Browsing by Author "Raffrenato, E."
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- ItemCarcass and meat quality attributes of Malawi Zebu steers fed Vachellia polyacantha leaves or Adansonia digitata seed as alternative protein sources to Glycine max(South African Society for Animal Science, 2019-05-09) Chingala, G.; Raffrenato, E.; Dzama, K.; Hoffman, L. C.; Mapiye, CletosTo enhance smallholder beef farmers' capacity to cope with animal feed shortages, especially dietary protein induced by climate change, it is important to evaluate the feeding value of low-cost protein sources naturally available in the environment. The aim of the study was to evaluate carcass and meat quality of Malawi Zebu steers fed diets containing Adansonia digitata (baobab) seed meal or Vachellia polyacantha (white thorn tree) leaf meal as alternative protein sources to Glycine max (soybean) under feedlot conditions. Thirty Malawi Zebu steers (181 ± 21.4 kg body weight; 29 months old) were individually fed forage-based diets made up of rangeland hay and maize bran, with either baobab seed meal, Vachellia leaf meal or soybean meal as a protein source for 120 days. At the end of the feeding trial, animals were slaughtered and the longissimus thoracis et lumborum muscle sampled for meat quality analyses. Steers fed soybean and baobab diets had higher subcutaneous fat thickness, carcass weights than those fed the Vachellia diet. Meat from steers fed the Vachellia and baobab diets had higher ultimate pH and water-holding capacity, and lower drip and cooking losses than meat from steers fed the soybean diet. Feeding baobab and Vachellia diets produced beef with lower lightness (L*) values than the soybean diet, characteristic of dark, firm and dry (DFD) beef. Steers fed the baobab diet had the highest gross profits followed by those fed the Vachellia and soybean diets, respectively. Overall, feeding the baobab and Vachellia diets improved gross profit but produced DFD beef compared to the soybean diet.
- ItemEffects of Saccharomyces cerevisiae, medium and forage type and their interactions on in vitro ruminal fermentation(Elsevier, 2020-09) Russouw, A.; Chevaux, E.; Chaucheyras-Durand, F.; Esposito, G.; Raffrenato, E.The objective of this study was to investigate the effects of a live yeast, Saccharomyces cerevisiae CNCM I-1077, at four doses (0, 1×105, 1×106 and 1 × 107 cfu/mL) according to the reducing medium used [Goering-Van Soest (GV), McDougall (MD) or Kansas State (KS)] on in vitro ruminal neutral detergent fibre digestibility (NDFd), rate of digestion of NDF (kd), organic matter digestibility (OMd), dry matter digestibility (DMd), pH as well as volatile fatty acids (VFA) concentration, using two forages (oat hay and wheat straw) with differing chemical composition. The maximum in vitro NDFd, DMd, OMd as well as kd were obtained with dose 1 × 106 cfu/mL, although differences between doses were not always significant. The pH estimates were the lowest with the 1 × 107 cfu/mL dose, but the differences were not all significant; however, 1 × 107 cfu/mL corresponded to significantly lower pH estimates compared to the control and 1×105 (6.51 vs. 6.60 and 6.59, respectively). The decrease in pH was accompanied by an increase in VFA concentrations as the yeast dose increased. The KS medium resulted in the lowest digestibility estimates, pH estimates as well as kd, regardless of yeast dose. The 1 × 106 cfu/mL was the better performing yeast dose in vitro resulting in higher digestibility estimates which indicates the yeasts ability to stimulate the microorganisms within the rumen by beneficially modifying rumen environment, thus promoting microbiota activity. The MD and GV media provide better environments for fermentation than the KS medium, resulting in higher in vitro NDFd, DMd, OMd, pH estimates as well as rate of NDF digestion. The MD and GV are also the media that resulted in more consistent results when analysing the effects of the live yeast. Our data suggest that the in vitro conditions have to be carefully chosen to be able to demonstrate rumen fermentation shifts with the use of live microbial additives.
- ItemTowards a regional beef carcass classification system for Southern Africa(South African Society for Animal Science, 2017-05-15) Chingala, G.; Raffrenato, E.; Dzama, K.; Hoffman, L. C.; Mapiye, CletosSouthern Africa is home to over 64 million cattle, of which 75% are raised on natural pasture in smallholder farming areas. Indigenous cattle breeds Bos indicus (zebu), B. taurus africanus (Sanga type) and their crosses with B. taurus (European and British) are the most dominant. Despite their dominance, indigenous cattle breeds in smallholder farming areas are commonly marketed through informal markets, and their contribution to formal national economies is therefore limited. This is partly because the current beef carcass grading and classification systems used in the region value inappropriately carcasses from slow-maturing indigenous cattle breeds that are ideally suited to being marketed off natural pasture. The existing systems use carcass yield and quality attributes, but do not predict eating quality at consumer level. Moreover, the principal criteria used to estimate carcass yield and quality, namely age, fat cover and conformation, are assessed indirectly and subjectively. The objective of the current review is to provide an overview of beef carcass grading and classification systems in Southern Africa and analyse their shortcomings in valuing carcasses from indigenous breeds and local production systems. In addition, the review highlights opportunities for improving these systems in Southern Africa and makes suggestions towards developing a regional beef carcass classification system.