Corriedale Lambs Research Articles

Desempenho de cordeiros Corriedale, puros e mestiços, terminados em pastagem e em confinamento

O experimento teve por objetivo avaliar o desempenho de cordeiros, do nascimento ao abate com 30-32kg de peso vivo na origem, usando-se 23 cordeiros Corriedale (C), 25 Bergamácia × Corriedale (BC) e 17 Hampshire Down × Corriedale (HC), terminados em pastagem de coast cross (Cynodon dactylon) ou em confinamento. O peso ao nascimento e o ganho de peso médio diário do nascimento ao desmame não foram influenciados pelo grupo genético (P>0,05). O ganho de peso médio diário do desmame ao abate (GPDA) de 0,144kg dos cordeiros confinados foi superior aos 0,106kg dos cordeiros em pastagem (P<0,05). O GPDA dos cordeiros BC (0,136kg) e HC (0,130kg) foram maiores (P<0,05) que o dos C (0,106kg) O sistema de terminação e de cruzamento (P<0,05) influiu no ganho de peso do nascimento ao abate (GPNA), com maiores ganhos observados para cordeiros confinados (0,137kg) e cruzados (0,132kg). Os cordeiros confinados atingiram o peso de abate (219 dias) mais cedo (P<0,05) que os da pastagem (258 dias). Os cordeiros terminados em confinamento, no dia do abate, apresentaram menor perda de peso da origem ao abate (3,16%), comparados aos da pastagem (5,17%) (P<0,05). Os resultados indicam que pode-se recomendar o cruzamento de ovelhas Corriedale com carneiros das raças citadas, bem como a terminação dos cordeiros em confinamento, desde que se tenha preocupação de avaliar os custos de produção deste sistema.

Influência do genótipo nos lipídeos totais e na fração insaponificável da carne de cordeiros

O objetivo deste trabalho foi comparar o conteúdo de lipídeos totais e componentes da fração insaponificável no Longissimus dorsi de cordeiros de cruzamento absorvente Ile de France x Corriedale (F1), em relação à raça Corriedale. Um total de vinte cordeiros machos inteiros foram divididos em dois grupos: cruza IF x C (n =10) e Corriedale (n =10). O manejo alimentar ovelha/cordeiro foi estabelecido em uma área de pastagem natural, melhorada. Os cordeiros foram abatidos com idade média de 150 dias e com pesos médios de 33,08 (±1,20) kg e de 26,42 (±1,37) kg, respectivamente. A gordura foi extraída, saponificada, os esteróis foram separados por cromatografia de camada delgada e o colesterol foi quantificado por cromatografia gasosa . Os resultados médios e os desvios padrões obtidos no músculo Longissimus dorsi das cruzas (IF x C) e da raça Corriedale, em g% foram: lipídeos totais 2,13 (± 0,42) e 2,12 (±0,41); teor de matéria insaponificável 3,28 (±0,65) e 3,69 (± 0,94); teor de esterol (na matéria insaponificável) 44,05 (±7,33) e 52,29 (±7,05) (P<0,01); enquanto o teor de colesterol (mg/100g base úmida ) foi de 38,37 (±4,58) e 39,16 (±7,09), respectivamente. O cruzamento IF x C (F1) não resultou em modificações para conteúdo de lipídeos totais e de colesterol, quando comparados com a raça Corriedale.

In vivo and ex vivo uptake of albendazole and its sulphoxide metabolite by cestode parasites: relationship with their kinetic behaviour in sheep.

