Analysis of records of embryo production in Red Brahman cows

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Title: Analysis of records of embryo production in Red Brahman cows
Author: Riano Rocha, Edgar Hernando
Abstract: Records of embryo production in Red Brahman donor cows (n=50 ) and F1 recipients (n=531 ) were evaluated from the collection day to the birth of the embryo produced . The effects of the sire of the donor and the embryo , protocol , season -protocol , and body condition of the donor on the total number of good , degenerated , unfertilized , and total embryos were evaluated . The number of donors collected for protocols 1 , 2 , and 3 were 50 , 39 , and 46 respectively . The production of good transferable embryos , and embryos /collection for protocols 1 , 2 , and 3 were 171 (4 .6 ) , 152 (4 .6 ) , and 208 (6 .3 ) respectively . The final status of each recipient was recorded as non -pregnant , resorption , abortion , and live calf . The model used to analyze pregnancy state was : protocol , embryo stage , embryo quality , corpora lutea size , and season . The effects of sire of the embryo , season -protocol , protocol , embryo stage , embryo quality , body condition score , and corpora lutea size on gestation length and birth weight were analyzed . Season -protocol affected (P <0 .05 ) the number of degenerated embryos . Mean number of degenerated embryos were higher (P <0 .05 ) during winter for protocols 2 and 3 than during other seasons . The ratio for good embryos differed (P <0 .01 ) by sire of donor . The final status of recipients was affected (P <0 .01 ) by protocol . The maximum percentage of live calves and the minimum percentage of non -pregnant recipients were achieved for protocol 3 . Gestation length differed (P <0 .01 ) by sire of the embryo , season -protocol , protocol , and body condition score . Spring -protocol 3 resulted in the shortest while Fall -protocol 2 resulted in the longest mean gestation length . Calf birth weight differed (P <0 .05 ) by season -protocol and by embryo quality . The lightest birth weights resulted from embryo quality grade 2 and from spring -protocol 3 . These results indicate that using protocols that combine 17 ? ? -estradiol , FSH and GnRH (protocol 3 ) during the spring in conjunction with selection for sire of donor can increase embryo production by Red Brahman cows . Use of protocol 3 with donors in the spring , selection of embryo sire for short gestation length and transfer of quality grade 2 embryos can be used to minimize the incidence of dystocia in recipients .
URI: http : / /hdl .handle .net /1969 .1 /2691
Date: 2005-11-01

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Analysis of records of embryo production in Red Brahman cows. Available electronically from http : / /hdl .handle .net /1969 .1 /2691 .

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