19 April 2023
Heat detection – what is the key to success?
Using AI in the suckler herd can offer a farmer many benefits. Increased adoption of AI provides access to some of the best and proven beef genetics in the country. Catherine Egan, Teagasc Beef Specialist, tells us more.
However, only 17% of suckler calves are born from AI sires, despite AI being the fastest way of making genetic improvement in the herd. It allows you to match each cow to a suitable bull to get a calf on the ground that suits your particular needs, such as ease of calving, beef carcass conformation, maternal traits or daily live weight gain.
Figures from ICBF show that the average stock bull sires 80 calves over its four year lifetime. When you take into account feeding costs of the bull and salvage costs, a bull on a 20 cow herd costing €2,000 will have a breeding cost of €32.50 per calf. This rises to €45 per calf if purchase cost is €3,000 and €57.50 per calf if the purchase price is €4,000. AI will cost on average €30 per serve and €10 for a repeat. While AI has been around for a number of years, the use of sexed semen has become a more viable option for herds in recent years. Developments in the sexing technology, herd trials which show improved conception rates and the introduction of two sexed semen labs in Ireland have increased the availability of sexed beef straws for suckler farmers this spring.
Good heat detection is critical to the success and failure of AI. About 10% of the reasons for failure to detect heats are attributable to ‘cow’ problems and 90% to ‘management’ problems. Management problems include: too few observations per day; too little time spent observing the cows; or observing the cows at the wrong times or in the wrong place, such as at feeding time.
What heat detection aids are available?
Vasectomised bulls with a chin-ball marking harness, active vasectomised teaser or detector bulls are very useful in identifying cows coming into or on heat. Vasectomy should be carried out 40-60 days prior to introducing the ‘teaser’ to the herd. Teaser bulls are particularly useful after the first three weeks of the breeding season, when fewer cows are in heat each day and when the level of heat-related activity in the herd is reduced as more cows become pregnant. Bulls should be fitted with a chin-ball harness 2-3 weeks before turn out with the herd. Teaser bulls require the same management as entire bulls and should be either castrated or culled after one season. Steers if recently castrated, are useful in identifying cows coming into or in heat.
Heat detection patches
A number of ‘scratch card’ type patches are affixed to the cow’s tail head. Friction from mounting rubs off the silver coating to reveal a bright colored patch underneath. These devices, when properly applied, are very useful as an aid to heat detection. When one of the aids is used, cows should be observed at least twice daily – early morning and late evening. Otherwise cows should be checked at least three times daily. Spend a minimum of 20-30 minutes observing them during each observation period.
Electronic indicators
Electronic indicators have also come onto the market that either fit on a teaser bull or on the cow/heifer. These devices monitor behaviour and will indicate on your phone if an animal is showing signs of heat. Most cows come in heat between 8pm and 8am. Therefore, late evening and early morning observations are critical to good heat detection. Follow the am/pm rule regarding time of AI.
Also read: Breeding the next generation of cows with Future Beef Farmer John Dunne
Also read: Matching the bull with the cow and using sexed semen