Volumen 4, NĂºmero 1
https://hdl.handle.net/10669/13505
2024-03-29T15:51:23ZLa vitamina E y la inmunidad de las aves
https://hdl.handle.net/10669/13510
La vitamina E y la inmunidad de las aves
Research done in the last 20 years has shown that vitamin E plays an important role in the development and modulation of the immune system. At least three mechanisms have been described of how the vitamin E modulates the birds immune system. The first mechanism is related with the antioxidant function of vitamin E on the cells of the immune system, maintaining the integrity of these cells and assuring an optimum immune response. The second mechanism is associated with the synthesis of eicosanoids, which modulate the production of prostaglandin and leukotrienes. The last one is associated with the synthesis of interferon and its antiviral response.Experimental evidences have shown that the immune response modulation through the supplementation of vitamin E improves diseases resistance in poultry. It is possible that the levels required to achieve this goal are higher than the level normally used by the industry to optimize productive parameters. Laboratory and field trials have shown that supplementation levels between 150 y 250 mg/kg of vitamin E improves the inmunocompetence of poultry and this can be translated into better productive and economic performance.
2013-06-04T00:00:00ZMuda forzada o "reciclaje" de gallinas en piso
https://hdl.handle.net/10669/13509
Muda forzada o "reciclaje" de gallinas en piso
Force molting of laying hens housed in littered floor. Results of field studies. Very little information is available on force molting of hen flocks housed in floor and litter facilities instead of cages. A field study was conducted with 9Isa-Brown flocks averaging 8 100 hens per flock together with the information of one Isa-Babcock 8-300 white hen's flock. A conventional fasting and no artificial light molting program was implemented in all flocks. The fasting period averaged 13.2 days with a minimum of 9 and a maximum of 15 days. This was the necessary period of time for the flocks to stop laying eggs and lose enough body weight. Flocks stopped production at72.2days without feed (11 min, 13 max); however, two flocks never stopped laying hens and their lower laying rate was 0.9 and 0.4% hen-day. The white flock halted production after 6 days fasting. Average weight loss for the brown hens were 20 % and 24.2% at 10 and 14 days of fasting, respectively (18.3 and 27.3% for the white flock). The daily weight loss ranged from 1.7 to 2.2%. The day previous to start the molting program, the average laying rate was 70.3% hen-day (60.0-78.8%) at70.6 (65.0-76.0) weeks of age. From the first egg after molting to 50% production the flock average 17.6 (13.0-22.0) days and peak egg production was 77.2% (67.2-84.2%) hen-day. It took the brown hen flocks an average of 34 days to reach 50% egg production from the first day of fasting. The white flock lasted 41 days to reach 50% production. The brown flocks reached 69% (1.9-10.7%) egg production above the level they had the day previous to the start of the molting program and stayed 12 (6-21) weeks above that laying rate value. They remained for 2.2 (0-8) weeks above 80% hen-day egg production. Hen mortality average 0.35%/ week (0.11-0.85) during the 40 days after fasting started. These data with hens in littered floor are quite different compared to information available on force molting of flocks in cages.
2013-06-04T00:00:00ZProblemas de mezclado y uniformidad en la industria de alimentos para animales
https://hdl.handle.net/10669/13508
Problemas de mezclado y uniformidad en la industria de alimentos para animales
Mixing and uniformity issues in the feed industry. This paper discuss the main issues related with proper mixing and feed uniformity on animal performance. An analysis is made of the factors that contribute to non-uniformity such as ingredient characteristics, insufficient mix time, mixer overload, worn on broken mixing components, ingredient build-up, improper sequence of ingredient addition among others. The main part of the paper is focus to diet uniformity and its effect on animal performance. The present-day information shows that coefficient of variation (CV) of growing animals are probably less sensitive to diet non uniformity that once thought, with a CV (Quanta as chromium analysis) of 72%bengadequate for broiler chicks and nursery pigs and a CV of at least 15% (and probably higher) being adequate for finishing pigs. At present, there is no "standard" testing procedure that gives accurate results on mixers performance. It is need to design new procedures and conduct credible research that will result in a better understanding of the value of uniformity and the cost of non-uniformity in livestock production. Howeve4 commercial feed manufactures still should exercise care to provide uniformity in diets that have feed additives, such as antibiotics, that are subject to testing by regulatory agencies, and the satisfaction obtained in producing quality feeds.
2013-06-04T00:00:00ZFactores de manejo que afectan los rendimentos de los cerdos posdetete
https://hdl.handle.net/10669/13507
Factores de manejo que afectan los rendimentos de los cerdos posdetete
Factors affecting baby pigs postweaning performance. Management postweaning is one of the most critical factor that affect future pig performance. Two main factors affecting the animal performance are the body weight at weaning and the environment. Lighter body weights animals obtained Iower gains and less efficient feed conversion at the same age of weaning. The environmental factors are those afected by the climate, social status and type of facilities. In relation to the climate, room temperature, air draught, ventilation, cleanness and wet floors are the most importante factors. Temperatures between 28 and 30 Co are the most convenient for the period two weeks after weaning. Temperatures below 24 Co causes diarrhea and low performance. The social environment is determined by the pig social order mixture of litters, size and weight of the groups, the floor space allowances and the size and type of feeders. The type of facilities include all-in all out, three side productions and the type of floor and pens.
2013-06-04T00:00:00Z