Growth and carcass characteristics of lambs sired by Dorper and Dorset rams

Growth and carcass merit of Dorset-(DO) and Dorper-sired (DP) lambs were compared over 3 yr in matings with 50% Dorset, 25% Rambouillet, 25% Finnsheep ewes. The DP were slightly lighter (P = 0.09) at birth than the DO lambs. In the first year of the study, DP lambs produced by AI using imported South African sires were heavier than DO lambs when weaned at 60 d of age (21.7 vs. 19.5 kg; P = 0.05). In yr 2 and 3, however, offspring of natural-service Dorper sires produced in the U.S. did not differ in weaning weight from DO lambs (16.9 vs. 17.8 kg; P = 0.02 for breed x year interaction). Lamb survival was also affected by breed x year interaction (P = 0.04). In 2000 and 2001, with 12 to 16% triplet or larger litters, mortality was higher for DP lambs (14.9 vs. 7.7%; P = 0.12). However, in 2002, with approximately 33% triplet or larger litters and with higher mortality levels in all birth types, DP lambs had fewer death losses than did DO lambs (23.2 vs. 36.1%; P = 0.11). No differences between DO and DP lambs were observed in postweaning gain during summer grazing or in drylot in autumn. At chilled carcass weights of approximately 25 kg, DP lambs were somewhat fatter than DO lambs, with greater body wall thickness (P < 0.01; 22 vs. 19 mm) and slightly greater backfat thickness (P = 0.15; 6.4 vs. 5.5 mm) and yield grades (P = 0.15; 2.9 vs. 2.6). The DP lambs also had more desirable leg scores (P = 0.01; 11.6 vs. 10.9) and slightly larger LM area (P = 0.13; 14.1 vs. 13.5 mm2) than did DO lambs, confirming acceptable muscling and conformation in carcasses from Dorper-sired lambs. However, differences were not observed in the percentage of carcass weight in the leg or loin, or in the lean:bone ratio in the dissected leg. Ultrasonic measurements of backfat thickness and LM area taken in live lambs before slaughter were positively associated with direct measures on chilled carcasses with correlations of 0.77 for backfat thickness and 0.51 for LM area.     

Evaluation of morphological lesions in selected internal organs in lambs of Kamieniecka,Pomorska and Polish Blackheaded Mutton sheep and their crossbreeds

Investigations were carried out on 40 rams aged 50 days (n = 8), Kamieniecka (K), Pomorska (P) and Polish Blackheaded Mutton (PBM) breeds and their crossbreeds (K x PBM, P x PBM). Microscopic evaluation of the liver, kidneys, spleen and heart muscle in the rams as well as ultrastructural analyses of their liver and semitendinous muscle showed that retrogressive lesions, circulation disturbances, inflammation and progressive changes occurred respectively: frequently, occasionally, rarely. Internal organs, particularly liver and kidneys, of crossbred rams (K x PBM and P x PBM) were almost two times more affected with morphological lesions than purebred lambs (K and P). However, in the semitendinous muscle these differences were more vivid in the ultrastructural analysis than in the histopathological or macroscopic observations. Results suggest that breed growth-rate differences have effects on the pathomorphological pattern of the liver and kidneys in lambs. On the bases of this evaluation, it can also be emphasised that young PBM rams are less susceptible to morphological lesions than the K and P breeds.     

Effect of zeranol implants in ram and wether lambs on performance traits, carcass characteristics, and subprimal cut yields and distribution.

