Pre-slaughter social activity of young bulls relating to the occurrence of dark-cutting beef

Abstract

Twenty bulls of three different breeds were tethered individually from 5 months until slaughter at 21 months. On the day of slaughter, the bulls were divided into groups of five animals, transported and then released in a pen. The first bull of the group was slaughtered 60 or 110 min after regrouping. Subsequent bulls were slaughtered individually at 50-min intervals. Social interactions among the bulls were recorded. Muscle pH, light reflectance values and water-holding capacity were measured in samples of m. longissimus dorsi. These characteristics showed correlations with the amount of non-agonistic social activity in which a bull had been involved before slaughter. The characteristics were also correlated with the number of agonistic interactions. Whether a bull was behaving as a dominant or a submissive animal did not influence the incidence of dark-cutting meat as judged by pH values. On the other hand, light reflectance values and water-holding capacity were correlated with the number of passive agonistic interactions (i.e. how many times a bull was attacked) and considerably less with the number of active interactions (number of attacks by the bull). The incidence of butting was not significantly related to muscle characteristics but mounting was significantly correlated with them.The study indicates that dark-cutting beef is primarily caused by physically exhausting activities such as mounting, and further modified by stress-inducing social interactions.

Comportamiento homosexual en rumiantes machos. Revisión

“…Some authors propose that inter-male mounting in ruminants is linked to social dominance [Gazelle (Gazella granti) Walther quoted by (8) ; White tailed deer (Odocoileus virginianus) Rue, quoted by (8) ; steers, quoted by (12,49) ]. In Soay lambs living in freedom, inter-male mounts are more frequent than male-female mounts, a fact that led Grubb (50) to propose that this behavior is an indication of social dominance.…”

“…Algunos autores propusieron que la monta entre rumiantes machos se vincula con la dominancia social [gazela (Gazella granti): Walther (1965) citado por (8) ; ciervo de cola blanca (Odocoileus virginianus ): Rue (1989) citado por (8) ; novillo: (12,49) )]. En corderos Soay en vida libre, la monta entre machos es incluso más frecuente que entre machos y hembras, lo que llevó a Grubb (50) a plantear que este comportamiento es un signo de establecimiento de dominancia.…”

“…For example, mounting frequency between both bulls and steers increases when new groups are formed (4) or when regrouped in slaughter houses (49,57) . In this case, the increase in mounts is significant during the first four hours, particularly between vasectomized males, affecting even meat quality (59) .…”

“…Por ejemplo, la frecuencia de montas entre toros y entre novillos aumenta con la formación de nuevos grupos (4) , o cuando los mismos son reagrupados en mataderos (57,49) . En este último caso, el aumento de montas es muy importante durante las primeras 4 h, particularmente entre machos vasectomizados, pudiendo incluso afectar la calidad de la carne (58) .…”

Does heterosexual experience matter for bucks' homosexual mating behavior?

“…As mixing unknown animals stimulates sexual activity Franc et al, 1988), our aim was to compare bucks' homosexual behavior after grouping 2 groups of bucks, one reared in permanent contact and the other in complete isolation from adult female goats. A complementary aim was to study if there was a relation between homosexual behavior and testosterone concentrations.…”