The current experiments correlate the disposition kinetics of albendazole (ABZ) following its intravenous (i.v.) and intraruminal (i.r.) administrations to Moniezia spp.-infected sheep, with the pattern of drug/metabolite uptake by tapeworms collected from treated animals. The ex vivo uptake pattern of ABZ and albendazole sulphoxide (ABZSO) by the same cestode parasite was also investigated. Naturally infected (Moniezia spp.) Corriedale lambs were treated with ABZ by either i.v. (Group A, n = 15) or i.r. (Group B, n = 15) administration at 7.5 mg/kg. Plasma and abomasal fluid samples were obtained over a 120-h period. Two animals per group were killed at 0.5, 1, 2, 4 and 6 h post-treatment; parasite material (tapeworms), bile and intestinal fluid samples were recovered. Furthermore, Moniezia spp. tapeworms obtained from sheep killed at the local abattoir were incubated with either ABZ or ABZSO for different time periods in a Kreb's Ringer Tris buffer (ex vivo experiments). Samples were analysed by high performance liquid chromatography for ABZ, ABZSO and albendazole sulphone (ABZSO2). ABZ plasma concentrations decreased rapidly and were not detectable beyond 10 h following i.v. administration. ABZSO and ABZSO2 were the metabolites recovered in plasma after both treatments. ABZ and its metabolites were extensively distributed to the digestive tract, mainly into the abomasal fluid, after the i.v. and i.r. administrations. The parent drug and its active ABZSO metabolite were recovered in tapeworms collected from both i.v. and i.r. treated lambs. However, the availability of both ABZ and ABZSO was higher in parasite material recovered from i.v. treated animals. The uptake of ABZ by the cestode parasite, both in vivo and ex vivo, was significantly greater than that of its sulphoxide metabolite, which agrees with the higher lipophilicity of the parent drug.

Pesos, rendimentos e perdas da carcaça de cordeiros Corriedale e mestiços Ile de France x Corriedale, terminados em confinamento

O experimento teve por objetivo comparar os cordeiros da raça Corriedale com mestiços (F1) Ile de France x Corriedale, quanto às variáveis: peso da carcaça, porcentagem de quebra ao resfriamento e rendimentos de carcaça. Trabalhou-se com 18 cordeiros de cada genótipo, desmamados aos 60 dias de idade, com 10 a 12kg de peso vivo e terminados em regime de confinamento total, onde dispunham à vontade de uma ração com 15% PB e 70% NDT. Foram abatidos com peso vivo entre 30 e 32kg. Não houve diferenças entre os grupos genéticos para as variáveis estudadas, embora estas estejam dentro das requisições do mercado regional atual. Observou-se valor médio de 4% de perda no peso de sacrifício, em relação ao peso de origem. O peso elevado de alguns componentes não constituintes da carcaça (cabeça, pele, sangue e fígado) representou 20,9% do peso vivo médio ao sacrifício e afetou negativamente o rendimento da carcaça. Os resultados obtidos não invalidam por si só, a utilização deste cruzamento em circunstâncias semelhantes, tendo em vista que outras variáveis envolvidas com a eficiência global do sistema de produção não foram estudadas e mostram que, a pesos vivos semelhantes, não existe diferença de genótipo sobre as perdas por transporte e resfriamento, e sobre rendimento de carcaça.

Infection kinetics and developmental biology of Cryptosporidium muris (strain MCR) in Korean native kids and Corriedale lambs.

A total of nine Korean native kids and two Corriedale lambs, 1-20 days old, were each inoculated per os with a single dose of 2 x 10(7) oocysts of Cryptosporidium muris (strain MCR) originated from mice to elucidate the kinetics and developmental stages of the coccidium in small ruminants. Irrespective of host's age, the prepatent period for both animals ranged from 19 to 35 days (28.1 days, on the average) and the patent period 16-85 days (47.8 days), and the total oocyst outputs showed enormous differences. Infection with greater numbers of oocyst outputs was not ordinarily established by transmission experiments. Oocysts discharged from the kids retained their infectivity by the mouse titration method. The immunogenicity of the coccidium and oocyst reproduction were proven by challenge infection and administration of prednisolone acetate, respectively. All the developmental stages of the coccidium in parasitophorous vacuoles were found by transmission electron microscopy in the pits of the gastric glands of a kid inoculated with oocysts and then necropsied on day 44 postinoculation. It indicated the full course of the host-parasite relationship in kids and lambs as well as mice.

A technique for correction of entropion in lambs

Entropion is a congenital defect in lambs with high incidence in some genetic groups. Complications can arise from conventional methods of surgical correction. A simple technique was developed in ten newly born Corriedale lambs. A fold of skin on the affected lid was removed using a crush and cut approach. Use of anaesthesia and suturing was eliminated. The bloodless surgery corrected the defect without an open wound and healing occurred uneventfully in three days.

Heritability of scrotal circumference in Corriedale rams

Measurements of scrotal circumference were recorded for 1154 ram Corriedale lambs at ten studs. The best estimate was 0.50±0.11 cm, which concurs with reports on other breeds. Due to this value and the importance of scrotal circumference on reproductive aspects, its employment has been suggested as an additional criterion in sheep selection plans.

