Influence of repeated restraint and isolation stress and electrolyte administration on carcass quality and muscle electrolyte content of sheep

Manejo pré-abate de ovelhas de descarte: perdas de peso corporal, qualidade da carne e comportamento animal

Objetivou-se com este estudo conhecer o comportamento de ovelhas da raça Santa Inês em diferentes estágios fisiológicos durante o manejo pré-abate, assim como a perda de peso corporal, valores de hematócrito do sangue das mesmas e a qualidade da carne. Utilizaram-se 21 ovelhas de descarte, que foram distribuídas nos respectivos tratamentos: T1 = ovelhas que permaneceram por 60 dias em lactação com seus respectivos cordeiros e abatidas um dia após o desmame dos mesmos; T2 = ovelhas que permaneceram por 60 dias em lactação com seus respectivos cordeiros e mais um período aproximado de 30 dias sem os cordeiros e posteriormente foram abatidas; e T3 = ovelhas que permaneceram por 60 dias em confinamento e que não pariram durante o ano. O peso das ovelhas após o transporte foi menor para as do tratamento 1 em comparação às do tratamento 2. Os valores de hematócrito no sangue das ovelhas antes do transporte, após o mesmo e após o jejum dos animais no curral de espera não diferiram entre si, com valor médio de 58,50%. Concluiu-se que a qualidade da carne proveniente de ovelhas de descarte em diferentes estágios fisiológicos não é alterada pelo manejo pré-abate, quando realizado de maneira correta (evitando o estresse animal), quanto ao pH da carne.

Effect of artificial rearing on lamb welfare and meat quality

Twenty male Comisana lambs were equally divided into two groups. Ten subjects were artificially reared, 10 others were ewe reared and used as control. Unseparated control animals displayed increased cellular immune response to a percutaneous injection of phytohemagglutinin (P<0.001). During the open field test, ewe-reared lambs showed a higher number of flight attempts (P<0.01). Carcass yield were higher for artificially reared animals (P<0.05). Conversely, legs of ewe-reared animals had significantly more fat (P<0.05) and a higher content of saturated fatty acids (P<0.001). Polyunsaturated fatty acid content was higher in artificially reared lamb meat (P<0.01), although the ratio n-6/n-3 was well above the recommended values. The triangle test showed a significant difference in sensory analysis between the two products (P<0.05). Finally, for both rearing systems legs without subcutaneous fat showed a higher percentage of polyunsaturated fatty acids and a corresponding lower content of saturated fatty acids (P<0.001).

Use of carcass weight to classify Manchego sucking lambs and its relation to carcass and meat quality

Eighty-seven Manchego sucking lambs raised exclusively on maternal milk were slaughtered. The carcasses were weighed immediately after dressing and classified according to hot carcass weight (HCW): low HCW (<5.5 kg), medium HCW (5.5 to 6.5 kg) and high HCW (≥ 6.5 kg). The effects of this classification system on carcass and meat quality were studied. Carcass conformation improved as carcass weight increased; carcasses became more compact. Carcass fatness increased (P< 0.001) as carcasses became heavier. With regard to the joints, leg (P< 0.001) and shoulder (P< 0.05) proportions decreased as carcass weight increased, whereas loin-rib (P< 0.001) and flank (P< 0.001) proportions increased. The proportion of fat in the leg clearly increased in the heavier carcasses (P< 0.001), while that of bone decreased (P< 0.001) and that of muscle was not affected. pH at 24 h in them. longissimusdorsi andm. semitendinosusdecreased as carcass weight increased. The only meat colour parameter affected by carcass weight was the yellowness index; lighter-weight carcasses displayed lower index (P< 0.05). Cooking losses were unaffected as carcass weight increased, whereas with regard to tenderness, the shear force value tended to be higher in the low carcass weight group. No differences between carcass weight groups were found in the sensory analysis. Fatty acid composition did not show any significant effect due to carcass weight except in stearic fatty acid (C18:0); C18:0 proportion decreased (P< 0.01) as carcasses became heavier. Carcass weight affected carcass quality (all carcass quality parameters studied were higher in the heavier carcasses), whereas meat quality varied little as a result the small variation between carcass weights in sucking lambs.

Ion distribution and protein proteolysis affect water holding capacity of Longissimus thoracis et lumborum in meat of lamb subjected to antemortem exercise

Exercise has been shown previously to reduce the water holding capacity (WHC) of meat in lamb. The consequence of changes in the distribution of ions pre- and post-rigor and proteolysis on WHC is relatively unknown. Twelve crossbred lambs were used to investigate the effect of exercise on the meat quality traits of the Longissimus thoracis et lumborum (LTL) muscle. There were no treatment effects on Warner-Bratzler shear force (WBSF), myofibril and sarcoplasmic protein solubility, denaturation or sarcomere length. With exercise the initial pH of the muscle was lower and the rate of pH fall to rigor was faster compared to controls. Exercise caused increased purge and meat fluid had a lower osmolarity, magnesium, potassium and sodium concentration. Proteolysis of desmin occurred after day 3 and vinculin on day 7 of ageing with exercise. It was concluded that exercise caused changes in the distribution of ions and the proteolysis of muscle proteins that reduced the ability of the muscle to bind or hold water.

