The Cukurova Meat Sheep, abbreviated CMS, is not a product of chance. It was assembled from four genetic streams: 37.5 percent Île de France, 37.5 percent Rambouillet, 12.5 percent Awassi, and 12.5 percent Sakız. The breeding strategy aimed to fuse the superior muscle development and growth performance of European meat-type breeds with the environmental resilience of local Turkish genetics. The Awassi, by contrast, is a fat-tailed breed that has been shaped over centuries in the hot, semi-arid regions of the Middle East. It tolerates high temperatures and humidity, thrives on limited feed, and digests nutrients with notable efficiency, making it a cornerstone of sheep production in southeastern Anatolia and the Mediterranean region. Until now, however, rigorous comparative data on the CMS under standardized conditions have been scarce.

The experimental design was deliberately simple and tightly controlled. Twenty single-born, intact male lambs, ten of each breed, were selected at similar ages and body weights, with Awassi lambs averaging roughly 27.9 kilograms and CMS lambs 27.7 kilograms at the start. The animals were housed in pairs in identical pens, a arrangement chosen to satisfy the strong herding instincts of sheep and minimize stress-related adaptation problems that could skew the data. After a two-week adaptation period during which the concentrate proportion of the diet was gradually increased to protect rumen health, the lambs were fattened for ten weeks on an 80:20 concentrate-to-roughage ration, fed ad libitum alongside alfalfa hay. All lambs were slaughtered on the same day at approximately 175 to 179 days of age, and meat analyses focused on the longissimus lumborum, the prized loin muscle that runs along the spine.

When it came to growth, the two breeds proved remarkably evenly matched. Initial and final live weights showed no statistically significant differences, and average daily gain was essentially the same across both groups. The Awassi lambs did eat more, recording higher daily feed intake, yet this appetite advantage did not translate into faster growth, meaning the CMS lambs achieved equivalent performance on less feed. Feed conversion ratio, the efficiency metric that divides intake by gain, did not differ significantly between breeds, but the pattern hints at the leaner economics of the meat-type composite. An interesting digestive footnote emerged from fecal analysis: Awassi lambs excreted feces with higher acid detergent fiber concentrations, suggesting a greater capacity for fiber utilization, a trait likely rooted in their long evolutionary history of subsisting on coarse roughage in harsh environments.

The carcass story is where the breeds genuinely diverge. Awassi lambs produced heavier hot and cold carcasses, a difference partly attributable to their higher slaughter weights and, crucially, to the tail fat that defines fat-tailed breeds. In the Awassi carcasses, tail fat alone constituted 14.73 percent of cold carcass weight, a substantial energy store with little commercial value in modern meat markets, while no tail fat was detected in the CMS carcasses. Awassi lambs also deposited more omental and mesenteric fat and showed greater fat thickness over the loin muscle, painting a picture of an animal geared toward energy storage. The CMS lambs, meanwhile, carried heavier weights and higher proportions of the forearm, rib, loin, and rump, precisely the regions where premium cuts are carved. The authors caution that because full tissue dissection was not performed, these cut weights cannot be read as direct proof of greater muscle mass, but the pattern is consistent with the breed’s meat-type design.

Physical meat quality, the suite of traits that determine how meat looks, cooks, and feels on the plate, was strikingly similar between the breeds. Postmortem pH values at 24 hours fell within the normal range for lamb, around 5.70 to 5.71, indicating that neither breed produced dark, firm, dry meat or the pale, soft, exudative defect that plagues poorly handled carcasses. Cooking loss, Warner-Bratzler shear force measured on raw loin samples, and the full texture profile analysis of cooked meat, covering hardness, springiness, cohesiveness, chewiness, and resilience, all showed no significant breed differences. The only physical divergence appeared in the chroma value of raw meat, where Awassi samples displayed higher color saturation, suggesting a more vivid red that could catch a shopper’s eye at the butcher’s counter. When the meat was cooked, myoglobin denatured as expected, shifting color toward lighter, browner tones in both breeds equally.

Beneath the surface, however, the chemical composition told a different story. Crude protein content was significantly higher in CMS meat, a difference the author attributes primarily to breed-related differences in muscle composition, possibly compounded by the fat-tailed Awassi’s tendency to divert energy into fat deposition rather than lean tissue. Mineral analysis using inductively coupled plasma mass spectrometry revealed that CMS meat contained significantly higher concentrations of potassium and magnesium, two intracellular minerals central to neuromuscular function, cellular homeostasis, and energy metabolism, while calcium, copper, iron, sodium, and zinc levels were equivalent between breeds.

