Reproductive performance and serum concentrations of progesterone of heat-stressed Holstein heifers subjected to timed artificial insemination and progesterone supplementation

Authors : Abelardo CORREA CALDERÓN, Juan Augusto HERNÁNDEZ RIVERA, Leonel AVENDAÑO REYES, Ulises MACIAS CRUZ, Raúl DIAZ MOLINA, Francisco Daniel ALVAREZ VALENZUELA, Arnoldo GONZALEZ-REYNA

Pages : 611-617

View : 5 | Download : 3

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Sixty-nine Holstein heifers were used to evaluate the effect of progesterone supplementation after timed artificial insemination insert ignore into journalissuearticles values(TAI); on conception rates of heifers under heat stress. Heifers were randomly assigned to 1 of 3 treatments: 1); control treatment insert ignore into journalissuearticles values(C);, visual detection of estrus. Heifers detected in estrous were inseminated according to the AM-PM procedure insert ignore into journalissuearticles values(n = 23);; 2); TAI insert ignore into journalissuearticles values(n = 24);, using a CIDR device insert ignore into journalissuearticles values(insert containing progesterone); placed intravaginally on day -10 and removed on day -2 with PGF2α given on day -3. Heifers were given 0.5 mg of ECP at CIDR insertion and a second injection insert ignore into journalissuearticles values(0.5 mg ECP); was given on day -2 and 48 h after all the heifers were inseminated insert ignore into journalissuearticles values(day 0);; and 3); TAI with progesterone supplementation insert ignore into journalissuearticles values(TAI+S; n = 22);, consisting of TAI plus progesterone supplementation with a used CIDR from day 4 to 14 after insemination. The maximum temperature humidity index during the study averaged 86, while the minimum was 77. Blood samples were collected from all heifers on days 5, 9, and 14 post-insemination for quantification of progesterone, thyroxine, and triiodothyronine levels. Respiration rate insert ignore into journalissuearticles values(RR); was measured at 1700 hours and rectal temperature insert ignore into journalissuearticles values(RT); at 1800 hours, 3 times per week. The conception rate did not differ insert ignore into journalissuearticles values(P > 0.05); among treatments insert ignore into journalissuearticles values(C = 40; TAI = 34.6; TAI+S = 44.4%);. The levels of progesterone were not increased insert ignore into journalissuearticles values(P > 0.05); by progesterone supplementation. Values for RR, RT, and thyroid hormones were similar among treatments insert ignore into journalissuearticles values(P > 0.05);. TAI combined with progesterone supplementation did not improve the conception rate of Holstein heifers under heat stress.
Keywords : Key words Conception rate, dairy heifers, heat stress, progesterone