NOT ‘cow’vid-19, not even infectious, but would you protect new calvers?

If a new viral disease at calving was found in 59% of cows, and 54% of heifers, associated with massively higher incidence of ketosis, metritis, displaced abomasum and premature culling, how many readers would vaccinate against it?

This make-believe infection, but very real condition in very many herds, is unseen/unknown calcium deficiency (not clinical milk fever). It is the subject of a new study of 407 cows and heifers, reported in January by the prestigious peer-reviewed Journal of Dairy Science (JDS).

In the first 60-days post-calving, 59% of cows with sub-normal blood calcium had nearly double the combined incidence of ketosis, metritis, displaced abomasum and premature culling compared with normal herd mates. Of course, all these conditions can lead to higher culling rates, though farmers may not realise they started with subclinical hypocalcaemia at calving. More details are available in the table and readers do not need an ‘expert’ to spell out here the losses arising from these conditions.

Click image to enlarge

For sub-normal first calved heifers, not normally associated with low calcium status, ketosis and metritis were more than three-times higher than in those with normal calcium status.

So what to do about this? Vet Dr Elizabeth Berry from Animax says farmers could ask their vet to take blood samples for analysis, then act on the results. “But would this be quick enough?” she asks. “And at what cost? It’s certainly worth asking.

“Of course, the relationship reported in the JDS paper between adverse events and calcium is association, not necessarily causation. So any preventive measures will probably not eliminate 100% of the gap between cows or heifers with normal and sub-normal calcium status.

“But it is a reasonable hypothesis – backed up by farmers’ experiences – that an effective calcium supplement at calving can close the gap.”

Such is the high cost of any one of these events that preventing some of them will generate a healthy financial return. Indeed, the JDS paper says that temporary sub-clinical calcium deficiency just after calving causes at least double the financial losses of long term debilitation or fatalities of downer cows caused by clinical milk fever.

It is for this purpose that Animax developed Easycal, an oral drench containing 65mg of available calcium. It comes in a 185ml (⅓rd pint) plastic bottle with tube applicator. Given just before or after calving, the calcium is absorbed over 12-15 hours to coincide with a natural dip in blood calcium caused by the onset of lactation. Cost is less than £10/cow.

Dr Berry explains that the impact of this post-calving dip is due to calcium’s role in muscle and nervous functions.

“Even a sub-clinical deficiency weakens muscle tone and strength, which are so critical at and just after calving. In addition to a quick and safe, unassisted birth for calves, peak muscle performance is essential to gut function along its entire length.

“Any shortcomings are highly likely to reduce feed intakes, probably explaining exaggerated ketosis incidence in cows and heifers with sub-normal calcium. Following a ketosis episode, of course, many animals never reach their potential for that entire lactation.”

Among Robert Hunter’s Jersey herd in Lanarkshire was a sixth calver that had given a 9,000 litre fifth lactation. Jerseys in general and older cows are much more prone to sub-normal calcium that other breeds and younger individuals. Instead of the emergency intravenous bottle of calcium that was required at all five previous calvings, Mr Hunter says a healthy calf and untroubled mother were the outcome following a bottle of Easycal as she got started, then a second bottle 12 hours later for good measure – bearing in mind the cow’s known history – that same evening.

Farmers can get more information from Animax livestock specialists here.