Autumn-calving suckler farms are well through calving by now, and in most cases, attention has started to turn to breeding.
Regardless of the calving system in place (spring/summer or autumn calving), breeding is a critical period for any suckler enterprise.
Beef and sheep advisor at the College of Agriculture, Food and Rural Enterprise (CAFRE) Dominic Mason recently outlined what determines reproductive efficiency within the suckler cow.
He said three factors are key in suckler-cow reproductive efficiency:
- The interval between calving and the return to normal heats;
- Heat detection efficiency – especially where artificial insemination (AI) is used;
- Overall conception rate per service.
For the breeding season to be a success this autumn, Mason said that there are “many things that must be correct and in order”.
“These parameters must be monitored to ensure the suckler cow returns to normal heats, so keeping the calving interval of that cow and the overall herd at an acceptable level for your business [is important],” he said.
On average, the time from calving to first heat in suckler cows is 50+ days. Many factors can influence this time for better or worse, but ultimately, suckler farmers should aim to have a cow calving every 365 days where possible.
Body condition score (BCS) at calving is a factor that will influence success at calving and a fast return to heat.
At calving, cows need to be fit and not fat, as overfat or very thin cows can result in calving difficulties and a delayed return to normal heats as a result.
Farmers should assess cows according to BCS routinely, aiming to have them in the optimum BCS of 3-3.5 and making sure to separate fat cows from thin cows as they will have different feed requirements.
“Depending on breed and mature weight, 1 BCS could be in the region of 75kg liveweight,” Mason explained.
Mineral feeding
Mason said that mineral feeding to calved cows should remain at the rate that they received pre-calving, continuing throughout the breeding season.
In most cases, 150g/head/day of a quality powdered mineral is suggested, according to supplier guidelines. Mineral feeding will have a positive effect on reducing cases of retained placentas and will improve calf vigour and help cows show stronger signs of heat as well.
Nutrition for autumn-calving cows
The CAFRE beef and sheep advisor stressed that nutrition once calved is of paramount importance, especially for first calved heifers, older cows and cows with multiple births, as requirements for maintenance, growth and production of milk will be different for each.
“Silage should be analysed and results used appropriately. Silage produced throughout 2022 is of varying quality and autumn-calving cows need quality silage,” he said.
“Aim to feed these cows 70 D-value silage where possible on an ad-lib basis. Where this silage quality is not available, discuss further with your nutritionist and top up with concentrates on the back of your silage analysis results.
“Supplementation depending on silage analysis could be in the region of 1kg to 3kg/head/day until breeding season has finished to maximise conception rates.
“If silage reserves are tight, feeding 1kg of concentrate can potentially replace 3-5kg of silage depending on quality and overall dry matter percentage (DM%).
“Failure to provide a quality diet at this stage could have detrimental effects, not only on the percentage of cows in-calf at scanning but also on calf performance and overall weaning weights.”
Heat detection
With reference to heat detection, Mason said the concept of restricted suckling for a period between the dam and the calf twice per day can speed up the onset of heat and decrease the days to service.
If practicing this, aim to commence once the cows are approximately 30 days calved and continue for roughly three weeks.
The CAFRE advisor said that it is suggested approximately 85% of these cows will show signs of heat within two-three weeks of the first separation.
He outlined that conception rates in the region of 60-70% are “more than possible” for suckler cows within both natural service and AI, but said semen quality, AI technique and bull fertility are all important.
AI advice
Mason said farmers should aim to have semen tanks topped up regularly with liquid nitrogen and avoid over-handling to avoid damage to straws.
Be confident in your AI skills he said, however you feel you are not capable of the job in hand, call in an expert technician to carry out the procedure.
Finally, in the lead up to the calving season, in preparation for breeding, it may be of benefit to ask your local veterinarian to carry out health and semen checks on your herd’s bull to assess his ability to serve and conceive.
Scanning autumn-calving cows
Pregnancy diagnosis can be carried out effectively from 40 days after last service or insemination, so good record keeping is essential.
This should be something that everyone carries out on-farm no matter what period you are calving down in.
Once cows have been diagnosed as in-calf, aim to keep the cows on a settled diet with no major changes in order to maintain the pregnancy.
However, if a pregnancy has not been successful, the CAFRE beef and sheep advisor said farmers can then decide whether other intervention is required, such as synchronisation of heat to allow the cow to conceive and stay within her current breeding window with an acceptable calving interval.
