Body length, height, heart girth, paunch girth, pre-slaughter weight varied significantly (P<0.001) with age and sex of animals (Table 1). It increased with the advancement of age and was higher for males than females for identical age groups. Pre-slaughter weight, empty live weight, hot carcass weight were highest in ram and lowest in ewe lamb. These might be ascribed to the size differences in males and females. Dressing percentage based on pre-slaughter weight, the weight of reproductive organs, weight of caul fat, kidney fat, the weight of total edible, the weight of different type fat and fat percentage were higher in female than male in same age groups. The hot carcass weight was in accordance with
Kumar et al., (2017). The loin eye area differed significantly (P<0.001) in all the groups. Our study results are in agreement with earlier findings
(Das et al., 2008).
Yields of edible and inedible offals (Table 1) differed significantly (P<0.001). It increased with the advancement of age and was higher for males than females. The weight of testis and testis fat increased with age. Weights of the spleen, caul fat, kidney fat, kidney, heart, liver, lungs, total edible offal, differed significantly (P<0.05).
The primal cut yield was affected significantly (P>0.05) by age and sex (Table 2).
Shinde et al., (2018) reported that half carcass weight increased significantly with age in Malpura sheep. Leg cut was the major portion of half carcass followed by neck and shoulder cut (Fig 1).
Pena et al., (2005) reported that sex affected the amount and type of fat deposited. The lean fat ratio was highest for G-1(G-
Rl). A higher lean fat ratio is always desirable. The meat bone ratio was highest for G-4(G-
Ea) while meat bone ratios in G-1 (G-
Rl) and G-2(G-
El) were comparable. With an increase in the animal age, the growth rate of muscles is unchanged while the growth rate of bone tissue reduces
(Koyuncu et al., 2007). Santos-Silva and Portugal (2001) observed that the meat/bone ratio increases with an increase in slaughter weight.
The meat quality was also affected due to age and sex in Malpura sheep. Markedly higher protein content was observed in the ewe lamb group. A significantly (P<0.001) higher fat content was recorded in the female group for the same age group. With the progression of slaughter age, fat and protein levels increased whereas moisture content declined
(Madruga et al., 1999). Tejeda et al., (2008) also found a non-significant effect of sex on moisture content. A muscle composition varies with increasing animal age irrespective of species, breed, or sex and in most cases; younger animals are considered to have less myoglobin, less intramuscular fat and more moisture
(Lawrie, 1998). Fat is the last tissue to mature and older animals tend to be fatter. The inter-muscular fat content of
Longissimus dorsi increased and moisture content decreased with increasing slaughter weight. Lipids are major components of the muscle structure that give the meat the sensory characteristics desired by the consumer such as juiciness, flavour and aroma
(Zorzi et al., 2013).
The pH of the meat is very important as it has a definite impact on meat quality and shelf life. The meat pH recorded after 45 minutes of slaughter was found to be comparatively higher in ewe lamb than others. The meat pH variation might be due to variations in animal age, pre-slaughter handling of animals, slaughter condition and handling of meat.
Tejeda et al., (2008) reported that animal sex did not affect meat pH. The cooking loss differed (P<0.05) significantly between the groups with comparatively higher values in ram lambs.
Yarali et al., (2014) recorded cooking losses of 26.80, 28.76 and 24.10 percent in
Longissimus thoracis et lumborum,
Longissimus thoracis and
Semitendinosus muscle, respectively. The firmness (N) and work of shear (N*sec.) differed significantly (P<0.001) between the groups with significantly higher in ram. The fibre diameter, hydroxyproline content and toughness of the meat had a positive correlation with the shear force value of meat while it has a negative correlation with the sarcomere length
(Biswas et al., 1989). The value obtained in the present study is in concurrence with the reports of
Sen et al., (2004) in yearling sheep reared under a semi-arid region. The heme iron content (μg/gm) and total meat pigment (ppm) differed significantly (P<0.001) with sex and age. A significantly higher total meat pigment was observed in ewes and increased with increasing age. The greater meat pigment concentration in aged sheep groups was attributed to the more heme pigment and myoglobin pigment
(Mamino and Horn, 1996). As animal age increases the myoglobin concentration increases which in turn improves red color intensity
(Warner et al., 2007). Advancement in sheep age leads to increased aerobic muscle fibres which raise myoglobin pigment leading to better red colour of meat. Nevertheless, the degree differs according to the breed and nutrition
(Warner et al., 2007). The salt soluble protein content was comparable (P>0.05) between the groups.
Ahmed et al., (2015) observed a non-significant effect of age on salt soluble protein content in goatmeat. The collagen content of meat in ewes was significantly higher compared to in other groups. Significantly higher collagen solubility was observed in ewe lambs (G-El). Collagen content and muscle fiber diameter increased while collagen solubility decreased with age. Intra-muscular collagen and cross-link formation depends upon the age of the animal and is directly proportional to age.
Polidori et al., (2017) observed a significant effect of age on collagen content in lambs. The collagen has a low rate of metabolic turnover which leads to the permanent formation of cross-linkages
(Purslow et al., 2012). The water holding capacity in ram lambs was comparatively higher than in other groups.
Stankov et al., (2002) observed a non-significant effect of age on water holding capacity in the young goat of Bulgarian breeds and crossbreeds of goats. A significantly larger muscle fibre diameter was observed in the ewes group. The myofibrillar fragmentation index was comparatively higher for ewe lambs. The myofibrillar fragmentation index is a measure of myofibrillar protein degradation
(Seideman et al., 1987). This was highly related to shear force and sensory tenderness ratings
(Calkins and Davis, 1980).