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.     

Effects of rearing system on meat quality,fatty acid and amino acid profiles of Hu lambs

To determine the effects of early rearing system on meat quality traits, fatty acid and amino acid profiles of meat, 48 Hu lambs were selected and randomly divided into four treatments: control lambs were ewe‐reared from birth to 60 days of age (ER), while treatment lambs were segregated from their dams at 10, 20 and 30 days of age, then artificially reared with milk replacer until 60 days of age (EW10, EW20 and EW30, respectively). All lambs had no access to the milk replacer or their dams from 61 to 90 days. Creep feed was supplied ad libitum to all lambs from 15 to 90 days of age. Artificially reared lambs (EW10, EW20 and EW30) had higher (p < .05) creep feed intake, average daily gain, slaughter weight, hot carcass weight, meat ether extract content, bright meat color (lightness and yellowness) than ewe‐reared lambs. The content of unsaturated fatty acids and monounsaturated fatty acids in EW10 and EW20 were greater (p < .05) than that in ER, whereas the proportions of saturated fatty acids in EW10 and EW20 were lower than that in ER (p < .05). The percentages of C18:0, C18:2, C18:3 and the ratio of polyunsaturated fatty acids and saturated fatty acids of artificially reared lambs were greater than ewe‐reared lambs (p < .05). The meat proportions of leucine, alanine and proline were higher (p < .05) in artificially reared lambs than ewe‐reared ones. Finally, the artificially reared system increased meat production and changed the fatty acid and amino acid profiles of meat, and it would be appropriate to rear Hu lambs artificially from 10 days with milk replacer.     

Concentration of copper, iron, manganese and zinc in muscle, fat and bone tissue of lambs of the breed German Merino Landsheep in the course of the growing period and different feeding intensities

A growth experiment with 108 lambs (breed German Merino Landsheep) was carried out in order to examine how gender, body weight and feeding intensity affect trace element concentrations in tissues and carcass. The lambs (50% male and 50% female) were fattened at three levels of feeding intensity ('low', 'medium' and 'high' by varying daily amounts of concentrate and hay) and slaughtered at different final body weights (30, 45 or 55 kg). Six male and six female animals were sacrificed at 18 kg live weight at the beginning of the comparative slaughter experiment. The left half carcass of each animal was divided into muscle tissue, fat tissue as well as bones and sinews and analysed for the trace elements copper (Cu), iron (Fe), manganese (Mn) as well as zinc (Zn). The body weight level influenced the Zn concentrations significantly in all tissues. In addition, the Fe concentration in the fat tissue was influenced by the body weight as well as the Cu content in the bone tissue. An influence due to gender could be seen for the Zn concentration in the muscle and fat tissue and for the Fe content in the fat and bone tissue as well as for the Cu concentration in the bones. The feeding intensity affected the Cu content in the muscle and bone tissue and also the Zn content in the muscle tissue. In the present study with lambs at body weight range from 18 to 55 kg on an average, 127 mg Fe, 87 mg Zn, 1.5 mg Cu as well as 1.1 mg Mn per kilogram dry matter were found in the bone tissue. In lamb muscle tissue combined from all parts (body weight range from 18 to 45 kg, both genders) the highest concentrations were for Zn and Fe [3.42 and 1.31 mg/100 g meat (wet weight basis)], while Cu remained far below these levels (0.08 mg/100 g meat and Mn was even below the detection limit of 0.025 mg/kg). Lamb muscle is a valuable source for highly available haem-Fe as well as for Zn and Cu in human nutrition.     

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.     

Effects of meloxicam or tolfenamic acid administration on the pain and stress responses of Merino lambs to mulesing