Broomfield Corriedales: A strain of sheep selectively bred for resistance to footrot

Broomfield Corriedales originate from a 15-year programme of selective breeding from sheep that evaded footrot when deliberately subjected to field challenge. To determine whether this policy may have resulted in improved resistance to footrot, trials were set up in which representative animals from the Broomfield blood-line were challenged with footrot by either experimental or natural infection, together with Corriedale sheep of similar age and sex but from flocks in which the disease is not known to occur. In another approach, the occurrence of footrot was compared in the offspring of Broomfield and of non-Broomfield sires mated with randomly selected ewes in a commercial Corriedale flock in which the condition was prevalent. Finally, the effects of natural challenge in Broomfield lambs were compared with those in a selection line of Corriedale lambs of which both parents had a history of chronic footrot disease. Footrot affected significantly fewer sheep of the Broomfield blood-line and to a markedly lesser degree than those chosen for comparison under identical challenge conditions. Where present, foot infections in Broomfield animals also tended to be less invasive and less persistent. Reduced footrot prevalence was also demonstrated in three birth cohorts of first-cross offspring of Broomfield sires relative to the offspring of other sires, though differences were not significant at all inspections. These findings, considered as a supplement to the historical development of the Broomfield flock, offer encouraging prospects for breeding programmes to enhance the resistance of sheep to footrot disease.

POSITIVE AIRWAY PRESSURE IN LAMBS SPONTANEOUSLY BREATHING AIR AND OXYGEN

Abstract The effects of 10 cm H2O positive endexpiratory pressure (PEEP) were studied in 26 unrestrained Hampshire and Corriedale lambs, breathing spontaneously air or pure oxygen. No changes in lung morphology, pulmonary mechanics or arterial blood gas tensions were detected after air breathing with 10 cm H2O PEEP for one week. No changes were found in mean pulmonary artery pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance or cardiac output in oxygen breathing lambs until minutes before death. Addition of PEEP to oxygen breathing accelerated the development of respiratory acidemia and death (PEEP group mean lifespan 54 3 4 hr, without PEEP mean lifespan 71 3 4 hr). Morphologic changes of acute oxygen toxicity were present in oxygen breathing lambs and lung water was increased. Oxygen breathing lambs died from apnea with hypercarbia and a markedly increased (A-a) DO2. An increase in pulmonary vascular resistance or right ventricular failure do not appear to be major factors in the syndrome of fulminant acute respiratory insufficiency due to oxygen toxicity in lambs.

A comparison of the performance of single and twin born Corriedale ewes and lambs

Reproductive performance of Corriedale sheep from the experimental farm at Mount Derrimut, Victoria, was studied over five years (1 968 to 1972) in a flock selected for the production of medium wool and the ability to produce twins. Traits measured included fertility at mating, lambing rate, twinning rate, mortality at birth and interval between mating and lambing. Ewes born as twins were less fertile at first mating, improved rapidly in their reproductive performance at subsequent matings, but then declined in fertility quite early in their breeding life. Twin lambs had a mortality rate at birth nearly three times that of singles, were lighter at birth, grew slowly up to weaning and produced less wool at weaning. Female lambs conceived as co-twins with male lambs tended to be disadvantaged in heir pre-natal development which could be due to an enhancement effect exhibited by the male co-twin.

Positive airway pressure in lambs spontaneously breathing air and oxygen

The effects of 10 cm H 2O positive endexpiratory pressure (PEEP) were studied in 26 unrestrained Hampshire and Corriedale lambs, breathing spontaneously air or pure oxygen. No changes in lung morphology, pulmonary mechanics or arterial blood gas tensions were detected after air breathing with 10 cm H 2O PEEP for one week. No changes were found in mean pulmonary artery pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance or cardiac output in oxygen breathing lambs until minutes before death. Addition of PEEP to oxygen breathing accelerated the development of respiratory acidemia and death (PEEP group mean lifespan 54 3 4 hr, without PEEP mean lifespan 71 3 4 hr). Morphologic changes of acute oxygen toxicity were present in oxygen breathing lambs and lung water was increased. Oxygen breathing lambs died from apnea with hypercarbia and a markedly increased ( A-a) DO 2. An increase in pulmonary vascular resistance or right ventricular failure do not appear to be major factors in the syndrome of fulminant acute respiratory insufficiency due to oxygen toxicity in lambs.

