July 2010 edition
Getting the best mastitis control at calving
The period around calving (two weeks before calving until two weeks after calving) is often the highest risk period for mastitis infections to occur. This period can be critical in determining the infection status of both the individual cow and the herd for the rest of the lactation. Milk quality for the whole season may depend on the success of mastitis control at calving.
Thus there are huge potential gains for farmers by preventing new infections in the calving period. Many of these infections can be prevented by implementing some relatively simple management changes. These management changes have proven to be very effective on many farms – and the real positive is that many of the changes cost very little or nothing at all.
Evidence from around the country is showing that Strep uberis is rapidly becoming one of the most common mastitis infections and it is almost certainly the most common infection around calving, so this article has particular relevance to herds wanting to control Strep uberis mastitis.
How can I get a clean dry calving area?
“If you have to look where you are putting your feet to avoid walking on cow pats, it’s too dirty for calving.”
Given that environmental bacteria (especially Strep uberis) are usually the most frequent mastitis infections around calving; the ideal place for cows to calve is a clean, sheltered, dry area, with very little faecal contamination. This can often be difficult to achieve as the choice of calving area is further complicated by the need to choose a calving paddock or calving pad where the cows can be easily supervised.
The best option for mastitis control is a clean grassed area with no surface water, however this has the added risk of potentially increasing the incidence of metabolic diseases such as milk fever – it is important to have other milk fever prevention strategies in place for cows that are calving in paddocks on grass.
The ideal calving paddock should have a good cover of grass and not been irrigated or contaminated with milking shed or feed pad effluent. This can continue to provide a clean environment if the paddock is large enough so that grass cover is maintained and faecal contamination is minimal. It is common for small areas, which perhaps provide shelter, to become overused and boggy – and wherever cows gather, so does their faecal output.
The only practical solution is to fence off such areas until they regenerate. If electric fences are shifted across a paddock at regular intervals, clean areas can be provided for new batches of calving cows. It is important to avoid ‘back-grazing’, where cows have access to recently contaminated areas in addition to their new area.
Calving pads can be a successful alternative for wet conditions. Drainage is probably the most important factor and can be supplied by providing sufficient fall on the pad, or by installing underground slotted PVC pipe drainage. However, many calving pads, especially those with poor drainage, quickly build up high levels of contamination and mastitis becomes a problem. If this is likely to be the case, then options include either limiting the number of cows on the pad, or limiting their time on the pad by only using the pad strategically during very wet periods.
A practical guide for assessing how clean and dry an area for calving is that no more than two pats of manure are present per square metre and no water is visible in foot prints. Faecal contamination from cow manure is the most common source of Strep uberis infection, so avoiding a build up of contamination can be critical in preventing infection.