OBJECTIVE: To determine the effectiveness of two long-acting non-steroidal anti-inflammatory drugs (NSAIDs) at reducing the pain and stress responses to mulesing in lambs. PROCEDURES: Merino lambs (n = 60) were allocated at 5 weeks of age to six treatment groups: (1) sham mules; (2) mules; (3) tolfenamic acid-sham mules; (4) tolfenamic acid administered 45 min before mulesing; (5) tolfenamic acid at the time of mulesing; (6) meloxicam at the time of mulesing. Plasma cortisol was measured at -0.75, -0.25, 0, 0.5, 1, 3, 6, 12, 24, 48 and 72 h relative to mulesing. Beta-endorphin concentrations in plasma were determined at 0, 0.5, 1, 6, 12, 24, and 48 h. Haematology was performed on blood samples taken at -0.75, 0, 24, 48 and 72 h. Plasma haptoglobin was measured at 0, 12, 24, 48 and 72 h. Rate of wound healing was determined 72 h post mulesing, and animal behaviour, including posture, was measured for 6 h after mulesing. RESULTS: The mulesed lambs exhibited large increases in plasma concentrations of cortisol, beta-endorphin and haptoglobin. All mulesed animals lost weight significantly in the week after mulesing, regardless of analgesic administration, but the difference in weight between mulesed and unmulesed lambs was less at the final measurement, 2 weeks after mulesing. Mulesed lambs spent significantly less time lying ventrally than control lambs. All lambs that were mulesed, including those administered NSAIDs, spent more time standing with a hunched posture and less time walking normally than control lambs. CONCLUSIONS: The NSAID treatments applied 45 min before or at the time of mulesing at the dose levels used in this study were not effective in reducing the acute response of lambs to mulesing.     

发酵麸皮多糖对肉羊肉品质、肌肉氨基酸组成及肌肉抗氧化酶和肌纤维类型相关基因表达的影响

试验旨在研究发酵麸皮多糖(FWBP)对肉羊肉品质、肌肉氨基酸组成及肌肉抗氧化酶和肌纤维类型相关基因表达的影响。选用50只体重为(20.17±3.33)kg的6周龄杜泊×小尾寒羊F1代杂交羔羊,随机分为5组,每组10只。对照组(Ⅰ组)饲喂基础饲粮,试验组(Ⅱ、Ⅲ、Ⅳ、Ⅴ组)分别饲喂在基础饲粮中添加50、100、200、400 mg/kg FWBP的试验饲粮,预试期14 d,正试期56 d。结果表明:1)Ⅱ和Ⅲ组肉羊背最长肌剪切力显著低于Ⅰ组(P<0.05)。2)Ⅱ、Ⅲ和Ⅳ组肉羊背最长肌中蛋氨酸(Met)含量显著高于Ⅰ组(P<0.05);Ⅳ组肉羊背最长肌中的半胱氨酸(Cys)含量显著高于Ⅰ组(P<0.05),而谷氨酸(Glu)和亮氨酸(Leu)含量显著低于Ⅰ组(P<0.05);Ⅴ组肉羊背最长肌中丝氨酸(Ser)含量显著高于Ⅰ组(P<0.05),而缬氨酸(Val)含量显著低于Ⅰ组(P<0.05)。3)各试验组肉羊背最长肌中过氧化氢酶(CAT)的mRNA相对表达量显著高于Ⅰ组(P<0.05),且Ⅲ组肉羊背最长肌中CAT的mRNA相对表达量显著高于Ⅱ、Ⅳ、Ⅴ组(P<0.05)。Ⅲ组肉羊背最长肌中谷胱甘肽过氧化物酶(GSH⁃Px)和超氧化物歧化酶(SOD)的mRNA相对表达量显著高于Ⅰ组(P<0.05)。4)Ⅲ组肉羊背最长肌中肌球蛋白重链(MyHC)Ⅰ和MyHCⅡa的mRNA相对表达量显著高于Ⅰ组(P<0.05),且MyHCⅡx的mRNA相对表达量显著低于Ⅰ组(P<0.05)。Ⅲ、Ⅳ和Ⅴ组肉羊背最长肌中MyHCⅡb的mRNA相对表达量显著高于Ⅰ组(P<0.05)。综上所述,饲粮中添加FWBP可以降低肉羊背最长肌剪切力,改善其氨基酸组成,提高肌肉抗氧化能力,诱导Ⅱx型肌纤维向Ⅰ和Ⅱa型肌纤维的转化,且以添加100 mg/kg效果较佳。     

Natural or replacer sources of milk in lambs during feeding adaptation: influences on performance,metabolism of protein and lipid and oxidative/antioxidant status

