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Campo Grande, Brazil

Sa Filho M.F.,University of Sao Paulo | Girotto R.,RG Genetica Avancada | Abe E.K.,Agropecuaria Abe | Penteado L.,Firmasa | And 5 more authors.
Journal of Animal Science | Year: 2012

Three experiments were designed to evaluate methods to optimize the use of sex-sorted sperm in timed AI (TAI) programs for suckled beef cows. In all 3 experiments, suckled Bos indicus cows were synchronized using an intravaginal progesterone (P4) device during 8 d and a 2.0-mg injection of intramuscular estradiol benzoate (EB) at device insertion. The females received PG and eCG (300 IU) at P4 device removal and 1.0 mg of EB 24 h later. The cows were inseminated 60 to 64 h after P4 device withdrawal. All cows had their ovaries scanned by transrectal ultrasound at TAI to indentify and to measure the largest follicle (LF) present. In Exp. 1, a total of 853 cows had their LF classified as <9 mm or ≥9 mm at the time of TAI; these cows were then randomly assigned to 4 groups according to their LF diameter (<9 mm or ≥9 mm) and the type of sperm used (sex-sorted or non-sex-sorted). There was an interaction (P = 0.02) between the type of sperm and LF diameter beginning at TAI[non-sex-sorted ≥9 mm = 58.9%a (126/214); non-sex-sorted <9 mm = 49.5%b (106/214);sex-sorted ≥9 mm = 56.8%ab (134/236); and sex-sorted <9 mm = 31.2%c (59/189), a≠b≠c = P < 0.05]. In Exp. 2, suckled cows (n = 491) were classified immediately before TAI as having displayed estrus or not (estrus or no estrus) between P4 device removal and TAI. These cows were randomly assigned to 4 groups according to the occurrence of estrus and the type of sperm (sex-sorted or non-sex-sorted). There were effects of the occurrence of estrus (P = 0.0003) and the type of sperm (P = 0.05) on pregnancy per AI [P/AI; no estrus, non-sex-sorted = 43.6% (27/62); estrus, non-sex-sorted = 58.5%; (107/183); no estrus, sex-sorted = 33.9% (21/62), and estrus, sex-sorted = 50.0% (92/184)]; however, no interaction between the occurrence of estrus and type of sperm was observed (P = 0.87). In Exp. 3, a total of 200 suckled cows presenting LF ≥9 mm at TAI were randomly assigned to receive sex-sorted sperm deposited into the uterine body (n = 100) or into the uterine horn ipsilateral to the recorded LF (n = 100). No effect of deeper AI on P/AI was found (P = 0.57). Therefore, the LF diameter at TAI and the occurrence of estrus can be used as selection criteria to identify cows with greater odds of pregnancy to receive sex-sorted sperm in TAI programs. In addition, performing TAI with sex-sorted sperm deeper into the uterus did not alter the pregnancy results. © 2012 American Society of Animal Science. All rights reserved. Source


Sa Filho M.F.,University of Sao Paulo | Penteado L.,Firmasa | Reis E.L.,University of Sao Paulo | Reis T.A.N.P.S.,University of Sao Paulo | And 2 more authors.
Theriogenology | Year: 2013

The objective was to compare reproductive performance of breeding programs that used natural service (NS), AI after estrus detection (ED), and timed AI (TAI). In experiment 1, 597 suckled beef cows were randomly allocated to one of four groups. Cows in the TAI+NS group (N = 150) were bred by TAI at 11 days after the onset of the breeding season (BS). Bulls were placed with cows 10 days after TAI and remained together until the end of the 90-day BS. Cows in the TAI+ED+NS group (N = 148) received TAI, then AI based on ED for the next 45 days, and finally NS for the last 45 days of the BS. Cows in the ED+NS group (N = 147) received AI based on ED during the first 45 days of the BS, followed by NS for the last 45 days of the BS. Cows in the NS group (N = 149) were bred by NS for the entire 90-day BS. Cows in the ED+NS or NS groups had a decreased (P < 0.001) hazard of pregnancy compared with cows in the two groups bred by TAI at the onset of BS. Also, cows bred by TAI (TAI+NS = 92.7%; and TAI+ED+NS = 91.9%) had higher (P < 0.01) pregnancy rates at the end of the BS compared with cows not bred by TAI (ED+NS = 85.0%; NS = 83.2%). In experiment 2, 507 suckled beef cows were randomly assigned to one of two groups at the onset of a 90-day BS. The NS group (N = 255) received only NS during the entire BS, and the TAI+NS group (N = 252) received TAI at the onset of the BS, followed by NS until the end of BS. Cows in the TAI+NS group had 63% higher hazard of pregnancy (P < 0.001) compared with cows in the NS group, and reduced the median days to pregnancy by 44 (11 vs. 55 days). However, there was no difference (P = 0.31) in proportion of pregnant cows at the end of the BS (TAI+NS = 77.0% vs. NS = 71.0%). Therefore, incorporation of TAI programs early in the BS increased reproductive performance of suckled beef cows. © 2013 Elsevier Inc. Source


Carvalho N.A.T.,Unidade de Pesquisa e Desenvolvimento de Registro | Gimenes L.U.,University of Sao Paulo | Reis E.L.,University of Sao Paulo | Cavalcante A.K.S.,University of Sao Paulo | And 10 more authors.
Revista Veterinaria | Year: 2010

In order to analyse anatomic particularities between buffalo and bovine females, the genital systems from 31 cyclic buffalo and 21 cyclic bovine were morphometrycally evaluated. The genital systems were dissected and the organs were separated and measured. The ovaries weight, the right ovary length and wideness, the number of cervix rings, the vagina and cervix length were higher in bovine than buffalo. Otherwise, the ovaries thickness, the left oviduct length, the uterine body, the left horn length and wideness were higher in buffalo than bovine. The left ovary length and wideness, the right oviduct length, the right uterine horn length and wideness did not differ between species. The knowledge of the anatomic particularities is important to the employment of reproductive techniques like artificial insemination and embryo transfer on these species. Source

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