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.     

A note on the reproductive performance of Damara,Dorper and Merino sheep under optimum management and nutrition for Merino ewes in the eastern wheatbelt of Western Australia

The reproductive performance of 48 Damara, 42 Dorper and 46 Merino ewes was evaluated under an optimum nutritional regime for Merino ewes that included one annual joining in a mixed (cropping and sheep) farming system in the eastern wheatbelt of Western Australia (W.A.) over a 3-year period. In 2005, when the Damara, Dorper and Merino ewes were aged between 8 and 9 months at joining and weighed 41.2, 42.4 and 33.3 kg with average body condition scores of 2.3, 2.4 and 1.8, respectively, their weaning rates were 71% (Damara), 81% (Dorper) and 13% (Merino). The Merino ewes had significantly lighter body weights and were lower conditioned (p < 0.001) resulting in significantly lower weaning rates (p < 0.001). In 2006, the Damara, Dorper and Merino ewes weighed 61.9, 69.5 and 61.6 kg at joining, with body condition scores of 2.8, 3.3 and 2.8, respectively, resulting in weaning rates of 52% (Damara), 122% (Dorper) and 117% (Merino). While the Damara and Merino weights and body condition scores were not different (p > 0.05), the Damara weaning rates were significantly lower compared with the Dorper and Merino groups (p < 0.001). The Dorpers were heavier and greater conditioned (p < 0.001); however, the weaning rates between the Dorper and Merino were not different (p > 0.05). In 2007, the Damara, Dorper and Merino ewes weighed 71.6, 77.1 and 70.2 kg at joining with body condition scores of 2.8, 2.8 and 2.5, respectively. Again, the Dorper ewes were heavier (p < 0.001) than the Damaras and Merinos, which were not different (p > 0.05). The Damara and Dorper had the same body condition while the Merino ewes were less and different (p < 0.05). However, there were differences in weaning rates between the three breeds (p < 0.001), of 64% (Damara), 105% (Dorper) and 134% (Merino). Over the 3-year period, under a nutritional management system optimal for Merino sheep and with one annual joining, with increasing age the Merino ewes weaned more lambs. However, while the Damara and Dorper ewes conceived and weaned relatively high lamb numbers when they were joined as lambs, their reproductive performance decreased over time. This nutritional regime resulted in increased levels of fatness of the Damara and Dorper ewes with no increase in reproduction rates under an annual joining system. A significant factor for the lower conception and weaning rates in the Damara ewes was the enlarged fat tail due to the increased fat levels, which made it difficult for the rams to impregnate the ewes.     

Live weight,conformation, carcass traits and economic values of ram lambs of Red Maasai and Dorper sheep and their crosses

Meat production is the most important trait in the breeding objectives of sheep production in East Africa. The aim of this study was to investigate breed differences in live weight, conformation, carcass traits and economic values for meat production among Red Maasai and Dorper sheep and their crosses. In total, 88 ram lambs, which were reared at the ILRI experimental station, Kapiti plains Estate in Central Kenya, were used for the study. The lambs were slaughtered at Kenya Meat Commission (KMC) at about 1 year of age. Prior to slaughter, the lambs were weighed, measured and assessed by experienced evaluators, and at the abattoir carcass traits were recorded. Large breed differences were found for most traits. Dorper lambs were heavier at delivery for slaughter and had better carcass grade but lower dressing percentage and fat levels than Red Maasai. Crossbreds were generally better than the parental breeds. Evaluators were willing to pay more for the Dorper lambs for slaughter although carcass weights later were shown not to be higher than for Red Maasai. Evaluators undervalued Red Maasai lambs by 8–13 % compared to Dorper lambs according to the prices quoted per kilogramme live or carcass weight by KMC. Live weight was better than any other live measure in predicting carcass weight. Due to the overall higher ranking of the crossbred lambs for meat production, Dorper may be useful as a terminal sire breed for crossing with Red Maasai ewes.     

