Fernando A. Souza

Seroprevalence of and risk factors for Toxoplasma gondii in sheep raised in the Jaboticabal microregion, São Paulo State, Brazil

Seroprevalence of and risk factors for toxoplasmosis in sheep from different properties in the Jaboticabal microregion, São Paulo State, Brazil were determined. Antibodies to Toxoplasma gondii were found in sera of 52.0% of 488 sheep tested by indirect fluorescent antibody test (IFAT > or =64). T. gondii seropositivity in sheep was significantly associated with gender of the sheep, pasturing system, contact with cats, and the use of mineral supplements and the type of feed.

Granjas leiteiras na região de Ribeirão Preto - SP

Nas atividades de exploracao leiteira, as construcoes para os animais sao fundamentais e de suma importância no processo de producao. Sendo assim, suas concepcoes devem basear-se em solucoes tecnicas e economicas, que oferecam condicoes eficientes e funcionais. O objetivo deste trabalho foi realizar um levantamento sobre as principais caracteristicas de granjas leiteiras localizadas em municipios paulistas proximos a Ribeirao Preto e no sul de Minas Gerais e recomendar solucoes, com base na literatura, para a execucao de projeto para a regiao de Ribeirao Preto-SP. O trabalho foi desenvolvido com base em estudos teoricos e observacoes in loco, considerando as seguintes construcoes: galpao de estabulacao livre; bezerreiro; sala de ordenha e seus anexos (pediluvio, lava-pes e curral de espera) e sistema de tratamento de dejetos. Dos resultados obtidos, verificou-se que a maioria das granjas leiteiras foi projetada sem criterios e com solucoes tecnicas nao eficazes.

Changes in the nutritive value and aerobic stability of corn silages inoculated with Bacillus subtilis alone or combined with Lactobacillus plantarum

Chemical composition, fermentation characteristics, in vitro digestibility and aerobic stability were evaluated in corn silage inoculated with microbial additives in two different experiments. Inoculant treatments (untreated, Bacillus subtilis and B. subtilis combined with Lactobacillus plantarum) were applied to fresh forages. Chopped corn plants (2B655 Hx) were ensiled in laboratory silos for periods of 7, 14, 21 and 63 days to evaluate the fermentation parameters. The experimental silos were weighed to determine gas losses. After the ensiling period, the silage was sampled to determine chemical composition and in vitro organic matter digestibility. To evaluate aerobic stability, chopped corn plants (AG‐1051) were ensiled in laboratory silos that were opened after 96 days of ensiling. The silage was placed in different buckets containing data loggers. The silage was sampled after 0, 4, 8 and 12 days of exposure to air to evaluate the microbial populations and pH. The data were analysed as a completely randomised design using a mixed repeated-measures model in the MIXED procedure of SAS. To evaluate each treatment relative to the fermentation times, a regression analysis using the PROC REG procedure of SAS was applied. A significance level of P < 0.05 was used. Inoculation with both strains increased lactic acid concentration, whereas the use of B. subtilis alone or combined with L. plantarum improved in vitro apparent organic matter digestibility. In the B. subtilis and B. subtilis combined with L. plantarum silages, moulds and yeasts decreased, and aerobic stability was improved. Inoculation with B. subtilis alone or combined with L. plantarum improved the nutritional value and aerobic stability of corn silage.

Age and gender influence the cardiorespiratory function and metabolic rate of broiler chicks during normocapnia and hypercapnia

Pulmonary ventilation (V˙(E)), body temperature (Tb), mean arterial pressure (MAP), heart rate (f(H)) and metabolic rate (V˙(O2)) were measured in 10 (d10)- and 21 (d21)-day-old male and female chicks exposed to 7% CO2. Under normocapnia, V˙(E) was higher in d10 chicks than in d21 due to a higher tidal volume; in females a higher respiratory frequency (f(R)) was also observed. The d10 birds presented higher f(H) and V˙(O2). The d21 females showed the highest CO2 ventilatory response due to increased f(R). MAP did not change during hypercapnia while a hypercapnic bradycardia occurred, except in d21 females. Hypercapnia induced a drop in Tb in all groups and an increase in V˙(O2) in d21 males. Overall, no gender effect is observed in cardiorespiratory and metabolic variables in d10 and d21 chicks under normocapnia, the differences in V˙(E) and f(H) between ages may be related to distinct metabolic demands of these phases. The d21 female chicks seem to be more sensitive to hypercapnia.

Is high protein diet a good nutrition strategy for broiler chickens reared at heat stress condition

It is well known that heat stress, in growing broiler chicks, impair the performance. Ain Baziz et al. (1996) reported that 53% of the impairment in the performance was due to reduction in feed consumption, but the last 47% was due to the direct effect of ambient temperature,per se. One of the approaches that have been proposed to avoid the effect of heat stress in broilers is related to the protein content in the diet, since protein metabolism is deeply involved in the caloric increment, as compared with fat or carbohydrate. According to Gonzalez-Esquerra and Leeson (2006) the Arg:Lys ratio, Met source and time to exposure to heat stress affect protein utilization in hyperthermic birds. Thus, this study was conducted aiming to verify if the increase of protein content in the diet, maintaining the Arg:Lys ratio, affects broiler chicks performance when reared at different environmental conditions.

Influence of natural shading on production index of broilers.

The proper use of natural resources in the design of broiler facilities reduces operating costs of the farm and optimizes production conditions. The natural shade surrounding the facilities may be an alternative for improving the internal conditions of the animal housing. The objective of this study was to evaluate the efficiency of shading in broiler sheds oriented east-west. To do so, we compared the productivity index (PI) of 29 broiler sheds, each with the same management, same density and building characteristics while the shades were divided into different sides of the barn, i.e., the northern side only, the southern side only, both south and north sides and no shade. Five flocks were produced annually. It was found that the flocks grown in the milder periods of the year, between autumn and spring, with shading on the south sides of the barns showed superior PI. As for the summer period, barns without shading showed higher PI.