In this article, Kevin McGrath, CAFRE beef and sheep adviser, Omagh discusses cow fertility, herd health and diseases, getting suckler cows back in-calf, cross-breeding, bull fertility.
Cow fertility is one of the main drivers of profitability within a suckler herd.
Optimising fertility increases the number of calves born and sold, subsequently leading to better farm output and increased profitability.
A cow must earn her place within the herd; otherwise, she becomes a drain on the herd’s overall output.
According to the Irish Cattle Breeders Federation (ICBF), the beef breed with the shortest gestation length is the Aberdeen Angus at 283 days, with the Blonde d’Aquitaine the longest at 294 days.
The average of all beef breeds is 288 days. With a target calving index of 365 days, this gives us 77 days to get our cows back in-calf. So, what are the main areas we should be focusing on to achieve this?
Cow body condition can have a significant influence on fertility. The hormones controlling both fertility and nutrition are closely linked. Naturally, a cow will prioritise milk to feed her calf before focusing on her own maintenance requirements.
Only when these requirements are met will reproduction become a priority. A cow that is too thin may have difficulties with calving, colostrum and milk production and will be more difficult to get back in-calf.
Excessive weight loss must also be avoided, with reductions in body condition taking place on a gradual basis. Group heifers and thin cows separately, then feed according to requirement.
Get suckler cows back in-calf – Dam and calf bonding effect
Suckler cows can take up to twice as long as a dairy cow to return to cycle. This is mainly due to the dam and calf bonding effect.
By separating the cow and calf from day 30, and practising twice daily suckling for two weeks, up to 85 – 90 % should show heat within 18 – 22 days.
It is important to separate both by at least 50 metres as sight and smell have a role in the bonding effect.
This can be a useful technique to bring forward first and late-calvers and to get suckler cows back in-calf.
Breeding to improve fertility within the suckler herd can be a slow process as reproduction traits have a low heritability.
However, crossbreeding (hybrid vigour), particularly when crossed with a third sire, can greatly improve reproductive traits.
Research supports this, citing increases in conception rates, calving ease, milk yield and an increase in calves raised to weaning.
Difficult calvings can greatly affect a cow’s ability to cycle.
Issues include oversized calves, overweight cows, inadequate pelvis size or heifers/cows, which are too small.
A lot of these issues can be avoided through better nutritional management with the correct choice of both dam and sire. It is important to practice good hygiene at calving. Uterine infections can subsequently lead to a prolonged calving interval.
Bull fertility greatly impacts calving interval and calving period. Approximately 25% of working bulls are sub-fertile or infertile. Rotate bulls or record service dates so that any potential issues can be identified early.
A bull that has tested fertile can go through periods of reduced fertility, especially if suffering health issues.
The bull must be in good condition and health at least ten weeks before the commencement of the breeding season.
Pregnancy diagnose (PD) your herd a month after AI or from when the bull has been removed. This will allow you to identify the problem cows requiring removal from the herd.
Disease can also have a large effect on herd fertility. Diseases such as Bovine Viral Diarrhoea (BVD), Leptospirosis and Johne’s disease can cause poor conception rates, increased abortions, stillbirths, and a higher calf mortality.
Discuss any issues with your vet, who will develop a vaccination plan where necessary.
Fertility management should be an important focus on farm.
Poor fertility can be a major cost to the business but is also an area where significant improvements can bring reward. Assess your current herd fertility, plan ahead, and focus on change if required.
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