Desempenho produtivo e reprodutivo e parâmetros sanguíneos de vacas leiteiras alimentadas com diferentes fontes de gordura no período de transição e inicio de lactação / Productive and reproductive performance and blood parameters of dairy cows feeding with different fat sources in transition period and early lactation

Milton Maturana Filho

This study was carried out to evaluate the use of different fat sources in dairy rations, in transition period and early lactation on follicular dynamics, reproductive efficiency, nutrients intake and digestibility, composition and milk yield, composition of protein fraction and energy balance. Third Holstein cows, with production of 30,0 Kg/cow/day on previous lactation, supply since 35 days before parturition until day 85 after parturition with one experimental ration during all experiment, the cows are allocated in free-stall, distributed in three experimental group, feeding with rations: 1) Control; 2) Refined Soybean oil; 3) Calcium salts of fatty acids (Megalac-E). Was evaluated daily the dry matter intake during though the experimental period. After parturition, the composition and milk yield samples used for milk analysis were collected weekly from the two daily milking. The samples of blood were collected with vacuolized tubes per puncture of coccygeal vein and/or artery. For obtaining the follicular dynamics data, was make daily the ultra-sonographic exam with Aloka 500 with linear probe of 5,0 MHz since 14º until 65º days of lactation (DEL), was evaluates the: Total follicle number, the follicles distribution on class : class1 (3-5mm), class 2 (6-9 mm) e class 3 (10-15mm), the diameter dominant follicle (FD) and Subordinated follicle (FS), the follicle number in each ovary (NOD, NOE), corpus luteum when present in left or right ovaries (CLOD an CLOE) and also was evaluated the reproductive efficiency index: Parturition-pelvic, First ovulation, pre ovulatory follicle of first ovulation, corpus luteum of first ovulation, Dominant follicle in fixed time artificial insemination, pregnancy rates of FTAI. The follicular dynamics data was analyzed with time repeated measures of PROC. Mixed, and orthogonal contrasts (control vs fat; OS vs SC), of SAS program version 9.1, with significant alpha of 5%. The reproductive data was submitting a variance analysis, orthogonal contrasts (control vs fat; OS vs SC) for PROC GLM and the chi-square analysis for PROC FREQ for pregnancy rates. Had no effects (P>0,05) of experimental rations on dry mater intake (DMI), on body condition score (BCS) and body weight in pre-partum period. The DMI (kg/day), body condition score change and body weight was influenced (P<0,05) for weeks in post-partum. The milk yield, and the corrected milk yield for fat, was not influenced (P>0,05) for experimental rations. When evaluated the orthogonal contrasts was observed a reduction on fat percentage and fat production on milk (P<0,05) for dairy cows feed with fat sources on rations, especially for the calcium soaps of fat acids. Was observed the interaction besides the experimental rations and the lactation weeks for corrected milk yield for 3,5% of fat. The energy balance was not influenced for the experimental rations in pre-partum period, had only time effect (P<0,001) pre-partum period. Had treatment, time and fat source effect on energy balance in post-partum period (P<0,001), when assessing the contrasts, the cows of calcium soap fatty acids group presented better energy balance in post-partum period when compared with the dairy cows of soybean oil. The blood concentrations of glucose, total proteins, albumin, urea, ureic nitrogen on blood, total cholesterol and HDL cholesterol, non esterified fat acids (NEFA) and -hidroxibutirate (BHBA) was not influenced (P>0,05) of fat sources on rations both in pre-partum period as post-partum period. All blood parameters presented days effects on post-partum period (P>0,05). When assessing the orthogonal contrasts, there was not differences between the experimental rations on blood parameters evaluated in this study on pre and post partum periods. There was interaction between time and experimental rations on glucose, total cholesterol and NEFA on post-partum period, and urea and nitrogen urea on blood in pre and post-partum periods. Had no differences on blood concentrations of HDL cholesterol (P>0,05) and total cholesterol in post-partum period between experimental rations. Had no interaction between time and experimental rations for BHBA concentrations in pre and post-partum periods. Had interaction between days in milk and the experimental rations (P<0,001) for NEFA concentrations on pos-partum period. The progesterone concentrations on pre and post-partum period was not influenced for experimental rations (P>0, 05). The experimental rations was not influenced (P>0,05) the variables, follicle on class 2, class3, dominant follicle, subordinated follicle, corpus luteum on right and left ovaries, t follicles numbers on left ovary The fat sources influenced (P<0,05) the variables total follicles numbers and the follicles numbers on class1. When assessing the orthogonal contrasts had effects (P<0,05), in relation to contrast Control vs. fat sources, it was observed the superiority for fat sources. Had no effects (P>0,05) of experimental rations on calving- pelvic, first ovulation, pre-ovulatory follicle of first ovulation, however was observed effect (P<0,05) in relation of variables corpus luteum of first ovulation and dominant follicle on TFAI. The dominant follicle in the TFAI presented the major diameter (P<0,05) for dairy cows feeding fat sources. Had treatment effect for TFAI pregnancy rates (P<0,05), where the dairy cows of soybean oil presented the lower TFAI pregnancy rates of 30,0%, the dairy cows of control group and calcium soaps of fat acids group presented the TFAI pregnancy rates of 50,0%. The fat suplementation on transition period and early lactation improving the productive performance, the metabolic profile on early lactation, and the follicle dinamycs and the reproductive performance in dairy cows.

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