Reactivity of Nellore steers in two feedlot housing systems and its relationship with plasmatic cortisol

To evaluate reactivity to assess the temperament of Nellore steers in two feedlot housing systems (group pen or individual pen) and its relationship with plasmatic cortisol, 36 experimental units were observed five times at 28-day intervals of weight management during a 112-day feedlot confinement. A reactivity score scale ranging from 1 to 5 was applied when an animal was in the chute system. To the calmest animal, a reactivity score of 1 was ascribed and to the most agitated, 5. Blood samples were collected for cortisol analysis. No differences were found in reactivity and feedlot system. There was a relationship noted between reactivity and feedlot time in both housing systems (P < 0.01). There was a relation between reactivity and cortisol levels for group animals (P = 0.0616) and for individual ones (P < 0.01). Cortisol levels varied among housing systems (P < 0.01). Feedlot time influenced the cortisol levels (P < 0.09 individual; P < 0.01 group) and when variable time was included, these levels changed, decreasing in the group pen and increasing in individual pens. The continuous handling reduces reactivity and plasmatic cortisol, and group pen system seems to be less stressfully than individual pens. (C) 2010 Elsevier B.V. All rights reserved.

Production systems - An example from Brazil

Important information about the Brazilian agribusiness, population and economy are presented in this paper, as well as details of beef production, market, industry and production system, to inform people involved in meat industry about details on demography, production, economy and production systems of a country that is the largest player in beef exports in the world and that uses, mostly, Bos indicus based bovine population, reared under pasture conditions, for meat production purposes. Herd size, genetic evaluation programs, quantity of beef produced and market is informed, with figures about the global and major players` production. Some discussion related to environmental concerns, methane emission and carbon fixation is also presented, as well as meat quality. Meat quality of fed animals is also compared with beef from animals that are raised in pasture conditions. (c) 2009 Elsevier Ltd. All rights reserved.

Effect of monensin on performance in growing ruminants reared under different environmental temperatures

To evaluate the effect of monensin on the performance of growing cattle under different environmental temperatures, 24 male calves (81.9 +/- 7.7 kg mean weight and 100 days old) were distributed in a 2 x 2 factorial arrangement, contrasting 0 or 85 mg monensin/animal per day at 24.3 or 33.2 degrees C (environmental temperatures). Monensin supplementation increased weight gain (P=0.036), improved feed efficiency (P=0.040), increased ruminal concentrations of volatile fatty acids (VFA; P=0.003) and decreased the molar proportion of butyrate (P=0.034); all effects irrespective of environmental temperatures. A temperature-dependent monensin effect was detected on nitrogen retention (P=0.018) and N retained:N absorbed ratio (P=0.012). Animals fed monensin retained higher N amounts than those of the non-supplemented ones when the environmental temperature was 33.2 degrees C. Environmental temperature and monensin supplementation showed an interaction effect on urine N concentration (P=0.003). Temperature did not affect N excretion in monensin-fed animals, but increased N excretion in the non-supplemented ones. Monensin increased the crude protein (CP) digestibility (P=0.094) for

Heat tolerance and the effects of shade on the behavior of Simmental bulls on pasture

The objectives were to assess the degree of thermolysis capacity as a characteristic of heat tolerance of the Simmental beef cattle and evaluate the effects of shade and shade type (artificial: AS, trees: TS, or no shade: NS) on daily behavior patterns during summer. Black globe temperature (BGT) was different under the two types of shade (P < 0.05) and was lower under the TS (P < 0.01) and under AS (P > 0.01) than average BGT in the sun. Animals when in AS used more intensely the shade (P = 0.002) mostly lying down under it (10.00-14.00 hours), while time standing was similar (P = 0.107) between TS and NS. Bulls without shade (NS) spent significantly more time at the water trough and most part of the day standing idle (72.4%, 10.1 h/14 h). TS bulls spent more time grazing/standing (P < 0.001). The Simmental bulls that were in TS and AS spent more time ruminating than bulls that stay without shade (NS). The availability of shade changes grazing, rumination and idling behavior of cattle in response to environmental conditions. Shade provided by trees can be more efficient than artificial shading as cattle spent more time grazing when tree shade was available. Thermolysis capacity can be used to select heat-tolerant animals.