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Tina Horn
Extension Agent, Augusta County
(540) 245-5750; tihorn@vt.edu
As you look out over your heifer crop with great anticipation, do you ever stop to wonder: How many of these future herd replacements are harboring an intramammary infection? How will these heifers affect my somatic cell count and the udder health of my current milking herd? How many will freshen with mastitis or a blind quarter? Recent research has shown that anywhere from 8 to 90 percent of all heifers harbor some type of intramammary infection prior to calving. The prevalence of those intramammary infections is related to issues such as overall herd infection status, housing conditions, fly control programs, climate, and time of year.
The economic losses due to mastitis and high cell counts are well documented but may actually be higher in heifers than in older cows. If the infection occurs while the mammary gland is still developing extensive damage can be done to developing secretory tissue, resulting in her never being able to meet her genetic potential. Losing a first calf heifer, having a heifer lose a quarter or develop a light quarter, or just a reduction in her potential for milk production at this point in her productive life is a major loss because all the rearing costs have been invested with no returns or reduced returns on the investments made.
So how do we reduce the risk of this happening? Developing a heifer mastitis prevention plan is critical. The plan must include diligent management and early detections in all ages of heifers from birth to calving. Start by segregating cows from calves which will reduce the chance of passing mastitis causing pathogens by the suckling of dirty udders or infected cows. Colostrum or waste milk from infected cows or cows with unknown status should not be fed to calves. If feeding whole raw milk to heifer calves consider pasteurization. Remember that feeding pooled milk increases your biosecurity risks, and that the pooled milk may increase the spread of Johne’s in your herd as well. Take measures to reduce the chance that calves with suckle one another.
For heifers of all ages, provide a clean, dry environment. It has been well documented that flies can contribute greatly to spread of intramammary infections so an effective fly control program is essential. This program should include routine maintenance in housing and feeding areas to reduce the build-up of manure and spoiled feed which are excellent breeding grounds for flies. Fly control products such as pour-on insecticides, sprays, and ear tags are also effective if managed properly and applied on a timely basis. Vaccination programs and antibiotic treatments have also proven to be a useful tool in preventing or managing intramammary infections in heifers.