Effects of sire breed on some reproductive traits of Nigerian Dwarf Sheep
The study examined the effects of four sheep sire breeds, namely: Nigerian Dwarf sheep (NDS), Permer (P), Uda (U) and Yankasa (Y) on the reproductive performance of NDS ewes in early rainy season (ERS) and early dry season (EDS). Ninety six NDS ewes were exposed to rams, producing 102 lambs during ERS and 80 NDS ewes were joined with rams giving 75 lambs during EDS. Two rams of each breed were used in these seasons. Each season’s lambs were reared as a single flock until they were weaned at 3 months of age. Breed of sire, type of birth, sex of lamb, age and body weight of ewe at breeding had no significant (p>0.05) effect on gestation length. All the cross bred lambs were superior to NDS at birth. In either season, U-NDS, followed by Y-NDS were significantly (p<0.05) superior to NDS-NDS by 19.91 and 18.58% respectively. A similar trend was observed in EDS. However, NDS was superior to others in ram fertility index in ERS but poorest in EDS. Ewe loss before delivery was highest in NDS followed by U-NDS. Fertility which was measured as percent ewes lambing of ewes joined to rams was best in P-NDS in ERS and in Y-NDS in EDS. In either season, P-NDS was more prolific (168.4 Vs 173.3) and with high
lambing % (155 Vs 105). Similarly, twinning was more in P-NDS in ERS (64.5%) but NDS was superior in twinning in EDS and it had no incidence of dystocia or observable cases of stillbirth. The study highlighted the relative potentials of the indigenous sire breeds compared with the imported Permer.
Key words: Sire breeds, Reproductive Traits, Nigerian Dwarf Sheep.