This study aimed to evaluate the effect of milk feeding using milk replacer (MR) or natural ewe's milk (NEM) for Lacaune lambs on performance, protein and lipid metabolism and oxidative/antioxidant status. These parameters were evaluated during the period of feeding adaptation, which corresponded to 12 days after ewe's separation. Fifteen lambs were selected and divided into two groups: Group A (n = 7) with lambs receiving natural milk; Group B (n = 8) with lambs receiving a milk replacer. Liquid food supply, for both groups, was set according to their body weight, given in two daily periods. Feed intake was also obtained by individual body weight and adjusted according leftovers. Blood samples were collected on three different days (0, 6 and 12) to perform the serum analysis of total protein, albumin, cholesterol, triglycerides, alanine aminotransferase (ALT) and urea. Additionally, the oxidative profile was analysed in sera samples through the assessment of TBARS (reactive substances thiobarbituric acid) and ROS (reactive oxygen species) which aims to identify lipid peroxidation and free radical levels, respectively, as well as the antioxidant profile evaluating glutathione S‐transferase (GST). There was no statistical difference (p > 0.05) between groups on levels of total protein, albumin and globulin. However, cholesterol (day 6), triglycerides (days 6 and 12), urea (day 6) and ALT (day 12) levels differed (p < 0.05) between groups. Values of total protein, globulin, ALT and TBARS differed (p < 0.05) along the time. The average weight gain and body weight differed (p < 0.05) only on day 12, showing that weight gain was higher for lambs fed with NEM. The performance of lambs fed with MR was impaired. Biochemical parameters had a slight variation between groups and along the time, as well as oxidative/antioxidant status did not change in the different liquid diets.     

碱蓬干草饲喂水平对羔羊肌肉及器官组织中矿物元素的影响研究

盐生植物碱蓬是北方盐渍化草地一种潜在的饲料资源,其矿物元素富集的特征增加了家畜采食后的矿物质缺乏和不平衡的风险.本试验重点研究了羔羊日粮中添加0％,25％,50％碱蓬干草饲喂50 d后,对羔羊肌肉组织、心、肝、肾中矿物元素含量的影响.试验结果表明,日粮中添加碱蓬对肌肉组织中钙含量有显著的影响(P＜0.05),随着碱蓬含量的增加,羊肉中钙含量显著的减少;铁含量随碱蓬增加有提高的趋势,而且接近显著的水平,铜含量表现降低的趋势,但统计差异不显著.肝中铁和铜的含量变化也表现出与肌肉组织相似的趋势.添加碱蓬对心和肾组织中的各种矿物元素无显著的影响.因此,短期饲喂碱蓬干草对羔羊组织中矿物元素无明显的不利影响,但长期饲喂应关注动物发生铁过量和钙、铜缺乏的风险.     

Effects of eccentric exercise on branched‐chain amino acid profiles in rat serum and skeletal muscle

Supplementation of branched‐chain amino acid (BCAA) is often used to attenuate exercise‐induced skeletal muscle damage and promote adaptation, but no definitive conclusion on the benefits of BCAA on muscle recovery after injurious exercise can be drawn. Exploration of the systematic BCAA alteration in muscular injury‐repair stage per se without any BCAA supplement should provide some useful information in favour of BCAA application in muscle regeneration after injury. One bout of 90‐min downhill‐running exercise was performed to cause rat skeletal muscle injury. After exercise, myofibrillar BCAA concentrations showed minor changes compared with exercise before, while serum concentrations of BCAA were lower after exercise. Especially, serum leucine, isoleucine and total BCAA concentrations 2 weeks post‐run were significantly lower than normal values of exercise before (p = 0.008, p = 0.041, p = 0.015). The data demonstrate that a single eccentric exercise can significantly decrease the serum BCAA concentrations, which mean high utilization of BCAA for myogenesis after injurious exercise.     

The effect of a topical anaesthetic formulation, systemic flunixin and carprofen, singly or in combination, on cortisol and behavioural responses of Merino lambs to mulesing