In two separate 2 x 2 factorial arrangements, 69 male, crossbred lambs were allotted randomly to the following treatments: 1) nonimplanted (NI) rams, 2) implanted (I) rams, 3) NI wethers, and 4) I wethers. In Trial 1, 36 lambs were allotted to treatment groups at birth (n = 9) and I lambs were implanted with 12 mg of zeranol between 1 and 3 d of age and again at weaning (average age of 62 d). Lambs were slaughtered at three time-constant end points of 78, 93, and 107 d on feed postweaning (average age of 155 d). Rams grew faster postweaning, were more efficient in their feed conversion, were heavier at slaughter, and had lower numerical yield grades than did wethers (P less than .05). Implanted lambs tended (P = .08) to grow faster and were (P less than .05) more efficient in their feed conversion than NI lambs. Rams produced heavier (P less than .05) trimmed subprimal shoulders, loins, and legs and had (P less than .05) a higher percentage of their carcass weight in the subprimal shoulder than did wethers. During Trial 2, NI rams (n = 8), I rams (n = 8), NI wethers (n = 8), and I wethers (n = 9) were allotted to treatment groups, and I lambs were implanted at average ages of 14, 55, and 98 d. After weaning, lambs were weighed every 14 d and were slaughtered 7 d after reaching a minimum weight of 50 kg (average age of 148 d).(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessing carcass and meat characteristics of Damara, Dorper and Australian Merino lambs under restricted feeding

Seasonal weight loss (SWL) is the most pressing constraint in ruminant production systems in tropical climates. SWL is controlled using supplementation, which is costly and difficult to implement in extensive systems, or using breeds adapted to tropical hot dry climates, like the Damara and Dorper. Albeit 15 years in Australia, little is known on how these sheep compare to Australian Merino. Here, the responses of the Damara, Dorper and Merino breeds to nutritional stress were compared. Seventy-two 6-month-old ram lambs, 24 from each breed, were allocated to growth (gaining 100 g/day) or restricted diets (losing 100 g/day, 85 % of maintenance needs). Animals were weighed and carcass and meat characteristics determined. Results point out to the existence of important differences between the three genotypes, in particular between the Merino and the Southern African breeds. Additionally, Merino ram lambs seem to have been more influenced by SWL than the other two, with consequences on meat characteristics.     

Comparisons of endocrinological and testis parameters in 18-month-old Ile de France and Romanov rams

Endocrinological and testis parameters of adult 18-month-old Ile de France (IF) and Romanov (Ro) rams were compared during sexual season. Testis weights, total volumes of intertubular tissue, and of blood and lymph vessels, total seminiferous tubule length, rete testis flow rate and daily production of germ cells were significantly higher in IF than in Ro rams. These variations originated from differences in Sertoli cell numbers, which were established before puberty. When daily productions of germ cells, of ABP or of RTF were expressed per Sertoli cell, they were higher in Ro than in IF rams. Quality of spermatids, as measured by their cellular size prior to elongation, was lower in Ro than in IF. The number of FSH-binding sites per Sertoli did not differ between the two breeds but FSH plasma levels were higher in Ro than in IF rams. Total numbers of Leydig cells per testis, their individual size or their LH-binding capacity did not differ significantly between the two breeds. However, the ratio of mean testosterone upon mean LH plasma levels were greater in Ro than in IF rams while both breeds had identical LH mean plasma levels.     

Effects of a controlled-release albendazole capsule on parasitism and production from grazing Merino ewes and lambs

SUMMARY: Effects of a controlled-release albendazole capsule (CRC) on nematode parasitism and production of Merino ewes and lambs were Investigated in a replicated grazing experiment between August 1986 and July 1989. The experiment was conducted on a site where the naturally occurring parasites were benzimidazole-resistant, with double the recommended dose of oxfendazole reducing faecal egg counts of Trichostrongylus colubriformis by less than 50%. Two CRC treatments were compared with a minimal treatment control and the widely-used strategic control program, Wormkill.
Egg counts and worm burdens of major parasite species of ewes and of lambs before and after weaning were significantly reduced by use of the CRC in ewes before lambing or in lambs at weaning. These parasitological effects were reflected in increased productivity of CRC ewes and lambs. Ewes given CRCs lost less weight and grew more wool during lactation than ewes given Wormkill or control treatments, while their lambs gained more weight and had heavier fleeces than lambs from Wormkill or control treatments. Where lambs were weaned by removing ewes from the lambing paddock, administration of the CRC at weaning to lambs whose dams had also been treated with the CRC did not result in improved production when compared with lambs from ewes dosed with CRCs and treated after weaning according to the Wormkill program. Some possible uses for the CRC in ewes and lambs were identified.     

