title: Evaluation of an on-farm method to assess colostrum IgG content in sows.
abstract: The objective of this work was to investigate the evaluation of swine colostrum immunoglobulin G (IgG) concentration using the Brix refractometer. Colostrum samples were collected across all teats, from 124 sows of mixed parities. According to sampling time, three categories were created: samples available from 9 h before the onset of parturition until the first piglet was born were classified as before farrowing; samples collected after the first birth until 4 h later were classified as during farrowing; and finally samples collected from this point until 14 h after parturition, were classified as after farrowing. Samples were drawn and divided into three portions; one was immediately analyzed, a second was refrigerated and the third was frozen at -20°C. Fresh and refrigerated colostrum samples were analyzed at the farm with a Brix refractometer. IgG content of frozen samples was analyzed using a Brix refractometer, with a subset of 42 samples also tested with a commercially available radial immune diffusion (RID) kit. The Brix percentage ranged from 18.3% to 33.2%. Brix percentage repeatability, assessed by the intraclass correlation coefficient (ICC), was very strong (fresh ICC=0.98, refrigerated ICC=0.88 and frozen ICC=0.99). One-way repeated-measures ANOVA showed that storage temperature did not affect BRIX percentage of colostrum IgG (P>0.05). ANOVA results show a significant effect of sampling time on colostrum immunoglobulin concentration, measured with both Brix and RID (Brix: P<0.003; RID: P<0.05). Immunoglobulin G concentration measured by RID ranged from 13.27 to 35.08 mg/ml. Pearson correlation coefficient revealed that Brix percentage was positively correlated (r=0.56, P<0.001) with RID results (regression equation: RID=1.01 (±0.2) Brix -1.94 (±5.66); R 2=0.31). The results of this study indicate that the Brix refractometer provides a simple, fast and inexpensive estimation of colostrum IgG in sows.
authors.affiliation: 1School of Agriculture, Food and Rural Development,Newcastle University,Newcastle upon Tyne,NE1 7RU,UK.
authors.forename: A
authors.initials: A
authors.lastname: Balzani
authors.affiliation: 2Institute of Genetic Medicine,Newcastle University,Newcastle upon Tyne,NE1 7RU,UK.
authors.forename: H J
authors.initials: HJ
authors.lastname: Cordell
authors.affiliation: 1School of Agriculture, Food and Rural Development,Newcastle University,Newcastle upon Tyne,NE1 7RU,UK.
authors.forename: S A
authors.initials: SA
authors.lastname: Edwards
mesh_terms: D000818:Animals; D003126:Colostrum / Q000737:chemistry*; D005260:Female; D005779:Immunodiffusion; D007074:Immunoglobulin G / Q000737:chemistry* / Q000378:metabolism; D011247:Pregnancy; D012031:Refractometry / Q000295:instrumentation / Q000662:veterinary; D013048:Specimen Handling; D013552:Swine / Q000502:physiology*; D013696:Temperature
chemical_list: D007074:Immunoglobulin G
keywords: Brix refractometer; colostrum IgG; evaluation; on-farm method; swine