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Physiological and Environmental Influences on Milk Composition and Host Response to Stress

Kensinger, Ronald
Pennsylvania State University
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  1. To quantify the levels of sterols such as estrone, estrone-sulfate and other conjugated forms of estrogen in the milk of dairy cows.
  2. To quantify levels of haptoglobin, an acute phase protein, and casein degradation in the milk of cows that have spontaneous bouts of clinical mastitis.
  3. To determine the value of various drugs used for dehorning dairy calves, while measuring calf growth performance and the inflammatory response, while also recording health data.
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Non-Technical Summary: Some authors have claimed that estrogens in milk are causing cancer and obesity, even though the evidence is weak. Mastitis leads to inflammation in the cow and reduces the quality of milk. Thus, this is an animal health and welfare issue as well as an economic problem. The public is concerned about the welfare of calves and other dairy animals, but little research has quantified the value of certain drugs that may be used in the dehorning process. The purpose of the proposed research is to: 1. Determine actual concentrations of estrone and estrone-sulfate in milk samples of dairy cows in various productive and reproductive states. 2. Will demonstrate a mechanism for mastitis to reduce milk quality, and also determine whether haptoglobin is a consistent response of the cow to intramammary infection. 3. Will determine if sedative, anesthesia and anti-inflammatory drugs in dehorning will improve growth rate, health and signs of inflammatin in calves.

Approach: Milk samples and potentially other processed dairy products will be analyzed for estrone and estrone-sulfate in milk, as some medical scientists have claimed that estrogens in milk are causing health problems. Milk fractionation will occur using solvent extraction, precipitation, enzymatic deconjugation followed by radioimmunoassay. For second objective studies, milk samples will be collected from spontaneously infected cows along with healthy quarter milk samples for analysis of casein structure (by SDS-PAGE) as well as concentrations of haptoglobin, an acute phase protein in milk. Third objective studies will use milk-fed calves to determine the value of use of sedative, anesthetic and anti-inflammatory drugs in the process of dehorning calves. Calf growth rate, health status and plasma levels of haptoglobin will be quantified to assess treatments imposed.

Funding Source
Nat'l. Inst. of Food and Agriculture
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Antimicrobial Resistance