Genetic parameters for carcass and meat quality traits and their relationships to liveweight and wool production in hogget Merino rams.

Genetic parameters for carcass and meat quality traits of about 18-month-old Merino rams (n = 5870), the progeny of 543 sires from three research resource flocks, were estimated. The estimates of heritability for hot carcass weight (HCW) and the various fat and muscle dimension measurements were moderate and ranged from 0.20 to 0.37. The brightness of meat (colour L*, 0.18 +/- 0.03 standard error) and meat pH (0.22 +/- 0.03) also had moderate estimates of heritability, although meat relative redness (colour a*, 0.10 +/- 0.03) and relative yellowness (colour b*, 0.10 +/- 0.03) were lower. Heritability estimates for live weights were moderate and ranged from 0.29 to 0.41 with significant permanent maternal environmental effects (0.13 to 0.10). The heritability estimates for the hogget wool traits were moderate to high and ranged from 0.27 to 0.60. The ultrasound measurements of fat depth (FATUS) and eye muscle depth (EMDUS) on live animals were highly genetically correlated with the corresponding carcass measurements (0.69 +/- 0.09 FATC and 0.77 +/- 0.07 EMD). Carcass tissue depth (FATGR) had moderate to low genetic correlations with carcass muscle measurements [0.18 +/- 0.10 EMD and 0.05 +/- 0.10 eye muscle area (EMA)], while those with FATC were negative. The genetic correlation between EMD and eye muscle width (EMW) was 0.41 +/- 0.08, while EMA was highly correlated with EMD (0.89 +/- 0.0) and EMW (0.78 +/- 0.04). The genetic correlations for muscle colour with muscle measurements were moderately negative, while those with fat measurements were close to zero. Meat pH was positively correlated with muscle measurements (0.14 to 0.17) and negatively correlated with fat measurements (-0.06 to -0.18). EMDUS also showed a similar pattern of correlations to EMD with meat quality indicator traits, although FATUS had positive correlations with these traits which were generally smaller than their standard error. The genetic correlations among the meat colour traits were high and positive while those with meat pH were high and negative, which were all in the favourable direction. Generally, phenotypic correlations were similar or slightly lower than the corresponding genetic correlations. There were generally small to moderate negative genetic correlations between clean fleece weight (CFW) and carcass fat traits while those with muscle traits were close to zero. As the Merino is already a relatively lean breed, this implies that particular attention should be given to this relationship in Merino breeding programmes to prevent the reduction of fat reserves as a correlated response to selection for increased fleece weight. The ultrasound scan traits generally showed a similar pattern to the corresponding carcass fat and muscle traits. There was a small unfavourable genetic correlation between CFW and meat pH (0.19 +/- 0.07).     

Fattening performance, carcass and meat quality characteristics of Kivircik male lambs

