Growth, carcass and sensory characteristics of m. longissimus lumborum from wethers fed silage diets made from maize or various sorghum varieties

Growth, carcass characteristics and eating quality of meat from South African Mutton Merino wethers fed maize or different sorghum silage diets were studied. Forty newly weaned wethers (20 kg) were randomly allocated to 10 dietary treatments, viz. non-bird-resistant grain sorghum silage (NGS), maize silage (MS), bird-resistant grain sorghum silage (BGS), forage sorghum silage (FSS) and a standard non-silage control diet consisting of equal proportions of maize meal and milled lucerne hay (C). Silage was included at 2 levels, namely 50% or 70% of the total diet on dry matter basis. Average daily gains of wethers were recorded from weaning to slaughter at 45 kg live mass. Carcass mass, dressing percentage, subcutaneous fat thickness and carcass length were recorded. Samples from the left m. longissimus lumborum were minced and stewed to determine foreign odours and flavours, while samples from the right m. longissimus lumborum were oven-roasted for subsequent sensory evaluation by an analytical sensory panel. Growth responses did not differ between wethers fed MS, NGS or BGS at inclusion levels of 50% or 70%. FSS at the 70% inclusion level resulted in poorer growth rates (p < 0.05) and longer feeding periods (p < 0.05) compared to the other silage diets. The best feed conversion efficiencies and shortest finishing periods were recorded by feeding MS at either the 50% or the 70% inclusion level, NGS at the 50% inclusion level, or BGS at the 50% inclusion level. Dressing percentages and subcutaneous fat thicknesses of wethers fed BGS and FSS at a 70% inclusion level were lower (p < 0.05) compared to those fed the other silage diets. No significant differences in sensory characteristics or cooking losses and no sensory defects were observed among wethers fed different silage diets. (South African Journal of Animal Science, 2000, 30(1): 36-42

Sensory characteristics of meat and composition of carcass fat from sheep fed diets containing various levels of broiler litter

The effect of high levels of broiler litter in the diets of sheep on sensory characteristics and composition of fat in mutton was evaluated. Thirty-six South African Mutton Merino wethers weighing ca. 41 kg were randomly allocated to four treatment diets containing 0, 28, 56 or 85% broiler litter. All wethers were slaughtered at a target body mass of 55 kg. Dressing percentage was calculated and the composition of fatty acids in the subcutaneous fat was analysed. An analytical sensory panel evaluated sensory characteristics of carcass samples and loin sample characteristics. High sensory scores (7 out of 10) were obtained for all dietary treatments. Compared to the other treatments, a high inclusion level (85%) of broiler litter in the diet reduced (p < 0.05) the flavour and overall acceptability of sensory samples, decreased concentrations of myristic acid (C14:0) and margaric acid (C17:0) in subcutaneous fat and increased linolenic acid (C18:3) concentrations. It was concluded that the inclusion of broiler litter in diets for sheep at levels of up to 56% should not adversely affect the sensory characteristics of the meat, but higher inclusion levels might have a slight adverse affect on subcutaneous fat composition and sensory characteristics. (South African Journal of Animal Science, 2000, 30(1): 26-32

Dietary influences on lutein pigments and carcass fat quality in wethers of different maturity types

