27 research outputs found
Expanding protection motivation theory: investigating an application to animal owners and emergency responders in bushfire emergencies
Effect of pasture feeding levels on the responses of lactating dairy cows to high energy supplements
Effect of pasture allowance and level of concentrate feeding on the productivity of dairy cows in late lactation
Influence of high energy supplements containing fatty acids on the productivity of pasture-fed dairy cows
Sustained testicular atrophy in bulls actively immunized against GnRH: potential to control carcase characteristics
The objectives were to determine whether active immunization against gonadotrophin releasing hormone (GnRH) induced a long-term suppression of testicular function in bulls, and to ascertain the effects of immunization against GnRH on carcase and meat quality characteristics. In experiment 1, 6-month-old Zebu bulls were assigned to: control (n = 25), no treatment: immunized (n = 31). immunized against GnRH at 0 and 4 months (anti-GnRH(2)). with a sub-set of bulls (n = 17) immunized again at 10 months (anti-GnRH(3)). After the second immunization, testicular growth ceased for 2 months in 14/31 (45%) bulls and for at least 6 months in 17/31 (55%) bulls. Among the latter bulls (anti-GnRH3) the testes did not grow for >1 year after the third immunization in 5/17 (30%) bulls. In experiment 2, 22-month-old Zebu bulls were assigned to: control (n = 14), no treatment; immunized (n = 17), immunized against GnRH at 0, 2 and 4 weeks. The testes decreased (P < 0.05) in size for 2 months after immunization in 11/17 (65%) bulls and then re-initiated growth, whilst in 6/17 (35%) bulls the testes continued to decrease in size for 4 months and did not re-initiate growth for 1 year. At slaughter, the latter immunocastrated bulls had carcase and meat quality characteristics the same as contemporary bulls that had been castrated before puberty. The findings demonstrated that active immunization against GnRH can induce a long-term suppression of testicular function in a proportion of bulls. Also, when bulls are immunocastrated after puberty, carcase and meat quality traits change from those typical of entire bulls to traits that are characteristic of long-term castrated bulls. (C) 2001 Elsevier Science B.V, All rights reserved
Feeding high energy supplements to pasture-fed dairy cows. Effects of stage of lactation and level of supplement
Effects of pasture and supplement quality on the responses of lactating dairy cows to high energy supplements
Use of a gonadotropin releasing hormone agonist implant as an alternative for surgical castration in male ferrets (Mustela putorius furo)
Surgical castration in ferrets has been implicated as an etiological factor in the development of hyperadrenocorticism in this species due to a castration-related increase in plasma gonadotropins. In search for a suitable alternative, the effect of treatment with the depot GnRH-agonist implant, deslorelin, on plasma testosterone concentrations and concurrent testes size, spermatogenesis, and the typical musky odor of intact male ferrets was investigated. Twenty-one male ferrets, equally divided into three groups, were either surgically castrated, received a slow release deslorelin implant or received a placebo implant. Plasma FSH and testosterone concentrations, testis size and spermatogenesis were all suppressed after the use of the deslorelin implant. The musky odor in the ferrets which had received a deslorelin implant was less compared to the ferrets which were either surgically castrated or had received a placebo implant. These results indicate that the deslorelin implant effectively prevents reproduction and the musky odor of intact male ferrets and is therefore considered a suitable alternative for surgical castration in these animals. (C) 2008 Elsevier Inc. All rights reserved