Antral follicle count classification selects fertile heifers without influencing the carcass traits.

This study aimed to evaluate the ovarian structure, estrus intensity, ultrasound carcass measurements, and pregnancy rate of Nelore breed heifers and cows in accordance with antral follicle counts (AFCs). We evaluated 503 heifers and 565 Nelore cows, with a mean age of 15.5±2.2 and 69.8±36.1 months, respectively, submitted to a fixed-time artificial insemination (FTAI) protocol. On day zero, all bovine females were examined using ultrasound to determine the AFC. The mean AFC of the heifers and cows were 20±8.6 and 22.5±8.4, respectively. The rib-eye area (REA) and fat thickness (FT) of the heifers (n = 119 for REA and n = 219 for FT) were measured using ultrasound imaging. The average conception rates at the first FTAI and at the end of the breeding season were 35.8% and 57.5%, respectively, for heifers and 45.1% and 78.9%, respectively, for cows. We demonstrated that the probability of pregnancy at the first FTAI and at the end of the breeding season for both young heifers and cows increased as the AFC decreased (P>0.001 and P=0.0123, respectively). FT and REA showed no correlation with AFC in heifers. The intensity of estrus expression was negatively correlated with AFC (-0.46; P<0.0001). In conclusion, Nelore heifers and cows with low AFC had a high probability of pregnancy during the entire breeding season. Thus, AFC can be used as a tool to select heifers with increased fertility without affecting carcass traits (REA and FT).

Bibliographic Details

Main Authors:	GHELLER, J. M., SILVA, G. C. da, SILVA, W. A. L. da, SILVA, A. F. da, COSTA FILHO, L. C. C., NOGUEIRA, E., MELO-STERZA, F. de A.
Other Authors:	JANAINA MENEGAZZO GHELLER, UNIVERSIDADE ESTADUAL DE MATO GROSSO DO SUL, Aquidauana-MS; GEANCARLOS CARRARO DA SILVA, UNIVERSIDADE ESTADUAL DE MATO GROSSO DO SUL, Aquidauana-MS; WILIAN APARECIDO LEITE DA SILVA, UNIVERSIDADE FEDERAL DE MATO GROSSO DO SUL; ALDAIR FÉLIX DA SILVA, UNIVERSIDADE ESTADUAL DE MATO GROSSO DO SUL, Aquidauana-MS; LUIZ CARLOS CÉSAR COSTA FILHO, PROCRIAR, Campo Grande-MS; ERIKLIS NOGUEIRA, CPAP; FABIANA DE ANDRADE MELO-STERZA, UNIVERSIDADE ESTADUAL DE MATO GROSSO DO SUL, Aquidauana-MS.
Format:	Artigo de periódico biblioteca
Language:	Portugues pt_BR
Published:	2023-07-19
Subjects:	População folicular, Inseminação Artificial, Ovário, Prenhez, Carcaça, Gado Nelore, Artificial insemination, Carcass quality, Follicular development, Animal ovaries, Pregnancy,
Online Access:	http://www.alice.cnptia.embrapa.br/alice/handle/doc/1155067
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