title: Serum testosterone concentration, efficiency of estrus detection and libido expression in androgenized beef cows.
abstract: Twenty multiparous, cyclic, nonlactating beef cows were blocked by dominance rank and randomly and equally allotted to 1 of 4 treatment groups: an untreated control group, a synovex-treated group which received 8 Synovex-H implants with no additional hormones, a testosterone-treated group which received 500 mg, i.m. and 1500 mg, s.c. testosterone enanthate on Day 1 with additional 1000 mg, s.c. doses of testosterone enanthate every 14 d, and a synovex + testosterone-treated group which received 8 Synovex-H implants with 500 mg, i.m. and 1500 mg, s.c. testosterone enanthate on Day 1 only. Blood samples were collected via jugular venipuncture once a week beginning 3 wk prior to start of treatment. In addition, samples were collected just prior to treatment; once a day for 1 wk after initiation of treatment; and then twice a week until 225 d after treatment. Efficiency of estrus detection was assessed 22 d prior to start of treatment and every 14 d thereafter for 98 d, using estrus detection trials with synchronized females or modified libido tests. Scores for estrus detection trials included total mounts in 1 h and the percentage of estrous cows detected. Libido was scored on a scale of 0 through 6. All testosterone treatments raised plasma testosterone concentrations above control and pretreatment levels (testosterone and synovex + testosterone > synovex > control; all P < 0.05). Synovex-, testosterone- and synovex + testosterone-treated females performed more mounts in 1 h than the controls (18, 9, 6 and 1, respectively; all P < 0.05). All testosterone-treated cows mounted a higher number of estrous females than the controls (P < 0.05). Only synovex + testosterone- and testosterone-treated cows received libido scores above pretreatment and control values. However, libido of testosterone-treated cows decreased over time, while that of synovex + testosterone-treated females remained high until Day 98. Libido scores correlated positively with the number of mounts in 1 h and the percentage of estrous females detected (0.70 and 0.44, respectively), and the correlation coefficient for these two factors was 0.63. In conclusion, the synovex + testosterone treatment was most effective for producing estrus detector females and libido testing was useful for evaluating sexual activity in androgenized females.
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, SC 29634, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Nix
authors.forename: J C
authors.initials: JC
authors.lastname: Spitzer
authors.forename: P J
authors.initials: PJ
authors.lastname: Chenoweth
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology* / Q000523:psychology; D004958:Estradiol / Q000097:blood / Q000502:physiology; D004971:Estrus / Q000502:physiology*; D005260:Female; D007989:Libido / Q000502:physiology*; D011863:Radioimmunoassay / Q000662:veterinary; D011897:Random Allocation; D012930:Social Dominance; D018709:Statistics, Nonparametric; D013739:Testosterone / Q000097:blood / Q000502:physiology*
chemical_list: D013739:Testosterone; D004958:Estradiol