Fertility is a significant driver for herd profitability for Jim Boyd, who manages the 260-cow East Kilbride-based Lettrickhills pedigree Holstein herd.

“We are running a high input, high output all-year-round calving herd averaging 11,800 litres milking through a robotic system and achieving 3.1 visits a day,” he explainED.

“Calving Index has fallen in the last five years from 410 days to a current average 394 days, however since every open day per cow is a big cost, we are targeting 385 to 390 days and using various measures to get there from a simple milk test to selecting sires for high fertility traits.

“We have a strict fertility policy. We start serving after 48 days and I would rather wait for up to 90 days after calving for a natural heat before intervention, as I believe these are more fertile heats.

"That means 80% of cows we wish to breed from get two services of sexed Holstein semen before they go to beef and if they don’t hold to either dairy or beef, then after 200 days they are classed as infertile,” he said.

He added that since introducing IDEXX’s pregnancy associated glycoprotein (PAG) 35 days after service, it has had a significant role in reducing CI to its current level. PAG is a simple milk test that helps to identify which cows are open and need to be served again. It is better to know sooner rather than later when a cow is in calf, he argued.

“We used to routinely PD every served animal, however I felt the more money we spent on fertility checks, the fewer cows we seemed to get in calf. These checks were being made at a time when it’s easy to upset a pregnancy whilst it is in the early stages of gestation and still very fragile."

In contrast, the PAG test is totally non-invasive. It’s time saving, labour saving and hassle free. The robotic milking system has introduced a calmness across the herd, and as a result, Jim does not like to disturb the cows more than he has to.

Also, with fewer staff on the farm and time pulled in a lot of different directions, he added that separating 25 to 30 cows each month in their set up could be stressful. Now, when the vet arrives, he only has to look at a handful of cows and usually those with silent heats, which in turn improves the overall welfare of the herd.

Jim said the logistics were simple. PAG is routinely carried out at Lettrickhills on a monthly basis at the time of CIS recording. Cows and heifers eligible for the milk test are cross checked with the milk recorder and marked on the computer system to be tested when the milk recorded sample reaches the lab for analysis.

He receives a text message from CIS when the results are ready for log in. Turnaround time is within three days.

“The milk test has consistently proved to be 98% to 99% accurate for both positive and negative tested cows. Some 3% to 4% fall in to the recheck bracket and usually result in 80% to 85% being in calf. They are automatically retested at the next recording free of charge, however I do get them checked as part of the vet’s routine visit,” he said.

Lettrickhills' daily routine includes checking the heat detection collars which Jim said offered accuracy. Genus AI makes a daily visit and Jim complemented the service , though he AIs cows and heifers himself to optimise ideal service time. Jim is also selecting Holstein sires for high fertility – a trait which he has come to conclude is ‘quite accurate’.

“Maintaining high herd health and welfare, including feeding to yield to maintain body condition score between two and three throughout lactation helps to minimise the challenge of metabolic disorders, as well as mastitis and feet problems, and in turn reduce stress which I believe can impact on fertility,” he said.

“Putting to good use other modern management tools, including PAG in the routine will equally help us reach our CI goals.”

PAG pregnancy checker

· Simple milk pregnancy test measures pregnancy associated glycoproteins (PAGs).

· PAGs are produced by the placenta once pregnancy is established

· Milk samples can be tested from 28 days post-insemination to find non-pregnant cows, and throughout gestation to confirm pregnancy status

· Some15% to 20% of cows may lose a pregnancy from 28 days after breeding

· Reliable pregnancy confirmation in at least 98.7% of cows

· Results are sent from the milk recording organisation either via email, text message or online

· Available from CIS, NMR and QMMS