Pre-weaning growth performance of crossbred lambs (Dorper × indigenous sheep breeds) under semi-intensive management in eastern Ethiopia

A study was conducted to assess the effect of genetic and non-genetic factors (litter size, sex of lamb, and parity of dam) on pre-weaning growth performance of crossbred lambs (75 % Dorper (DR) 25 % indigenous lambs; and 50 % Dorper 50 % indigenous lambs) under semi-intensive husbandry practices in eastern Ethiopia. Data from a total of 275 Dorper sire breed × indigenous (Blackhead Ogaden [BHO] and Hararghe Highland [HH]) crossbred lambs with different genetic group of the parental breeds were collected for three consecutive years (2009 to 2011). Pre-weaning growth performance attributes of crossbred lambs studied were birth weight, weaning weight, and pre-weaning average daily gain. Data were analyzed using the GLM procedure of SAS (2003). Breed group and non-genetic factors significantly affected pre-weaning growth performance. Lambs with 75 % Dorper and 25 % indigenous had higher (P?<?0.01) birth weight than 50 % DR and 50 % HH but similar to 50 % DR and 50 % BHO. Weaning weight and pre-weaning live weight gain were higher (P?<?0.01) for ¾DR¼BHO and ¾DR¼HH than 50 % Dorper inheritance. Single-born lambs had higher weight at birth, weaning weight, and pre-weaning average daily gain as compared to twins. Sex comparison is significant (P?<?0.05) and male lambs recorded highest pre-weaning growth performance compared to female counterparts. Parity, season, and lambing year significantly (P?<?0.01) influenced the pre-weaning growth of crossbred lambs. Therefore, it could be concluded that 50–75 % Dorper inheritance improved pre-weaning growth performance of indigenous breeds of Hararghe Highland and Blackhead Ogaden sheep. The result also suggested culling of ewes older than fourth parity to improve the pre-weaning growth performance of lambs.     

Texel sheep are more resistant to natural nematode challenge than Suffolk sheep based on faecal egg count and nematode burden

Limited information is available on differences between sheep breeds with respect to helminth resistance under temperate conditions. The present study was designed to confirm and extend preliminary findings on observed breed differences in resistance to naturally acquired gastrointestinal nematodes in Suffolk and Texel sheep. Three trials were carried out. In trial 1 (1999-2003) lambs co-grazed from birth were faecal sampled at various time points up to 17 weeks of age. Worm burden was assessed at 17 weeks of age from a minimum of six lambs per breed in each of the 3 years. In trial 2, faecal egg count (FEC) was determined on six farms with co-grazed Suffolk and Texel purebred lambs. In trial 3 (2001-2003), ewes were faecal sampled at winter housing. In all three trials, an influence of breed on resistance to naturally acquired trichostrongyle infection was demonstrated. In trial 1, significantly higher FEC and worm burden was observed in Suffolk compared with Texel lambs following natural challenge. In trial 2, FEC recorded in lambs from six farms confirmed the breed differences previously observed. A breed difference in resistance to GI parasites was also observed in older ewes. In both breeds, an age effect on the FEC was observed with younger ewes having greater FEC than older ewes.     

Evaluation of the South African Dorper as a terminal sire breed for growth,carcass, and palatability characteristics

The South African Dorper is an important terminal meat sire breed in Africa that was recently imported into the United States. The objective of this study was to evaluate the Dorper as a terminal meat sire breed for U.S. production. Semen from purebred Dorper sires was used to artificially inseminate Columbia ewes to produce F1 crossbred lambs. Growth and carcass characteristics of F1 Dorper-Columbia lambs (n = 165), F1 Suffolk-Columbia (n = 89), and purebred Columbia lambs (n = 207) were compared based on subsets of the total number of animals. The F1 Dorper lambs grew significantly slower (313 g x d(-1)) and weighed less (29.8 kg) than F1 Suffolk- (357 g x d(-1), 33.5 kg) and Columbia-sired lambs (328 g x d(-1), 31 kg) at 77 d of age. However, at a weaning age of 118 d weaning weight and ADG did not differ (P > 0.20) among sire breed groups. Postweaning growth of F1 Dorper(239 g xd(-1)) wether lambs did not differ from that of purebred Columbia wethers (230 g x d(-1)) but was less than that of F1 Suffolk lambs (259 g x d(-1); P= 0.09). Feed efficiency did not differ among breed types. Breed types had similar dressing percentages (53%), shoulder fat depth (2.8 mm), body wall thickness (3 cm), leg conformation score (Choice), Yield grade (2.4), and Quality grade (Choice). Weight of wholesale shoulders and racks made up approximately 38% of the carcass weight in the Columbia and F1 Suffolk-Columbia type but only 33% in the F1 Dorper-Columbia lambs. However, the more expensive wholesale loins from F1 Dorpers were heavier (P < 0.01) than the other breed types. Total weights of wholesale legs were similar among F1 Dorpers and F1 Suffolks but were heavier than those for the purebred Columbia (P < 0.05). Percentages of total wholesale primal cuts were similar among breed types (P > 0.10). Chemical composition of the carcass did not differ significantly between breed types with a mean composition of 52% moisture, 30% lipid (ether extract), 17% protein, and 0.76% ash. Warner-Bratzler shear force values were less (P < 0.05) and sensory panel ratings for tenderness were significantly more favorable for lamb chops from Dorper sired lambs. Dorper rams can be used as terminal meat sires to produce lambs whose growth rate to 118 d of weaning age, postweaning ADG and feed efficiency, and carcass characteristics are similar to that of Suffolk crossbred lambs and purebred Columbia lambs but with a slight improvement in tenderness.     

