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|Title: ||Trends in milk production, calving rate and survival of cows in 14 Irish dairy herds as a result of the introgression of Holstein-Friesian genes|
|Authors: ||Evans, Ross D|
Berry, Donagh P.
Garrick, D. J.
|Issue Date: ||Aug-2006|
|Publisher: ||Cambridge University Press|
|Citation: ||R. D. Evans, P. Dillon, F. Buckley, D. P. Berry, M. Wallace, V. Ducrocq and D. J. Garrick (2006). Trends in milk production, calving rate and survival of cows in 14 Irish dairy herds as a result of the introgression of Holstein-Friesian genes. Animal Science, 82, pp 423-433. doi:10.1079/ASC200660.|
|Series/Report no.: ||Animal Science;vol 82|
|Abstract: ||Trends in milk production, calving rates, and survival were monitored on a potential 5580 primiparous and multiparous Holstein-Friesian dairy cows across 14 Irish seasonal spring-calving dairy farms between the years 1990 and 2001. Over this period calving rate to first service (CALV1) reduced by 0·96% per year (55 to 44%; P< 0·001), calving rate to first and second service (CALV12) reduced by 0·84% per year ( 77 to 70%; P< 0·001) and herd average parity number reduced by 0·10 lactation per year (4·3 to 3·5; P<0·001). The proportion of North American Holstein Friesian (NAHF) genes in the cows increased by 5·5% per year (8 to 63%; P<0·001), while pedigree index for milk yield (PIMILK) of the cows increased by 25 kg per year ( P<0·001). The predicted difference of the sires of the cows for calving interval and survival increased by 0·5 days (P<0·001) and reduced by 0·12% ( P<0·001) per year, respectively. A negative association was found between increased phenotypic milk yield, NAHF and PIMILK and reduced calving rates as assessed by CALV1 and CALV12. Increased proportion of NAHF genes exhibited a negative effect on survival ( P<0·001) whereas increased levels of heterosis had a positive impact on survival ( P<0·001). The results of the present study indicate that in seasonal calving herds in Ireland a need for direct selection on traits related to fertility and survival is required to arrest and reverse the declining trends in calving rates and survival.|
|Appears in Collections:||Animal & Bioscience|
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