A descriptive epidemiological study of mastitis in 12 Irish dairy herds

: Factors relating to the occurrence of mastitis were studied on 12 Irish dairy herds with histories of elevated somatic cell count (SCC) and/or increased incidence of clinical mastitis cases. Milk recording data were analysed, housing conditions and calving areas were examined; dry cow therapy, clinical mastitis records, milking technique and aspects of milking machine function were assessed.Herds with a ratio of less than 110 cubicles per 100 cows were more likely to experience environmental mastitis. Herds with inadequate calving facilities, where cows spent prolonged periods on straw bedding, were likely to acquire environmental mastitis. In the majority of the herds, the selection of dry cow therapy lacked adequate planning. The majority of farmers took no action to reduce pain experienced by cows suffering mastitis. Deficiencies in parlour hygiene were evident in all herds experiencing elevation in SCC.     

泌乳牛蛋白质利用效率的研究

试验选用日产奶量相近、泌乳60~100d、平均体重650±10kg、3~5胎的中国荷斯坦奶牛76头，应用营养模型对日粮蛋白质利用效率进行分析，探讨限制IDCP利用率的因素。结果表明：①日粮RDP的利用效率67.7%； NY/T34-2004与NRC(2001)估测的IDCP分别为2338.1与2505.4.8g/(头·d)，差异较大的重要原因是，NY/T34-2004是假定所有原料的RUP的消化系数为0.65。这一假定值不适合选用RUP消化率高的原料配合的高产奶牛日粮；②依据NRC(2001)的营养需要模型，试牛IDCP的需要量为2143.8g/(头·d)，而日粮供给的IDCP为2505.4 g/(头·d)，IDCP利用效率只有85.6%。选用乳蛋白质中EAA含量作参照，利用理想蛋白质理论，进一步对IDCP中EAA与蛋氨酸含量分析显示，两者降低了IDCP利用效率的12.3 %。结果提示，对成年泌乳牛，适宜的IDCP中EAA含量应接近乳蛋白质中EAA含量。