Characteristics of Lacha and Rasa Aragonesa lambs slaughtered at three live weights

A study was made of differences in the quality of meat from Lacha (L) and Rasa Aragonesa (RA) lambs slaughtered at 12, 24, or 36 kg live weight. Lambs from both breeds were weaned at 25 to 57 d, approximately 11.5 to 18.5 kg live weight, and fed concentrate and barley straw until slaughter at 24 and 36 kg live weight. Hot carcass weight, cold carcass weight, conformation, color, firmness, and thickness of backfat and color of rectus abdominis muscle were recorded on the carcass. Final pH (pHu), instrumental color (L*, a*, b*), myoglobin concentration, chemical composition, and water-holding capacity (WHC) of the longissimus muscle, shear force of the biceps femoris muscle, and iodine values and fatty acid composition of the i.m. and s.c. fat depots were determined. The percentage of fat in the longissimus muscle increased with live weight, and values for RA lambs were higher than those for L lambs. The WHC of meat from RA lambs was lower at 24 kg than at 12 or 36 kg slaughter weight. Live weight and breed had no effect on the shear force of the biceps femoris muscle. There was an increase in myoglobin concentration in the longissimus muscle with increased live weight in both breeds. The fatty acid content of s.c. and i.m. fat, which was not affected by breed, declined with the increase in slaughter weight. The polyunsaturated fatty acid content of the s.c. fat depot increased, whereas that of the i.m. fat depot decreased, with the increase in slaughter weight in both breeds. Subcutaneous fat had a higher content of heptadecanoic acid (17:0) than i.m. fat, and this increased with the increase in slaughter weight. In both depots, there was an increase in oleic acid (18:1) at 12 kg in RA lambs and at 24 kg in L lambs. In the s.c. fat depot, there was a progressive increase in linoleic acid (18:2) content with the increase in live weight in both breeds. There was a higher degree of unsaturation in the s.c. fat of RA lambs than in that of L lambs, which was reflected in the iodine value.     

Body live weight and milk production parameters in the Majorera and Palmera goat breeds from the Canary Islands: influence of weight loss

Seasonal weight loss (SWL), caused by poor quality pastures during the dry season, is the major limitation to animal production in the tropics. One of the ways to counter this problem is to breed animals that show tolerance to SWL. The objective of this study was to understand the effect of feed restriction in milk production and live weight (LW) evolution in two goat breeds, with different levels of adaptation to nutritional stress: the Majorera (considered to be tolerant) and the Palmera (considered to be susceptible). A total of ten animals per breed were used. Animals were divided in four groups (two for each breed): a restricted group (restricted diet) and a control group. LW and milk yield parameters were recorded through a trial that lasted 23 days in total. Overall, there were no significant differences between both restricted groups, regarding neither LW nor milk yield reductions (LW reduction 13 % and milk yield reduction of 87 % for both restricted groups). In what concerns control groups, there were no significant differences between breeds, thought there were different increments at the end of the trial for both breeds regarding LW (6 and 4 %, for Majorera and Palmera, respectively) and milk yield (28 and 8 %, respectively for Majorera and Palmera). The lack of statistically significant differences between Palmera and Majorera LW and milk yields in restricted groups may be due to the fact that the controlled trial does not replicate harsh field conditions, in which Majorera would excel, and the stress induced by those differences.     

