title: Benefits of different urea supplementation methods on the production performances of Merino sheep.
abstract: The impact of urea supplementation of sheep feed was examined in two experiments. In Experiment 1, 48 8-month-old Merino wethers were randomised into three groups by liveweight and each group was fed one of three diets: (1) untreated oaten chaff hay; (2) hay treated with urea in-paddock (pre-experiment); or (3) hay treated with a 2% urea solution using a feed mixer. In Experiment 2, 48 4-month-old Merino ewes were randomised into three groups and each group received one of the following roughages: (1) untreated oaten chaff hay, (2) hay treated with a 2% urea solution in a feed mixer, or (3) a 20 kg urea lick block. Both experiments lasted 40 days, and sheep liveweight (kg), average feed intake (g/day), average daily gain (ADG) and body condition score (BCS) were recorded. Ruminal fluid and blood samples were collected on days 20 and 40 from animals in Experiment 1. Sheep supplemented with additional urea had a greater average dry matter (DM) intake (Experiment 1, P = 0.038; Experiment 2, P = 0.001), ADG (Experiment 1, P = 0.043; Experiment 2, P = 0.041) and average final liveweight (Experiment 1, P = 0.048), compared to sheep receiving no additional supplementary urea. On both days 20 and 40 in Experiment 1, blood analyses revealed that urea supplemented sheep had elevated levels of urea, creatine kinase and total protein (P <0.05). Urea supplementation most likely influenced blood urea and total protein concentrations, as supplemented sheep had an increased crude protein intake (through increased feed intake of urea treated roughage with a higher crude protein percentage). By providing additional urea, the DM intake of sheep in both experiments was increased and offers a practical strategy when providing supplementation to sheep. The practice can benefit sheep production by increasing the nutritional value and digestibility of low energy crop stubbles, when fed over dry summer months to help maintain BCS.
authors.affiliation: Livestock Innovation, Department of Agriculture and Food, 3 Baron-Hay Court, South Perth, WA 6151, Australia. Electronic address: joshua.sweeny@agric.wa.gov.au.
authors.forename: Joshua P A
authors.initials: JP
authors.lastname: Sweeny
authors.affiliation: Livestock Innovation, Department of Agriculture and Food, 444 Albany Highway, Albany, WA 6330, Australia.
authors.forename: Victoria
authors.initials: V
authors.lastname: Surridge
authors.affiliation: Wellard Group, 1A Pakenham Street, Fremantle, WA 6160, Australia.
authors.forename: Pia S
authors.initials: PS
authors.lastname: Humphry
authors.affiliation: Macquarie Group, 1 Shelley Street, Sydney, NSW 2000, Australia.
authors.forename: Harriet
authors.initials: H
authors.lastname: Pugh
authors.affiliation: Catholic Agricultural College Bindoon, 3398 Bindoon-Dewars Pool Road, Bindoon, WA 6502, Australia.
authors.forename: Kristen
authors.initials: K
authors.lastname: Mamo
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000822:Animal Husbandry / Q000379:methods*; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects*; D000818:Animals; D001774:Blood Chemical Analysis / Q000662:veterinary; D001823:Body Composition / Q000187:drug effects; D004032:Diet / Q000662:veterinary*; D004043:Dietary Fiber / Q000032:analysis; D019587:Dietary Supplements; D005247:Feeding Behavior / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D011897:Random Allocation; D012417:Rumen / Q000187:drug effects / Q000502:physiology; D012756:Sheep / Q000254:growth & development / Q000502:physiology*; D014508:Urea / Q000378:metabolism* / Q000494:pharmacology*; D015430:Weight Gain / Q000187:drug effects
chemical_list: D004043:Dietary Fiber; D014508:Urea
keywords: Blood parameters; Feed intake; Liveweight gain; Sheep; Urea supplementation