Milk recording may be nothing new, but interpreting records correctly can maximise their value and improve herd health and fertility.
With this in mind, Sotirios Karvountzis, vet at XLVet practice Shepton Vet Group, has developed Milk Alert, a monthly report available to clients, aimed at summarising and highlighting potential problems linked to yield, quality, SCC and fertility data.
Such a strategy proved invaluable for dairy farmer Alex Green, who farms 130 Jerseys, calving all year round at Mill House Farm, Chesterblade, Somerset.
|Vet Sotirios Karvountzis says milk records can act as an early warning system to potential problems.|
Monitoring the number of PD+ cows rather than calving interval, allows fertility problems to be identified earlier, says Mr Karvountzis. “With calving interval there is a several month lag before issues are seen. Simply looking at the numbers of cows in calf acts as an early warning system.”
Records showed cows were expressing heats at normal intervals, with just 15% cycling irregularly. The disease status of the herd was also good. “BVD and leptospirosis can cause problems with re-absorption and abortion. This herd has been involved in a regular BVD testing programme which has failed to identify any problems, so disease can be eliminated.”
Bulk milk quality levels identified the origin of the problem. Milk protein in July and August showed a drop to 3.12% and 3.51% respectively for cows up to 100 days post calving.
“Freshly calved cows are the most vulnerable to dietary changes and so give a good indication of any problems,” explains Mr Karvountzis. “This drop in protein indicated lack of energy in the diet, which was showing itself two months later in reduced fertility.”
The problem was exasperated by a continuing increase in yield over the year. “Yield has never been a problem, with average yield increasing from 15.76 litres/cow/day in April 2008 to 17.98 litres in December and 20.80 litres/cow/day in April this year.
“However, energy supplied via the ration had not increased to match this demand resulting in a reduction in fertility and body condition,” Mr Karvountzis continues.
In response to these findings and after discussion with consultant, James Shenton from The Farm Consultancy Group, some key changes were made to the diet.
“By simplifying the diet and improving access to out-of-parlour feed, intakes significantly improved from 14.5kg DM/day to 15.5kg DM/day,” explains Mr Shenton.
“Protected fats were also taken out of the diet and the ration was balanced with better use of home grown forages – essentially we lowered the overall protein level, but increased the energy level of the ration and improved intakes.”
On Mr Karvountzis’s recommendations, Mr Green also introduced a teaser bull to allow easier identification of heats. “We introduced an Angus cross Friesian bull into theherd. The Angus stood out against the colour of the herd making spotting cows in heat a lot easier.”
There are a number of factors to consider when choosing a teaser bull, says Mr Karvountzis. “Angus or Hereford cross is a good choice due to their calm temperament.
“Age is also important. When a bull is too young he is difficult to vasectomise and an older bull may not last as long.”
Overfeeding is often a problem with teaser bulls. “When a bull is kept in with the cows it is easy for him to get fat feeding on the milking ration. This will ultimately cause health problems and affect lifespan – when this is a problem, separate him from cows at feeding.”
Since making these nutritional changes and introducing the bull, Mr Green has seen marked improvements. “Heats are more visible and more sustained since increasing the volume and quality of the ration and the number of PD+ cows has markedly improved to 84 cows (65%) in April this year,” he says.