Breed and environmental influences on weaner lamb production in Zimbabwe

Performance of the Dorper and Mutton Merino breeds and their crosses was assessed from 1,305 ewe and 1,453 lamb records from six lambing seasons. Dorper and Mutton Merino were mated in all combinations under an accelerated lambing system and crossbred females were mated to Suffolk rams. The Dorper and Mutton Merino breeds were not significantly different for fertility, pre-weaning lamb growth and survival. Suffolk sired lambs from crossbred ewes grew rapidly and were heaviest at birth and at weaning. They also survived better than lambs from the other breeding groups and this contributed to the higher weaning rate (P less than 0.05) in crossbred ewes. Weight of weaned lambs per ewe exposed to the ram per season was 12% higher (P less than 0.05) in the Dorper than the Mutton Merino ewes. However lifetime production was 28% higher (P less than 0.01) in Mutton Merino ewes due to significantly superior longevity. Crossbred ewes were highly productive. Individual heterosis was not significant but estimates were positive for most traits. Growth rate and survival of lambs increased as age of dam increased to 48 and 40 months respectively. Lambs born to previously non-lactating ewes were heavier and survived better than lambs born to ewes lactating in the previous season. Lambs born and reared as singles were 25% heavier at birth (P less than 0.001) and 52% heavier at weaning (P less than 0.001) than those born and reared as twins. Male lambs grew faster and were 7% heavier at weaning than females (P less than 0.001).     

思州鸡肌肉品质分析

随机选取相同条件下放牧饲养的120日龄思州鸡10只,公、母各半,进行肌肉品质测定。结果显示,思州鸡肌肉嫩度好,干物质含量高,钙含量丰富,硒和铁含量较低,锌含量适中;胸肌11种脂肪酸中以油酸、棕榈酸、亚油酸和硬脂酸为主,占脂肪酸总量的92.20%,不饱和脂肪酸含量占69.35%,必需脂肪酸占15.31%;17种氨基酸中以谷氨酸、天冬氨酸、赖氨酸和亮氨酸为主,占氨基酸总量的44.22%,必需氨基酸、鲜味氨基酸、甜味氨基酸、芳香族氨基酸、支链氨基酸和抗氧化氨基酸含量分别为39.40%、26.18%、20.09%、7.06%、18.08%和11.61%。因此,思州鸡肌肉品质优良,肉质风味好。     

The Damara in the context of Southern Africa fat-tailed sheep breeds

Sheep production is one of the most important activities in animal production in tropical regions. Southern Africa (SA) fat-tailed sheep such as the Afrikaner, Namaqua Afrikaner, Nguni, Persian Black Head, Tswana, Pedi, Sabi, and particularly the Damara are important animal genetic resources very well adapted to their harsh home environments. In this review, autochthonous sheep genetic resources of SA are reviewed regarding history and productive performance. A special focus is made to the most internationalized of such breeds: the Damara. The following aspects are reviewed: history, standards, productive performance in SA, and importation to Australia. Finally, a reference is made to the influence of fat-tailed sheep formation of composite breeds such as the Dorper or the Meatmaster.     

Fatty acid profile of plasma,muscle and adipose tissues in Chilota lambs grazing on two different low quality pasture types in Chiloé Archipelago (Chile)

