Data on the use of breeding records of dairy cattle farm of Fenghuang-shan in Chengdu areas during a period of six years is systematically analyzed. The results show that Holstein heifers have their 1st estrus at an average age of 513.6±46.7 d which is not related to the calving season. Estrus mostly occurs in the months with mild ambient temperature (March, April, May, November and December). ...

four hundered and ninety five (495) smallholder dairy farms active in 52 villages of different cities in chaharmohalo bakhtiari province, keeping 1321 lactating within a total of 2811 mature cows (lactating and dry) were used. these herds were taken during winter 2009 to summer 2010 to assess some of the production, reproductive and economic performance traits under smallholder management syste...

A total of 141 lactation records from 70 F, Friesian d x Bunaji & cattle maintained at the National Veterinary Research Institute's dairy farin, Vom, 1970 - 1975 was utilized. Measurements were made milk production traits economic importance, Average yield 1694 kg in 258 days. Mean 305 day 1896 kg. The third and fourth lactations superior to first second (P <0.05). Differences lengths sm...

Associations between rearing conditions and the risk of culling in dairy cows were studied by survival analysis. Data were collected from 1039 Swedish Red cows, 1029 Swedish Holsteins, and 56 cows of other milk or cross-breeds, representing all female animals born in 109 Swedish herds during 1998. Length of productive life was defined as the number of days from 1st calving to culling. The appli...

The successful genetic selection for higher milk production caused a dramatic decline in the reproductive performance of dairy cows all over the world during the last decades. Achievement of optimum herd reproductive performance (calving interval of 12 or 13 months with the first calf born at 24 months of age) requires concentrated management activities especially during the first 100 days foll...