Vet viewpoint: Late-cut silage causing health problems in dairy cows

Dominic Alexander, Belmont Vets, Herefordshire

We ran a recent farmer workshop on “Safe and Effective use of Medicines” and some key points came out of the meeting. Using the correct drug for the specific condition at the correct time will not only lead to more effective treatment, but is less expensive, too. It came as a surprise to some that when they thought they had changed their wormer, all they had done, in fact, was change the brand name, as the active drug was the same as their old brand.

See also last month’s Vet Watch

When vaccinating your sheep or cattle, we recommend using the Sterimatic sterilising system. Some say they are unable to use them, but once you’ve mastered the slightly different technique, you will be hooked. Shearers tell us they see fewer abscesses on ewes where farms use Sterimatic.

Jonathan Stockton, Kingsway Vets, Skipton

As stocks of first- and second-cut silage have started to run out on many farms, the introduction of third and even fourth cut has provided many farmers with a challenge. This appears to be due to unusually high pHs and low dry matters in the preserved feed, leading to instability, secondary fermentation and high ammonia. This results in poorer intakes with the resultant milk drop and increase in problems in the milking portion of the herd.

Repeat analysis of remaining stocks of grass silage should be undertaken and adjustments made in the constituents of the diet to keep crude fibre levels and energy up and crude protein levels down.

Ian Gill, Thrums Vet Group, Kirriemuir

In January, Scotland entered phase three of its BVD eradication scheme. This will require continued mandatory annual screening and some restrictions on sale and movement. During the past 12 months, our practice has screened almost 100 herds and only six have showed exposure to BVD. In those herds showing positive antibodies in their calves, we carry out further screening to identify any persistently infected (PI) animals. Four herds have gone on to use tissue ear tagging at birth to allow identification and removal of PIs as soon as possible.

Eradicating BVD virus, which lowers an animal’s immunity to diseases such as scour and pneumonia, is one cost-effective way of reducing antibiotic resistance.

Steve Trickey, Chapelfield Vets, Norfolk

We’ve seen a rise in cases of calf scours, both in dairy and beef calves. Testing to find out the cause is important .

The most important factors in trying to prevent calf scours is ensuring adequate colostrum intake quickly enough, and hygiene, keeping the calf environment as clean as possible. Blood testing calves less than a week old gives an indication of whether they are getting enough from the colostrum.

Fluid therapy is vital in the treatment of scours as calves die from dehydration, and correcting the fluid loss is vital. Oral fluids with electrolytes if given before calves are too dehydrated should be enough, but if calves become weak and hypothermic, intravenous fluids are often required.