Tightening the calving interval within commercial beef herds can significantly reduce costs and improve margins. Chloe Palmer reports on how this can be achieved on-farm.
An extended calving interval is one of the main factors leading to reduced weaning weights and higher feed costs, according to industry experts.
Keith Cutler, partner with the Endell Veterinary Group, Salisbury, and past president of the British Cattle Veterinary Association, suggests the calving interval can provide a good indication of the standard of herd management and overall herd health status.
He says: “Calves born early in the calving period tend to be healthier so will grow better and be heavier at weaning. Consequently, they will be more valuable.”
Mr Cutler refers to a self-perpetuating cycle where cows which calve early have a longer time period for uterine evolution and for a return to ovarian cyclicity resulting in higher fertility. Similarly, for cows calving later in the period, the problem is exacerbated year-on-year.
“Cows which calve later in the period will slip each year and eventually fail to get in calf. They will then either have to be culled or they must be carried round for a year, but either way they are a significant cost to the herd.”
Mr Cutler refers to management of cow nutrition, bull fertility and infectious disease control as the three key management factors affecting the length of the calving period.
Cows reductions and therefore boosted margins are two of the benefits of working on tightening calving intervals in beef herds
“Cows should be on a rising plane of nutrition prior to bulling to promote cycling the ovaries and to improve the quality of eggs. For spring-calving herds, this critical time usually coincides with a flush of spring-grass which is ideal.
“On average, one in 10 bulls on-farm is sterile and an additional two in 10 are sub-fertile, so a pre-breeding examination is highly recommended to rule out the risk of infertility.”
Identifying whether infectious disease is present within a herd is also essential so appropriate action can be taken.
Mr Cutler says synchronisation and artificial insemination (AI) are ‘under-used tools’, but farmers should be wary of viewing them as a quick-fix solution because management of a herd must be ‘spot-on’ for this strategy to be effective.
He says: “Synchronisation and AI can be particularly useful for tightening up the tail-end of the calving pattern. Synchronisation secures the best possible time for service and AI eliminates the risk of an infertile bull as it enables the best genetics to be sourced.”
Simon Marsh, principal lecturer at Harper Adams University, shares Mr Cutler’s concerns about the impact of an extended calving period for beef producers and says the cost to the industry is considerable.
He says tackling issues to achieve compact calving periods will have wider benefits for animal welfare and business profitability: “Herds recording a calving period of less than nine weeks are weaning calves at an average weight of 47kg greater than herds where the calving period is 18 weeks or more. Calving periods extending beyond 12 weeks equate to an additional cost of £3.55 per cow per day.”
Mr Marsh says cow management prior to bulling is critical: “Poor condition at bulling where body condition score falls to less than 2.5 is one of the most common reasons for poor fertility.”
Mr Marsh advocates calving at two years old where it can be achieved because it can result in significant financial gain.
He says: “Aim for heifers to calve two to four weeks before the main herd so they have sufficient time to adjust before other cows calve.
“This will mean heifers are actually younger than two years old when they calve, but they are likely to have been bred from the most fertile cows in the herd which calved in the first few weeks of the calving period.”
Mr Marsh points to bulls which have been over-fed prior to sales then come back to the farm to a grass-based diet as another potential problem.
He says: “We see many bulls which are over-fleshed in the sale ring because they have been fed a high proportion of concentrate and this has been shown to reduce fertility and longevity.
“Once the same bull is working in a commercial herd, it is usually fed a very basic diet prior to being turned out with the cows and this can reduce their performance.”
Mr Marsh says improved genetics may offer part of the solution and estimated breed values can be used to select for improved maternal traits when choosing bulls.
He says: “The aim should be more fertile female replacements and to achieve this, farmers should be looking for traits such as 200-day milk, age at first calving, maternal calving ease, calving interval and longevity.
“I would urge farmers not to consider bulls with very high mature cow weights or 400- and 600-day growth, since this will subsequently increase cow size. The objective must be to breed small- to medium-sized cows which are milky and prolific and can produce calves weighing 50 per cent of the cow weight at 200 days.”
Recognised targets are:
Source: Eblex stocktake 2014 report for suckler herds; results from top third of producers
Average calf value at housing vs calving period (based on £2/kg)
Relationship between cow size and calf size
He observed cows were becoming too fat and suspected a problem of low fertility in one of his bulls.
He says: “We were finding we were still calving the tail-end of the herd in August, which meant it was October before cattle were ready to go for slaughter. This delay was having an impact on our cashflow.”
Around the same time, Eblex was looking for focus farms for its Better Returns Programme and Neil Flower was happy to volunteer. Herd data was analysed and revealed a long, drawn-out calving period of 18 weeks.
He says: “The Aberdeen-Angus utilise grass very well and rarely lose any flesh over winter. When we condition scored our cows, we found a proportion had a body condition score of five and many of the remaining animals were scoring four.”
The decision was made to calve heifers at two years old rather than two-and-a-half so they were less likely to become over-fat in the first place.
Mr Flower says: “We had to feed some concentrate to heifers so we could achieve the target bulling weight of 65 per cent of their expected mature weight. We fed 2kg of a 16 per cent blended protein over winter and fed a 14 per cent protein in spring.
“All six of these heifers attained the desired weight of 400kg at 15 months old when they were served.”
A forage analysis was undertaken which showed a deficiency of salt, so now salt licks are continuously available to cows.
Removing the bull after 12 weeks has paid dividends and Mr Flower is now routinely having a ‘bull MOT’ on his two stock bulls 10 weeks before putting them in with the cows.
“Having bulls tested proved relatively inexpensive compared to the risk should they have been infertile.”
The results have proved impressive and this spring more than 80 per cent of the early spring-calving herd calved within three weeks of the first calf arriving. For the later herd, due to calf from the beginning of May, the figure was even higher.
“We hope to be finished by the end of June and it has been much easier to manage. This spring, we have opted for synchronisation and artificial insemination on six heifers as it is difficult to detect when they are bulling. This will allow us to bring new genetics into the herd.”