Tesis doctoral de Nuria Mach Casellas
In the present thesis, strategies to increase efficiency in intensive beef production focused mainly on feeding and management practices have been studied. the first strategy proposed to increase the efficiency of intensive beef production has been the improvement of carcass and meat quality. Indeed, a study was conducted to evaluate the effect of different pre-slaughter factors on the incidence of high ultimate ph and extreme carcass bruises, and to make proposals pertaining to management, technical, or economic decisions, which could lead to improvements on the high incidence of high ultimate meat ph and the extreme carcass bruises observed in intensive beef production systems. Unfortunately the objective per se was not achieved because the variability of ultimate meat ph and carcass bruises explained by these factors was very low. In consequence, the percentage of beef carcasses with high ultimate meat ph (up to 13%) and extreme bruises (up to 2%) needs to be accepted as normal by the current beef industry. Burdizzo castration of pre-pubertal (8 months of age) holstein bulls has also been studied as an animal management practice, in order to improve carcass and meat quality. For instance, results from this study stated that castration improves the grade of backfat classification, the intramuscular fat content, colorimetric parameters, and tenderness. Furthermore, as the optimal tenderness might be achieved in castrated animals without a long ageing period, it represents a good competitive advantage for the spanish beef industry. However, burdizzo castration might fail in 23% of the cases, and might reduce the total weight gain during the finishing phase. Additionally, the practice of castration illustrates the delicate balance between animal welfare and some management practices on the farm. Therefore, further research (specially in acute and chronic pain and stress) will be necessary to ensure that castration is a good method of improving the meat quality in holstein bulls. Finally, the supplementation of specific omega-3 rich-ingredients in the ruminant diets has also been proposed as a strategy to increase the carcass and meat quality. Effectively, the supplementation of whole linseed of up to 12% of total dry matter intake, enhances meat quality, and additionally converts meat into functional food (meat rich in omega-3), without affecting animal performance and rumen fermentation. The opportunities for expansion of the market seem to be quite favourable and the interest of the consumers is quite high, but the diffusion of these products in the community area is slowed down by some obstacles, including certification, the prices of whole linseed, and its availability. the second strategy proposed to increase the efficiency of intensive beef production has been the reduction of feeding cost through the use of industrial by-products. Indeed, the study of the effect of the inclusion of crude glycerin up to 12.1% of total dry matter intake, as an alternative energy source, to substitute cereals in the diet, has been proposed. Fortunately, the inclusion of crude glycerin of up to 12.1%, does not incur any negative effects in performance, ruminal fermentation, metabolism, animal health, or carcass and meat quality parameters. However, today the reduction of feeding cost through the inclusion of crude glycerin may not be a feasible strategy as a result of the high price of crude glycerin in relation to other concentrate ingredients. in summary, the present thesis not only provides the results of different feeding and management strategies to improve intensive beef production efficiency, but also highlights concerns about their constrains and limitations.
Datos académicos de la tesis doctoral «Management and feeding strategies in young holstein bulls fed high-concentrate diets«
- Título de la tesis: Management and feeding strategies in young holstein bulls fed high-concentrate diets
- Autor: Nuria Mach Casellas
- Universidad: Autónoma de barcelona
- Fecha de lectura de la tesis: 17/12/2008
Dirección y tribunal
- Director de la tesis
- María Devant Guille
- Tribunal
- Presidente del tribunal: sergio Calsamiglia blancaforf
- anders Karlsson (vocal)
- (vocal)
- (vocal)