The fatty acid and amino acid analyses added further texture to the comparison. Overall fatty acid profiles were similar, an expected outcome given that all lambs consumed the same cereal-based diet and ruminant meat lipids are dominated by dietary and microbial sources processed through ruminal biohydrogenation. One exception stood out: arachidonic acid, an omega-6 polyunsaturated fatty acid embedded in muscle membrane phospholipids, was significantly higher in CMS meat, a shift the study links to breed-related differences in lipid metabolism and muscle development. Among the 26 amino acids identified, most were present at similar levels, but CMS meat carried significantly more glutamic acid, a key component of myofibrillar proteins and a major contributor to savory umami flavor, and notably more taurine, an amino sulfonic acid involved in muscle energy metabolism and cellular regulation. The absence of detectable omega-3 fatty acids in both breeds reflects the cereal-heavy ration and the extensive biohydrogenation that occurs in the rumen, a reminder that diet, not just genetics, shapes the lipid profile of meat.

The study’s limitations are candidly acknowledged. Twenty lambs from only two sires per breed is a modest sample, feed intake was recorded at the pen level rather than for individual animals, and sensory panels and molecular analyses fell outside the study’s scope. Yet the core message survives these caveats: under identical feeding and management, breed effects in these lambs manifested not in how fast they grew or how tender their meat felt, but in where the carcass carried its value and what its muscle contained. For a livestock sector grappling with rising demand for animal protein, urbanizing consumer markets, and the need to make every kilogram of feed count, the Cukurova Meat Sheep’s combination of leaner carcass composition, more muscle in high-value cuts, and elevated protein, taurine, and arachidonic acid represents a compelling case that targeted crossbreeding can reshape the economics and nutrition of lamb meat without sacrificing the eating quality that consumers expect.

Subject of Research: Comparative growth performance, carcass traits, and meat quality of Awassi and Cukurova Meat Sheep lambs under identical fattening conditions

Article Title: Growth performance, carcass traits, and meat quality of Awassi and Cukurova Meat Sheep lambs

Article References: Durmuş, M. (2026). Growth performance, carcass traits, and meat quality of Awassi and Cukurova Meat Sheep lambs. Archives Animal Breeding, 69(4), 569-583. https://doi.org/10.5194/aab-69-569-2026

Image Credits: AI Generated

DOI: 10.5194/aab-69-569-2026

Keywords: sheep, lamb meat, Cukurova Meat Sheep, Awassi, carcass traits, meat quality, fattening performance, fatty acids, amino acids, taurine, animal breeding, Türkiye

Researchers at the College of Agriculture and Animal Husbandry of Qinghai University, working at the Black Tibetan Sheep Breeding Centre in Guinan County, randomly assigned 60 two-month-old male lambs weighing 13 to 14 kilograms to two groups. One group was castrated after weaning, while the other remained intact. Both groups were housed in separate pens but managed and fed identically, and after a one-week acclimatisation period the formal feeding trial ran for 120 days. At the end of the trial, six animals from each group were humanely slaughtered under animal welfare protocols following a 12-hour fast, and muscle samples were collected bilaterally between the ninth and eleventh ribs, flash-frozen on dry ice, and stored at minus 80 degrees Celsius until analysis. The work was approved by the Animal Ethics Committee of Qinghai University under approval number QUA-2020-0709.

The team then subjected the meat to an unusually rigorous battery of tests combining classical meat-science measurements with modern metabolomics. Conventional quality indicators included pH at 24 hours post-mortem, cooking loss, drip loss, Warner-Bratzler shear force, cooked meat percentage, and texture profile parameters such as hardness, elasticity, chewiness, cohesiveness, and resilience. Nutritional composition, namely crude protein, moisture, and crude fat, was determined using accepted AOAC methods. To peer into the molecular machinery underlying these traits, the scientists deployed untargeted metabolomics on an Agilent 1290 Infinity ultrahigh-performance liquid chromatography system coupled to an AB Triple TOF 6600 mass spectrometer operated in both positive and negative ionisation modes, alongside targeted amino acid quantification using UPLC-ion mobility separation with multiple reaction monitoring on a 5500 QTRAP instrument, and fatty acid profiling by gas chromatography-mass spectrometry after methyl esterification.

The physical results were striking. Meat from the castrated group, designated BTC, showed significantly lower drip loss than meat from intact rams, designated BTN, indicating better water retention during storage, a trait consumers associate with juicier, more tender products. At the same time, cooking loss, elasticity, chewiness, and cohesiveness were all significantly higher in the castrated group, changes the authors attribute to shifts in muscle fibre type and structure that they plan to characterise in future work. The pH values of both groups fell within the normal fresh-meat range of roughly 5.67 to 6.28 at 24 hours, although the castrated animals trended lower, and there were no significant differences in cooked meat percentage, hardness, or resilience. Crucially, castration did not alter the crude composition of the meat: moisture, protein, and fat contents were statistically indistinguishable between the groups, meaning the animal’s fundamental nutritional payload remained intact.

