John Harvey's dairy cows face heat stress as main shed at Drum Farm hits 31.5°C

Like the rest of the county, or at least it seemed that way, we also got a good crop of hay which should last us a couple of years! On the cereals front, we combined about 18 acres of winter barley which came it at around 3.2tonnes per acre. Whole crop wheat was pitted a few weeks ago and ran heavy enough to leave us about 35 acres to combine although it’s not quite ripe enough yet to combine.

The downside of course to that heatwave in the middle of July was that the temperature was conducive to the wellbeing of neither man nor beast. We had a peak temperature in the main cow shed of 31.5°C with the THI (temperature-humidity index) reaching just over 80 which is moderate heat stress for cattle. Thankfully though that was only for a very short period of time and most days the temperature in the sheds peaked at nearer 25°C so the cows coped pretty well. And by doing things like, staggering moving them to the collecting yard for milking so that they weren’t congregating in a large group, there was actually very little impact on milk production.

That said, we’ve finally seen our usual summer shift to higher yields at slightly lower milk solids (MS) in the last few weeks with the cows giving over 42.5 litres/day @ 3.88 %BF and 3.35%P which equates to around 3.1kg of MS/day compared to our usual figure of just under 3kg/day.

As I have mentioned previously, we use a combination of sexed Holstein semen and standard Aberdeen Angus semen for inseminating our cows. The idea being that this is the most efficient way as it allows us to produce enough Black and White heifer calves to maintain the herd without having to buy in stock. While minimising the number of Black and White bull calves which have very little value as they are much less efficient at converting feed to beef than their beef brethren.

Now by and large the technology for sexing the bull semen works quite well with the expected industry standard expectation being that it should achieve 90% females, with some companies claiming as good as 97%. So, we were to say the least, disappointed when we checked back on our records and found that in fact we’ve been getting <84% females from the sexed semen over the last year. This means that around a fifth of the male sperm must have still been viable in this sexed semen which really isn’t great.

The big problem here is that there is a lack of transparency, as it’s hard to get any data from the semen companies as to the selective purity of their product. And from buying the semen to being able to see any trends ourselves it is going to take most farmers at least 15 to 24 months to build up enough data. Interestingly, having asked around locally it seems that we’re not the only ones to have seen/perceived this issue with this particular company, although in most cases people are just aware of a surfeit of bulls rather than having hard figures.

So, if you do think you’re experiencing more bulls from sexed semen than you’d expect it is definitely worth going back through your birth records on ScotEID (it’s relatively easy to tease the data apart on the new interface) and get in touch with the semen company if they don’t seem to be meeting the industry standard. And certainly, don’t be fobbed off that it is in isolated case- chances are it’s not! And unless we apply pressure there’s no incentive for them to improve.

And this is actually quite an important issue as increased use of sexed semen (allowing increased use of beef semen) is often touted as one of the ways in which we can reduce the carbon footprint of the dairy industry.

This evening sees the awards presentation and dinner for the South West Scotland Holstein Society Herd Competition. Seems like the field gets bigger every year with a total of 14 herds entered this year. So, I’d just like to wish everyone good luck.