Plan for profit by fertility testing stock bulls
Fertility checks are becoming a critical tool for many beef breeders. Debbie James finds out why
More than a quarter of farm bulls whose fertility was tested by the UK’s largest veterinary group were sub-fertile.
Out of the 411 bulls examined by the Westpoint Veterinary Group, two to three months before they were due to breed, 30.1% failed the test. The abnormalities in nearly half of the group could not be detected through a basic clinical examination, because the defects were semen related.
If these abnormalities were not picked up, and the bulls had been used for breeding, the results could have had serious implications upon profitability, says Alex Walters, associate director of Westpoint Veterinary Group.
Livestock systems with sub-fertile bulls can expect higher return rates, which can lead to an excessive number of barren cows. “The cost of carrying a cow to the point of breeding and only then finding out she is empty at scanning can be substantial,” Mr Walters explains.
At 47.7%, semen abnormalities were the most common single reason for fertility failure in the bulls tested. This was followed by reproductive tract abnormalities (19.6%), musculoskeletal system abnormalities (16.3%) while other reasons accounted for approximately 16%.
Mr Walters believes the nationwide review confirmed the value of these clinical and reproductive examinations. “A substantial proportion of the bulls we tested pre-purchase or pre-breeding were found to be unfit for the intended purpose. Therefore their owners or prospective owners were spared the economic consequences of using sub-fertile or infertile bulls as breeding animals.
“The review reinforced the value of performing clinical and reproductive examinations in bulls while reiterating the necessity of semen analysis as part of pre-breeding and pre-purchase examinations.”
Testing has only become more common in the UK in the last 10 years. “Testing has been more widely available commercially in Australia, Canada and the USA for longer, but we have really only embraced it in the last 10 years. Some farmers can often be skeptical, but these tests are not detrimental to the animal’s fertility,” said Mr Walters.
Westpoint has seen a big rise in the number of farmers opting for fertility testing; it expects to carry out over 500 tests in the next 12 months. “Pre-purchase examination is becoming popular. The cost of buying a bull can be exceptional, in many cases over £4,000 an animal. A fertility examination costs less than 3% of this figure,” Mr Walters points out.
The criteria applied are centered on an animal being capable of achieving a minimum 60% conception rate within a group of approximately 40-50 eligible breeding cows. This equates to at least 93.6% being pregnant after a nine-week breeding period and 60-65% of cows calving within the first cycle.
Beef producer Tim Piper recently tested all 13 of his bulls and all were found to be fertile. He has been using the testing mechanism for the last three years and this spring he calved 75% of his herd in the first five weeks. He has learned from experience the value of testing. “Before we started testing we had a bull that proved to be sub-fertile, but we didn’t find out until we scanned the cows. Some were in calf and some weren’t,” says Mr Piper, who runs a herd of 250 Continental-cross cows at Owley Farm, Wittersham.
“It led to a very protracted calving period, because cows were returning to service. We had to sell anything that was empty.”
Mr Piper has a mixture of Limousin, Blonde d’Aquitaine and Simmental bulls and runs a bull to every 25 breeding cows in his spring-calving herd. The economic implications of even a single bull being sub-fertile are considerable.
The fertility tests are included in a Westpoint health package known as a Profit Improvement Plan (PIP), which also includes pregnancy diagnosis and routine herd health planning. “I’ve realised the importance of testing. It costs us under £100 a bull, which is a small amount to pay compared to the cost of a live calf or a barren cow.
“Cows are worth a lot more money than they were and with everything getting much tighter we can’t afford to feed empty cows. Every cow has got to maximise her potential from an economic point of view. When we were getting a headage payment at least there would be the guarantee of that income if a cow was empty, but now we can’t afford to keep any freeloaders.”
The test can also be effective at identifying bulls that are more or less productive than farmers may think. Mr Piper has two ageing bulls, a 10-year-old and an 11-year-old, and expected them to fail the test. “They both passed with flying colours,” he says. “Both bulls are in very good condition and provide the genetics we require, so we will continue to use them with the reassurance of knowing that they will be performing as they should be.”
This year he will be running a bull with 11 groups and retaining two bulls as “spares”.
Reproductive issues can be reversible, therefore animals included in the Westpoint review, which were presented with a history of a high return rate or an excessive number of barren cows in a group, were generally recorded as problematic breeders, but not necessarily “written off” after just a single test.
In circumstances where a bull fails an examination and potentially reversible problems, such as semen abnormalities, are identified, the bull can be deferred and retested two months later. The rationale for this, according to the Westpoint evidence-based review, is that the production of a single sperm cell takes approximately 60 days before it is stored in the epididymi for a further 12 days. The sample being analysed is therefore “historic” at the time of testing. “Retesting allows an opportunity for sperm unaffected by an initial insult in a recovered animal to complete a cycle and be interpreted on a separate occasion,” says Mr Walters. “It is sensible to re-examine failed animals with suspected reversible defects, where permissible.”
This also highlights why it is critical to have a thorough history of the animal at the beginning of any bull fertility examination.
It is standard best practice in pedigree beef herds to test semen before breeding bulls are sold.
However, bull fertility examinations do have some limitations, according to the Westpoint review, particularly in relation to assessment of libido and achievement of intromission. These are not routinely monitored as part of the procedure, but serving ability and capacity examinations can be performed as adjuncts to provide further information in specific cases where needed.
Infectious disease status, including venereal disease monitoring through blood sampling or sheath culture, in addition to other testing can also be useful in many cases, Mr Walters suggests.