Rumen-protected linseed oil supplementation: Energy status.

IORIO, J.D.; PALLADINO R.A.

Congreso; ADSA Anual Meeting; 2018

The aim of this research was to evaluate the effect of supplementing calcium salts of linseed oil (AG-Ca; rich in linolenic acid (C18:3 n-3)) in order to partially replace corn grain on energy status during the early lactation. In a 10-week assay, thirty-eight primiparous and multiparous Holstein dairy cows (with 55± 18.1 DIM, 594± 96.8 kg of BW, 2.71± 0.4 of BCS, 2± 1.4 lactation number and milk production of 38± 9.4 l/day) were used in a complete randomized block design. Cows were assigned to one of two treatments (O3: AG-Ca supplementation or CON: non) and were blocked by DIM, number of lactation, BW and milk production. Samples of blood were analyzed for glucose (GLU), β-hydroxybutyrate (BHBA), GH, INS and IGF-1 once every 15 d. The BW, BCS (1-5), and milk production were recorded weekly. Isoenergetic diets were formulated to meet requirements of a Holstein dairy cow of 650 kg BW with 40 DIM, producing 40.0 kg/d of milk with 3.6% fat. Diets of both groups (O3 and CON) included 8 kg DM of alfalfa pasture (Medicago sativa), 13,5 kg DM of TMR (63.5 % corn silage, 18.0 % soybean meal, 10.6% cracked corn and 7.9% alfalfa hay) and treatment concentrate (O3, 5.2 kg DM including 0.85 kg/d of Ag-Ca (DM: 82,3% DM, 13,2% ashes, 86,8% EE y 35,82% de C18:3 n-3) and CON, 5.9 kg DM including cracked corn) given at milking time (twice a day). Total DMI were estimated by NRC (2001) whilst pasture DMI was estimated by subtracting TMR and concentrate DMI to Total DMI. Data were analyzed using the MIXED procedure of SAS with significance declared at P≤ 0.05. Supplementation doesn´t change milk production, neither blood parameters of GLU, BHBA, INS, GH, IGF-1, BW and BCS.