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Making Sure Somatic Cell Count Does Not Rise With Temperatures

06 August 2013

As summer hots up, look at controlling mastitis pathogens by limiting fly populations, using teat sealants and in severe cases, using vaccines, advises Christina Petersson Wolf, Extension Dairy Scientist at Virginia State University.

Although the national limit for bulk tank somatic cell count (SCC) has not been reduced, many cooperatives have already instated lower limits, some as low as 250,000 cells/mL, says Mrs Petersson.

These lower limits put utmost importance on maintaining bulk tank SCC through the hot summer months. It is during these months when the incidence of mastitis and the bulk tank SCC tend to rise–in part, due to additional stressors placed on the cows. 

However, Mrs Petersson writes that there are steps we can take to reduce the impact these summer months have on milk quality. Of paramount importance is maintaining a clean and dry environment for all cows. New mastitis infections predominantly occur in the early dry period, around the time of calving and into early lactation.

For this reason, we cannot forget about dry cow housing or the calving pens. Freestalls should be raked out at each milking, calving pens should be cleaned out between each birth and loose housing should be maintained on a daily basis. Additionally, animals on pasture must be fenced out of bodies of water.

For those producers using sawdust as a bedding material, consider purchasing kiln-dried sawdust and adding hydrated lime as a conditioner.

The general rule of thumb for the application of lime is 2 lbs./stall/day or 2 parts bedding to 1 part lime for loose housing.

Skimping on the application rate can render the conditioner ineffective therefore, it is important to apply in adequate quantity and frequency to maximize effectiveness. Aside from bedding, we also have tools at our disposal that help to improve milk quality.

Fly control will help reduce the spread of certain mastitis pathogens, including Arcanobacterium pyogenes, also known as ‘Summer Mastitis’. This type of mastitis is very difficult, if not impossible, to treat and therefore, much easier to prevent.

Secondly, the use of an internal teat sealant during the dry period has been shown in research studies to reduce new mastitis infections seen at calving.

Although this may not be necessary in all herds, it is something to consider if your herd historically has an environmental mastitis problem at calving. Similarly, the J5 vaccines help to reduce the severity of
clinical coliform mastitis.

The summer months are known to be particularly problematic when it comes to coliform infections. Therefore, some veterinarians have started recommending whole-herd vaccinations prior to the heat of the summer. 

If your herd has had problems in the past with summertime coliform mastitis, discuss this option with your veterinarian. Finally, “know your bug”. It is important to know the pathogens causing mastitis on
your farm.

Routine culturing of all clinical mastitis cases will provide you with the information you need to combat the problem most effectively. Herds with a predominant environmental mastitis problem (coliform, Strep. uberis, for example) will need to focus their preventive efforts differently than a herd with a predominant contagious mastitis problem (Staph. aureus, for example).

The summer months continue to bring about concern related to milk quality. However, in most instances mastitis is easier to prevent than it is to treat. Therefore, our focus needs to turn to the management tools we have at our disposal and maintaining a clean, cool and comfortable environment for our cows.

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