Supplementation of Lactating Cows Grazing Stargrass (\u3ci\u3eCynodon nlenfuensis var. nlenfuensis\u3c/i\u3e) with Conjugated Linoleic Acid: Effects on Persistency and Estimated Net Energy Balance

Thirty crossbread cows grazed stargrass (Cynodon nlenfuensis var. nlenfuensis) receiving 4kg/d of a supplement formulated to provide 115% of metabolizable protein requirements from the 4th to the 11th week of lactation. The cows received either 150g/head/day of Megalac (Control) or 150g/head/day of a Ca-protected conjugated linoleic acid (CLA, Church & Dwight). Residual effects of treatment were evaluated in weeks 12th and 13th. Milk production increased in CLA treated cows (P\u3c 0.05). CLA decreased milk fat content (P\u3c 0.0001) and yield (P\u3c 0.01). Protected CLA increased protein content (P\u3c 0.01) and yield (P\u3c 0.01). The CLA residual effect on milk fat ends within one week after withdrawal but the benefits on milk yield and total solids production continued, due to the increased persistency. The estimated energy balance and intake were not greatly affected by treatment, as treated cows had higher milk volume and had higher protein productions