Effects of zeranol implantation and late castration on sexual, agonistic and handling behavior in male feedlot cattle

Masturbation in the Animal Kingdom

Masturbation is one of the most common sexual behaviors in humans. It is also a phylogenetically widespread trait of various other mammalian and some non-mammalian species. Several hypotheses have been proposed aiming to explain the function of masturbation in primates and other species. These were mainly based on observations of nonhuman primates such as rhesus macaques or bonobos and rodents such as African ground squirrels. Based on these observations various scholars suggested that masturbation improves ejaculate quality, decreases the risk of contracting sexually transmitted infections or is merely a by-product of sexual arousal and thus an alternate outlet to copulation. While these theories may explain some facets of masturbation in some species, they do not explain why masturbation is so widespread and has developed in various species as well as our hominid ancestors. Moreover, the research on which these theories are based is scarce and heavily focused on male masturbation, while female masturbation remains largely unexplored. This sex difference may be responsible for the one-sided theorizing that attributes a specific biological benefit to masturbation. We propose that the widespread prevalence of masturbation in the animal kingdom may be better explained by viewing masturbation as a primarily self-reinforcing behavior that promotes pleasure both in human and in nonhuman species.

Is meat quality of forage-fed steers comparable to the meat quality of conventional beef from concentrate-fed bulls?

BACKGROUND

Replacing concentrates with forages in the diet of finishing cattle to satisfy societal demands and for economic reasons is a target for beef farmers, but this change may affect meat acceptance. In the Mediterranean area, young bulls are usually finished on concentrates (Conventional beef). Alternatively, steers can be finished on grass with supplements (G-supp); however, if carcasses are too lean, meat quality may be negatively affected. To increase fat deposition, grazing steers were finished on a total mixed ration composed of alfalfa hay and corn (TMR). Thus the objective of the study was to compare the quality of Longissimus muscle of the three systems.

RESULTS

Conventional beef had low yellowness and similar lightness and redness values compared with the beef from the forage-based systems, which differed slightly. The meat of the G-supp and TMR steers had higher conjugated linoleic acid (CLA) and total n-3 polyunsaturated fatty acid (PUFA) contents and lower n-6/n-3 PUFA ratio (more appropriate from a human health point of view) but was tougher than the Conventional beef.

CONCLUSION

The Conventional beef was better accepted by consumers than the beef from both forage-based systems because it was the most tender. Thus tenderness of meat from forage-fed steers should be improved to ensure consumer acceptance. © 2017 Society of Chemical Industry.

Anti-Muellerian hormone, inhibin A, gonadotropins, and gonadotropin receptors in bull calves after partial scrotal resection, orchidectomy, and Burdizzo castration

Eight-week-old calves were either castrated by partial scrotal resection (SR) without removing the testes (n = 10), Burdizzo (BZ) clamp (n = 10), orchidectomy (OR; n = 10), or were left gonad intact as controls (CO; n = 10). Concentrations of anti-Muellerian hormone (AMH), inhibin A, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) in plasma were determined from 16 to 48 weeks of age. At 18 months, testes of SR, BZ, and CO bulls were obtained and the immunolocalization of LH and FSH receptors and AMH analyzed. Concentration of AMH in plasma of CO and SR bulls decreased with increasing age (P < 0.001). A similar AMH profile in CO and SR indicates that SR did not induce a true cryptorchid state. In groups OR and BZ, AMH was undetectable. Plasma inhibin concentration was higher in groups CO and SR than BZ and OR (P < 0.001). Plasma LH and FSH concentrations decreased over time (P < 0.001) and were higher in groups BZ and OR than SR and CO (P < 0.001). In the testes, immunolabeling for AMH existed in Sertoli cells of CO and SR but not BZ bulls. FSH receptors were localized in Sertoli cells, Leydig cells, spermatocytes, and the epididymis of CO and SR animals, whereas LH receptors were restricted to Leydig cells. In BZ animals, FSH and LH receptors and AMH were absent, indicating complete testicular degeneration. In conclusion, AMH is a more reliable marker for the presence of testicular tissue in bulls than inhibin. Scrotal resection did not induce a true inguinal cryptorchid state but affected testicular responsiveness to gonadotropic stimulation.

Beef cattle welfare in the USA: identification of priorities for future research

This review identifies priorities for beef cattle welfare research in the USA. Based on our professional expertise and synthesis of existing literature, we identify two themes in intensive aspects of beef production: areas where policy-based actions are needed and those where additional research is required. For some topics, considerable research informs best practice, yet gaps remain between scientific knowledge and implementation. For example, many of the risk factors and management strategies to prevent respiratory disease are understood, but only used by a relatively small portion of the industry. This is an animal health issue that will require leadership and discussion to gain widespread adoption of practices that benefit cattle welfare. There is evidence of success when such actions are taken, as illustrated by the recent improvements in handling at US slaughter facilities. Our highest priorities for additional empirical evidence are: the effect of technologies used to either promote growth or manage cattle in feedlots, identification of management risk factors for disease in feedlots, and management decisions about transport (rest stops, feed/water deprivation, climatic conditions, stocking density). Additional research is needed to inform science-based recommendations about environmental features such as dry lying areas (mounds), shade, water and feed, as well as trailer design.

