Estratégias para a pecuária leiteira: efeitos da inclusão de gordura protegida na dieta e utilização de feromonioterapia em vacas da raça Holandês

Abstract

The use of protected fat in the diet of dairy cows, as well as the use of pheromone therapy to reduce management stress, are examples of tools that can be implemented in dairy cattle farming. In this study, two experiments were conducted with strategies that can be used to enhance animal performance. The objective of the first experiment was to evaluate the impact of a hydrogenated fat (H) rich in saturated fatty acids (SFA) (C16:0 and C18:0) and two calcium-protected fats (Ca) with different SFA (C16:0 and C18:0) and unsaturated fatty acid (UFA) profiles (cis-9 C18:1) compared to a control group (no fat supplementation) on dry matter intake, milk production, milk composition, as well as metabolic and zootechnical parameters of Holstein cows after peak lactation. The experimental period was divided into three periods of 22 days each. During each period, four animals per group were used, totaling 16 animals per period and 48 cows (n=48) in total at the end of the experiment. The groups were divided based on lipid composition: H-saturated (n=16), Ca-saturated (n=16), Ca-mix (n=16), and Control Group (n=16). Daily milk production was measured, as well as dry matter intake (DMI). Milk samples were collected twice a week for analysis of milk constituents (fat, lactose, protein, casein, urea nitrogen, and total solids) and somatic cell count (SCC). Blood samples were collected weekly for analysis of non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), albumin, triglycerides (TGL), urea, and glucose. Statistical analyses were conducted using JMP Pro 14 software, and the significance level adopted was P≤0.05. The Ca-mix and Ca-saturated groups, compared to the Control group, had lower milk protein content (P<0.05). SCC was lower in the treatment groups compared to the Control group (P<0.05). Regarding biochemical analyses, the H-saturated group had a higher concentration of BHB compared to the Ca-mix group (P=0.05), with no effect on the other parameters. No effects were observed on feed intake, milk production, body weight (BW), or body condition score (BCS). In conclusion, when comparing the three fat-supplemented groups, the inclusion of calcium-protected fats reduces SCC. Furthermore, the provision of unprotected hydrogenated fat results in higher protein and casein content, as well as a higher concentration of BHB in the blood. In the second project, the objective was to determine the influence of a synthetic analog of bovine calming substance (BCS) on milk production, feed intake, and blood analyses in cows during the transition period. Twenty-four multiparous Holstein cows (from 28 days prepartum to 21 days postpartum) were randomly assigned to two groups: Control (n=12) and BCS (n=12). Each animal received 5 mL of the BCS on days 28 and 14 prepartum and on the day of parturition, applied topically to the nape of the neck. Feed intake was assessed daily using smart feeders, as was milk production, which was electronically determined. Six milk samples were collected from each animal during the experimental period for chemical composition and SCC analysis. Six blood samples were collected from each animal for future biochemical analyses (NEFA, BHB, cortisol, myeloperoxidase, and paraoxonase 1). Statistical analyses were conducted using JMP Pro 14 software, and the significance level adopted was P≤0.05. Cows treated with BCS showed higher milk production (P<0.05) than the Control group. DMI in the prepartum and postpartum periods was higher in the Control group than in the treated group (P<0.05). The BCS group showed reduced plasma cortisol levels postpartum (P<0.05). In conclusion, 10cows treated with BCS had higher milk production, lower DMI, and lower plasma cortisol concentrations compared to the control group, demonstrating the effect of BCS in reducing stress during the transition period.