Based on this example, the number dairy-bred males born reduces to three due to 90% female probability of sexed semen.
The number of cows bred to high-dairy beef index (DBI) beef artificial insemination (AI) in the first three weeks increases in this example to 65.
Sexed semen
The use of sexed semen has increased significantly in recent years, as the supply of straws and number of bulls sexed increases.
For many dairy farms, unless it is being used in a fixed-time AI programme, there are concerns around reduced conception rates, timing of service and even the handling of straws.
But, it is important to remember that you should be only using sexed semen of the top cows in your herd – which should have the highest levels of fertility.
This should offset the potential reduction in conception rates and the cows not selected for dairy AI should be bred to high-DBI beef AI.