The objective of this study was to determine the fattening performance and carcass and meat quality characteristics of Kivircik twin male lambs. Twelve lambs at approximately 5?months of age were subjected to a finishing diet for 60?days. Average live weight of lambs at the beginning and the end of the fattening were 23.14?±?0.84 and 39.0?±?1.01?kg, respectively. Daily live weight gain and feed conversion efficiency were found as 0.265?±?0.007 and 6.14?kg, respectively. Hot carcass weight, cold carcass weight, and dressing percentage were 19.6?±?0.6 and 18.9?±?0.6?kg and 48.1?±?0.3%, respectively. Kidney-pelvic fat weight, internal fat weight, and m. longissimus dorsi area were 0.117?±?0.023 and 0.364?±?0.041?kg and 15.26?±?0.70?cm(2), respectively. The percentages of leg, back loin, forearm, shoulder, neck, flank-chest, kidney-pelvic fat, and internal fat in carcasses of the lambs were found as 34.1?±?0.4%, 19.6?±?0.3%, 21.0?±?0.2%, 7.0?±?0.3%, 10.5?±?0.3%, 7.2?±?0.2%, 1.3?±?0.1%, and 1.8?±?0.1%, respectively. Averages water content, ash, protein content, and fat content of meat samples were 73.4%, 1.0%, 19.5% and 3.6%, respectively. pH and thiobarbituric acid reactive substances values of meat samples were 5.55 and 0.056?±?0.017. L*(lightness), a*(redness), and b*(yellowness) values were recorded as 43.87, 12.69, and 10.22, respectively. Thus, we conclude that fattening performance, carcass, and meat quality of Kivircik lambs are satisfactory levels than that of other native breeds.     

The effect of Johne's disease on production traits in Romney, Merino and Merino x Romney-cross ewes

AIM: To quantify the effects of clinical Johne's disease on the performance of Romney, Merino and Merino x Romney-cross ewes. METHODS: The performance of ewes was compared using eight birth cohorts (1971-1978). Merino and Merino-cross genotypes included New Zealand Merino and Australian Superfine Merino sources. Intensive monitoring of Johne's disease was undertaken over the production years 1975-1982. Positive diagnostic evidence of Johne's disease was established post mortem from lesions of granulomatous enteritis associated with high numbers of acid-fast bacilli. Over years, data on a total of 2,341 Romney ewes and 1,292 Merino and Merino x Romney-cross ewes were recorded, consisting of annual records of liveweight (LWT), greasy fleece weight (FWT), number of lambs born per ewe per year (NLB), and lifetime productivity of ewes. RESULTS: A total of 82 (3.5%) Romney ewes and 62 (4.8%) Merino and Merino x Romney-cross ewes were diagnosed with clinical Johne's disease over the 8-year monitoring period, equivalent to 0.9% and 1.2% annual cases for these breeds, respectively, of the ewes present at mating. The percentage of clinical cases (p<0.04) and the age at death from Johne's disease (p<0.02) were lower for Romneys than for Superfine Merinos. The mean age of death from Johne's disease was 3.41 (standard error (SE) 0.06) years, lower than the mean disposal age from the flock of 5.03 (SE 0.02) years for clinically normal ewes (p<0.001). In their final year of production, ewes with clinical Johne's disease had lower LWT by 5.3 kg (10.5% of the mean; p<0.001), lower annual FWT by 0.54 (SE 0.10) kg (14.2%; p<0.001), fewer NLB by 0.15 (SE 0.07) lambs (13%; p<0.05), and lower litter weaning weights by 3.6 (SE 1.3) kg (15%; p<0.01) compared with clinically normal ewes. The size of the production losses associated with Johne's disease depended on the age to which ewes survived. Considering all production years of ewes (up to 8 years), the total weight of lambs weaned by ewes with clinical Johne's disease was 30.9 (SE 3.4) kg lower (46%; p<0.001) than the total from clinically normal ewes. CONCLUSIONS: Clinical Johne's disease led to significant losses in LWT, FWT, NLB, and in the lifetime production of ewes, amounting overall to a 46% reduction in productivity (p<0.001). CLINICAL RELEVANCE: Productivity losses from clinical cases of Johne's disease would be of considerable economic importance in flocks with a high incidence of the disease. The lack of good diagnostic tests for Johne's disease in the live animal, and the lack of active surveillance programmes, has made it difficult to establish the true prevalence of Johne's disease in sheep flocks in New Zealand, and its economic consequences.     

