Efectos del incremento de carga en variables bio-económicas en sistemas de producción de leche

This work analyzed the effect of two stocking rates above the national average (1.5 VO/ha and 2.0 VO/ha) on: (i) forage production and harvest; (ii) grazing and supplementation times; (iii) per cow and per hectare milk production; (iv) margin over feeding costs. For forage production and harvest a model of total randomized design was used to analyze the results, using both stocking rates as treatments and paddocks as experimental units. For grazing and supplementation times, and for milk production a total randomized blocks was used with stocking rate as treatment and two blocks were repetitions were located. The experiment was conducted on the Centro Regional Sur (Camino Folle km 35.500, Canelones; Lat. - 34.613 Long. - 56.218), experimental field of the Faculty of Agronomy of the University of the Republic. The experiment took place between 1^st march to 20 of december of 2017. 56 ha and 96 milking cows were utilized, distributed in 4 grazing platforms over which 4 groups of 24 cows each were located. There was no effect of increasing stocking rate over forage production and harvest. Forage management and supplementation levels utilized were probably the responsible factors on these results. There was no effect of stocking rate on individual milk production, but there was a significant increase in milk and milk solids production per hectare with increasing stocking rate. These results turn increasing stocking rate very tempting as a strategy to increase farms productivity and income. Never the less, it must be considered that such balance in per cow milk production through stocking rate was possible by a significant increase of supplementation, which implicates an increase in feeding costs as well as infrastructure for supplements management. From the economic point of view there was no difference between treatments in the daily margin over feeding cost per cow, but there was a significant increase in the margin over feeding cost per hectare when increasing stocking rate. These means that there was an improvement in the income of the system when increasing stocking rate for these work.