title: Evaluation of factors associated with immunoglobulin G, fat, protein, and lactose concentrations in bovine colostrum and colostrum management practices in grassland-based dairy systems in Northern Ireland.
abstract: The objectives of this study were to investigate colostrum feeding practices and colostrum quality on commercial grassland-based dairy farms, and to identify factors associated with colostrum quality that could help inform the development of colostrum management protocols. Over 1 yr, background information associated with dairy calvings and colostrum management practices were recorded on 21 commercial dairy farms. Colostrum samples (n = 1,239) were analyzed for fat, protein, lactose, and IgG concentration. A subset was analyzed for somatic cell count and total viable bacteria count. Factors associated with nutritional and IgG concentrations were determined using both univariate and multivariate models. This study found that 51% of calves were administered their first feed of colostrum via esophageal tube, and the majority of calves (80%) were fed >2 L of colostrum at their first feed (mean = 2.9 L, SD = 0.79), at a mean time of 3.2 h (SD 4.36) after birth, but this ranged across farms. The mean colostral fat, protein, and lactose percentages and IgG concentrations were 6.4%, 14%, 2.7%, and 55 mg/mL, respectively. The mean somatic cell count and total viable count were 6.3 log10and 6.1 log10, respectively. Overall, 44% of colostrum samples contained <50 mg/mL IgG, and almost 81% were in excess of industry guidelines (<100,000 cfu/mL) for bacterial contamination. In the multivariate model, IgG concentration was associated with parity and time from parturition to colostrum collection. The nutritional properties of colostrum were associated with parity, prepartum vaccination, season of calving, and dry cow nutrition. The large variation in colostrum quality found in the current study highlights the importance of routine colostrum testing, and now that factors associated with lower-quality colostrum on grassland-based dairy farms have been identified, producers and advisers are better informed and able to develop risk-based colostrum management protocols.
authors.affiliation: Agri-Food and Biosciences Institute, Sustainable Livestock, Large Park, Hillsborough, BT26 6DR, United Kingdom; Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 18-30 Malone Road, Belfast, BT9 5BN, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Dunn
authors.affiliation: Agri-Food and Biosciences Institute, Newforge Lane, Belfast, United Kingdom BT9 5PX.
authors.forename: A
authors.initials: A
authors.lastname: Ashfield
authors.affiliation: Animal and Grassland Research and Innovation Centre (AGRIC), Teagasc, Grange, Dunsany, Co. Meath, Ireland.
authors.forename: B
authors.initials: B
authors.lastname: Earley
authors.affiliation: Sisaf, Unit 15A Innovation Centre, Queen's Road, Belfast, United Kingdom BT3 9DT.
authors.forename: M
authors.initials: M
authors.lastname: Welsh
authors.affiliation: Agri-Food and Biosciences Institute, Newforge Lane, Belfast, United Kingdom BT9 5PX.
authors.forename: A
authors.initials: A
authors.lastname: Gordon
authors.affiliation: Agri-Food and Biosciences Institute, Sustainable Livestock, Large Park, Hillsborough, BT26 6DR, United Kingdom. Electronic address: Steven.Morrison@afbini.gov.uk.
authors.forename: S J
authors.initials: SJ
authors.lastname: Morrison
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002417:Cattle; D003126:Colostrum / Q000378:metabolism*; D005260:Female; D065948:Grassland; D007074:Immunoglobulin G / Q000378:metabolism; D007785:Lactose; D009660:Northern Ireland
chemical_list: D007074:Immunoglobulin G; D007785:Lactose
keywords: calves; colostrum; dairy; immunoglobulin; immunoglobulin G