Farm First Newsletter January 2012
ARE COWS THIN BECAUSE THEY ARE LAME, OR LAME BECAUSE THEY ARE THIN?
So which do you think is correct?! A recently reported study by Bicalho and colleagues from Cornell used ultrasound to measure the thickness of the digital cushion, which is the pad of fat between the pedal bone above and the horn of the sole below.
They scanned 500 cows and found at high correlation between
1. the fat pad thickness and the presence of sole ulcers and white line abscesses (thin fat pad gave more disease)
2. fat pad thickness and body condition score – thin cows had thinner fat pads
3. fat pad thickness and stage of lactation. By 120 days the fat pad was at its thinnest (as were most cows) and hoof lameness at its highest.
This does not mean that changes around calving are no longer thought to be important. The poorer suspension (and subsequent increased movement) of the pedal bone inside the hoof just before and just after calving increases the risk of coriosis and this leads to the subsequent production of defective horn. A thinner fat pad exacerbates these effects.
Conclusions – take extra care over the comfort of your cows around calving (and yes, thin cows get more lameness!). We at last seem to be getting away from the obsession by some that lameness is primarily a dietary problem (although it is accepted that acidosis can lead to low biotin and subsequently increased lameness). In fact the authors concluded that diet can at most be only a contributory factor in most herds, although they did acknowledge that high yielding cows would lose more weight, lose more thickness of the fat pad and then develop more lamenesss.
Use of Elastrator Rings in Calves
Recent submissions to AHVLA regional laboratories indicate that the illegal practice of applying rubber elastrator rings to the scrotum, particularly of purchased, entire calves aged over seven days, is occurring. Legislation prohibits the application of a rubber ring or other device to constrict the flow of blood to the scrotum of cattle older than seven days of age. The Veterinary Surgeons Act (1966) allows persons over the age of 18 (17 for supervised animal husbandry students) to carry out castrations on calves less than two months of age using for example a burdizzo. Only a veterinary surgeon can carry out castrations in calves over two months of age and an anaesthetic must be used. In all cases the procedure used must minimise the pain and suffering to the animal, be performed in good hygiene conditions, and in accordance with best practice.
In addition to the practice being illegal, it is likely that the calves which had the elastrator rings applied at greater than seven days of age would have been subjected to prolonged discomfort which would have reduced growth rates, and increased their susceptibility to disease.
New bovine and ovine illness in Germany and Holland
What appears to be a new virus has been discovered in the North Rhein Westphalia district of the west of Germany, and in Holland. It has been named Schmallenberg virus after the small town where it was first discovered.The virus was originally seen in cattle, from August to October, when it caused a moderate fever, with temperatures up to 40 degrees centigrade, inappetance, loss of condition, diarrhoea in some cases, and a drop in milk yield of up to 50%. All the cattle recovered, BUT there is a considerable sting in the tale in that in the last few weeks, many of the affected cattle have either aborted, or had stillborn calves. Typically these calves have limb deformities, stiff limbs, crooked necks, sometimes a twisted spine, or hydrocephalus. Numerous calves born alive to affected cows have failed to live longer than a day or two. They have severe brain damage and appear to be “Dummies”, which are unable to suck.
At the same time, there have been numerous reports of similarly deformed lambs being born, mainly in Holland, again put down to Schmallenberg disease. Research is at a very early stage and the virus has yet to be isolated, but DNA sequencing shows it to be an orthobunyavirus. In Australia, the best known of these viruses is spread by midges, but it is yet to be shown whether this will happen in this case.
If you have any lambs or calves born with these typical deformities, AHVLA are interested in sampling affected animals. Equally, if you're experiencing unusually high levels of abortion in either cattle or sheep please contact us to discuss how we should investigate, for either this or more common causes of the problem.MeetingsFarming Connect are sponsoring a meeting to be held on 19 January at 7:30 pm. Subject of the evening's discussions is “Lameness in sheep, the causes, treatment and prevention”. Please contact us nearer the time for details of the venue.
Anyway hope you all had a good Xmas and wishing you all a prosperous 2012!