The metabolomics told a richer story. Principal component analysis clearly separated castrated from non-castrated samples, and supervised PLS-DA and OPLS-DA models, with high explained variance and predictive statistics, confirmed significant metabolic segregation between the groups. In the negative ion mode alone the team identified 586 metabolites, dominated by lipids and lipid-like molecules at about 31 percent of the total, followed by organic acids and their derivatives at nearly 24 percent. Applying strict criteria of variable importance in projection greater than 1 and a P value below 0.05, the researchers pinpointed 34 differentially abundant metabolites, 15 of them upregulated and 13 downregulated in castrated sheep. Notable upregulated compounds included uric acid, vitamin C, malate, glutamine, oleic acid, and ammelide, while compounds such as L-malic acid, maltotriose, D-lactose, inosine 5′-monophosphate, and several phospholipid species were reduced.

Pathway analysis using the Kyoto Encyclopedia of Genes and Genomes illuminated the biological circuits most affected by castration. Purine metabolism, general metabolic pathways, bile secretion, the phosphotransferase system, glyoxylate and dicarboxylate metabolism, pyrimidine metabolism, and ABC transporters emerged as the key pathways distinguishing the two groups. The authors propose that DL-2-phosphoglycerate, upregulated in castrated muscle, feeds into glycolysis where it is converted by enolase to phosphoenolpyruvate and then by pyruvate kinase to pyruvate, ultimately contributing to lactate formation and the slight decline in muscle pH observed 24 hours after slaughter. ABC transporters, one of the most extensively studied protein families in biology, may in turn shuttle metabolites across membranes, modulating the amino acid content of muscle tissue in concert with the phosphotransferase system and glyoxylate and dicarboxylate metabolism.

Targeted metabolomics added nutritional depth. Of 31 amino acids and derivatives detected, 11 were significantly elevated in castrated sheep, and the totals for non-essential amino acids, umami amino acids, and overall amino acid content were all significantly higher than in intact rams. Umami compounds such as aspartate and glutamate are central to the savoury taste that makes lamb so prized, and the finding mirrors earlier reports that castrated boars carry more umami amino acids than females. Meanwhile, fatty acid profiling identified 40 fatty acids, 23 of which differed significantly between groups. Levels of saturated, monounsaturated, and polyunsaturated fatty acids were all significantly higher in castrated animals, the n-6 to n-3 ratio shifted significantly, and oleic acid, the dominant monounsaturated fatty acid, was upregulated, consistent with previous castration studies in goats, cattle, and pigs.

Correlation analysis wove these threads together. Drip loss was negatively correlated with uric acid, suggesting that the castration-driven rise in this purine metabolite, routed through purine metabolism, bile secretion, and general metabolic pathways, may help the muscle hold onto its water. Total and non-essential amino acid scores correlated positively with vitamin C, malate, glutamine, oleic acid, and ammelide, all of which were elevated in castrated sheep, while elasticity showed a strong positive relationship with oleic acid and ammelide. The researchers note that prior work links purine metabolism to enhanced umami flavour and that guanine content correlates positively with savoury intensity in pork, lending plausibility to the idea that castration subtly tunes flavour chemistry as well as texture in Tibetan mutton.

The study is not without limits. Given cost and animal ethics considerations, only six castrated and six intact sheep were analysed, and the authors acknowledge that additional quality-relevant metabolites may await discovery in larger cohorts. Still, the practical implications are considerable. Castration improved several eating-quality traits and boosted amino acid and fatty acid levels while reducing drip loss, but it also raised cooking loss and saturated fatty acid content. The team suggests that future feed formulation for castrated flocks, for example incorporating flaxseed to push the fatty acid profile toward beneficial n-3 species, could amplify the benefits while offsetting the drawbacks. For the herders of the Qinghai-Tibet Plateau, and for a growing global market that prizes distinctive, high-quality lamb, an ancient pastoral custom now rests on a firm molecular foundation.

Subject of Research: Effects of castration on meat quality and muscle metabolites in Black Tibetan sheep on the Qinghai-Tibet Plateau

Article Title: The effects of castration on the quality of black Tibetan sheep meat and muscle metabolites

Article References: Xu, X., Han, L., Yue, Q., Hou, S., Luo, Z., Gui, L., Yang, B., Wang, Z., Yuan, Z., & Sun, S. (2026). The effects of castration on the quality of black Tibetan sheep meat and muscle metabolites. Food Science of Animal Resources, 46(1), Article 91. https://doi.org/10.1007/s44463-026-00067-8

Image Credits: AI Generated

DOI: 10.1007/s44463-026-00067-8

Keywords: castration, Black Tibetan sheep, meat quality, metabolomics, amino acids, fatty acids, drip loss, oleic acid, purine metabolism, ABC transporters, Qinghai-Tibet Plateau, lamb meat