INGESTIVE BEHAVIOUR OF DAIRY COWS GRAZING L0LIUM PERENNE L. PASTURES WITH DIFFERENT TYPES AND LEVELS OF NEOTYPHODIUM LOLII (LATCH, CHRISTENSEN AND SAMUELS)

Abstract

The ingestive behaviour of dairy cows grazing L. perenne cv. Quartet with different levels and types of endophyte was evaluated over a 5-month period (Spring-Autumn). The trial was carried out in Osorno, on pastures of L. perenne cv. Quartet with: Low levels of endophytes (BES); endophyte AR1; and high levels of endophytes (AES). The pastures occupied individual plots of 160 m² and were grazed by 20 dairy cows. The evaluated variables in pre and post grazing were herbage mass and the components of the yield of individual tillers. During grazing, bite number per minute and grazing preference were assessed. After grazing, tiller density and apparent intake of herbage mass were measured. The study corresponded to a Complete Randomized Block design with three blocks. ANOVA and Canonical Variate Analysis (CVA) were applied. Growth features between cultivars were similar. The remaining lamina length after grazing was smaller for Quartet AES and AR1 in relation to Quartet BES, which was consistent with the higher apparent intake of herbage mass for these treatments. The CVA showed that the largest differences between treatments were explained by available herbage mass before and after grazing and the lamina length before grazing. Grazing cows discriminated between the type of L. perenne according to its endophyte and season: cv. Quartet BES was preferred during November and December, cv. Quartet AR1 was preferred in January and during March the cows did not discriminate between the different types of cv. Quartet.