Efecto de la caminata en las respuestas productivas de vacas lecheras

In pasture-based dairy systems predominant in Uruguay, the efficiency of energy utilization by dairy cows is a key factor for the competitiveness and sustainability of the sector. In these systems, physical activity associated with the movement of cows between the milking parlor and feeding or grazing areas may increase maintenance energy requirements and affect the partitioning of energy between maintenance and production. The objective of this study was to evaluate the effect of walking activity on the productive performance of dairy cows and its impact on dry matter intake (DMI) and energy utilization efficiency. The experiment was conducted at the “Dr. Mario A. Cassinoni” Experimental Station (EEMAC), Faculty of Agronomy, Universidad de la República, during July and August 2024. A total of 24 Holstein cows in mid-lactation (15.7 ± 2.6 weeks in milk), with an average body weight (BW) of 634 ± 40 kg and body condition score (BCS) of 2.77 ± 0.06 units, were assigned to two treatments: cows without walking activity (SIN-CAM; n = 12) and cows subjected to a daily walking distance of 8 km (CAM; n = 12). Results showed that walking activity did not affect (P ³ 0.14) milk yield, energy-corrected milk yield, milk composition, DMI, or metabolizable energy (ME) consumption. However, regarding changes in BW and BCS differed between treatments (P £0.04). SIN-CAM cows gained BW and maintained BCS, whereas CAM cows maintained BW but experienced a reduction in BCS, indicating greater energy expenditure associated with physical activity. Accordingly, the energy retained in tissue (ER-tissue) was greater in without walking activity cows (P=0.03). Thus, adjusted gross energy efficiency was less for CAM than SIN-CAM cows (SIN-CAM = 1,42; CAM = 1,17; ES=0,08). In conclusion, a daily walking distance of 8 km in mid-lactation dairy cows did not affect milk yield, milk composition, DMI. However, walking increased maintenance energy expenditure, reducing body reserve deposition and decreasing the efficiency of energy utilization.