There is no information about the effect of different pasture types on tissue fatty acid profiles of a native rustic lamb breed of the Chiloe Archipelago, the Chilota. Eight Chilota lambs were grazed on a ‘Calafatal’ pasture (CP), a typical secondary succession of Chiloé Archipelago (Chile) and eight Chilota lambs were located to graze on naturalized pasture (NP) of Chiloé. Botanical, chemical and lipid composition of the two types of pastures and of different lamb tissues (muscle, subcutaneous – and tail adipose tissues) and plasma were performed. Both pasture types induced high n‐3 polyunsaturated fatty acids (PUFA) and CLAcis‐9,trans‐11 proportions in Chilota meat. Thus, in muscle, Chilota lambs grazing CP showed higher sum PUFA, sum n‐6 PUFA proportion and n‐6/n‐3 PUFA ratio compared with Chilota lambs grazing NP. In tail fats of Chilota lambs grazing CP significantly higher proportions of 18:3n‐3, sum saturated fatty acids, sum PUFA, n‐3 and n‐6 PUFA were detected compared with Chilota lambs grazing NP. Feeding of different pasture types (CP vs. NP) caused significant differences in fatty acid composition of muscle and the two fat depots in Chilota lambs, but also point to tissue‐specific responses of de novo synthesized fatty acid deposition in the tissues.     

深县猪肉质及营养价值分析

本研究选择国外猪种杜洛克和中国地方猪深县猪体重 95 kg 的阉割公猪各 5 头,比较 2 个猪品种背最长肌之间肉质、氨基酸、脂肪酸和微量元素的差异。结果表明:杜洛克猪的肌内水分、肉色、大理石纹、滴水损失、粗蛋白质和脂肪含量低于深县猪(P<0.01);杜洛克猪背最长肌中谷氨酸、天冬氨酸、精氨酸、组氨酸、丝氨酸、脯氨酸、甘氨酸、苏氨酸、半光氨酸、丙氨酸、缬氨酸、苯丙氨酸、异亮氨酸、酪氨酸、亮氨酸、呈味氨基酸总量、必需氨基酸和总氨基酸含量低于深县猪(P<0.01);杜洛克猪背最长肌的饱和脂肪酸含量棕榈酸、豆蔻酸、硬脂酸和花生四烯酸多不饱和脂肪酸亚油酸和亚麻酸低于深县猪(P<0.01);单不饱和脂肪酸棕榈油酸含量低于深县猪(P<0.01),而油酸没有显著性差异;杜洛克猪背最长肌中微量元素钾、锶、铜、锌、硅和铬含量均低于深县猪(P<0.01),镍差异显著(P<0.05)。结果显示,中国地方猪深县猪在肉质及营养价值方面优于瘦肉型的杜洛克猪,为深县猪的品种资源保护和肉产品的开发利用提供依据。     

杜泊绵羊与小尾寒羊杂交后代肌肉风味的研究

本研究旨在通过对肌肉氨基酸和脂肪酸的检测,探讨杜泊羊与小尾寒羊杂交对肌肉风味的影响,为选育优质肉羊品种提供理论依据。结果表明：从氨基酸总量来看,杜寒F1较小尾寒羊和杜泊羊分别提高30．06％和0．57％,杜寒F2较小尾寒羊和杜泊羊分别提高29：49％和0．13％;从主要脂肪酸含量来看,杜寒F1较小尾寒羊和杜泊羊分别降低0．29％和10．05％,杜寒F2较小尾寒羊和杜泊羊分别降低13．54％和22．01％;从挥发性脂肪酸来看,杜寒F1较小尾寒羊和杜泊羊分别降低2．93％和6．44％,杜寒F2较小尾寒羊和杜泊羊分别降低21．24％和24．09％。杂交后代杜寒F1和杜寒F2氨基酸含量有所提高,同时能够降低羊肉膻味。     

A comparison of serum biochemical changes in two breeds of sheep (Red Masai and Dorper) experimentally infected with Fasciola gigantica.

Twelve Red Masai and 12 Dorper sheep aged between 6 and 9 months, were acquired from a fluke-free area and sheep of each breed divided into two equal groups of six. Each animal in one group of each breed was experimentally infected with 400 viable metacercariae of Fasciola gigantica. The other groups acted as uninfected controls. Blood samples were taken at weekly intervals for the determination of serum bilirubin, albumin, and gamma glutamyl transferase levels. Following the establishment of infection, albumin levels declined in both breeds of infected animals without any significant difference between the two breeds. However, serum bilirubin and gamma glutamyl transferase (GGT) in the infected animals were elevated significantly more in the Dorper than in the Red Masai sheep. Based on these findings, it would appear that Dorper sheep are more susceptible to the infection than Red Masai sheep.     

