Synchronisation and AI on trial in sucklers

Increasing the use of artificial insemination (AI) in suckler herds allows for a greater range of higher-quality genetics to be used on specific cows.

At an event organised by AgriSearch, AFBI and CAFRE near Portaferry last week, host farmer Artie Birt said that for AI to work effectively on his 180-cow spring-calving suckler herd, a synchronisation programme is essential.

“For me, AI by watching for heats is a non-runner; I simply wouldn’t have the time. With a synchronisation programme, you have three or four handlings of the cows which, if you have the right set up in the yard, takes a lot of the work out of it,” he said.

Artie is one of 12 suckler farmers from across NI that have completed two years of a synchronisation and AI trial.

AgriSearch field officer David Anderson said that 1,100 animals have taken part in the study to date. It involves two programmes for cows and heifers, which differ in the number of handlings and the veterinary medicine used, as outlined in Figure 1.

Results shown are for first-service conception rates and vary across farms from 35% to 88%. On average, the minimal handling heifer treatment has delivered slightly poorer conception rates so far, but there is little difference in results from the two different programmes used on cows.

Results

On Artie’s farm in the first year of the trial, both heifer treatments were used on two batches of 26 heifers. Results differed significantly with a 35% conception rate for “heifer one” compared with 81% for “heifer two”.

“Artie was slightly reluctant to try the heifer one treatment again but for the sake of the trial agreed. This year, however, heifer one had a higher conception rate of 73% with heifer two getting 63%,” David said. He added that the poor results for ‘‘heifer one’’ in 2015 could have potentially been due to very warm weather during the treatment period.

In 2015, Artie had 40 cows undergoing “cow two” treatment with a 55% conception rate, and this year he had 132 cows on the “cow one” treatment, with 65% holding at first service. “They will not all calve in one day. A batch could be spread out over 20 days between early and late calvings. But you can plan and get organised for that week when the bulk will be calving,” Artie said.

David pointed out that even if only average results of 50% first-service conception are achieved, synchronisation still allows good progress to be made in getting cows in calf and tightening calving intervals.

He said that care should be taken to select cows for synchronisation that are suitable and most likely to be artificially inseminated. Issues to consider include previous calving difficulties, body condition score, minimum requirement of 42 days from last calving and temperament.

“Cows are checked by a vet before CIDRs are inserted to make sure that they are ready for treatment. Planning with vets and AI technicians is essential prior to starting treatments,” David said.

Costs

Costs outlined in Figure 1 are for synchronisation only and do not include AI costs. Artie pointed out that costs associated with feeding and depreciation of stock bulls on suckler farms amount to around £700 per year per bull on average, and these costs are often ignored by farmers when calculating costs.

Artie has reduced the number of bulls on his farm from seven to two since he began using AI. He typically has 93% of cows in-calf after three cycles, which is probably as good as what can be achieved with a fertile bull in with a group of cows.

Artie generally uses Charolais and Limousin AI bulls on his mostly Simmental, Charolais and Limousin cross cows. Most cows run with stock bulls in the second cycle, but some receive repeat AI, with Artie pointing out that these are easier to detect in a set number of days following synchronisation. Easy-calving Simmental AI bulls are generally used on heifers.

“The most important thing for us in selecting a bull is calving ease. An AI catalogue also gives you more accurate estimated breeding values (EBVs) from proven bulls than there would be at most bull sales. We also have a strong focus on selecting for good temperament,” Artie said.

Room for improvement in NI suckler herd

Increasing the productive life of cows and replacement heifers comes down to reducing both calving intervals and average age at first calving in suckler herds, Dr Francis Lively from AFBI said at last week’s event.

Data from BovIS shows that the average age at first calving and the average calving interval in the NI suckler herd is 30.6 months and 420 days, respectively.

Lively said that there was “massive room for improvement” to increase output in the NI suckler herd. “A suckler cow has got to go in-calf to produce a calf every year or else go out of the system. Farmers should be aiming to calve down heifers at 24 months,” he said.

Farmers were told that calving heifers at 24 months requires good management from weaning to calving. Heifers need to be treated as priority stock with access to the best quality forage. This added cost from feeding higher quality material was far outweighed by the extra costs that come from retaining heifers to calve down at 30 to 36 months, even if lower quality feed is offered, said Lively.

Condition

For mature cows, managing body condition score by assessing animals, batching and then feeding accordingly early on was highlighted as essential for improved fertility.

Lively said that spring-calving cows should have a condition score of 3 at housing, 2.5 at calving and a score of 2 at breeding.

“At calving, if cows are too fat it can lead to harder calvings, and if cows are too lean it can impact on a cow’s ability to start cycling after calving,” he said.

AFBI vet Jason Barley told farmers that the presence of diseases such as BVD, leptospirosis and IBR in herds can affect production targets by reducing fertility in cows through either lower conception rates or abortions. “All three diseases are very prevalent in Ireland. Vaccinations are available for them and is something I recommend to farmers,” he said.

Another factor that can affect fertility is trace element levels in animals. Barley said that an iodine deficiency will lead to short or silent heats in cows resulting in reduced conception rates with both AI and natural service. Lower iodine levels can also lead to potential stillbirths or weakly calves being born that are slow to suckle.

Selenium deficiency in cows can reduce conception rates and cause weakly calves and thick placenta which increases the risk of calves being suffocated during birth, said Barley. He added that copper deficiencies are less common in NI but recommended carrying out a herd mineral check that covers these three trace elements. The test involves blood being taken from a sample of animals and sent to AFBI for analysis. The cost is £52.50.

“This should be done before looking at giving supplements for trace elements such as drenches, pour-on or long-acting boluses,” Barley said.