In northern NSW its been a pretty mild winter. I've noticed plenty of growth in paddocks as I've been out and about. I've also seen plenty of new calves. I haven't talked to many people about the calving rates just yet, but every year there are always a few disappointments following calving.
Calving losses can be caused by a number of things. These range from physical difficulties in calving such as breech birth. Large, heavy calves often cause losses. Big calves can be the result of the nutrition offered to cows before calving, or from the choice of the bull. Often these two factors are the biggest causes of calving difficulty.
Losses at calving are an issue. However there can be other reasons for low numbers of calves born each year. One of the big causes isn't always easy to observe.
Leptospirosis is a bacteria which infects cattle causing abortions, and in some cases will also reduce the level of milk production in females.
The abortions caused by Leptospirosis often occur after 5 months of pregnancy. If you have pregnancy tested your females earlier than this, losses from Lepto won't be picked up until calving time.
Leptospirosis can effect all livestock as well as feral animals including pigs and native mammals. The real risk with Lepto is it can also effect humans, and cause real health problems (http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0014/110084/leptospirosis-in-cattle-herds.pdf).
The disease is spread through animals shedding bacteria in their urine, or in fluids at birth or abortion. The bacteria can survive in the environment, particularly in mud, damp soil and water. Cattle can ingest the bacteria from any of these sources.
So how widespread is Leptospirosis? Its a very common disease, but getting some numbers on the levels of infection has been a challenge. Last week I saw some figures from a study conducted by Jillian Kelly, the District Vet with the Central West LHPA. This study was done with unvaccinated cattle herds in the Central West.
The study found 16% of feral pigs on farms were likely to be shedding the bacteria. The study also found 22% of mobs of pigs (more than 5 pigs) had an active shedder.
In cattle, the study found 25% of the herds were infected with the Pomona strain of Lepto, and 38% with the Hardjo strain.
I've no doubt there is plenty more to learn from this study.
I reckon what we have learnt is that Lepto is an issue which is bigger than many people recognise. The Hardjo strain is responsible for "abortion storms" and if this occurs after pregnancy testing, then the losses won't be picked up until calving, and can cause huge impacts on the profitability of the enterprise.
I'm also very conscious of the need to protect yourself, your family and your staff from the risks of this disease. I've spoken to people who have had Leptospirosis and the stories of their illnesses are really distressing. I reckon when you know you can prevent something from occurring for human health reasons, let alone for productivity reasons, you'd be mad not to have a prevention plan in place.
Leptospirosis can be prevented through good vaccination programs. I reckon vaccination is essential. When you get this in place, then you can start to address other issues, like your feral pig population! If you want some advice in putting a vaccination program together, don't hesitate to give me a call and we can work out the best program for your situation.