Influence of dietary protein supply on resistance to experimental infections with Haemonchus contortus in Ile de France and Santa Ines lambs

The effect of Haemonchus contortus infection in sheep fed with a moderate and high protein content diet was evaluated in two breeds of sheep. Forty-eight Ile de France and Santa Ines lambs were maintained indoors since birth, in worm-free conditions. The lambs were allocated after weaning in four groups of six animals per breed, which were either infected or remain uninfected and given access to either a moderately or highly metabolizable protein diet. The moderately and highly metabolizable protein diets were calculated to supply 75 and 129 g metabolizable protein per kg of dry matter (MP/kg DM), respectively. The infection consisted of a trickle infection with 300 infective larvae, three times a week, for 12 weeks. Significant differences were observed for mast cell, globule leukocyte and eosinophil counts in the abomasal mucosa of the infected groups compared to the control of both breeds (P<0.05), regardless of the diet supplied. Significantly higher IgA anti-L5 antibody was detected in the infected Santa Ines groups than in the infected Ile de France groups (P<0.05). Increased metabolizable protein supply resulted in larger body weight gain and higher packed cell volumes for both breeds (P<0.05). Both breeds showed an increased ability to withstand the pathophysiological effects of H. contortus infection when given access to the highly metabolizable protein diet. However, increased metabolizable protein supply resulted in reduced worm burdens in Santa Ines lambs but not in the Ile de France lambs (P<0.05). The present results show that the increase in protein content in growing lamb diets may benefit resistance and resilience to gastrointestinal parasites but that these benefits may vary among breeds.     

Evaluation of columbia, USMARC-Composite, Suffolk, and Texel rams as terminal sires in an extensive rangeland production system: III. Prefabrication carcass traits and organ weights

To evaluate terminal-sire breeds, harvest BW, prefabrication carcass measurements, and organ weights were evaluated over 3 yr for 518 crossbred wether lambs (ovis aries). Lambs were produced by single-sire matings of 22 Columbia, 22 USMARC-Composite (Composite), 21 Suffolk, and 17 Texel rams to adult Rambouillet ewes. Lambs were raised to weaning under an extensive western rangeland production system and finished in a feedlot on a high-energy finishing diet. Wethers were randomly assigned to be harvested at an average BW of 54.4, 61.2, or 68.0 kg and then transported to The Ohio State University abattoir for harvest. Wether BW was recorded before transport (off-test BW) and before harvest. Prefabrication carcass measurements and organ weights were recorded either after harvest or after an approximate 24-h chill. At comparable numbers of days on feed, Suffolk-sired lambs had heavier (P < 0.01) off-test BW, harvest BW, HCW, chilled carcass weight (CCW), and kidney weights than lambs sired by the other breeds. Suffolk-sired lambs had more (P < 0.01) kidney-pelvic fat than did Columbia-sired lambs; Composite- and Texel-sired lambs were intermediate and did not differ (P > 0.06) from the other crossbred lambs. Texel- and suffolk-sired lambs had larger lm area and greater conformation scores than Columbia-sired lambs (P < 0.03). Texel-sired lambs had greater (P < 0.01) body wall thickness, quality grades, and leg scores than Columbia-sired lambs. Composite- and Suffolk-sired lambs did not differ from each other or from lambs sired by any other breed for body wall thickness (P > 0.18) and were intermediate for quality grades and leg scores. Sire breed did not affect (P > 0.05) shipping shrink, dressing percentage, pelt weight, liver weight, and fat depth. Adjusting data to a comparable off-test BW or CCW modified sire breed rankings for some measurements. Texel-sired lambs were equal or superior to lambs sired by other breeds for HCW, CCW, dressing percentage, pelt weight, LM area, quality grade, and leg and conformation scores. However, Texel-sired lambs also had values for kidney-pelvic fat weight, fat depth, and body wall thickness that were equal to or greater than those of lambs sired by the other breeds, indicating increased fatness at comparable BW. Producers can use these results to select terminal-sire sheep breeds that will complement their production system and improve market lamb value.     

