title: Effect of milk replacer and concentrate intake on growth rate, feeding behaviour and systemic metabolite concentrations of pre-weaned bull calves of two dairy breeds.
abstract: Early-life nutrition affects calf development and thus subsequent performance. The aim of this study was to examine the effect plane of nutrition on growth, feeding behaviour and systemic metabolite concentrations of artificially reared dairy bull calves. Holstein-Friesian (F; n=42) and Jersey (J; n=25) bull calves with a mean±SD age (14±4.7 v. 27±7.2 days) and BW (47±5.5 v. 33±4.7 kg) were offered a high, medium or low plane of nutrition for 8 weeks using an electronic feeding system which recorded a range of feed-related events. Calves were weighed weekly and plasma samples were collected via jugular venipuncture on weeks 1, 4 and 7 relative to the start of the trial period. The calves offered a high plane of nutrition had the greatest growth rate. However, the increased consumption of milk replacer led to a reduction in feed efficiency. Holstein-Friesian calves offered a low plane of nutrition had the greatest number of daily unrewarded visits to the feeder (P<0.001). β-hydroxybutyrate (BHB) concentrations were greater in F calves on a low plane of nutrition (P<0.001). Although there was no effect of plane of nutrition, BHB concentrations in F calves increased before weaning, concomitant with an increase in concentrate consumption. Urea concentrations were unaffected by plane of nutrition within either breed. Jersey calves on a low plane of nutrition tended to have lower triglycerides than those on a high plane (P=0.08), but greater than those on a medium plane (P=0.08). Holstein-Friesian calves offered a high plane of nutrition tended to have greater triglyceride concentrations than those on a medium plane (P=0.08). Triglycerides increased from the start to the end of the feeding period (P<0.05), across both breeds. A medium plane of nutrition resulted in a growth, feeding behaviour and metabolic response comparable with a high plane of nutrition in pre-weaned bull calves of both F and J breeds.
authors.affiliation: 1Animal & Grassland Research and Innovation Centre,Teagasc,Dunsany,C15 PW93 Co. Meath,Ireland.
authors.forename: C J
authors.initials: CJ
authors.lastname: Byrne
authors.affiliation: 3Department of Biological Sciences,University of Limerick,V94 T9PX Limerick,Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Fair
authors.affiliation: 1Animal & Grassland Research and Innovation Centre,Teagasc,Dunsany,C15 PW93 Co. Meath,Ireland.
authors.forename: A M
authors.initials: AM
authors.lastname: English
authors.affiliation: 1Animal & Grassland Research and Innovation Centre,Teagasc,Dunsany,C15 PW93 Co. Meath,Ireland.
authors.forename: D
authors.initials: D
authors.lastname: Johnston
authors.affiliation: 2School of Agriculture and Food Science,University College Dublin,D04 F6X4 Belfield,Dublin 4,Ireland.
authors.forename: P
authors.initials: P
authors.lastname: Lonergan
authors.affiliation: 1Animal & Grassland Research and Innovation Centre,Teagasc,Dunsany,C15 PW93 Co. Meath,Ireland.
authors.forename: D A
authors.initials: DA
authors.lastname: Kenny
mesh_terms: D020155:3-Hydroxybutyric Acid; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001947:Breeding; D002417:Cattle / Q000145:classification / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D005247:Feeding Behavior; D008297:Male; D008892:Milk; D009752:Nutritional Status; D014508:Urea; D014886:Weaning
chemical_list: D014508:Urea; D020155:3-Hydroxybutyric Acid
keywords: Holstein-Friesian; Jersey; dairy breeds; plane of nutrition; pre-weaning