Effectiveness of electrolytes at alleviating dehydration and improving carcass characteristics of adult sheep in lairage

The aim of this work was to examine the effectiveness of a commercial electrolyte mixture in alleviating dehydration and improving carcass characteristics of adult sheep under commercial processing conditions. Two separate experiments were conducted to investigate this aim. Experiment 1 had 2 hydration treatments (water with and without electrolytes) and sheep commenced their treatments on their arrival at the abattoir. Animals were then slaughtered at the lairage times of 24, 48 or 72 h. Experiment 2 had the same treatments and an additional no water (no electrolyte) treatment. In the second experiment only, animals from each of the treatment groups were allocated into 2 stimulation groups, so that on the production line the carcasses were either treated with high voltage stimulation or not treated. Experiment 2 animals were grazed for 2 weeks at the abattoir prior to commencement of the treatments. Animals were slaughtered after a lairage time of 24, 48 or 72 h, except for animals on the no-water treatment: these animals had lairage times of 24 or 48 h only. It was found in both experiments that there was no difference (P>0.05) between the water treatments for all carcass and meat quality traits measured. Lairage time had an effect (P<0.05) on urine specific gravity in both experiments. Urine specific gravity decreased as lairage time increased in experiment 1, but an opposing trend was found in experiment 2. In experiment 1, as lairage time increased, GR (total tissue depth at the 12th rib) decreased. Electrical stimulation in experiment 2 lowered (P<0.05) the initial pH and interacted with lairage time causing differences in cook loss for meat aged for 1 or 7 days, but had no impact on other traits.

Duration of restraint and isolation stress as a model to study the dark-cutting condition in cattle1,2

Holstein steer calves (n = 32; 156 +/- 33.2 kg average BW) were used to evaluate the duration of restraint and isolation stress (RIS) on endocrine and blood metabolite status and the incidence of dark-cutting LM. Calves were blocked by BW and assigned randomly within blocks to one of four stressor treatments: unstressed controls (NS) or a single bout of RIS for 2, 4, or 6 h. Venous blood was collected via indwelling jugular catheters at 40, 20, and 0 min before stressor application and at 20-min intervals during RIS. Unstressed calves remained in their home stanchions and, except for blood sampling, were subjected to minimal handling and stress. Serum cortisol and plasma lactate concentrations were increased (P < 0.01) during the first 20 min after RIS application, and remained elevated throughout the 6 h of RIS. Plasma concentrations of glucose and insulin were greater (P < 0.05) in RIS calves than in NS calves after 80 and 100 min of stressor application, respectively; however, RIS did not (P > 0.80) affect plasma NEFA concentrations. Calves were slaughtered within 20 min of completion of RIS, and muscle samples were excised from right-side LM at 0, 0.75, 1.5, 3, 6, 12, 24, and 48 h after exsanguination for quantifying LM pH, and glycogen and lactate concentrations. The pH of the LM from calves subjected to 6 h of RIS exceeded 6.0, and was greater (P < 0.05) at 24 and 48 h postmortem than the pH of NS calves or calves subjected to 2 or 4 h RIS. Muscle glycogen concentrations did not differ (P = 0.16; 25.58, 10.41, 13.80, and 14.41 micromol/g of wet tissue weight for NS and 2-, 4-, and 6-h RIS, respectively), and LM lactate concentrations tended to be lower (P = 0.08) in calves subjected to 6 h of RIS. At 48 h after exsanguination, the LM from calves subjected to 6 h of RIS had more (P < 0.05) bound and less (P < 0.05) free moisture than did the LM from NS calves or calves subjected to 2 or 4 h of RIS. Additionally, the LM from RIS calves was darker (lower L* values; P < 0.05) than the LM of NS calves. Visual color scores for the LM were greatest (P < 0.05) for calves subjected to 6 h of RIS and least (P < 0.05) for NS calves. Subjecting lightweight Holstein calves to 6, 4, and 2 h of RIS resulted in six (75%), two (25%), and two (25%) carcasses characteristic of the dark-cutting condition, respectively. There were no dark-cutting carcasses produced from NS calves. Thus, RIS may be a reliable animal model with which to study the formation of the dark-cutting condition.

Early handling increases lamb affinity for humans

Domestic animals that are socialized to humans are often more easily managed and less timid than those that are not. We examined whether increased handling and artificial feeding of domestic sheep, Ovis aries, at an early age would decrease their subsequent timidity towards people. Forty-eight lamb twin sets were divided into four treatment groups for 2 days of treatment at ages 1-3, 3-5, 5-7 or 7-9 days. Treatment lambs were fed milk replacer and were handled four times/day for 5-min periods. Their twins, used as controls, were left with their dams. Two 5-min tests of lamb temperament were conducted at ages 2, 4, 6, 8, 10, 15 and 25 days. Testing consisted of a stationary human encounter, in which lambs' responses to a sitting person were recorded continuously, and a moving human encounter, in which lambs' responses to a person walking at 0.5 m/2 s were recorded by instantaneous scans. Measures included latency to proximity (<2 m) and arm's reach (<1 m) of the person, time spent in proximity and within arm's reach, average distance (m), mean number of human contacts, number of lambs contacting a person and following/approach/avoidance. Treatment lambs showed significantly greater affinity for humans than their twin controls. The 1-3-day treatment group showed the greatest response to treatment, consistently outperforming controls in all of the above measures. These results suggest that 40 min of positive human contact at age 1-3 days reduces lamb timidity to people. Socialization of lambs to humans need not disrupt the primary lamb-dam bond, and it may have positive management as well as welfare implications.\C 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour.