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Autumn calving is ideally suited to using AI as cows are housed for the winter period.
This makes it easier to watch for heats and handle animals for insemination.
However, successful AI does require higher levels of management.
So to improve conception rates, outlined are 10 tips to successfully using AI in autumn-calving herds.
1 Housing cows before breeding starts: AI always works best when cows are not stressed. Housing cows at least two weeks before the start of the breeding period will improve conception rates.
By housing early, cows will be settled in the shed and transitioned on to a steady winter diet. This will greatly improve cow fertility.
Housing cows on the point of breeding, or just after insemination, is not recommended as the change in environment increases stress and negatively affects fertility.
2 Steady diet until the end of breeding: offer cows a consistent diet from housing until four weeks after breeding has finished. A steady intake of silage and concentrate means there are no fluctuations in energy intakes, which is important for breeding.
Remember that August- and September-calving cows are at peak milk production in October and November, which coincides with breeding.
Therefore, cows have a huge requirement for energy in the diet. If the diet is not supplying adequate energy, fertility will suffer.
Offer cows the best-quality silage on the farm, ideally forage over 70 DMD. Supplement with 1kg to 2kg/day of concentrate, depending on fodder quality and the amount in reserve.
While ration prices are high, cows in the middle of breeding are not the animals to sacrifice in an attempt to keep the meal bill under control. For 67 DMD to 69 DMD silage, feed 2kg to 3kg/day, as necessary.
3 Separate thinner cows and heifers for priority feeding: thinner cows and first-calved heifers should be penned separately from the main herd now. This allows these animals to access feed without bullying from stronger cows.
It is important that these cows get additional feed to regain body condition before breeding starts. Thin cows will be slower to return to heat and conception rates will be lower. Feeding an extra 1kg/day of concentrate per cow will help to build condition, as will restricting calves to suckling twice daily.
4 Restrict calves from suckling: allowing calves to suck their dam for one hour in the morning and one hour in the evening will also help cows come back into heat much sooner.
Heats also tend to be much stronger, which is crucial for getting the timing of insemination correct.
There is no negative impact on calf performance from restricting suckling to twice daily. Once cows are settled in calf, calves can be given unrestricted access to the cow again.
Simply lock the calf in the creep pen between each designated feeding period. Ideally, this method works best when the cow cannot see the calf in the creep pen.
5 Mineral supplementation: ensuring that cows are properly supplemented with minerals and trace elements is crucial for good conception rates. Minerals can be offered in a variety of methods, all with their own merits.
6 Fluke treatments: make sure cows have been treated for fluke before breeding. With early housing, this means choosing a fluke product that targets the parasite at early immature stage.
In first-calved heifers, a wormer is also beneficial to ensuring breeding animals are clear on internal parasites. Healthy cows are more likely to be fertile, helping conception rates to AI.
7 Heat detection: with AI, heat detection becomes the responsibility of the farmer. With cows housed and settled in the shed, heat detection will be easier compared to using AI at grass.
There are aids that will help pick up cows in heat. Cameras in the shed are also a good idea, as you can observe animals without entering the shed and disturbing them.
When watching for heats, spend 20 to 30 minutes morning and evening with a third period fitted in during the day, if possible.
On entering the shed to watch cows, do not start pushing in silage. This will only encourage cows to come forward and eat, disrupting their natural behaviour.
8 Use the am-pm rule for insemination: timing of insemination is important to get the best chance of cows holding to service. Following the am-pm guide is a good rule of thumb.
This means a cow seen in standing heat during the morning should be served in the evening and vice versa.
9 Stress-free handling: when a cow is seen in heat, she should be moved to the crush for insemination once the technician arrives. The cow should return to the group pen as soon as she has been inseminated.
At all times, keep stress to a minimum. Good handling facilities will reduce stress and make it easier to move cows for insemination.
Running cows through the crush a few times before breeding will help familiarise animals with the handling setup.
In the case where a farmer works off-farm, don’t leave a solitary cow or heifer in the handling pen for hours until the technician arrives.
Ideally, having a couple of contemporaries standing in pen will reduce animal stress.
10 Recording insemination dates and watching for repeats: once cows have been inseminated, mark the service date and pay attention for signs of repeat breeding activity around 18 to 21 days later.
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