Samples of raw milk from bulk cooling tanks were collected in five municipalities of the Southwestern Brazilian Amazon to establish the prevalence of Staphylococcus aueus and Streptococcus agalactiae, as well as to ev...Samples of raw milk from bulk cooling tanks were collected in five municipalities of the Southwestern Brazilian Amazon to establish the prevalence of Staphylococcus aueus and Streptococcus agalactiae, as well as to evaluate the milk composition and its correlation with the bulk tank somatic cell count (BTSCC). A total of 250 samples were collected to investigate the causal agents of bovine mastitis in whole milk, from 50 bulk milk tanks in each municipality. Under laboratory conditions, the samples were diluted to 1/10 and 1/100, and samples of 0.1 ml from each dilution were plated in triplicate on selective media for Staphylococcus aureus and Streptococcus agalactiae. To evaluate the correlation between the major milk components (fat, protein and lactose) and the BTSCC, samples were collected for 18 months from 73 dairy herds. The presence of the above-mentioned contagious mastitis pathogens was detected in 97.2% (243/250) of refrigerated raw milk samples evaluated. Analysis of the major milk components and BTSCC demonstrated that during the study period, fat compo-nent showed the largest variance, followed by protein and lactose, which also showed significant variances.展开更多
本研究旨在探究北京地区中国荷斯坦牛干奶期长度(DPL)的变化规律及其变异对奶牛各项生产性能的影响,包括产奶性能、繁殖性能、初乳品质和乳房健康。收集了北京地区34个牧场出生于2009—2018年136231头中国荷斯坦牛的干奶日期、生产性能...本研究旨在探究北京地区中国荷斯坦牛干奶期长度(DPL)的变化规律及其变异对奶牛各项生产性能的影响,包括产奶性能、繁殖性能、初乳品质和乳房健康。收集了北京地区34个牧场出生于2009—2018年136231头中国荷斯坦牛的干奶日期、生产性能记录、繁殖性能记录等。通过整理试验牛群的干奶记录,揭示了北京地区中国荷斯坦牛1胎和2胎DPL的群体规律,利用固定模型分析了胎次、产犊季节、场-产犊年和初产月龄对DPL的影响;此外,利用固定模型分析了DPL的变异对日产奶量、乳脂率、乳蛋白率、首末次配种间隔(interval from first to last insemination,IFL)、产犊至首次配种间隔(interval from calving to first insemination,ICF)和初乳品质的影响,利用Logistic回归过程分析了DPL的变异对首次配种受胎率(conception rate of first insemination,CR)、首次配种56 d不返情率(56-days non-return rate of first insemination,NRR56)、难产率和乳房健康的影响。研究结果显示,北京地区中国荷斯坦牛DPL平均为58.81 d,胎次、产犊季节、场-产犊年和初产月龄均对DPL有显著影响(P<0.05)。DPL的变异对日产奶量、乳蛋白率、ICF、CR、NRR56、难产率和乳房健康有显著影响(P<0.05)。干奶期短的奶牛测定日平均乳蛋白率、CR和NRR56更高;DPL适中的奶牛测定日平均产奶量更高、乳房健康水平更好、ICF更短、难产率更低。本研究在国内利用大规模牛群数据揭示了中国荷斯坦牛DPL的群体规律,可为中国规模化奶牛场提升管理水平提供参考。展开更多
文摘Samples of raw milk from bulk cooling tanks were collected in five municipalities of the Southwestern Brazilian Amazon to establish the prevalence of Staphylococcus aueus and Streptococcus agalactiae, as well as to evaluate the milk composition and its correlation with the bulk tank somatic cell count (BTSCC). A total of 250 samples were collected to investigate the causal agents of bovine mastitis in whole milk, from 50 bulk milk tanks in each municipality. Under laboratory conditions, the samples were diluted to 1/10 and 1/100, and samples of 0.1 ml from each dilution were plated in triplicate on selective media for Staphylococcus aureus and Streptococcus agalactiae. To evaluate the correlation between the major milk components (fat, protein and lactose) and the BTSCC, samples were collected for 18 months from 73 dairy herds. The presence of the above-mentioned contagious mastitis pathogens was detected in 97.2% (243/250) of refrigerated raw milk samples evaluated. Analysis of the major milk components and BTSCC demonstrated that during the study period, fat compo-nent showed the largest variance, followed by protein and lactose, which also showed significant variances.
文摘本研究旨在探究北京地区中国荷斯坦牛干奶期长度(DPL)的变化规律及其变异对奶牛各项生产性能的影响,包括产奶性能、繁殖性能、初乳品质和乳房健康。收集了北京地区34个牧场出生于2009—2018年136231头中国荷斯坦牛的干奶日期、生产性能记录、繁殖性能记录等。通过整理试验牛群的干奶记录,揭示了北京地区中国荷斯坦牛1胎和2胎DPL的群体规律,利用固定模型分析了胎次、产犊季节、场-产犊年和初产月龄对DPL的影响;此外,利用固定模型分析了DPL的变异对日产奶量、乳脂率、乳蛋白率、首末次配种间隔(interval from first to last insemination,IFL)、产犊至首次配种间隔(interval from calving to first insemination,ICF)和初乳品质的影响,利用Logistic回归过程分析了DPL的变异对首次配种受胎率(conception rate of first insemination,CR)、首次配种56 d不返情率(56-days non-return rate of first insemination,NRR56)、难产率和乳房健康的影响。研究结果显示,北京地区中国荷斯坦牛DPL平均为58.81 d,胎次、产犊季节、场-产犊年和初产月龄均对DPL有显著影响(P<0.05)。DPL的变异对日产奶量、乳蛋白率、ICF、CR、NRR56、难产率和乳房健康有显著影响(P<0.05)。干奶期短的奶牛测定日平均乳蛋白率、CR和NRR56更高;DPL适中的奶牛测定日平均产奶量更高、乳房健康水平更好、ICF更短、难产率更低。本研究在国内利用大规模牛群数据揭示了中国荷斯坦牛DPL的群体规律,可为中国规模化奶牛场提升管理水平提供参考。
