Evaluation of three Lolium perenne L. cultivars with dairy cows, in the high tropic of Nariño-Colombia

Abstract

The objective of the study was to evaluate three ryegrass (Lolium perenne L.) cultivars with dairy cows, in the high tropic of Nariño-Colombia, in two localities: Pasto (PAS) and Cumbal (CUM). In each locality nine cows were used, in a Latin square design (3 x 3) with three treatments (T), corresponding to each cultivar to be evaluated: T1: ryegrass Columbia, T2: ryegrass Samson, T3: ryegrass Ohau. The dry matter intake (DMI) and milk production (MP) were estimated, and samples were collected to analyze: fat, protein, total solids and milk ureic nitrogen (MUN). There was no statistical difference in the DMI among the ryegrasses in the localities. In PAS significant differences were found among cultivars in the variable milk production (p < 0,05); with Samson and Ohau higher production was obtained (17,5 and 17,1 kg/cow/day) with regards to Columbia (15,5 kg/cow/day). In the content of fat and non-fatty solids in the milk, there were no differences among the treatments in any of the two localities. However, significant difference (p < 0,05) was found in the milk protein in PAS (3,48; 3,61 and 3,47 % for Columbia, Samson and Ohau, respectively). For the variable MUN (mg/dL), significant difference (p < 0,05) was observed in the PAS locality. It is concluded that L. perenne showed similar nutritional characteristics in the two localities where they were established. The response in milk production and compositional quality was considered good, taking into consideration that the animals did not receive supplementation and the trial was conducted in the dry season, in which the pasture yields decrease.