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51.
Analysis of early survival of Holstein-Friesian heifers of diverse sire origins on commercial dairy farms in Kenya 总被引:1,自引:1,他引:0
D. K. Menjo B. O. Bebe A. M. Okeyo J. M. K. Ojango 《Tropical animal health and production》2009,41(2):171-181
The use of imported semen within the Holstein-Friesian cattle population in Kenya has contributed to increased milk production
per cow, however, information on how this has impacted on functional traits, particularly early life survival and reproductive
performance is scarce. This study evaluated age at first calving (AFC), survival to age at first calving, and survival to
four years of age using survival analyses techniques, in Holstein-Friesian cattle on four dairy farms in Kenya. The heritability
estimate obtained for AFC was 0.15 ± 0.06 for an average AFC of 1058 days. Animals sired by New Zealand and Australian born
bulls had the earliest average AFC (907 days). On average, 25% of all the heifers born were culled prior to attaining a first
calving, while 34% were culled prior to four years of age. Though the highest proportion of losses was due to unspecified
reasons, the relative risk of being culled was highest when an animal had a specific disease, and the first 60 days of life
were the most critical for survival. Daughters of sires from South-Africa and Israel tended to have better survival rates
than those sired by bulls originating from other regions. Unfavourable selection towards animals sired by Kenyan born bulls
was evident. The economic implications of the high rate of early mortality need to be evaluated in order to assist livestock
producers make informed decisions on choice of sires for breeding. 相似文献
52.
Alexandre G Leimbacher F Maurice O Domarin D Naves M Mandonnet N 《Tropical animal health and production》2009,41(4):635-644
To be successful, initiatives to improve farmer's goat production should directly address the needs and objectives of the keepers while promoting rational use of local genetic resources. A survey was carried out to implement a genetic policy governing meat goat farming in Martinique (11400 heads and 33400 ha arable land). The questionnaire comprised a total of 27 items with 306 modalities, and included questions on farm structure, crop and animal productions, management of feeding, reproduction and health control. The sample consisted of 33 farmers with 644 ha and 2680 goats (1286 does and 52 bucks), 97% of does in the studied sample were crossbred, 56% of bucks were" imported" breeds (Boer or Anglo-Nubian). The number of goats per farm varied from 16 to 582. The feeding system was predominantly grazing, according to a rotation (55% of cases) or continuous grazing system (42%). On 62% of farms, the males remained with the females permanently, also 83% of farmers did not resort to methods of controlled-mating. The first criteria used for choosing animals (80 to 90% of answers) of both sex, were development and conformation. Assuming that adaptive together with productive traits are important in tropical zones, it is advisable to better define the maternal lineage of the local livestock (presently very sparse records), to improve reproduction management and culling strategies (poor and inadequate management practices do not support any genetic improvement programme), and to guide the farmers in their decisions by employing concerted interprofessional actions (choice of meat breed, market studies). 相似文献