Achieving good fertility in dairy cattle requires a whole team approach, bringing together overall management, veterinary input and nutritionist skills, farmers were told at an Intelligent Feeding Forum meeting in Garstang, Lancashire. Farmers Guardian reports.
Adam Collantine, Dugdale’s Nutrition dairy consultant, said: “A fertility programme runs from heat detection through to two or three weeks after calving.
“Most dairy farmers are ideally looking for a 365-day calving index, or as near as they can get.
“The cow is pregnant for about 280 days, so to achieve a 365-day index, she needs to be back in-calf in about 85 days, but how practical is this?”
Mr Collantine said assuming cows’ uteruses could get in-calf, key questions were whether all cows were coming on heat, this was being observed, cows were being inseminated at the right time and were getting in-calf.
Part of the issue here was watching cows for signs of heat and ensuring whoever was doing this knew what to look for.
Typically, cows were on heat for 12 hours, of which they were standing on heat and head mounting for about half this.
Some 90 per cent of cows on heat would mount each other, but only about 40 per cent would stand to be mounted.
Some 40 per cent would not show a standing heat. In addition, cows did not show heats in temperatures of more than 21degC and duration tended to reduce as milk yields rose. Good well-lit housing was an important aid to observation of heat behaviour.
Records were important, Mr Collantine said, and it was worth remembering pregnancy rates were a more reliable measure than conception rates in assessing group fertility, as there was nowhere to hide in the figures used.
Mike Murphy of Oakhill Farm Vets, Preston, said: “Dairy cow fertility is a huge topic and we all have to work together to improve different areas on different farms to get a gradual improvement in fertility.
“Studies from the 1950s to the present time show cows giving an increasing amount of milk, but with a lower first service pregnancy rate. It appears more milk means less fertility, but I do not think things are as simple as that.
“I think we need to look back at the 1970s and what has changed on farms over the last 20-30 years, with bigger farms, more cows, less labour, people moving to more confined systems and fewer grazing herds.
“Even in really good setups with good ventilation, good lighting, nice sandbeds and cubicles with wide passages, there have been problems with fertility.”
Mr Murphy said there had also been fertility problems following moves to low input/low output grass systems in New Zealand, as well as in grass-only systems in Ireland.
In the UK, NMR and Reading University were producing reports from dairy farms across the country. Encouragingly, last year’s figures have shown small improvements in health and fertility.
There were undoubtedly many factors contributing to these improvements, but these might include improved genetic indices, helping select bulls for fertility, longevity and fitness traits, as well as milk production.
Each farm was different and it was important to identify the root causes of problems on individual farms. Certainly, he believed routine vet visits about every two weeks would quickly pay for themselves in identifying and dealing with problems at an early stage.
Bill Hardman, Dugdale Nutrition’s technical manager, said the key aims of feeding in maintaining fertility were to consistently achieve optimum body condition pre-calving, but not to overfeed energy in the dry period, and also aim to minimise clinical and sub-clinical milk fever.
He said: “High dry matter intakes in fresh cows helped minimise negative energy balance – think glucose and starch and do not overfeed fat.”