OBJECTIVE: To determine the pain responses of lambs to mulesing, and the effectiveness of potential analgesic treatments. PROCEDURES: Merino lambs (n=64) were allocated at 5 weeks of age to eight treatment groups: 1) sham mules; 2) conventional mules; 3) topical anaesthetic, incorporating lignocaine, bupivicaine, adrenaline and cetrimide, applied immediately after mulesing; 4) flunixin + topical anaesthetic, with flunixin administered 2.5 mg/kg s.c. 90 min before mulesing; 5) carprofen + topical anaesthetic, with carprofen administered 4 mg/kg s.c. 90 min before mulesing; 6) carprofen, administered as above; 7) flunixin, administered as above; and 8) carprofen + flunixin, administered as above. Plasma cortisol was measured at 0, 0.5, 6, 12 and 24 h relative to mulesing. Animal behaviour, including posture, was recorded for 12 h after mulesing. RESULTS: The conventional mules lambs exhibited large increases in plasma cortisol, reduced lying and increased standing with a hunched back compared with sham mules animals. Topical anaesthetic reduced the cortisol peak to mulesing and hunched standing, and increased lying compared with the conventional mules treatment, but generally did not result in values equivalent to sham mules animals. Carprofen, flunixin, and carprofen + flunixin treatments did not reduce the cortisol response to mulesing but substantially ameliorated some changes in behavioural postures. Flunixin + topical anaesthetic reduced the cortisol peak following mulesing and substantially ameliorated most changes in behavioural postures. Carprofen + topical anaesthetic abolished the cortisol peak following mulesing and substantially ameliorated most changes in behavioural postures. All mulesed animals lost weight in the week after mulesing regardless of analgesic administration, but there were no significant differences in growth rate between any of the eight treatments over the 3 weeks after mulesing. CONCLUSIONS: Analgesics can moderate the pain response of lambs to mulesing. The welfare outcome for lambs of mulesing could be improved by use of a combination of local anaesthetic and long acting non-steroidal anti-inflammatory drug.     

复合氨基酸对断奶仔猪肝脏能量状态、游离氨基酸含量及其相关基因表达的影响

为进一步探明复合功能性氨基酸的应用效果与机理,在前期研究的基础上,本试验研究了日粮中添加复合氨基酸对断奶仔猪肝脏能量状态、游离氨基酸及相关基因表达的影响。将16头体重相近的（21±3）日龄断奶仔猪随机分为对照组和复合氨基酸组,每组8个重复。分别饲喂添加0.99%丙氨酸（与试验组等氮）和1.00%复合氨基酸（谷氨酸：谷氨酰胺：精氨酸：甘氨酸：N-乙酰半胱氨酸=5：2：2：1：0.5）的基础日粮。于试验第21天前腔静脉采血,屠宰取肝脏样品,待测。结果表明,与对照组相比,复合氨基酸显著降低了仔猪血浆ALT和AST活性（P<0.05）;显著提高了仔猪肝脏总蛋白含量、RNA/DNA和总蛋白/DNA（P<0.05）,显著降低了仔猪肝脏MDA和H₂O₂含量（P<0.05）;显著提高了肝脏精氨酸和二磷酸腺苷（ADP）含量（P<0.05）;显著上调了肝脏氨基酸转运载体b^0,+AT和y⁺LAT2基因、谷胱甘肽硫转移酶ω2基因（GSTO2）、干扰素γ基因（IFN-γ）、脂蛋白酯酶基因（LPL）的表达（P<0.05）,显著下调了脂肪酸合成酶基因（FASN）的表达（P<0.05）。以上结果表明,日粮中添加1.00%复合氨基酸可以改善肝功能,提高抗氧化能力,可以调控仔猪肝脏能量状态及游离氨基酸代谢,并可能影响肝脏的脂肪代谢和免疫功能。     

复合添加剂对肥育猪肌肉氨基酸组成影响的研究

为了研究自行配制的猪用复合维生素、复合微量元素和复合生物活性物质添加剂的不同水平组合对猪肉中氨基酸组成的影响,采用了3因素5水平二次回归通用旋转组合设计,以大×长仔猪为试验动物,进行了93d饲养试验。结果表明:采食11号日粮第11组试猪背最长肌中必需氨基酸(EAA)、鲜味氨基酸(FAA)和总氨基酸(TAA)含量最高,均值为7.58%、6.23%和18.20%,比对照组高10.98%、12.05%和10.57%,差异极显著(P<0.01);试验条件下,猪肉中EAA总量、FAA总量与3种复合添加剂水平呈极显著的回归关系,猪肉中EAA总量和FAA总量都较高时,相应各复合添加剂在猪饲粮中的添加量分别是复合维生素1260.019mg/kg、复合微量元素2191.668mg/kg和复合生物活性物质5496.512mg/kg。     

