Mineral and vitamin supplementation on sheep farms: a survey of practices and farmer knowledge

Abstract Mineral and vitamin (MV) supplementation is a routine management practice in many pasture-based systems of prime lamb production. The aim of the current study was to establish the MV supplementation practices on Irish sheep farms and farmer’s knowledge and opinions in relation to supplementation strategies and MV deficiencies. A survey, consisting of 22 questions, was administered to all farmers participating in the Teagasc National Farm Survey (NFS) in 2016 which had a sheep enterprise (n = 177). The Teagasc NFS is a stratified random sample of farms with each farm assigned a weighting factor so the results are representative of the national population of farms. Sixty-nine percent of respondents supplemented their flocks with MV in addition to concentrate feed. Twenty-two percent supplemented based on laboratory analysis results (soil, herbage, blood, or tissue analysis). Thirteen percent supplemented based on veterinary advice with only 30% of this advice based on laboratory analysis results. Sixty-five percent supplemented for reasons other than laboratory analysis or veterinary advice; mainly due to tradition and previous experience. The most common stages to supplement ewes were pregnancy (78%), lactation (61%), and pre-mating (50%). Fifty-one percent supplemented lambs post weaning. Mineral buckets (free access solidified molasses-based licks containing MV and in plastic containers) and drenching (oral dosing with MV containing liquid) were the most common methods of supplementing ewes and lambs, respectively. Generic MV products (containing multiple minerals and vitamins) were the most commonly used followed by cobalt only products. Ease of use/labor requirements and cost were the most important factors influencing choice of supplementation method. Forty-six percent rated their level of knowledge on mineral requirements of sheep as “limited or no education/knowledge”. Supplementation with MV did not increase (P > 0.05) ewe productivity (number of lambs reared/ewe joined) or gross margin/ewe. It is concluded that most supplementation decisions in sheep production systems are undertaken in the absence of veterinary advice or laboratory results, therefore are not evidence based. Knowledge transfer activities need to be designed to communicate best practice as regards MV supplementation.