Maintaining production and Low Somatic Cell Counts During Summer Heat Stress

Maintaining production and Low Somatic Cell Counts During Summer Heat Stress

Heat Stress has the potential to greatly diminish herd performance and profitability. However, the impact of heat stress can be minimized by taking steps to prepare your herd to perform well during the hot summer months. Consider the following areas when making heat abatement preparations:

  1. Cooling Systems: Functional and efficient cooling systems located throughout the facility are essential for minimizing heat stress. Provide adequate shade in areas where cows congregate; Shade must block >80% of the sun and allow for adequate ventilation. Fans should be inspected and cleaned to ensure they are in proper working order.
  2. Overcrowding: Overcrowding of pens during heat stress increases competition for resting areas and bunk space; this increases the incidence of lameness and decreases overall herd productivity.
  3. Ration Factors: Research has shown that exposure to heat stress conditions lowers rumen pH, predisposing the cow to acidosis and claw lesions. It is essential to monitor forage chop length to ensure diets contain adequate amounts of effective fiber. TMRs should be formulated to minimize sorting. Excessive amounts of rumen fermentable carbohydrates should be avoided. Supplementation with trace minerals (zinc, manganese and copper) has been shown to help decrease severity of hoof lesions and help maintain claw integrity and decrease the incidence of lameness during and after periods of heat stress.
  4. Hoof Trimming: Routine hoof trimming is essential for minimizing the incidence of lameness during heat stress. Avoid over trimming, which may result in thin soles and increased lameness. If the sole gives when you push on it with your thumb, the sole is too thin. Overgrown toes should be trimmed to ensure proper weight distribution in the claw, minimizing lameness.



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Ways to Reduce Somatic Cell Counts:

Summer traditionally sees a rise in overall herd SCC in Ontario. With this in mind here are some tips to help you keep your SCC under control:


  1. Keep cows clean and dry at all times. This assures clean teat surfaces and prevents bacteria from entering the teat end.
  2. Do individual cow SCC tests monthly to help identify herd trends and pinpoint the infected cows.
  3. Consider periodically running a bulk tank culture to find out what kinds of bacteria are causing intramammary infections. Consider culturing affected quarters to aid treatment decision making.
  4. If bulk tank culture results show a high level of contagious mastitis pathogens (Staph aureus, Strep ag, mycoplasma) identify infected cows by individual cow culturing. Reduce cow to cow spread and remove the high SCC quarters from the milk supply.
  5. If bulk tank culture results show high levels of environmental pathogens, improve bedding management and pre-milking cow prep. Replace all organic bedding in every stall regularly (weekly) with clean bedding. Every day, replace the bedding in the back half of the stall with fresh, clean bedding. Remove soiled bedding and manure to keep cows clean.
  6. Improve consistency in milking procedures. Include a pre- and post- milking teat dip, 10 to 20 seconds of cleaning, at least 30 seconds of contact time for the teat dip, and a thorough teat end wiping before attaching the milking unit. Plan routine to achieve 90-120 second prep-lag time. Make sure all cows are milked consistently the same.
  7. Include forestrip during cow prep to identify high SCC quarters and keep milk from those quarters out of the bulk tank. CMT testing is a great cow-side way to screen for those high SCC quarters.
  8. Cull chronically high SCC cows that do not respond to therapy.
  9. Treat all quarters of all cows at dry off with an approved dry cow intramammary tube.
  10. Consider using a dry cow teat sealer especially if your herd experiences a high incidence of fresh cow mastitis.
  11. Provide dry cows with adequate space, ventilation and clean bedding. DHI data shows that up to 35% of cows and heifers calve with high SCCs (infected during dry period/close up period).
  12. Keep cows as cool and comfortable as possible during hot weather.
  13. Control Flies.
  14. Maintain milking equipment in good working order. Develop a routine performance check and maintenance program. Replace rubber parts at recommended intervals. Be sure cleaning is done consistently and properly.

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