Why Test for BVDV (Pestivirus) – A Case Study

by Dr Charlie Blackwood BVDV – also  known as Pestivirus – is a complicated disease which has got more publicity in the last few years. The next article gives an outline of the various problems BVDV can cause. In Australia, most dairy farms have BVD at some level and often don’t see severe problems. This is because the virus is circulating through the herd and the losses are often hard to detect. BVD causes the most severe losses when cows or calves have little or no immunity to the virus and then it is introduced. However, even in a herd with reasonable levels of BVD, there can be groups of animals which have little or no immunity. Luckily we can test the milk vat to test the level in the milking herd and if we blood test 6 to 10 young animals we can get an idea of their immunity. Case Study: Farm milks 250 cows with reasonable fertility and no obvious calf problems. To monitor for BVDV we took a sample from the vat and tested for the level of BVDV antibodies. This indicates there was a high level of BVD in the herd even though the effects were not obvious. We will start control in the herd, but the immediate concern was the young stock entering the herd soon. Blood test results from the group of in-calf heifers and from the separate group of 6 month old calves were: Results Despite the reasonably high level of BVD in the herd, the in-calf heifers have almost no immunity to BVD and there is no PI or carrier animal...

Pregnancy loss in dairy cows after day 35 of gestation

by Dr Charlie Blackwood Over the last couple of months, we have undertaken the first round of pregnancy testing to detect cows in calf to AI in many of our clients’ herds. In the next couple of months, we will do the second-round tests to detect bull matings in these herds. One of the frustrating aspects of the modern dairy cow is the loss of pregnancies after they have been confirmed pregnant. Across the world, the proportion of cows identified as early pregnant, who then fail to calve or calve to a later conception date is increasing. It is a trend we have noticed in the herds we service. At a recent seminar organised by the InCalf team at Dairy Australia, a presentation was given by Dr Richard Shephard on pregnancy losses after confirmed diagnosis in four Gippsland dairy herds. A total of 1756 cows were available for analysis. All herds were owned by a single owner and management across the herds was very similar. The study was done in 2015. Of 1149 cows confirmed pregnant following a spring mating program, there were 90 pregnancy losses between day 35 and 140 of pregnancy. This equates to a loss of 7.8% of pregnancies! Two factors were significantly associated with pregnancy loss: Milk production in litres – cows producing 30 litres of milk at peak lactation had the lowest loss of pregnancy. Cows producing both more, and less than 30 litres had greater losses of pregnancy than cows producing 30 litres. The risk was higher the further away from 30 litres a cow’s production was. Clinical mastitis – cows with clinical...

Keeping everyone safe on farm

by Jason Chuck, Practice Manager The tragic recent news of two experienced stock agents being killed while working cattle should serve as a warning to all people involved in the livestock industries. It is a confronting reminder of the unpredictability and danger associated with working with large animals in confined spaces, and highlights the risks that even experience and good cattle handling facilities cannot completely mitigate. According to WorkSafe, twenty seven Victorians lost their lives in workplace accidents in 2017, and fourteen of these fatalities occurred on farms. These accidents often occur while doing routine tasks that the victims have done countless times before, and according to Adam Watson, head of operations and emergency management at WorkSafe, they often occur due to a failure to properly identify and manage workplace hazards. Cows and bulls are the second-most likely causes of animal-related deaths of people in Australia. Falls from horses are the most common animal-related deaths for people, with dog-related deaths third, according to National Coronial Information System data. (The Age, 4th January 2018) There are numerous resources online to support farm owners and managers in identifying safety hazards on farm, and managing the likelihood and severity of these risks. General principles to follow include: Identify hazards on your farm. This is best done in consultation with staff and contractors who regularly work on site, and needs to be an ongoing process. Set up a method for those who work on your farm to report hazards as they are discovered, such as ineffective or broken equipment, live exposed electrical wires or dangerous animals. Assess the risk for each hazard. A...

Bovine Pestivirus (BVDV) and mucosal disease in cattle

by Dr Charlie Blackwood Bovine pestivirus and Bovine Viral Diarrhoea (BVDV) are the same disease – different people call it different things. We will call it BVDV in this article. BVDV is one of the most complicated cattle diseases we deal with. Don’t worry if you need to ask or read articles a few times to understand the disease. We often do as well. BVDV can be a serious threat to dairy farm production and profitability. This article, some of which comes from the Western Australian Department of Agriculture, explains the effect of BVDV on different groups of animals. Table 1: What immunity status definitions mean Naïve Never infected Cattle that have never been infected or challenged by BVDV. They have no antibodies to the virus. Immune Have been infected but are not carriers Cattle that have been infected with BVDV but are not carriers. They have antibodies and are immune to future infections. There are two ways this immunity can occur: infection as BVDV circulates through the herd – immunity is lifelong (‘natural immunity’) vaccination – annual boosters needed to maintain immunity. Persistently Infected (PI) Carriers Carriers of BVDV secrete the virus for their entire life. They exhibit variable signs and degree of disease and most die 1–2 years after birth. The calf of a persistently infected heifer or cow will also be persistently infected. Persistently infected bulls are also potent spreaders of BVDV. What happens when BVDV occurs? The effect of BVDV depends on whether it occurs in unborn calves, pregnant cows, feedlot or other cattle. Unborn calves Most of the harm done by BVDV is to...

Watch out for grass seeds!

By Dr Mark Lewis BVSc In the spring and summer months we often have dogs presented to us with problems caused by grass seeds. Just one of these simple and apparently harmless seeds can in fact cause severe health problems and in the country our pets come into contact with millions of them each spring and summer! The shape of grass seeds means that they move forwards and a grass seed left embedded in the coat will quite quickly penetrate through the skin. Once the grass seed has pushed through the skin it will track its’ way along through the body causing infection and tissue trauma. After playing in the grass dogs will often have grass seeds lodged in their coats, the most common place for grass seeds to lodge is between the toes on the paws but they can also lodge in other areas. It is very important to check your dog all over, with special attention to the area between the toes after he or she has been walking through long grass. If a grass seed enters the paw it will then move up the leg causing swelling and lameness. The other common place for grass seeds to cause problems is in the ear shown in the photograph on the left. If a seed lodges in the hair near the ear canal it will move down the actual ear canal until it reaches the eardrum. If the grass seed is left in the ear too long it will then rupture the eardrum and enter the middle ear. At this stage there is often irreversible damage. When a...

MOvember at Warrnambool Veterinary

MOvember is here! The men of Warrnambool Veterinary have teamed up with the Movember Foundation to change the face of men’s health! Movember is a fun initiative that supports men’s health. The program began in 2003 with 30 people taking part in a pub in Melbourne to over 5 million now. Countries involved span the globe including Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Finland, France, Hong Kong, Germany, Ireland, Netherlands, New Zealand, Norway, Singapore, South Africa, Spain, Sweden, Switzerland, UK and USA. Over 1200 men’s health projects have been funded since its inception and we would like to be active and be part of Movember in 2017. These gents will each grow a moustache during the month of November to raise funds and awareness for men’s health—specifically testicular cancer, prostate cancer, mental health, and suicide prevention. Here they’ve started with a clean shave, and “mo” updates will be posted throughout the month. To learn more about the Movember Foundation and to support the WVC team, go...