The effect of weight loss on protein profiles of gastrocnemius muscle in rabbits: a study using 1D electrophoresis and peptide mass fingerprinting

The study of physiological changes occurring during selection contributes to an improved understanding of relationships leading to efficiencies in animal production. To investigate the effects of food restriction in gastrocnemius muscle protein expression, 20% weight reduction was induced in New Zealand White (meat producing) and wild rabbits, using one‐dimensional gel electrophoresis and peptide mass fingerprinting. Lower expression levels of myosin heavy chains were found in the Wild Rabbits Restricted Group, while myosin light chain and α‐crystallin proteins were not detected in restricted groups. Glyceraldeyde‐3‐phosphate dehydrogenase and glycogen phosphorylase expression levels were similar for all experimental groups. Phosphopyruvate hydratase β was not detected in the wild rabbit restricted diet group. Pyruvate kinase levels were 50% lower in the New Zealand Restricted group. LIM protein detection was absent in the control New Zealand group. Results also show relevance of actin in preserving muscle structure in depressed food availability, the sensitivity of both myosin light chain and α‐crystallin protein to restricted feed and the role of PK in the resistance of New Zealand rabbits to food restriction.     

Reduced dietary protein level influences the free amino acid and gene expression profiles of selected amino acid transceptors in skeletal muscle of growing pigs

This study was conducted to evaluate the effect of reduced dietary protein level on growth performance, muscle mass weight, free amino acids (FAA) and gene expression profile of selected amino acid transceptors in different fibre type of skeletal muscle tissues (longissimus dorsi, psoas major, biceps femoris) of growing pigs. A total of 18 cross‐bred growing pigs (Large White × Landrace × Duroc) with initial body weight (9.57 ± 0.67 kg) were assigned into three dietary treatments: 20% crude protein (CP) diet (normal recommended, NP), 17% CP diet (low protein, LP) and 14% CP diet (very low protein, VLP). The results indicated improved feed‐to‐gain ratio was obtained for pigs fed LP and NP diets (p < 0.01), while the pigs fed VLP diet showed the worst growth performance (p < 0.01). There was no significant difference in the weights of longissimus dorsi and psoas major muscle between LP and NP groups (p > 0.05). Majority of the determined FAA concentration of LP group were greater than or equal to those of NP group in both longissimus dorsi and psoas major muscle (p < 0.01). Further, the mRNA expression levels of sodium‐coupled neutral amino acid transceptor 2, L‐type amino acid transceptor 1 and proton‐assisted amino acid transceptors 2 were higher in skeletal muscle tissue in LP group compared to those of the pigs fed NP or VLP diet. These results suggested that reduced dietary protein level (3 points of percentage less than recommended level) would upregulate the mRNA expression of amino acid transceptors to enhance the absorption of FAA in skeletal muscle of growing pigs. There seems to be a relationship between response of AA transceptors to the dietary protein level in skeletal muscle tissue of different fibre type. To illustrate the underlying mechanisms will be beneficial to animal nutrition.     

Accurate analysis of taurine,anserine, carnosine and free amino acids in a cattle muscle biopsy sample

We have established an analysis method for some free amino acids (FAAs), as well as taurine (Tau), anserine (Ans) and carnosine (Car), in a fresh biopsy sample from cattle muscle. A series of model biopsy samples, corresponding to the mixtures of lean meat, fat and connective tissue, was prepared and showed high correlation coefficients between the compound concentration and the 3‐methylhistidine (3‐MeHis) content derived from hydrolysis of the biopsy sample (r = 0.74–0.95, P < 0.01). Interference from blood contamination could not be neglected, because the concentration of some FAAs in blood was comparable to that in muscle. However, it was possible to control the contamination of Tau, Ans, Car, glutamic acid, glutamine, asparatic acid and alanine to less than 5.0% when the blood contamination was controlled to less than 23%.These results suggest the necessity of measuring 3‐MeHis as an index of lean meat and hemoglobin as an index of blood contamination when compounds in muscle biopsy samples are evaluated. We have carried out a series of these analyses using one biopsy sample and reveal differences in Tau, Ans, Car and some FAAs in beef muscle after different feeding regimes.     