Effect of the repartitioning agent cimaterol on growth, carcass and skeletal muscle characteristics in lambs

Ten crossbred (Suffolk X Rambouillet) whether lambs were randomly assigned to receive 0 or 10 ppm cimaterol (CIM) in a completely mixed high-concentrate diet for 8 wk. Total weight gain and feed efficiency were improved 29% (P less than .05) and 14%, respectively, in the CIM-fed group. CIM also improved (P less than .01) dressing percent by 4.9 percentage points and improved yield grade by one grade. CIM increased longissimus muscle (LD) area 38% (P less than .01) and the yield of four lean cuts 28% (P less than .01). No difference was found in the proportion of type I (slow-contracting, oxidative) and type II (fast-contracting, mixed glycolytic/oxidative) fibers in LD and semitendinosus (ST) muscles between control and CIM groups, indicating no change in fiber type. The cross-sectional area of type II fibers in LD and ST muscles of the CIM group was 2,081 and 1,951 micron 2 as compared with 1,391 and 1,296 micron2 of the control group, respectively. The increase was approximately 50% (P less than .01). No difference was found in cross-sectional area of type I fibers, indicating that the increase of muscle mass was due to hypertrophy of type II fibers only. DNA concentration (micrograms/g wet muscle or microgram/g protein) of CIM muscle was much lower (P less than .01) than that of control muscle, suggesting that the protein accretion in muscle was accomplished without additional incorporation of nuclei from satellite cells.     

Dietary protein and chromium tripicolinate in Suffolk wether lambs: effects on production characteristics, metabolic and hormonal responses, and immune status.

Thirty-two Suffolk wether lambs were fed for 84 d in a 2 x 2 factorial experiment using two levels of dietary protein (9.0 to 12.1% CP, low protein, LP; or 12.8 to 14.4% CP, high protein, HP) and supplemental Cr (none, C; or 400 ppb Cr as chromium tripicolinate, Cr). At 14- to 21-d intervals, lambs were weighed, and jugular blood samples were collected. Mean ADG and carcass weight (P > .10) did not differ. In lambs fed HP, Cr reduced liver weight and increased kidney weight (P < .01). Lambs fed HP had elevated plasma urea N (PUN; P < .01) and albumin (P < .04). During an i.v. epinephrine challenge on d 43, plasma cortisol declined in lambs fed Cr (Cr x time, P < .03) and in lambs fed LP (CP x time, P < .001). An i.v. glucose tolerance test conducted 3 h later showed that supplemental Cr decreased glucose clearance rate in lambs fed HP (CP x Cr, P < .10) but not in lambs fed LP. On d 62, PUN was increased in lambs fed HP (P < .001) between 0 and 3 h postprandial, and there was a Cr x CP interaction (P < .04). Postprandial plasma NEFA declined with Cr vs C (Cr x time, P < .07) and with HP vs LP (CP x time, P < .10). By d 66, lambs fed Cr had an elevated (P < .03) blood platelet and fibrinogen content. Chromium increased erythrocyte count in lambs fed HP (Cr x CP, P < .08), and isolated peripheral lymphocytes had greater blastogenic response to 4 microg/mL of phytohemagglutinin (Cr x CP, P < .001). The lymphocyte response to pokeweed mitogen (.2 microg/mL) was reduced in lambs fed Cr (P < .10). In the present experiment, Cr supplementation had minimal and inconsistent effects on production and metabolic criteria of lambs.     

