SPOT-ON FERTILITY PROFILES…
SPOT-ON FERTILITY PROFILES…
Producers involved in dairy
cow fertility research with
Nottingham University are
already seeing benefits.
Jessica Buss reports
MILK progesterone profiles helped one of Nottingham Universitys study farmers achieve a 368-day calving interval despite study requirements to leave some non-cycling cows untreated for at least 80 days when profiles show they are not cycling.
John Lamming has 95 cows averaging 7350 litres at The Grange, Market Rasen. By monitoring progesterone profiles he knows when to watch cows for heat and which cows need vet treatment.
He is also saving on semen and drugs which would otherwise have been used on cows when they were unlikely to conceive. Cows treated by the vet for infertility too early at 50 days after calving often return to service. Waiting an extra 30 days, therefore, doesnt have a detrimental effect on calving interval, he says. And, other cows may be seen and served before 80 days so there are gains from progesterone testing in this way. But he admits the policy would not suit a block calving herd.
Although the herds fertility results look good with the calving interval down 12 days on 1995, a wide range of calving intervals has developed within the herd. Cows that are 40-days calved are served when seen bulling to calve at around 340 days, but there are still difficult cows.
Mr Lamming admits that before the study extra semen, extended calving intervals, and vet treatment were costing in excess of £10,000 a year – that bill has now reduced.
Pregnancy rates have improved with 70% of cows holding to first service and only 1.48 services/pregnancy. In 1995, before the progesterone testing for the current study began, 59% of cows were pregnant to first service and 1.68 services/pregnancy used.
Culling for infertility has also reduced, with only 11 of 22 culls due to sub fertility last year, compared with 19 of 24 culls in 1995.
"Were now in control of fertility. When there is a problem we see it. If not, we dont have to worry. When we identify an infertile cow, we check her history and then decide on the best action."
Mr Lamming was chosen for the study because he reared his own replacements and kept good records, which since 1993 have been computerised.
"With the computer we were beginning to see that daughters of a particular cow have the same infertility problems. One cows daughters all have long inter-service intervals – but the mother is fine. Other families follow patterns regarding fertility treatment. With some families, no matter how hard you try to alter the pattern with drugs, it keeps repeating," he says.
"Cows that come bulling of their own accord are used to breed replacements. Cows with multiple repeats are served with a beef sire. In the past all cows were served to black-and-white sires to build up cow numbers. Now we are more selective and I am confident heifers will be more fertile as less fertile families have not been bred from." He hopes to develop a more fertile herd to minimise having to cull cows and heifers for infertility as has been necessary in the past.
HOW SAMPLES SHOW COWS THAT CYCLE
FOR the study Mr Lamming or his herdsman take milk samples from cows three-times-a-week.
The sampling fits into the milking routine and can be handled with only one person milking. Not all cows need to be sampled but because the herd calves all the year round there are usually some cows less than 80 days calved which need sampling. Milk sampling continues until cows are confirmed pregnant.
Samples are sent to a lab for analysis. Mr Lamming has tried on-farm progesterone test kits. But he says that these all rely on colour change and it is easy to bias results. With lab test the figures are accurate rather than high/low or not sure.
Test results are faxed back and then each cows last three weeks figures are checked. Mr Lamming then goes through his computer records to see which cows are cycling and produces an observation list.
Kamar heat detectors save observation time and there are no special observation periods. Mr Lamming reckons to identify 95% of the bulling cows within five minutes of walking into the field to collect them for milking. But he has learnt that Kamars must be replaced once the colour has changed. This is done as a routine once a week and the AI man takes off the patches when he serves the cows. Cost is about £1/detector, with about three fitted to each cow.
Some cows in the herd are being used in a study to determine if inducing cycling sooner after calving improves conception rate. The study is based on the theory that if a cow has more heat cycles before service she has a higher pregnancy rate. Results so far look good. Mr Lamming has already seen three cows that previously had long inter-service intervals became pregnant sooner this year than last.
John Lamming… convinced of the benefits of milk progesterone testing.
IMPROVING FERTILITY
• Identify heats accurately.
• Vet treatment more successful
after early diagnosis.
• Breed replacements from fertile
cows.