G. Garibotto

Efecto del peso al sacrificio sobre la calidad de la canal y de la carne de corderos Corriedale puros y cruza

The effects of slaughter weights on light lambs (n=45): 22.3 ± 2. 8 kg and 60 ± 2.4 days of age and heavy lambs (n=21): 43. 1 ± 6.3 kg and 169 ± 8.9 days of ...

POST WEANING FEEDING MANAGEMENT AND PERFORMANCE OF MERINO EWES GRAZING ON NATURAL AND IMPROVED PASTURES AT MATING SEASON

In the uruguayan Basalt region, the reproductive performance of 300 Merino ewes and the effect of 3 post-weaning feeding managements (PWFM: I: 1.2 cm height of available forage and 16 ewes/ha; II: 2.03 cm height of available forage and 5 ewes/ha; III: 2.5cm height of available forage and 1 ewe/ha) as well as 2 feeding levels before and during the breeding season (FLM: native pastures: green DM/ha: 883kg, CP: 114g/kg DM, NDF: 781g/kg DM and improved pastures: DM /ha: 1270kg, CP: 194g/kg DM, NDF: 598g/kg DM) were studied with a factorial arrangement of treatments. The PWFM extended for 70 days, ewes were mated in the period from 13/4/96 to 13/5/96 and FLM were applied for 30 days, starting 15 days before beginning of breeding. There were not differences on the ovulation rate (P>0.05); however, the P values might indicate some effect of the treatments. The number of born lambs/ewe served increased with the ovulation rate because the higher number of ovulations balanced their less viability, individually considered. Actually, the number of born lambs/ewe served was higher with animals coming from PWFM III (1.18, 1.11 and 0.96, PWFM III, II and I, respectively; P = 0.02) and with the animals grazing on improved pastures at mating period (1.13 and 1.03, improved pastures and natural pastures, respectively; P = 0.10), were those which showed slight higher ovulation rate.

Variation in instrumental meat quality among 15 muscles from 14-month-old sheep and its relationship with fibre typing

The aims of the present study were to describe intermuscular differences in meat-quality traits in 15 young-sheep muscles, and to study the associations between meat quality and fibre typing across all (pooled) muscles as well as in previously selected homogeneous contractile–metabolic groups of muscles (slow-oxidative, intermediate and fast-glycolytic muscles). Meat-quality traits (pH, colour, expressed juice, cooking losses, tenderness and sarcomere length) and fibre typing were evaluated after 24 h of slaughter in 15 muscles from five cross-bred young sheep. Across all the studied muscles, intermuscular differences in some meat-quality traits (pH24, a* and expressed juice) seemed to be mainly explained by muscle oxidative activity, while intermuscular variation in other meat-quality traits (L*, b* and Warner–Bratzler shear force) were mainly explained by differences in fibre sizes. Within fast-glycolytic muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower ultimate pH, higher L* values, lower a* values and longer sarcomeres. Within intermediate muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower ultimate pH, higher L* values, shorter sarcomeres and reduced meat tenderness. Within slow-oxidative muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower amounts of expressed juice, lower a* values and reduced meat tenderness. The present study has contributed to a better understanding of the influence of muscle fibre types on intermuscular meat-quality variation, suggesting that although muscle fibre diversity may explain, at least in part, intermuscular differences in meat quality, these associations can also slightly vary among muscle contractile–metabolic groups.

Opciones genéticas para el engorde de corderos

En el mundo existen una variedad de razas muy vasta que constituyen una importantisima fuente de variacion genetica. El uso de cualquiera de ellas en un sistema de produccion tendra – sin dudas – efectos marcados en la productividad en su mas amplia acepcion. Sin embrago, existen una serie de criterios que es importante considerar a la hora de plantear este tema ya que de su correcta valoracion dependera el resultado que puede tener la introduccion de cualquier material genetico a un pais y -en definitivacolmar o no las expectativas generadas al decidir importar dicho material. En este sentido se analizan tres aspectos: a. Representatividad y numero de ejemplares: resulta inmediatamente obvio que es extremadamente peligroso extraer conclusiones a traves del uso de solo unos pocos reproductores; de la misma forma que tampoco tendria sentido utilizar muchos, pero no identificar sus montas. Que decir de la representatividad que los reproductores que se decida usar tengan de las cabanas de las cuales provienen. El tema es muy amplio y por razones de espacio sugerimos tres trabajos: dos extranjeros (Kirton et al., 1995; Fogarty et al. 1998) y otro nacional (Bianchi y Garibotto, 2007 a), donde queda bastante claro que la variacion que existe dentro de cualquier Opciones geneticas para el engorde de corderos

Desempeño de corderos Corridale y cruza faenados a los 5 meses de edad. 1. Mortalidad neonatal y medidas de peso vivo, ganancia diaria y grado de terminación

Durante un ano se evaluo en dos localidades el efecto de los cruzamientos entre 21 padres Corridale (C), Texel (TX), Hampshire Down (HD), Southdown (SD), Ile de France (IF) y Milchschaf (MI) y 560 ovejas Corridale sobre el desempeno al parto y la velocidad de crecimiento y grado de terminacion de los corderos. Los apareamientos fueron en otono, realizandose los servicios a corral y con control de paternidad. La mortalidad de corderos fue baja (6%), al igual que la proporcion de partos asistidos (<6%), no observandose ninguna tendencia clara respecto a los tratamientos. Los cruzamientos presentaron ventajas comparativas sobre la raza lanera pura en terminos de ganancia diaria y peso vivo. Los mejores resultados se lograron con la raza IF y cuando el producto de venta correspondia al cordero pesado (220 g/dia y 38.2 kg, 211 g/dia y 36.7 kg, 212 g/dia y 36.4 kg, 208 g/dia y 35.8 kg, 202 g/dia y 35 kg vs 186 g/dia y 32.6 kg; ganancia diaria y peso vivo de corderos pesados IF, MI, SD, HD y TX y C, respectivamente). Los corderos producto de cruzamientos con razas carniceras (IF, TX, HD y SD) presentaron mejor grado de terminacion a la faena que los C o los cruza MI que no difirieron de los puros. Se discuten las implicancias practicas de estos resultados.