The effect of dietary calcium and phosphorus supplementation in zeolite a treated dry cows on periparturient calcium and phosphorus homeostasis.

Previous studies have proved the possibility of preventing parturient hypocalcaemia by zeolite A supplementation during the dry period, and a recent in vitro study has indicated a marked calcium (Ca) as well as phosphorus (P) binding effect of zeolite A in rumen fluid solutions. Because of the connection between the Ca and P homeostatic systems, the preventive effect against parturient hypocalcaemia may arise from zeolite induced decreased availability of dietary Ca as well as P. In the present study, the expected Ca and P binding capacity was challenged by feeding high and low levels of dietary Ca and/or P to zeolite A treated dry cows. Twenty-one pregnant dry cows were assigned to four experimental groups receiving a dry cow ration unsupplemented or supplemented with extra Ca and/or P. During the last 2 weeks of the dry period all cows additionally received 600 g of zeolite A per day. A high level of dietary P prepartum significantly decreased the plasma Ca concentration before as well as immediately after calving (day 0-3). Conversely, the plasma inorganic phosphate concentration was higher among these cows than among cows receiving no supplemental P. The prepartum dietary Ca level significantly affected the serum 1,25-dihydroxyvitamin D concentration during zeolite supplementation, whereas the periparturient plasma Ca concentration was apparently not affected by the dietary Ca level. During zeolite A supplementation plasma parathyroid hormone was significantly higher among cows receiving additional P. The urinary deoxypyridinoline/creatinine ratio was not affected by the prepartal dietary Ca or P level. Serum aluminium (Al) was significantly higher during zeolite A supplementation than during the preceding period, indicating partial destruction of the zeolite in the intestinal tract with subsequent release and absorption of Al. It is suggested that the effect of prepartum zeolite supplementation on the periparturient Ca homeostasis depends on the level of Ca as well as P in the dry cow ration.

Farmers' choice of medical treatment of mastitis in Danish dairy herds based on qualitative research interviews.

A qualitative research study was conducted to describe and analyze farmers' perspectives on their own choices regarding decisions to have cows treated for mastitis. Through qualitative research interviews of 16 Danish dairy farmers, four levels of the decision-making process used by farmers to decide whether or not to treat a cow with antibiotics were identified. Those levels were: 1) symptom level (seriousness of the mastitis case), 2) cow level (to the extent a cow fulfilled goals of the farmer and the herd), 3) herd level (the situation of the herd, e.g., in relation to milk quota), and 4) level of alternatives (whether the farmer regards such practices as blinding of teats or homoeopathy as serious alternatives to antibiotic treatment). All four levels could be recognized in all herds, but with differing weights and relative importance across herds. Directions of different possibilities within each level also varied among farmers. By identifying those four levels, a model for understanding the farmers' choices is provided. This provides background for dialogue with each farmer about choices in the context of each specific herd. It also provides insight into implications of mastitis treatments for effective treatment versus issues of antibiotic resistance when discussing choices on a more general level. Communication and understanding between farmers and their veterinarians and cattle-oriented advisors is essential. Farmers were shown to be coherent in their choices of treatment, but their decisions often seemed to differ from normal veterinary recommendations. Such differences have to be understood and implemented into effective decisions for the whole farm.