The aim of this research was to study the effect of high-maize diets and pelleting on the accumulation of lutein pigments and appearance of the subcutaneous fat in Dorper and SA Mutton Merino wethers. High and medium energy maize diets were fed to Dorper and SA Mutton Merino wethers from an initial live weight of ca. 21 kg to a target weight of 43 kg. Fat colour and firmness were evaluated subjectively on a 5-point scale. Samples of the subcutaneous fat and feed were collected for fatty acid and lutein analyses. Loin samples (L1-L6) were oven-roasted and fat characteristics evaluated by a trained sensory panel. The concentrations of lutein pigments and total long-chain fatty acids were influenced mainly by the fattening period (p<0.05) and pelleting of the diets (p<0.05). Lutein concentrations increased during longer fattening periods and resulted in lower colour scores for subcutaneous fat. Neither breed nor the maize content of the diet significantly affected the concentration of lutein in the subcutaneous fat. Lutein concentrations resulted in lower subjective colour scores (p<0.05) and improved the aroma of lamb during carving (p<0.05). The present results suggest that the 'unacceptable' lutein pigments contribute to the typical aroma of lamb.Die doel van die studie was om die invloed van hoe mielie-diete en verpilling van hoe mielie-diete op die aansameling van luteinpigmente en voorkoms van die subkutanevet van Dorper en SA Vleismerino hamels te bestudeer. Hoe en medium energie mielie-diete is aan Dorper en SA Vleismerino hamels vanaf ca. 21 kg tot teikenmassas van 37 en 43 kg gevoer. Onderhuidse vetmonsters en voermonsters is versamel vir vetsuur- en luteinontledings. Subkutanevet-eienskappe is subjektief geevalueer op 'n 5-punt skaal. Monsters van die linker lende (L 1-L6) is geoondbraai en vet-eienskappe is sintuiglik geevalueer deur 'n opgeleide proepaneel. Die konsentrasies van lutein pigmente en totale langketting-vetsure is beinvloed deur die tydperk van vetmesting (p<0.05) en die verpilling van die dieet (p<0.05). Luteinkonsentrasies het verhoog tydens langer vetmestingsperiodes terwyl die kleur van die subkutane vet verswak het. Die ras en vlak van mieliemeel-insluiting in die dieet het geen betekenisvolle invloed gehad op die konsentrasies van lutein in die subkutane vet nie. Die konsentrasie van luteinpigmente het die subjektiewe kleurtellings verlaag (p<0.05) en aroma tydens voorsny verbeter (p<0.05). Die huidige resultate dui daarop dat 'n klein hoeveelheid van die 'onaanvaarbare' luteinpigmente bydra tot die tipiese aroma van lamsvleis.https://www.sasas.co.za/resources/sa-journal-animal-sciencehj2020Animal and Wildlife Science

Live animal and carcass characteristics of South African indigenous goats

Eighty-nine intact male, castrates and female South African indigenous goats in three age groups (0, 2 - 6 and 8 permanent incisors) and two pre-slaughter conditioning groups; namely, the non-conditioned which were slaughtered within three months of purchase and the pre-slaughter conditioned, which were slaughtered 6 - 10 months after purchase or birth were used. The effect of sex, age and pre-slaughter conditioning on live animal, carcass dimensions and carcass composition were evaluated. The goats were large with live weight, carcass weight and carcass dimensions in the range of the large breeds of southern Africa. They had a high lean and low fat content. Intact males were suited for high chevon yield because they were heavy, had a high lean and low fat content, and losses during dressing and chilling were reduced by improved nutrition. Goats between 2 - 6 teeth yielded heavy carcasses that were comparable to goats in the 8-teeth group, and had proportionately more lean and less carcass fat. The hind limb was ideal for high lean and low fat, high value cuts but the dorsal trunk was bony and yielded less lean. Pre-slaughter conditioning improved the overall size of the goats and reduced the losses during slaughter and chilling. It also improved the lean / bone and lean and fat / bone indices

Acceptability of chevon from kids, yearling goats and mature does of indigenous South African goats : a case study

Consumer sensory evaluations of oven-roasted goat and sheep m. longissimus dorsi samples were conducted in two series to determine the acceptability of chevon from indigenous South African goats to consumers. Chevon samples were from goat carcasses of known description. In series I, castrate and female goats and female sheep, all with 2 – 6 permanent incisors, were compared. Castrate males were significantly heavier and yielded heavier carcasses than the female goats. Nonetheless, the two groups did not differ significantly in carcass and meat characteristics. Cooking losses from mutton samples were significantly higher than losses from chevon from female goats only. In series II, male kids (milk teethed), old does (8 permanent teeth) and sheep (2 – 6 permanent teeth) were compared. Does were heavier at slaughter, but the mean carcass weight did not differ significantly from that of the kids. There were no significant differences between the does and kids in carcass tissue composition and sarcomere lengths. The pHu of does was significantly higher than that of kids. Cooking losses from mutton and chevon samples in series II did not differ significantly. Amongst the consumer characteristics, level of education was the most important determinant of consumer acceptance of the sensory attributes and intended frequency of consumption in both series. Population group was a significant factor in the judgement of the more diverse meats of series II only. Sensory evaluations indicate that all meat types were highly acceptable to the consumers who on average were willing to eat any of the meats at least once a week. The study indicated that chevon from indigenous South African goats is acceptable to consumers and may be as acceptable as mutton, provided that the meat is from goats of about two years of age or younger