Incidence of precocious puberty in developing beef heifers

• Published in: Journal of animal science Vol. 74; no. 10; p. 2462
• Main Authors: Wehrman, M.E. (University of Nebraska, Lincoln, NE.), Kojima, F.N, Sanchez, T, Mariscal, D.V, Kinder, J.E
• Format: Journal Article
• Language: English
• Published: United States 01.10.1996
• Subjects: AGE; Aging - physiology; Animals; Body Weight - physiology; BOVIN DE BOUCHERIE; Cattle - blood; Cattle - growth & development; Cattle - physiology; CICLO ESTRAL; COMPLEMENT ALIMENTAIRE; CORPS JAUNE; Corpus Luteum - metabolism; Corpus Luteum - physiology; CUERPO LUTEO; CYCLE OESTRAL; DESTETE; DURACION; DUREE; EDAD; Female; GAIN DE POIDS; GANADO DE CARNE; GANANCIA DE PESO; GENISSE; Incidence; MADUREZ SEXUAL; MATURITE SEXUELLE; NOVILLA; PASTOREO; PATURAGE; PESO; POIDS; PROGESTERONA; PROGESTERONE; Progesterone - blood; Random Allocation; SERUM SANGUIN; SEVRAGE; Sexual Maturation - physiology; SUERO SANGUINEO; SUPLEMENTOS; TAUREAU; TORO; VACA; VACHE
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/1996.74102462x

The objectives of this study were to determine the incidence of precocious puberty and effect of exposure to a bull on the incidence of precocious puberty in beef heifers. The experiment was conducted using 120 heifers during 1990 and 1991. Heifer calves were randomly assigned to be pastured in the presence (n = 30 heifers/yr) or absence (n = 30 heifers/yr) of a bull starting at 140 +/- 14 d of age for the duration of the study. Heifers were 402 +/- 14 d of age at the time the study was completed. Blood samples were collected weekly to determine the age of onset, duration and cessation of luteal function. Heifers were considered to have exhibited a precocious puberty when the onset of luteal function was before 300 d of age. There was no effect of exposure to a bull on the incidence of precocious puberty, and therefore the data were pooled. The incidence of precocious puberty was greater (P 0.02; X(2)