It’s got to that time of year - count down to housing, that’s if you’ve not already brought the cows in, writes Calum Smith. Whilst keeping dry cows out at grass eases the workload, if an effective milk fever prevention plan isn’t in place, then it’s a decision that can prove a very costly mistake.
Clinical milk fever incidence are currently around 10% in UK dairy herds while subclinical cases can affect up to 75% of the herd. Cows suffering from milk fever are up to nine times more likely to suffer from a miscellany of other metabolic disorders.
Why the risk? Grazed grass has many negatives in terms of both chemical and physical properties.
Chemical: fresh grass can contain an over-supply of potassium. Potassium interferes with the cow’s ability to switch on her ‘calcium making’ mechanism; slowing it down when she needs calcium most, at the point of calving. Now some argue that supplying calcium coming up to calving can help, often it can, but results are very variable, the fact is that her requirement for calcium is much higher than any amount supplied through diet. Consequently, feeding calcium runs the risk of slowing down her own calcium making mechanism whilst also leaving her short of supply. A double hit for the cow.
Physical: autumn grass does not promote rumen fill and despite being a natural product, it can slow down rumen function.
So, what is the solution for dry cows towards the end of the grazing season?
Far off dry cows: if you still have any grazing, then intakes need to be controlled in order for cows to maintain condition score 3. Dry cow studies have shown that these cows will over consume energy, often up to and as much as 60% more than requirement.
Typical older pasture will range from 10ME to 11.5ME. An average 680kg Holstein Friesian requires 100MJ to 110MJ of energy; consequently, she can only afford to eat 11kg of dry matter whilst grazing 10ME pasture without supplements. Put the same cow onto 11.5ME grass and her limit is 9.5kg of dry matter. Keeping a high stocking density is crucial, knowing grass cover helps to calculate where you need to be to manage those intakes. Also having straw available helps to create rumen fill and keep the cow full.
Two weeks prior to calving: to achieve a successful transition, take full control and house.
To help the rumen prepare for a successful lactation offer a diet comprising high quality protein – 13% to 15% CP with a starch level no less than half the level fed to the milking cows, or 8% if milk cow diet is unknown. Introduce fibre, preferably chopped wheat straw along with some farm forage.
“Clinical milk fever was hanging over the herd; incidents were running at 30% with the vast majority of incidences found amongst the autumn calvers. Worse still, we were losing cows and also having to deal with too many retained cleansings,” Grant explains. “Despite our best efforts to prevent last year’s extra vet bill, we decided once and for all to get on top of the issue.
“We’ve got the grass up here, and rotational grazing is our preferred and cheapest option, however even towards the end of the grazing season, it’s difficult to control. For the first two thirds of the six-week dry period we graze them on bare fields and then house for the final two weeks in order to maintain body condition score 3.
“During that final two week period, we had fed big bale silage and straw, until last year when Calum Smith advised us to introduce X-Zelit. He explained how the additive forces stimulation of the hormonal system to allow absorption of calcium from body reserves and to mobilise calcium release from the skeleton. When supply stops at calving the hormonal system is primed and ready to absorb calcium and supply the blood with the necessary calcium.
“Cows are subsequently more energetic, have higher feed intakes and are ‘ready to go’. Consequently, they are less likely to fall in to energy deficit. Whilst introducing the additive was another investment decision at £15 per cow or £1,200 for the autumn calvers, it had such a massive impact. The net benefit worked out at over £47,000.” See Table 1. “Milk fever incidents reduced by 100%, retained cleansings by 100%, vulval discharge/metritis by 100%, and we had no vet call outs.”
Furthermore, the additive had an added knock effect on milk yield, up an average two litres per day throughout lactation and it introduced a significant improvement to fertility. “These cows began cycling three weeks earlier enabling us to reduce their average calving interval by 40 days and maintain a tight block calving.”
There’s also unquantifiable savings made on time and hassle, he says. “I’m now able to end the day without worrying about calving cows and confident I won’t have to wake up in the small hours to administer calcium bottles.”
Table 1: Drumore Farm improved physical & financial performance
Article first published by Advanced Nutrition.
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