Supplementing rumen-protected linseed oil: ovarian dynamics

IORIO, J.D.; BENTANCOUR, M.E., DANELÓN, J.L., PALLADINO, R.A., ALVAREZ UGARTE, D.H. Y WAWRZKIEWICZ, M.

Congreso; ADSA Anual Meeting; 2019

The objective of this study was to evaluate the effect of supplementing calcium salts of linseed oil (AG-Ca; rich in linolenic acid (18:3(n-3)) on the ovarian dynamics in dairy cows. In a 10-week assay, 38primiparous 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 andmilk production of 38 ± 9.4 kg/d) were used in a complete randomizedblock design. Cows were assigned to one of 2 treatments (O3: AG-Casupplementation (0.85 kg/d AG-Ca) or CON: no fat) and were blockedby DIM, number of lactations, BW, milk production and corpus luteumpresence. Isoenergetic diets were formulated to meet requirements of aHolstein dairy cow of 650 kg BW with 40 DIM, producing 40.0 kg/d ofmilk with 3.6% fat (NRC, 2001). A timed artificial insemination (TAI)at 80 DIM preceded by a PreSynch (14/12) + OvSynch protocol wasimplemented for the first service and ovarian dynamics were studiedduring the OvSynch and TAI. A portable ultrasound Aquila Pro (Piemedical) B mode in real time, with lineal transducer of 8 MHz, wasused to determine the presence and sizes of ovarian structures (follicles (FOL) and corpora lutea (CL)), and the gynecological condition.Supplementation does not change milk production and energy statusof the cows (Iorio, 2018). After PreSynch, 72.22% of cows of O3 and75% of CON, presented CL. Linseed oil supplementation had neithereffect on the emergence of a new follicular wave (O3: 2.22 ± 1.20 dvs. CON: 2.78 ± 1.79 d; P = 0.217) nor the size of preovulatory follicles (O3: 16.66 mm vs. CON: 16.27 mm; P = 0.707). Conversely,linseed oil supplementation had effect on the volume of the main CL6 d after TAI (O3: 17.60 mm vs. CON: 13.67 mm; P = 0.0218). Datawere analyzed using the MIXED of SAS with significance declared atP ≤ 0.05. These results probably highlight the importance of linseedoil supplementation on FOL and CL development, which may lead tobetter pregnancy indexes.