Study Shows Effect of Diseases on Cow Conception Rates
NEW ZEALAND - Bovine viral diarrhoea (BVD) is widespread and Meat Wool New Zealand-funded research shows farmers should expect on average 5 per cent more dry cows at pregnancy testing if it is confirmed.
29 July 2009
2 minute read
While BVD was found in 65 per cent of 94 herds included in Meat & Wool New Zealand’s Beef Fertility project, it had varying effects on fertility. Two of the 94 herds had in-calf rates 15 per cent lower while others had no drop in fertility at all. A 5 per cent drop in fertility was the average. Having a persistently infected animal (i.e. shedding the virus) was linked to lower in-calf rates.
“Farmers should make it a priority to have a plan to reduce the impact of BVD or to protect the herd,” says Meat & Wool New Zealand Farm Services Research Manager Dr Andy Bray. “The project showed that 12 per cent of farmers vaccinated their cattle against BVD.”
The Beef Fertility project, which was carried out by Massey University, also investigated the incidence of leptospirosis and neospora caninum (neosporosis).
Half all the beef herds tested had at least one heifer with antibodies to neosporosis. However, there was no clear link between neosporosis and in-calf rate at pregnancy testing. Despite this, the single-cell parasite disease can cause abortion in mid pregnancy.
Leptospirosis doesn’t hold great risks to cow fertility but two forms of it – Hardjo and Pomona – cause most of the human forms of leptospirosis in New Zealand. These can be transmitted through human/animal contact.
Hardjo was seen in 62 per cent of all herds tested and Pomona was almost half as common (26 per cent). Twenty-five percent of the 568 surveyed beef farmers stated they vaccinated their herds against leptospirosis, but only nine out of the 94 tested herds had been vaccinated against leptospirosis.
None of the above cow diseases are transferable to humans through eating cooked beef.
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