Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/24/2006
Publication Date: N/A
Technical Abstract: Katahdin ewes were mated to Dorper, Texel, Suffolk or Katahdin rams (3 rams/breed; 8-10 ewes each) to compare growth performance and parasite resistance of the crossbred lambs. Lamb BW was measured at birth (=d0), and then every 30d to d210 (adjusted). Fecal egg counts (FEC) were determined at d60 and 90. Packed cell volume (PCV) was determined from d90-210. Lambs were dewormed on d90 and then if PCV<20%. There was no influence of sire breed on lambs born/ewe lambing (2.4±0.1) or lamb birth weight (4.0±0.2 kg). Lamb BW, ADG and PCV were influenced by a breed*day interaction (P<0.01). At d30, Suffolk- (SK) sired lambs were heavier (P<0.02) than purebred Katahdin (KA) lambs while Dorper- (DK) and Texel-sired (TK) lambs were intermediate. At d60, BW for SK and DK>KA and SK>TK lambs (P < 0.007) and at all other time points measured, BW for SK>DK>TK=KA lambs (P<0.04). On d30, ADG for SK>KA and TK while DK ADG was greater than KA (P<0.03). Generally, from d60 to120, ADG for SK lambs>DK>TK=KAT lambs (P<0.03). At d150-210, SK lambs had a greater (P<0.01) ADG than KA and TK lambs, while DK lambs were intermediate. The PCV of TK lambs was higher (P<0.01) than DK lambs at d90, while that of KA and SK were intermediate. At d120, all lambs had similar PCV while at d150 KA and TK lambs had greater (P<0.01) PCV than SK and DK lambs. At d180 and 210, SK lambs had the lowest (P<0.01) PCV of all lamb breed types. FEC were similar among all breed types at d90, but at d120, DK and SK lambs had greater (P<0.01) counts compared to both KA and TK. Age at first deworming was less (P<0.04) for SK and DK lambs than for KA and TK lambs, fewer (P<0.05) TK lambs needed deworming than other breed lambs and DK and SK lambs were dewormed more often (P<0.006) than KA and TK lambs. Overall, pasture-raised SK lambs grew faster than KA, DK, and TK lambs with DK lambs growing faster than KA and TK lambs. However, KA and TK had greater parasite resistance than SK and DK lambs.