260
Effect of genotype and dietary supplement on live weight changes and average daily gains in ram lambs

Tuesday, March 17, 2015
Grand Ballroom - Posters (Community Choice Credit Union Convention Center)
Tumen Wuliji , Department of Agriculture and Environmental Sciences, Lincoln University, Jefferson City, MO
J. D. Caldwell , Department of Agriculture and Environmental Sciences, Lincoln University, Jefferson City, MO
Bruce C. Shanks , Department of Agriculture and Environmental Sciences, Lincoln University, Jefferson City, MO
Heather Smith , Callaway County Extension Center, Fulton, MO
Heather Hilsenbeck , Department of Agriculture and Environmental Sciences, Lincoln University, Jefferson City, MO
Luke S. Wilbers , Department of Agriculture and Environmental Sciences, Lincoln University, Jefferson City, MO
Amy Bax , Department of Agriculture and Environmental Sciences, Lincoln University, Jefferson City, MO
Samaneh Azarpajouh , Department of Agriculture and Environmental Sciences, Lincoln University, Jefferson City, MO
Abstract Text:

Hair and meat sheep production is a diversified livestock enterprise in the US. While terminal sheep breed like Texel has a reputation for high carcass yield and leanness, hair sheep may be better adapted to marginal or poor grazing conditions and disease resistance. The objective of this study is to evaluate post-weaning growth and carcass performance in Katahdin (KAT) and Texel × Katahdin crossbred (TxK) ram lambs in an 8-week pen feeding experiment. Forty five ram lambs, consisting of 21 KAT and 24 TxK ram lambs, were evenly divided into 3 group feeding pens by stratification using both initial live weight (LW) records and genotype. Rams were provided ad libitum access to the same quality hay and water supply as per pen. Corn-grain supplements were offered at 340 g/hd/d for 1- week as an adaptation period and increased to 636 g/hd/d during the 8-week trial. The LW (kg) and ADG (g) were recorded at biweekly intervals. The back fat thickness (BF, mm) and loin eye muscle area (LEA, cm²) were measured using an ultrasound scanning machine fitted with backfat probe over 12th rib of lambs. Live weight, ADG, LEA and BF measurements were analyzed by the mixed procedures of SAS. Mean values of LW changes, ADG, LEA and BF measurements are shown in Table 1. The live weight records at biweekly intervals did not differ except at the 8th week interval (P < 0.05). The total weight changes and ADG were significantly higher (P < 0.05) for KAT compared with TxK. There was no statistical difference between groups for LEA and BF measures although these were recorded slightly higher for TxK ram lambs. The current results showed that Katahdin ram lambs perform slightly but significantly better than Texel × Katahdin crossbred lambs in pen feeding condition with corn-grain supplements.

Table 1. Live weights (LW), LW change (LWC), average daily gain (ADG), lion eye muscle area (LEA), and backfat thickness (BF) measurements in Katahdin and Texel x Katahdin (TxK) crossbred ram lambs

Live weights

Week 0

(kg)

Week 2

(kg)

Week 4

(kg)

Week 6

(kg)

Week 8

(kg)

LWC

(kg)

ADG

(g)

LEA

(cm²)

BF

(mm)

Katahdin

33.79

34.31

36.51

42.19

44.50

10.71

191

11.38

4.5

TxK

35.02

34.72

36.88

41.88

43.16

8.14

145

11.68

4.6

SE

0.98

0.97

0.94

1.08

1.23*

0.25*

4.4*

1.65

1.2

 *: P < 0.05.

Keywords: genotype, live weight, average daily gain