Production, Forage Quality, and Performance of Holstein Cows under Intermittent Grazing on Tifton 85

Abstract

Tropical forage grasses compose the base diet of the Brazilian cattle herd due to their low production cost, high production potential, and good adaptation to various Brazilian ecosystems. In recent years, the search has intensified for alternatives that increase the yield in pasture milk production systems. Thus, the present study evaluated the production and quality of Tifton 85 grass in relation to the production parameters (e.g. greater leaf: stem ratio), and milk quality of Holstein cows in an intermittent grazing system during different seasons of the year. The experiment was conducted at the Córrego da Ponte Farm in Santa Helena de Goias, Goias, Brazil, from April 2014 to March 2015. The experiment used a completely randomized design with nine replicates and the four seasons (fall, winter, spring, and summer) as treatments. The Holstein cows had a live weight of 560±36.8 kg and averages four years of age. The grazing method used was a mob-stocking, with one day of grazing and 19 days of rest. The results showed that Tifton 85 was efficient regarding production parameters (total dry mass) and forage quality (IVDMD, NDF, ADF). The milk production was satisfactory during the fall, spring, and summer. The forage showed limited production during the winter, due the highest NDF, ADF levels and lower IVDMD (P < 0.05), which was directly reflected in the milk yield, fat, protein and lactose (P < 0.05). A reduction in the stocking rate or an increase in the number of paddocks is advisable during the winter to maximize milk production without compromising forage development. The correlation data showed the importance of consuming better-quality forage to increase milk production without compromising the levels of milk solids.