Some effects of botanical composition of pasture on growth and wool production of weaner sheep

August-born Corriedale lambs were weaned at ten weeks old and, for the following 12 months, were grazed on 16 plots. Each plot had been sown six years previously, to one of eight pasture mixtures which differed in their grass component, but not in their clover component. Trifolium perenne, Phalaris tuberosa, Dacylis glomerata, Trifolium repens, T . subterraneum, and T. fragiferum were sown. Hordem leporinum volunteered in most plots. Where perennial grass species were sown, Trifolium repens (white clover) contributed less than two per cent to the pasture present on the plots. For the two plots where perennial grass was not sown, white clover contributed up to 31 per cent. The total for all sown clover species present in the pasture varied from approximately 100 to 1000 kg ha-1, or approximately 3-30 per cent. Apart from the two plots where perennial qrass was not sown, the clover species present was mainly Trifolium subterraneum (subterranean clover). Average fleece weights varied from 3.1-4.9 kg on the different plots. The amount of sown clover present in the pasture accounted for 77 per cent of the between-plot variation in fleece weight and 66 per cent of the between-plot variation in annual liveweight gain. Measurements of pasture growth were made for four pasture mixtures. Total pasture growth showed differences of over 50 per cent due to pasture mixture, yet, when grazed at 20 weaners per hectare, differences in annual liveweight gain and fleece weight (10 months wool), due to pasture mixture, did not exceed 10 per cent. Annual liveweight gain and fleece weight were not correlated total pasture growth. However, pasture growth rate measured at monthly intervals, accounted for 43 per cent of the variation in mean daily liveweight gain during these individual months.

A note on the haem pigment concentration of lamb as influenced by age and sex

SUMMARYMyoglobin and haemoglobin concentrations were determined in the m. longissimus dorsi of 133 Dorset Horn × Corriedale lambs, varying in age from 98 to 310 days, and killed at a live weight of 32 kg. Analysis of the data showed that age, over the period studied, was not a critical factor in determining the myoglobin concentration within the muscle. The average pigment level in the muscle of ewes was some 20% greater than in ‘cryptorchids’ and approximately 10% greater than in wethers. Haemoglobin was found to represent about 40% of the total haem pigment.

Effects of variation in age and birth weight on fleece traits at eighteen and thirty months

Simple regression coefficients of fleece traits, measured at 18 and 30 months of age, on variations in age at sampling (as determined by the date of birth) and on birth weight were calculated for eight flocks in Western Victoria (4 Merino, 3 Corriedale, 1 Polwarth). The regression coefficients of fleece traits on age variation were generally small and not significant. The regression coefficients of fleece traits on birth weight generally showed an increase in greasy and clean fleece weight and per cent clean scoured yield, and a decrease in mean fibre diameter with increase in birth weight. Variation in age and birth weight contributed to the variation in clean wool weight at 18 months of age by 0.1-5.2 per cent, and 0.1-6.2 per cent respectively; at 30 months of age, the contributions were 0.1-2.3 per cent and 0.0-11.0 per cent respectively. Merino, Corriedale, and Polwarth lambs had mean days of birth (from day of first lamb birth) of 20.6, 22.3, and 14.4, and mean birth weights of 7.85, 8.01, and 9.68 lb respectively.

Genetic factors affecting the milk intake of lambs

The actual amount of milk produced by a ewe is influenced both by her own potential to produce milk and by the potential of the lamb to obtain it. Two experiments were carried out to investigate the relative importance of these factors. In each experiment there were two genetically different groups of ewes, of which some reared their own single lambs and some reared single lambs from the other group fostered onto them. In both experiments, the effect of the genotype of the lamb was greater than that of the ewe. In the first experiment, during the period 6–24 days after parturition, ewes suckling strong-wool lambs produced 7.2 g/hr more milk than those suckling Peppin lambs, while the strong-wool ewes themselves produced only 4.6 g/hr more than the Peppin ewes. In the second experiment, during the period 0–28 days after parturition, ewes suckling Corriedale lambs produced 11.6 g/hr more milk than those suckling strong-wool Merino lambs, whereas the Corriedale ewes themselves produced only 4.4 g/hr more than the strong-wool Merino ewes. The lamb genotype effects were statistically significant. In a third experiment, in which the strong-wool and medium-wool Merinos were compared when suckling twins, the strong-wool exceeded the medium by 10.8 g/hr in milk production for the period 6-24 days after parturition. Some implications of the results are discussed.