Influence of protein supplementation during late pregnancy and lactation on the resistance of Santa Ines and Ile de France ewes to Haemonchus contortus

This experiment aimed to evaluate the effect of periparturient metabolizable protein (MP) nutrition on resistance to Haemonchus contortus in single rearing Ile de France and Santa Ines ewes. The restriction-fed iso-energetic diet was calculated to provide either 0.8 (low MP diet) or 1.3 (high MP diet) times MP, from three weeks before parturition until eight weeks into lactation. The ewes were experimentally infected with 1000 H. contortus infective larvae (L3) three times a week (Mondays, Wednesdays and Fridays), starting five weeks before the predicted date for parturition until a total of 15,000 L3 had been administered. While both breeds showed elevated fecal egg counts (FEC), these values were significantly lower for Santa Ines ewes than Ile de France ewes, but were independent of level of MP feeding. The latter also did not affect lamb weight gain and ewe body weight variation in each breed. Packed cell volume and total plasma protein for Santa Ines in all periods were significantly higher than those for Ile de France ewes (P<0.01) but were not affected by nutrition. In contrast, levels of serum IgG and IgA antibodies against somatic H. contortus infective larvae and adult antigens were similar between breeds but higher in animals that received high MP diets (P<0.05). The reduced body score of ewes at the beginning of the experiment probably influenced their high susceptibility to incoming larvae. Since, unexpectedly, MP scarcity was not achieved in this experiment, our data support the view that Santa Ines ewes are more resistant to H. contortus than Ile de France ewes.     

Effect of cohabitation with white-faced ewes on estrous activity of Hampshire and Suffolk ewes exposed to rams in June

Two groups of 24 Hampshire and 26 Suffolk purebred ewes each were used to study effects of cohabitation with cyclic white-faced (WF) ewes on estrous activity in June. Ewes lambed in January, February and March and had been isolated from mature rams since the previous fall breeding. From June 1 to July 2, treated (T) ewes were exposed to vasectomized rams and to 65 WF ewes; control (C) ewes were exposed only to vasectomized rams. Ovulation was assessed with biweekly serum progesterone assays; crayon marks were used to detect estrus. Daily observations of ram behavior were conducted to assess sexual activity of rams joined with T and C ewes. Cohabitation with WF ewes increased (P less than .01) ovulation percentages from 46% in C (42% for Hampshires and 50% for Suffolks) to 76% in T ewes (79% for Hampshires and 73% for Suffolks). Mating percentage also was increased (P less than .05) by cohabitation with WF ewes from 14% for C ewes to 30% for T ewes. Rams with T + WF ewes spent more (P less than .05) time checking ewes for estrus than did rams with C ewes. Hence, cohabitation with cycling WF ewes increased ovulation and mating percentages. Many acyclic T ewes first ovulated after 10 or more days of teasing, possibly due to increased ram contact in the presence of WF ewes.     

Fattening performance,slaughter, carcass and meat quality traits of Karayaka lambs

In order to verify the fattening performance, slaughter and carcass characteristics and to investigate the changes in some meat quality traits of Karayaka lambs weaned at 3 months of age, 39 lambs (23 males and 16 females) were used as experimental animals. The lambs were fed a concentrate mixture and alfalfa hay (120 and 168 g crude protein and 2,700 and 1,951 ME/kg, respectively) for a period of 60 days of fattening period. Male lambs were superior (p < 0.05) to female lambs in terms of daily weight gain (270.4 vs. 205.4 g; SEM = 9.46), hot and cold carcass weights (16.7 and 16.0 vs. 14.1 and 13.4 kg, respectively; SEM = 0.35), intra-muscular fat ratios (1.9% vs. 2.5%; SEM = 0.12) and dripping loss of semitendinosus muscle 3 days postmortem (8.1% vs. 10.2%; SEM = 0.36). The relative weights of some organs, the meat quality traits (pH, cooking loss, shear force, CIELab colour characteristics) and proximate analyses (dry matter, protein and ash) of longissimus dorsi and semitendinosus muscle samples from lambs were not affected by sex (p > 0.05). Dripping loss, pH and colour characteristics were affected by storage time (p < 0.05). These results provide a basic understanding of performance and meat quality of Karayaka sheep which may have potentials in improving sheep production using an indigenous sheep breed in Turkey.