Effects of a topical anaesthetic formulation and systemic carprofen, given singly or in combination, on the cortisol and behavioural responses of Merino lambs to castration

Objective   To determine the effectiveness of a topical anaesthetic formulation (Tri-Solfen) with or without the administration of a non-steroidal anti-inflammatory drug (carprofen) on the pain and distress response associated with ring or surgical castration of ram lambs.
Procedures   Merino ram lambs (n = 78) were allocated to 10 treatment groups: 4 groups of knife-castrated lambs and 4 groups of ring-castrated lambs received carprofen (4 mg/kg SC) and Tri-Solfen; 2 control groups (sham) received carprofen at 0 or 4 mg/kg SC. Measurements included plasma cortisol and haptoglobin concentrations, haematology, and behaviour, including posture.
Results   Knife-castrated lambs had higher peak cortisol and integrated cortisol responses for the first 6 h after treatment and greater concentration s of circulating acute phase proteins than ring-castrated lambs, both of which were significantly different from the sham controls. Tri-Solfen applied to the knife castration wound significantly reduced both the peak plasma cortisol concentration and the integrated cortisol response for the first 6 h and improved lying behaviour in the first 12 h. Carprofen reduced the cortisol response to knife castration at 30 min, but elevated the cortisol responses at 24 and 48 h. Carprofen nearly halved the number of acute pain behaviours associated with ring castration. There were no significant additive or synergistic effects from combining the analgesic treatments. Tri-Solfen applied to the tail wound provided no detectible benefits during ring castration + tail docking.
Conclusions   The physiological and behavioural responses suggest that ring castration has less impact on the lamb than knife castration. The specific analgesic treatments can provide modest amelioration of the pain and discomfort associated with castration. Alternative doses or application methods may enhance their efficacy.     

Carcass traits,meat quality,antioxidant status and antioxidant gene expression in muscle and liver of Hu lambs fed perilla seed

The effects of perilla (Perilla frutescens L.) seed on carcass traits, meat quality, antioxidant status and antioxidant gene expression in the liver and muscle of Hu lambs were investigated in this study. Sixty Hu lambs (23.02 ± 1.36 kg) were randomly divided into four experimental groups receiving diets containing 0%, 5%, 10% or 15% perilla seed (CD, 5%PFSD, 10%PFSD and 15%PFSD, respectively). The addition of perilla seed had no significant impacts on carcass traits (p > .05). There were no differences in pH, meat colour, drip loss, cooking loss or shear force among the four treatments (p > .05). Addition of perilla seed increased (p < .05) deposition of intramuscular lipids but had no effect on other chemical components in the longissimus dorsi (LD) (p > .05). The 15%PFSD diet decreased the total antioxidant capacity (T‐AOC) and malondialdehyde (MDA) content in the liver (p < .05 for both) but increased the activity of these antioxidant enzymes in LD (p < .05 for both). Compared to CD, addition of perilla seed increased superoxide dismutase (SOD) and glutathione peroxidase (GPX) expression in the liver and LD (p < .05 for all). These results indicate that perilla seed supplementation in lambs’ diets can increase deposition of intramuscular lipids and improve muscular oxidative status and meat quality.     

Expression of genes related to liver fatty acid metabolism in fat‐tailed and thin‐tailed lambs during negative and positive energy balances

Fat‐tailed sheep breeds can tolerate periods of negative energy balance without suffering from elevated concentration of plasma non‐esterified fatty acid (NEFA). This ability was attributed to unique metabolism of fat‐tailed adipose depot, whereas role of liver as an influential organ in fatty acid metabolism was not evaluated yet. Hence, current study was conducted to evaluate the effects of negative and positive energy balances on liver expression of genes related to fatty acid metabolism in fat‐tailed and thin‐tailed lambs. Lambs experienced negative (21 days) and positive (21 days) energy balances and were slaughtered at the beginning and end of negative energy balance and at the end of positive energy balance. Real‐time quantitative polymerase chain reaction (RT‐Q‐PCR) was conducted to evaluate changes in gene expression. Expression of diglyceride acyltransferase 1 (DGAT1), 3‐hydroxy‐3‐methylglutaryl‐CoA synthase 2 (HMGCS2) and apolipoprotein B (APOB) was not affected by genotype, energy balance and their interaction. Expression of carnitine palmitoyltransferase 1 (CPT1) was significantly higher in liver of fat‐tailed comparing to thin‐tailed lambs regardless of energy balance (p < 0.02). Catalase mRNA abundance was increased in response to negative energy balance (p < 0.02), and severity of this enhancement was higher in fat‐tailed lambs (p < 0.06). Expression of CPT1 was positively correlated with expression of HMGCS2 in both fat‐tailed (p < 0.05) and thin‐tailed lambs (p < 0.002); however, the correlation was weaker in fat‐tailed lambs (0.72 vs. 0.57, respectively, for thin‐tailed and fat‐tailed lambs). There was a positive correlation between DGAT1 and APOB genes expression in fat‐tailed lambs (0.94; p < 0.001), whereas this correlation was not observed in thin‐tailed lambs. Results demonstrate that liver of fat‐tailed lambs has higher capacity for metabolism of mobilized NEFA exposed to liver during negative energy balance.     