Comparison of performance of F1 Romanov crossbred ewes with wool and hair breeds during spring lambing under intensive and extensive production systems

The objective was to evaluate wool (Dorset and Rambouillet) and hair (Dorper, Katahdin, and White Dorper) breeds for their ability to complement Romanov germplasm in two distinct production systems by estimating direct sire and grandsire effects on lamb growth, survival, and ewe productivity traits. Rams of the five breeds (n = 75) were mated to Romanov ewes (n = 459) over a 3-yr period to produce five types of crossbred lambs (n = 2,739). Sire breed (P > 0.06) did not impact body weight or survival traits of the first-generation crossbred (F1) lambs. The productivity of retained crossbred ewes (n = 830) mated to Suffolk and Texel terminal sires was evaluated at 1, 2, and 3 yr of age in each production system. In the intensive production system, labor and harvested feed were provided for sheep that lambed in March in barns, and ewes were limited to rearing two lambs with additional lambs reared artificially. Ewes in the extensive production system lambed in May on pasture and were responsible for rearing all lambs born with no labor or supplemental feed provided before weaning. A total of 1,962 litters and 4,171 lambs from 2,229 exposures to two terminal sire breeds (Suffolk and Texel) were produced in the experiment. Crossbred ewes in the intensive production system were mated in October, resulting in larger litter sizes than crossbred ewes mated in December for the extensive production system. However, single- and twin-born lamb mortality was similar between the two systems that differed greatly in labor, feed, and facilities. Lambs produced in the intensive system received concentrate feed from an early age and were heavier at 24 wk of age than lambs produced in the extensive system. These outcomes resulted in greater 24-wk litter weight in the intensive than in the extensive system (P < 0.0001). Unexpectedly, the relative performance of crossbred types did not differ importantly between production systems. White Dorper × Romanov crossbred ewes had numerical advantages in productivity in each system; however, differences between ewe types were not significant. In the extensive system, without labor and shelter at lambing or supplemental feed until weaning, 3-yr-old crossbred ewes of all types averaged 1.78 lambs marketed per ewe lambing, and 40% of the ewes that gave birth to triplets weaned their entire litters. These results document that prolific sheep and extensive systems can be successfully combined if appropriate crossbred types are used.     

Isolation-perfusion of ovine hind limbs. IV. Effects of level of activity on amino acid and glucose metabolism

Twenty-one wether lambs averaging 30.0 kg were utilized in a study to determine the influence of level of muscular activity (via electrical stimulation) on metabolism of amino acids and glucose of isolated-perfused hind limbs. Treatments consisted of: (1) control, (2) low electrical stimulation and (3) high electrical stimulation. Mean perfusion flow rate was unaffected by treatment or time of perfusion. Perfusion pressure and hematocrit were increased (P less than .05) by stimulation. Glucose levels decreased from a pretreatment average of 44.7 to 41.3, 26.8 and 20.0 mg/dl for treatments 1 to 3, respectively. Lactic acid levels increased from the pretreatment mean of 37.7 to 46.7, 63.8 and 69.4 mg/dl, respectively. Plasma-free fatty acids were utilized from the perfusate at .84, .76 and .68 meq X liter-1 X min-1, respectively. Perfusate urea N levels were unaffected by treatment or time of sampling, but perfusate ammonia levels increased in all treatments (ammonia levels for treatments 1 to 3 increased by .50, 1.09 and 1.47 mg/dl, respectively). Perfusate amino acid changes suggested a flux of some amino acids from muscle to perfusate due to electrical stimulation, but perfusate branched chain amino acid concentrations decreased in all treatment groups. Fifty microcuries of 14C-lysine were included in the initial perfusate. Total perfusate radioactivity in all treatments declined with time, reflective of lysine uptake by the muscle. Total perfusate lysine concentration changed less markedly, suggesting that muscle is contributing to maintenance of plasma amino acid levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

