Produção Nacional
Revisado por pares
Cooled semen for fixed-time artificial insemination in beef cattle
2015; CSIRO Publishing; Volume: 28; Issue: 7 Linguagem: Inglês
10.1071/rd14185
ISSN1448-5990
AutoresJuliana Corrêa Borges-Silva, Márcio R. Silva, Daniel B. Marinho, Ériklis Nogueira, Deiler C. Sampaio, Luiz Orcírio Fialho de Oliveira, U. G. P. de Abreu, Gérson Barreto Mourão, Roberto Sartori,
Tópico(s)Reproductive Biology and Fertility
ResumoThis study evaluated the use of cooled semen in a fixed-time artificial insemination (FTAI) program compared with frozen–thawed semen to improve pregnancy rates in beef cattle. Ejaculates of three bulls were collected and divided into two treatments: (1) frozen–thawed semen and (2) cooled semen. Egg-yolk extender without glycerol was used for the cooled semen treatment. Straws (25 × 106 spermatozoa) were submitted to cooling for preservation at 5°C for 24 h, after which FTAI was performed. Nelore cows (n = 838) submitted to FTAI were randomly inseminated using frozen–thawed semen or cooled semen. There was a 20% increase in the pregnancy per AI (P AI–1) using cooled semen compared with frozen–thawed semen (59.9 ± 4.7 vs 49.4 ± 5.0%; P < 0.005). There was no difference in P AI–1 among the bulls (P = 0.40). The frozen–thawed semen had fewer functional spermatozoa than did the cooled semen when evaluated by sperm motility (61.7 vs 81.0%), slow thermoresistance test (41.7 vs 66.7%) and hypoosmotic swelling test (38.3 vs 53.7%; P < 0.05). The percentage of sperm abnormalities did not differ between the freeze–thawing and cooling processes (18.6 vs 22.1%; P > 0.05). Because there was less damage to spermatozoa and improvement in P AI–1, the use of cooled semen instead of frozen–thawed semen is an interesting approach to increase reproductive efficiency in cattle submitted to a FTAI protocol.
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