Endocrine testicular function and spermatogenesis persist in calves after partial scrotal resection but not Burdizzo castration

Bull calves for fattening are often castrated during the first weeks of life. Because androgens stimulate growth, there is an interest in males that are infertile but exposed to endogenous testicular steroids. Such a situation occurs in cryptorchids and has been imitated by shortening the scrotum to an extent that the testes are located in a near-inguinal position. In this study, effects of partial scrotal resection (SR) and Burdizzo castration (BZ) on endocrine testicular function, testes histology and on weight at slaughter were studied and compared to orchidectomized (OR) and gonad-intact calves (CO; n = 10 per group; age at castration, 54 ± 3 days; fattening period, 474 ± 11 days). Plasma testosterone concentrations were determined repeatedly, and testes were collected for histopathology at slaughter. We hypothesized that SR inhibits spermatogenesis without loss of testicular steroidogenesis. Group SR animals gained more weight than groups OR and BZ (P < 0.01). Plasma testosterone concentration increased in groups SR and CO (P < 0.01 vs. BZ and OR). Histologically, in all SR animals, testicular and epididymal tissue was identified with a seminiferous epithelium of up to three-cell layers in two animals. Germ cells including elongated spermatids were present in three animals. Shortening of the scrotum thus induced varying degrees of testicular degeneration but 3/10 animals had to be suspected as fertile. In one BZ animal, spermatids were identified whereas in the remaining BZ animals, testes and epididymides consisted of sclerotic fibrous tissue. Partial SR thus induced a cryptorchid-like status but fertility in individual animals must be assumed.

The effect of different levels of gonadotropin-releasing hormone antibody titres on plasma hormone concentrations, sexual and aggressive behaviour, testis size and performance of bulls

To determine the effect of different levels of gonadotropin-releasing hormone (GnRH) antibody titres (AT) on plasma hormone concentrations, behaviour, testes size and performance, Friesian bull calves (no. = 72) were immunized against either human serum albumin (HSA) conjugated to Cys-Gly-GnRH (no. = 48; immunized) or HSA (no. = 24; controls) at 8 to 10 weeks of age. One booster immunization was administered on either day 28 or 56 (no. = 24 GnRH-immunized and no. = 12 control per booster day). Based on AT 1 week post respective booster, 12 immunized and six control bulls were allocated to one of three AT groups, control (C), medium (M) and high (H) with mean AT of 0·3 (s.e. 0·1), 32 (s.e. 2) and 51 (s.e. 2)% binding at a plasma dilution of 1: 160; respectively. Bulls were blood sampled and weighed every 14 days, and testicular measurements taken every 28 days, from days 0 to 533. Behaviour was observed for 4 h once weekly while bulls were together at pasture and, within AT group, for 20 min 1 week before slaughter. At slaughter, testes and carcass measurements were made. Appropriate data were analysed by ANOVA and correlation coefficients (i) determined. Behavioural data were analysed using x2. Mean AT for M and H treatment groups during the experiment were 36·5 and 44·8% binding at a 1: 160 dilution (P > 0·05, pooled s.e.d. 5·9%), respectively. Level of AT decreased (P < 0·05) mean testosterone concentrations (1·74, 1·36 and 1·21 (s.e.d. 0·17) ng/ml for the C, M and H treatment groups, respectively) and testes size (e.g. length, 10·0, 8·9 and 8·1 (s.e.d. OS) cm) in the M and H groups compared with the C bulls. There was no effect of AT level on luteinizing hormone and insulin-like growth factor-1 concentrations or on average daily gain. Bulls in the M group had the lightest testes and lowest masculinity score compared with the C and H groups (both P < 0·05). Bulls in the H group had greater backfat thickness than the C bulls (P < 0·05). Bulls in the M and H groups were less aggressive and sexually active than the C bulls (P < 0·05). In conclusion, GnRH AT in both the M and H groups persisted for the duration of the experiment, and these AT were significantly different for a critical period pre-puberty; however they both had similar effects and caused extended periods of reduced testes growth, testosterone concentrations, and aggressive and sexual behaviour compared with C bulls but there was no detrimental effect of AT on growth or carcass characteristics.

Veterinary pharmacovigilance. Part 2. Veterinary pharmacovigilance in practice -- the operation of a spontaneous reporting scheme in a European Union country -- the UK, and schemes in other countries

Veterinary pharmacovigilance, as it operates in the European Union (EU), covers a very broad remit, including adverse effects in treated animals, exposed humans and the environment, and in addition, it extends to cover the violation of maximum residue limits. The mainstay of veterinary pharmacovigilance is the spontaneous reporting scheme working along side other systems such as those reporting on residues surveillance. One of the most well established schemes in the EU is that operating in the UK and this paper examines the evolution of that scheme and some of its findings, data from other countries, and information available from the literature. It also tentatively examines the ways that pharmacovigilance can be used for regulatory purposes, and the contribution from pharmacoepidemiology.

Aggressive behavior

This article considers the major fighting-related activities of the most common food animals. Instead of being seen as a largely pathologic phenomenon born solely of frustration and pain, aggressive behavior is now regarded as a natural part of an animal's behavioral equipment for survival and reproduction. There is a need, spurred by consideration for both productivity and animal well-being, to understand the fundamentals of the aggressive behavior of domestic species so that one can accommodate for this behavior in systems of livestock management.