Dairymen at a recent training course on fertility got a shock as they discovered the true financial implications of poor fertility. Sarah Trickett reports
Poor conception rates, extended calving intervals and reducing days to first service were just some of the reasons dairymen were attending a fertility workshop organised by Kingshay, as part of Livestock Health South East, a training project funded by the South East England Development Agency through the Rural Development Programme for England.
It seemed for each of the 20-plus people attending the event, every one had at least one niggling fertility issue which couldn’t be pinpointed to anything specific.
Speaking at the workshop, agricultural consultant Phil Clarke said poor reproductive performance was one of the main causes of income losses for dairy producers. “These losses are often overlooked because they are indirect costs. If poor fertility could be seen as a bill, then drastic changes would occur.”
Mr Clarke estimates that every 5% increase in conception rate will typically increase income by £600 a year. “By decreasing days to first service from 80 days to 60 days, increasing heat detection efficiency from 50% to 60% and increasing conception rate from 35% to 50% net income can be increased by £9000.
“Most reproductive losses occur through lost milk yield, with peak yield traded for late lactation yield and loss of mature animals, enforced infertility culling and more replacements, additional AI and vet costs, disruption of calving pattern and loss of valuable genetics,” he said.
But Mr Clarke warned that if improvements were to be made to fertility it was by management. “Producers must be committed on a daily basis to improving the herd’s reproductive performance and having sound reproductive management will increase income and profits.”
Kingshay Dairy Manager shows 27% of all cullings were directly related to fertility management and Mr Clarke feared that with rising replacement costs, farmers were being tempted to keep animals with fertility problems, instead of replacing them.
“Holding on to cows with fertility problems will inevitably extend calving interval and with cost a day per unit of extending calving interval estimated at between £4 and £4.50, this is a significant cost over an entire herd,” he said.
Costs of infertility (£)
“Declining fertility cannot be blamed on any one breed. But the problem is that breeding has excelled faster than housing and management, so many cows are not suited to the environment, with consequential effects on fertility.”
Mr Clarke also believed fertility measures used in the UK were misleading. “You can’t just look at ‘traditional efficiency’ figures such as conception rate, calving interval and service/conception because they can be deceptive.
“For example, if you have 100 cows, but only one is served and the other 99 are not served because they didn’t show signs of heat, your conception rate would show as 100%. Yes, this is an extreme example, but you need to know what is happening in the whole herd rather than just the animals you’ve served,” he said.
Australia and New Zealand already used progressive measurements such as 80-day submission rates, 100-day in-calf rates, 200-day not in-calf rates and heat detection rates. “Progressive measurements take into account the whole herd and focus on getting cows pregnant within a specific period rather than analysing how many serves it took to get a pregnancy.
“Pregnant cows are far more valuable than empty cows, so focus on pregnancies not efficiency factors,” he said.
But to apply any of these progressive measurements good record keeping was needed, said Kingshay’s Robert Mintern.
“Clear, precise records are essential to an effective routine and accurate records allow producers to spot and deal with problems before they become too costly.”
Methods of record keeping included diaries, 19-day wall chart calendars, individual cow records and Bray Boards as well as several computer systems. Mr Mintern also suggested drawing up an “action list” containing cows due for calving, drying off, pregnancy diagnosis and repeat cycles, focusing attention on individuals.
“Record keeping is essential in understanding where the animal is in her oestrus cycle and, therefore, when best to inseminate,” said Mr Mintern.
Prior to standing heat, cows may display other behaviours indicating when they were coming into heat. For example, 48 hours before standing heat, butting and rubbing may occur and about 12 hours before heat they may try mounting other cows.
“If any of the behaviours are seen and action lists are drawn up, you would know more accurately when to look out for an individual’s standing heat.
“Every time a cow fails to conceive or misses her cycle the financial cost is estimated at £40 a cow. So the first step to improving herd fertility is maintaining a high heat-detection rate.
“Increasing heat detection rate up to 90% can allow you to get another 20 cows in calf and doing three planned 20-minute blocks looking for cows standing heat can increase detection rates up to 90%,” he said.
The best time to observe cows was when out to pasture and at dawn and dusk, with 69.5% of all mountings taking place between 6pm and 6am. “If you can’t do three 20-minutes sessions, then one 20-minute session is better than four five-minute sessions,” said Mr Mintern
He estimated delay in serving a cow after the voluntary 60-day waiting period cost £2 a day and every time a cow was seen bulling, but not served after this period was costing £43.47 for every heat cycle. “This is more than double the cost of a typical dose of semen,” he said.
But with increasing red tape and form filling, Mr Mintern said heat detection aids offered valuable support for management, but should never be used as a replacement for visual observations.
“Tail paint and tail crayons are two of the most effective and cost-effective products, although they do require good record keeping and regular observation to determine when the paint mark is being removed or triggered. Bad weather may also affect the results,” he said.
Kamar heat-mount detectors, Estrus Alert, which uses self-adhesive scratch sheets at the top of the tail head and the Mount Count integrated electronic hardware and software system detecting each time a cow was mounted were also regularly used as detection aids.
Factors affecting heat
Several factors could influence the expression of heat, such as the cow energy balance, general health and level of stress, environmental aspects such as temperature and floor/loafing area and people factors such as knowledge of heat signs and the number of checks a day.
Heifers could often be hard to detect in heat and in a Kingshay longevity study had been shown as having the most serious fertility problem. “The heifer has a hard job in her first lactation, growing, milking and getting her back in calf. So her transition into the main dairy herd has to be a stress free as possible.”
Mr Mintern recommended allowing heifers to settle into the group before they calve, training them to use cubicles well before calving, reducing stocking densities in buildings to ease competition for eating and lying space. “When heifers are coming in last at milking, this is often a clear sign they are under stress,” he said.
Correct cow nutrition and maintaining the correct body condition score throughout lactation was also something having a great impact of cow fertility, said Mr Clarke.
“Controlling weight loss in early lactation is vital and increasing early lactation body condition score by 0.5-1 point extends the calving interval by 8.5 days. Increasing the BCS loss by more than one point will extend the calving interval by 19 days, costing a typical 7000-litre herd £94 a cow or 0.77p/litre,” he said.
“Condition scoring should be part of a regular management routine. Body condition score two is the critical level and you don’t want to go below that. To achieve an optimum condition score of 2.5-3 at drying off, cows below 2.5 should receive extra supplementation and should be dried off early. Those above 3.5 should receive less supplementary feed.”
Suggested intervals for scoring included start of lactation when cow’s condition falls to 2-2.5. At day 75 cows should be measured again and condition should be increasing. Between day 190 and 300 cow’s condition should be maintained between 2.5 and 3.
“Feeding correct nutrition and maintaining good rumen health is vital in maintaining cow condition. Rumen acidosis can depress diet and forage plays a major part in preventing acidosis. Except in high-yielding cows, when more than 40% of the ration is concentrate the risk of acidosis is increased,” said Mr Clarke.
Foamy muck was a clear sign of acidosis. Pats should be about 3-4 cm high with some structure and little undigested material, he said. Using gloves and sieving dung would reveal particles not being digested and would allow producers to adjust the diet accordingly for better digestion.