Document Type : Research Paper
Authors
1
Department of Animal Science, Agricultural College, Shahrekord University, Sharekord, Iran
2
Department of Animal Science, Agricultural College, Shahrekord University, Sharekord, Iran.
3
Department of Animal Science, Chaharmahal and Bakhtiari Agricultural and Natural Resources Research and Education Center, AREEO, Shahrekord, Iran
Abstract
The purpose of the current study was to investigate the effect of gestation length (GL) on productive performance of dairy cows and the health of Holstein calves. In total, 3,780 Holstein singleton cows (1,994 heifers and 1,786 cows) from two commercial dairy farms were used. The mean of GL for 3,780 cows was 276 ± 5 d, which were classified as short (SGL; more than 1SD less than the population mean, mean = 267, range 258 to 270 d), average (AGL; population mean ± 1SD, mean = 276, range 271 to 281 d), and long (LGL; more than 1SD greater than the population mean, mean = 284, range 282 to 294 d) gestation length. In primiparous cows, milk yield was not different across groups. However, in multiparous cows, the SGL cows had lower milk yield than the AGL cows. In both primiparous and multiparous cows, calf birth weight was lower in SGL group than AGL group, but the LGL group had higher calf birth weight than AGL group. The incidence of pneumonia and diarrhea of calf were not affected by the GL. In general, cows with short GL had lower productive performance and calf birth weight, but the incidence of pneumonia and diarrhea of the calf were similar among groups.
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