Effect Of Selenium Source And Supplementation Rate In Ewes On Selenium Status Passive Immunity And Growth Performance Of Their Lambs

Author : Jerad Robert Jaborek
Publisher :
ISBN 13 :
Total Pages : 195 pages
Book Rating : 4.:/5 (978 download)

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Download or read book Effects of Energy Source, Energy Level, Sex, and Age on Growth, Performance, Carcass Characteristics, Meat Characteristics, and Flavor Intensity of Lambs, Yearling Ewe Lambs, and Mature Ewes written by Jerad Robert Jaborek and published by . This book was released on 2016 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sheep were fed to determine the effects of energy source, energy level, lamb sex, and sheep age on growth, performance, carcass and meat characteristics and the flavor profile of sheep. Ninety six lambs (n=48 ewes and n=48 wethers) were offered ad libitum access to whole shelled corn (WSC), ad libitum access to alfalfa pellets, or access to a WSC offered at 85% of the ad libitum diet. Lambs were raised to 59.0 and 63.5 kg for ewe and wether lambs, respectively, before being removed from the feeding trial, with 48 lambs (n=24 ewes and n= 24 wethers) being sent for slaughter and the other 48 lambs remaining on feed until a year of age. Lambs offered ad libitum access to WSC had the greatest average daily gain (ADG), efficiency of gain (G:F), and cheapest feed cost per unit of gain (COG) when compared to lambs offered alfalfa pellets and limit-fed WSC. Lambs offered WSC produced heavier and fatter carcasses due to greater dressing percentages and lower visceral organ weights compared to lambs offered alfalfa pellets. Differences due to sex were minimal because the experiment was designed to harvest lambs at similar points of maturity. Lambs (long-feds) that remained on feed were fed for an additional 118 days before deciding to remove lambs early (294 days of age instead of 365+ days of age) because they became too fat and heavy to structurally support themselves in the feedlot. Long-fed lambs offered ad libitum access to WSC still had the greatest ADG and G:F when compared to long-fed lambs offered alfalfa pellets and limit-fed WSC. Long-fed lambs offered ad libitum access to WSC also produced the fattest carcasses, while limit-fed lambs produced carcasses with similar amounts of fat to alfalfa fed lambs. Sixteen yearling ewe lambs and 16 mature ewes were also fed ad libitum WSC and ad libitum alfalfa pellet diets to compare meat characteristics with the 16 ewe lambs fed the same two diets. Numerical differences were observed for greater G:F, lower dry matter intake, and lower COG when yearling ewe lambs and mature ewes were offered WSC compared to alfalfa pellets. Offering WSC also decreased the total tract weight and increased the amount of fat deposited on carcasses from yearling ewe lambs and mature compared to offering alfalfa pellets. Meat characteristics were analyzed in two trials. Trial 1 was a completely randomized design with a 3 × 2 factorial arrangement of treatments to identify differences due to sheep age and diet. Trial 2 was a completely randomized design with a 3 × 2 × 2 factorial arrangement of treatments to identify differences due to diet, lamb sex, and lamb age. Samples from the loins and ground shoulder were saved to determine the percent extractable lipid and ultimate pH. Loins and ground shoulder patties were cooked used in an untrained taste panel to rate lamb flavor intensity, off-flavor intensity and off-flavors. Loins were also used to conduct slice shear force as an objective measurement of tenderness. The ultimate pH decreased with increasing sheep age, with ewe lambs tended to have greater pH measurements compared to yearling and mature ewes and shorter-fed lambs having greater pH compared to long-fed lambs. Slice shear force measurements were lower for loins aged for 14 day compared to loins froze on day 1. A taste panel representative of typical lamb consumers in the Midwest typically reported greater lamb flavor and off-flavor intensity scores due to increasing sheep age and feeding alfalfa pellets compared to feeding a WSC diet. Correlations between lamb flavor and off-flavor intensity mean scores with other carcass and meat characteristics demonstrated no significant linear relationship with carcass fat measurements. Other variables with significant linear correlations only displayed weak correlations with lamb flavor and off-flavor intensity. Overall, these variables that demonstrate a lack of correlation exhibits the difficulty the American sheep industry has with classifying quality lamb on a consistent basis. The use of feeding a WSC diet at greater levels of restriction can offer producers cheap, efficient performance, with reductions in energy expended towards maintaining visceral organs, and reduce carcass fatness at heavy slaughter weights.