Evaluation of dam breeds in crossing with Dorper sire breed for production of early slaughtering lambs

Author(s)

Juliano Issakowicz

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB)
• Defense date: 2015-04-08

Examining board members

Helder Louvandini; Luciana Morita Katiki; Liris Kindlein; Débora Botequio Moretti; José Cleto da Silva Filho

• Advisor: Helder Louvandini; Mauro Sartori Bueno

Abstract

The objectives of this study were to evaluate the parasitic infection; reproductive and productive performance of Morada Nova (MN) and Santa Inês (SI) sheep crossed with Dorper rams; and to evaluate productive performance; carcass and meat characteristics of Morada Nova (MM) and Santa Inês (SS) lambs and that of the crossbred ½ Dorper x ½ Morada Nova (MD) and ½ Dorper x ½ Santa Inês (SD) lambs, finished in feedlot system. Fifty one MN sheep (33,1 ± 4,98 kg initial body weight - BW) and 52 SI sheep (51,8 ± 7,07 kg BW), all multiparous, aging from 2 to 4 years old were used. The sheep were kept in Panicum maximum cv. Aruana pasture and from the final third of gestation up to lactation period they were housed in collective pens, receiving corn silage ad libitum and 400 g/animal/day of concentrate. After weaning, 32 lambs, 8 MM (15,0 ± 1,0 Kg BW), 8 SS (18,4 + 1,0 Kg BW), 8 MD (16,1 ± 1,0 Kg BW) and 8 SD (21,3 ± 1,0 Kg BW) aging about 70 days old, finished in feedlot system and fed on a 40:60 corn silage and concentrate diet were slaughtered around the body weight of 35 Kg. In both maternal breeds the parasitic infection was characterized by the predominance of Hamonchus genus parasites, and it has increased in pre and postpartum periods; the MN sheep were capable of maintaining reduced parasitic infection at 30 days after giving birth. The parasitic infection has not affected blood parameters, which were maintained in the reference range of the species, with some differences being observed between breeds according to blood collection dates. Both maternal breeds presented good reproductive performance, producing lambs that presented increased birth and weaning weight when crossed with Dorper ram; MN sheep when crossed with Dorper ram have produced lambs that presented weaning weights similar to that of lambs produced by SI sheep when mated with SI ram. Crossbred lambs SD and MD presented similar productive performance and carcass characteristics, with increased tissue deposition in more commercially appreciated areas when compared with pure breed lambs. In the meat characteristics evaluations, no differences were observed between the studied groups for meat color, softness and juiciness but the crossbred lambs produced meat with reduced fat content, with SD lambs presenting fat profile more suitable for human consumption than MD lambs (AU)

• FAPESP's process: 12/23780-9 - EVALUATION OF MATERNAL BREEDS IN CROSSING WITH DORPER BREED SHEEP IN THE EARLY PRODUCTION OF SLAUGHTER LAMBS
• Grantee: Juliano Issakowicz
• Support Opportunities: Scholarships in Brazil - Doctorate