Post-Weaning Performance in Columbia and Corriedale Lambs

Post-Weaning Performance in Columbia and Corriedale Lambs

子めん羊の皮膚温度の変化

Changes in skin temperature at five sites of the body under environmental temperature varying from 10° to 30°C werestudied in a psychrometric room where relative humidity was constantly 70 per cent or below. Two 4 - month - old (lambs Nos., 58-5 to 7) and two 10 month-old (lambs Nos., 57-2 to 4) Japanese Corriedale lambs were used. Results obtained are as follows.1. The skin temperature varied with an increase of environmental temperature and with sites of body. The lowest skin temperature was recorded at the fore-shank and the highest at the neck, breast, and flank. The variation of skin temperatures at these three sites showed no consistent trend. The ear gave an intermediate skin temperature.2. The increase of environmental temperature caused a greater rise of skin temperature at the fore-shank than any other site. Cosnequently, the variation of skin temperature was very small at all sites at a low environmental temperature.3. When a I mb was exposed to a constant environmental temperature of 25° or 30°C, its skin temperature changed in 10 minutes. In 4 -month -old lambs, however, skin temperature showed a rise in 20 minutes when they were placed at an environmental temperature of 30°C.4.The skin temperatures determined at an environmental temperature of 30°C were closely associated with the environmental and rectal temperatures.5. Although no possible age difference was found in skin temperature under the increasing environmental temperature, the skin temperatures were higher in 4-month- old lambs under the high environmental temperature than in older ones.

仔めん羊の体温調節機能

Two Japanese Corriedale lambs, 6 months old, were used for investigation under field conditions. Rectal temperature and cardiorespiratory behavior were recorded daily throughout the summer of 1955. In another experiment two 11-month-old and three 3-to 4-month-old lambs were exposed to varying environmental temperatures at low relative humidity in a psychrometric room, and their physiological responses were measured in the same manner.1) Rectal temperature rose and respiration rate increased following the elevation of environmental temperature from 10° to 30°. The highest rise in rectal temperature was observed when environmental temperature was about 25°. A remarkable change in respiration rate generally occurred when enviromental temperature was changed from 20° to 25°. No change in pulse rate could be ascribed to environmental temperature.2) These results suggest that the critical point of environmental temperature may be about 25°, at which the body-temperature regulating mechanism of the lamb may be affected by heat stress.3) Changes of rectal temperature were less in 11-month-old lambs than in younger ones. The bodytemperature regulating capacity of the lamb was also recognized at 3 months of age.

コリデール種緬羊の毛胞群に関する研究

The present study has been carried out to observe changes of the hair follicle population in the Corriedale sheep skin in relation to lamb growth. The animals examined were 4 Corriedale lambs and a small patch of skin was taken from the shoulder, side and the thigh region of each lamb at 1, 3, 6, and 9 months after birth. Each skin sample was prepared histologically and the differences of the follicle densities, of the follicle bundle densities and of the diameters of the follicles due to different individuals and also to different body regions and ages of lambs, were studied.The results obtained were as follows;(1) The follicle density and the follicle bundle density in the skin of Corriedale sheep were found to vary according to ages of lambs. The maximum values of density were observed at 1 month or 3 months of age and the decreased values after these months until 9 months after birth.(2) The relative values of the follicle density and the follicle bundle density in different body regions of lambs differed in different individuals and of definite order in the values was found.(3) The mean diameters of the follicles varied according to individuals, to body regions and also to ages of lambs. They showed the highest values at 3 or 6 months after birth, and the decreased values after these months until 9 months after birth.The larger diameters were found at the side or thigh region, and the smaller at the shoulder region.(4) When the diameters of the primary follicles were compared with those of the secondary follicles of different body regions and also of different ages after birth, a tendency that the former was larger than the latter was observed.

Effects of Some Environmental Factors on Weanling Traits of Range Columbia, Corriedale and Targhee Lambs

Effects of Some Environmental Factors on Weanling Traits of Range Columbia, Corriedale and Targhee Lambs