Influence of gender on carcass yield of twin lambs Blackbelly x Pelibuey at 56 days of age / Influência do gênero no rendimento de carcaça em cordeiros gêmeos Blackbelly x Pelibuey aos 56 días de idade

The aim of this study was to determine the influence of gender on pre-weaning growth, yield and weight of primal cuts of the carcass of Blackbelly x Pelibuey lambs. 16 twin lambs were used. The lamb gender was the fixed factor. The variables evaluated were: body weight at birth and at weaning, average daily weight gain, weight and yield of carcass and primal cuts: neck, arm, thorax, abdomen and leg. Gender did not affect (P>0.05) body weight at birth. However, the pre-weaning average daily weight gain and body weight at weaning were affected (P<0.05) by the gender. Hot carcass yield and weight and primal cuts were not affected (P>0.05) by the gender of the lamb. Nevertheless, the area of the Longissimus dorsi muscle and cavity fat were different between males and females (P<0.05) 11.5±0.73cm2 and 198±0.05 g vs 9.3±0.73cm2 and 282±0.05g, respectively. In conclusion, in twin lambs Blackbelly x Pelibuey males had greater average daily weight gain and body weight at weaning than females. Carcass yield and weight and primal cuts were not affected by the gender of the lamb. However, males had greater area of the L. dorsi muscle than females and these in turn had a greater amount of cavity fat than males.(AU)

Objetivou-se determinar a influência do gênero no crescimento pré-desmame, no rendimento e no peso dos cortes primários de carcaça de cordeiros Blackbelly x Pelibuey. Utilizaram-se 16 cordeiros gêmeos. Os dados foram analisados em um desenho completamente ao acaso, em que o gênero dos corderos foi o fator fixo. As variáveis avaliadas foram: peso vivo ao nascimento e ao desmame, ganho diário de peso, peso e rendimento de carcaças e dos cortes primários: pescoço, braço, tórax, abdômen e perna. O gênero não afetou (P>0,05) o peso vivo ao nascimento. No entanto, o ganho diário de peso e o peso vivo ao desmame foram afetados, sendo esses valores superiores nos machos (P<0,05). O peso e o rendimento das carcaças quentes e dos cortes primários não foram afetados (P>0,05) pelo gênero do cordeiro. Entretanto, a área do músculo Longissimus dorsi e a gordura cavitária foram diferentes entre machos e fêmeas (P<0,05): 11.5±0.73cm2 e 198±0.05g vs. 9.3±0.73cm2 e 282±0.05g, respectivamente. Em conclusão, nos cordeiros gêmeos Blackbelly x Pelibuey, os machos tiveram maior ganho diário de peso e maior peso vivo ao desmame do que as fêmeas. O peso e o rendimento da carcaça bem como os cortes primários não foram afetados pelo gênero do cordeiro. Todavia, os machos tiveram maior área do músculo L. dorsi que as fêmeas e estas tiveram maior quantidade de gordura cavitária que os machos.(AU)

Desarrollo de rssistencia a nematodos gastrointstinales en ovinos de pelo desaafiados con diferentes niveles de infección / Develoment of reesistance to gastrointstinal nematode in hair sheep cchallenged with different levels of ineection

Se utilizaron 24 corderos Katahdin x Pelibuey, distribuidos al azar en cuatro grupos desafiados con los siguientes tratamientos: a) 25 larvas infectantes (L3) de nematodos gastrointestinales (NGI) por kg de peso vivo (PV); b) 50 L3 PV, c) 100 L3 PV y el grupo testigo (0 larvas). El experimento se dividió en tres etapas: 1) infección experimental y estabulación de corderos, 2) reinfección en pastoreo y 3) estabulación. En cada etapa se determinó el número de huevos de nematodos por gramo de heces (HPG), el peso vivo (PV) y el volumen celular aglomerado (VCA). El análisis se realizó con medidas repetidas en el tiempo. Los corderos infectados con 100 L3 tuvieron mayor HPG (1.642 ± 1.183) que los infectados con 50 L3 (1.140 ± 1.313 HPG) y los de 25 L3 (458 ± 371 HPG). Con 50 L3 los corderos tuvieron el menor VCA (23,7 ± 4,8%). Con 100 L3 se observó menor VCA que el grupo testigo y el de 25 L3 (26,2 ± 3,9; 28,0 ± 4,1 y 27,3 ± 4,2 %, respectivamente). Las ganancias de peso se redujeron respecto al testigo en un 22% en los de 25 larvas, 60% en los de 50 larvas y 61% en los de 100 larvas. El grupo infectado con 100 larvas obtuvo, durante la segunda etapa, el menor HPG (2.033 ± 2.553 HPG), un incremento del VCA (27,8%) y mayor ganancia de peso (3,7 kg) que los otros grupos, por lo que se concluye que con la dosis de 100 L3 se obtienen menores conteos fecales de huevos de NGI, mayor VCA y mejor ganancia de peso bajo condiciones de reinfección en pastoreo.

24 Katahdin x Pelibuey male lambs were used. The lambs were random in four groups with the following treatments: a) 25 infective larvae (L3) of gastrointestinal nematodes (GIN) per kg of body weight (BW), b) 50 L3 BW, c) 100 L3 BW and the control group (0 L3). The experiment was divided into three stages: 1) Experimental infection in stabling, 2) grazing infection and 3) housed lambs. At each stage were determined the number of nematode eggs per gram of feces (EPG), body weight and packed cell volume (PCV). The data analysis was performed using a repeated measures model in time. The lambs infected with 100 L3 had higher EPG (1642 ± 1183) in comparison with the treatment of 50 L3 (1140 ± 1313 EPG) and 25 L3 (458 ± 371 EPG). With 50 L3 the lambs had the lowest PCV (23.7 ± 4.8%). With the application of 100 L3 also had lower PCV than control group and 25 L3 (26.2 ± 3.9, 28.0 ± 4.1 and 27.3 ± 4.2%, respectively). It was observed a decrease in weight gain of all infected groups compared to the control group, by 22% in lambs with 25 larvae, 60% in the 50 larvae and 61% in animals of 100 larvae. During the second stage, the group infected with 100 larvae there was a reduction of EPG (2033 ± 2553 EPG), an increase in PCV (27.8%) and increased kg (3.7 kg) with respect to other infected for this reason was concluding that lambs receiving 100 L3 had lowest nematode faecal egg count, highest PCV and gain daily weight during the grazing reinfection.