杜泊羊和巴彦淖尔多胎羊杂交后代肉品质分析研究

为了评价杜泊羊与巴彦淖尔多胎羊杂交后代的肉品质,以杜泊羊×巴彦淖尔多胎羊杂交F₁代羔羊和新疆维吾尔自治区库尔勒市当地绵羊羔羊为研究对象,采用常规方法测定2种羔羊肌肉组织的理化指标、营养成分含量以及矿物质含量,利用统计学方法比较二者相关指标的差异。结果表明,杜泊羊×巴彦淖尔多胎羊杂交F₁代羔羊肌肉组织的pH_{45 min}值和熟肉率显著高于当地绵羊羔羊（P<0.05）,剪切力和失水率显著低于当地绵羊羔羊（P<0.05）;杂交F₁代羔羊肌肉中的粗灰分含量显著低于当地绵羊羔羊（P<0.05）,粗蛋白和粗脂肪含量均显著高于当地绵羊羔羊（P<0.05）;杂交F₁代羔羊肌肉中的铁含量极显著高于当地绵羊羔羊（P<0.01）,且铜、锰、镁、钙、锌含量均显著高于当地绵羊羔羊（P<0.05）。综上表明,杜泊羊×巴彦淖尔多胎羊杂交F₁代羔羊的肉品质优于当地绵羊羔羊。     

坝上长尾鸡与海兰褐鸡肌肉营养成分对比研究

坝上长尾鸡是河北省唯一被列入《中国畜禽遗传资源志》的地方家禽品种。为了更好地保护和开发利用坝上长尾鸡资源,本试验选取相同饲养管理条件下200日龄的该鸡种和海兰褐鸡各180只,每组随机分为5个重复,每个重复36只。在同一条件下常规饲养,于230日龄每组挑选10只鸡屠宰,对肌肉中主要营养成分进行了比较分析。结果显示:1)坝上长尾鸡肌肉中的粗蛋白质和粗脂肪含量与海兰褐鸡相比差异不显著(P0.05)。2)2个鸡种间胸肌、腿肌中的必需氨基酸含量差异不显著(P0.05);坝上长尾鸡肌肉中的呈味氨基酸(谷氨酸、天冬氨酸、甘氨酸和丙氨酸)含量显著高于海兰褐鸡(P0.05),腿肌中的苦味氨基酸——苯丙氨酸含量显著低于海兰褐鸡(P0.05)。3)坝上长尾鸡腿肌中的不饱和脂肪酸、饱和脂肪酸和总脂肪酸含量显著低于海兰褐鸡(P0.05);坝上长尾鸡腿肌中的花生四烯酸和二十二碳六烯酸含量显著高于海兰褐鸡(P0.05)。4)坝上长尾鸡胸肌中的镁(P0.01)和铁(P0.05)含量显著或极显著高于海兰褐鸡,腿肌中的钠(P0.05)、镁(P0.01)和铁(P0.05)的含量显著或极显著高于海兰褐鸡。由此可见,坝上长尾鸡和海兰褐鸡的肌肉均品质优良,且坝上长尾鸡肌肉品质优于海兰褐鸡。     

7月龄陶赛特×小尾寒羊F1代公母羔羊肌肉化学成分的比较研究

试验对7月龄陶赛特×小尾寒羊F₁代（简称陶×寒F₁）公母羔羊肌肉化学成分进行了比较研究。试验选择了在集约化饲养方式下饲养的7月龄陶赛特×小尾寒羊F₁代公羔、母羔各5只进行屠宰,分别取背最长肌后测定常规营养成分、氨基酸、长链脂肪酸、胆固醇、矿物元素等养分的含量。结果表明,陶×寒F₁公羔、母羔之间在背最长肌中干物质、粗蛋白质、粗脂肪、粗灰分、钙、磷等含量上均无显著差异（P>0.05）。各种氨基酸含量、总必需氨基酸含量、总非必需氨基酸含量、总氨基酸含量差异均不显著（P<0.05）。公羔与母羔背最长肌中大部分脂肪酸的含量、总不饱和脂肪酸含量均无显著差异（P>0.05）,但公羔背最长肌中亚油酸的含量提高20.3%（P<0.05）,胆固醇含量降低约32%（P<0.05）。羔羊不同性别之间背最长肌中的镁、锌、铜、锰含量没有显著差异（P>0.05）,但母羔背最长肌中的铁含量比公羔的高约26%（P<0.05）。因此,7月龄陶×寒F₁公羔、母羔肌肉的营养价值基本相同。