Evaluating the effect of calcium,magnesium and sodium supplementation of Merino ewes on their lambs' growth

Our study aimed to investigate responses to supplementation of calcium (Ca), magnesium (Mg) and sodium (Na) to lactating ewes and lambs grazing barley forage from lamb marking to weaning. A 10-ha paddock sown to barley was subdivided into eight plots as four replicates of two treatments. Merino ewes (n = 104) with lambs at foot were stratified to the eight plots (13 ewes and 21 lambs/plot) based on number of lambs (twin or single) and ewes' weight. Supplemented groups had access to mineral supplements (30 g/ewe/day) supplying 12 g/ewe/day ground limestone, 12 g/ewe/day Causmag® and 6 g/ewe/day coarse salt in a ratio of 2: 2: 1 by weight (as fed) from day 0 (a day before lamb marking) after sample collection. Control groups were not supplemented with minerals. Blood, milk and urine samples from ewes and blood from lambs were collected at different time points, namely, a day prior to lamb marking (day 0), 14 days after the commencement of study (day 14), and 28 days after the commencement of study (day 28). Weight of the lambs was also recorded at each time point. We found that the concentration of the forage minerals (Ca, Mg and potassium (K)) was lower on day 28 than on day 0 (P < 0.025). Liveweight gain was greater in the first 14 days compared with the second weight gain period (P < 0.001). The interaction of time and treatment was significant for liveweight (P < 0.001). Due to the improvement in weight gain of supplemented lambs, we recommend that mineral supplementation during late lactation is beneficial considering the low cost of minerals, even though the mineral content of the forage was not deficient.     

Effect of sex and feeding system on feed intake, growth, and meat and carcass characteristics of fattening Assaf lambs

The effect of feeding system and sex on intake, growth and carcass and meat characteristics of Assaf fattening lambs was studied. Twenty four weaned Assaf lambs, half males and half females were used. After an adaptation period, lambs were randomly assigned to one of the two feeding systems studied. Control lambs received ad libitum commercial concentrate (70% barley, 22% soybean meal, 4.8% wheat, 0.5% bicarbonate, 2.7% mineral–vitamin premix) and barley straw. Free Choice lambs had ad libitum and separate access to whole barley grain and a protein supplement (73.3% soyabean meal, 16% wheat, 1.7% bicarbonate, 9% mineral–vitamin premix). Lambs were slaughtered at 25 kg LBW. Feed intake was not significantly affected by sex (P > 0.05) but Free Choice lambs showed higher dry mater intake than the Control lambs. Nevertheless, only males from the Free Choice group showed an improvement in feed efficiency rate (P < 0.05) and average daily gain (P < 0.01) relating to the Control lambs. Neither feeding system nor feeding system × sex interaction significantly affected non-carcass weight, fat depots, cold carcass weight, dressing percentage, main proportions of commercial cuts and meat characteristics (P < 0.05). As it was expected, female lambs showed a lower average daily gain and a higher feed conversion efficiency than male lambs (P < 0.001) which was related to a greater fat deposition. Meat characteristics were unaffected by sex, with the exception of longissimus lumborum fat content, which was higher in female lambs.The present results suggest that Free Choice feeding system might be suitable for intensively reared male lambs since improvements in daily weight gain and feed conversion rate were achieved, with no adverse effect on carcass and meat quality. Despite the selected diet of both, males and females, did not differ in the crude protein content, the use of Free Choice feeding system for female lambs did not improve performance compared to the Control group.