SciELO - Scientific Electronic Library Online

 
vol.56 issue4Interaction between cumulus cells and the activity of protein kinase C at different stages of bovine oocyte nuclear maturationLibido test and breeding activity of Nelore bulls author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Journal

Article

Indicators

Related links

Share


Arquivo Brasileiro de Medicina Veterinária e Zootecnia

Print version ISSN 0102-0935On-line version ISSN 1678-4162

Abstract

SANTOS, M.D. et al. Reproductive potential of Nelore bulls submitted to different bull: cow proportion. Arq. Bras. Med. Vet. Zootec. [online]. 2004, vol.56, n.4, pp.497-503. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352004000400011.

This study evaluated the reproductive potential of 20 Nelore bulls, submitted to different bull:cow ratio. Correlations among the serum testosterone concentration, scrotal circumference, sperm quality and libido were also estimated. The bulls selected by andrologic evaluation and the libido test were alloted to the following bull:cow ratio (treatments): 1:25 (T1), 1:50 (T2), 1:75 (T3) e 1:100 (T4), with five replicates per treatment. Blood samples were collected to determine serum testosterone concentration. Semen physical and morphologic characteristics, scrotal circumference and libido of the bulls did not differ among treatments. The pregnancy rate of the cows was not affected by treatments (means of 42.1, 66.5 and 71.0 % for breeding season of 30, 60 and 90 days, respectively). The testosterone concentration was not affected by treatments and the mean serum testosterone concentration was 4.04ng/ml, which peaked at 9am. The correlations between the libido, semen physical and morphologic characteristics, and the scrotal circumference of the bulls were low. Nelore bulls with good sperm quality and libido supported a large number of cows, and the bull:cow ratio of 1:100 did not reduce the pregnancy rate.

Keywords : andrologic evaluation; bull:cow ratio; fertility; libido; testosterone.

        · abstract in Portuguese     · text in Portuguese     · Portuguese ( pdf )

 

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License