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Effects of Whole-Grain Supplementation on Health, Growth, and Profitability of Pasture-Raised Lamb

Applied Research

Amanda Grev
Forage Extension Specialist
University of Maryland Extension
Keedysville

Abstract

Energy is often the most limiting nutrient in pasture-based diets. The objectives of this project were to compare the health, growth, and market value of lambs raised on pasture with and without whole-grain supplementation to determine if the additional energy provided would improve the profitability of pasture-based lamb production. In mid-June 2020 and 2021, Katahdin ram lambs (n=79 in 2020; n=99 in 2021) arrived at the Western Maryland Research and Education Center. After a 10-d acclimation period, lambs were allocated into two equal treatment groups based on age, bodyweight (BW), body condition score (BCS), birth type, and fecal egg count (FEC). Lambs in the pasture group (PAST) rotationally grazed 2 ha of high quality, mixed pasture for 100 d. Lambs in the supplemented group (SUPP) grazed similar pastures and were hand-fed a daily energy supplement (whole barley) at 0.45 kg/head/d. Both groups were handled bi-weekly to determine BW, BCS, and FAMACHA© scores. Individual fecal samples were collected upon arrival and at 1-2 additional time points each year. At the conclusion of grazing in 2020, lambs were ultrasound scanned to determine carcass traits. Data was analyzed using mixed model analysis, with statistical significance set at P ≤ 0.05. Average daily gain (ADG) varied considerably among weigh periods and standard deviations were large, indicating wide variation in individual performance. Final BW did not differ between groups in 2020 but was greater for SUPP lambs (36.2 kg) than PAST lambs (33.0 kg) in 2021 (P = 0.02). Across both years, SUPP lambs had higher ADG (0.14 kg/d) and final BCS (2.8) compared to PAST lambs (0.11 kg/d; BCS 2.6; P ≤ 0.02). Final FEC and FAMACHA© scores were lower for PAST lambs (240 EPG; FAMACHA© 1.6) than SUPP lambs (468 EPG; FAMACHA© 2.0) in 2020 (P ≤ 0.05) but were similar between groups in 2021. SUPP lambs had greater backfat (4.77 mm) compared to PAST lambs (4.17 mm; P = 0.03), but loin area was similar between groups. Altogether, these results indicate a slight growth advantage for the SUPP lambs; however, the value of the additional gain likely would not cover feed expenses.

Poster has NOT been presented at any previous NACAA AM/PIC

This poster is being submitted for judging. It will be displayed at the AM/PIC if not selected as a State winner. The abstract will be published in the proceedings.

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Authors: Amanda Grev, Susan Schoenian, Jeff Semler, Dahlia O'Brien
  1. Grev, A. Forage Extension Specialist, University of Maryland Extension, Maryland, 21756
  2. Schoenian, S. Small Ruminant Extension Specialist, University of Maryland Extension, Maryland, 21756
  3. Semler, J. Agriculture Extension Agent, University of Maryland Extension, Maryland, 21756
  4. O'Brien, D. Small Ruminant Extension Specialist, Virginia State University, Virginia, 23806