Dairy cows with different milk urea nitrogen breeding values display different grazing behaviours

The objective of this study was to describe the diurnal pattern grazing behaviour multi-parous dairy cows divergent for milk urea N breeding values (MUNBV) and consistency these differences across different sward compositions (perennial ryegrass [RG; Lolium perenne L.] or with plantain [Plantago lanceolata L.; RGPL]) stages lactation (early late lactation). Jaw movement recorders were fitted 24 animals in early 16 lactation, 12 assigned diet diet, 8 remaining diet. For each half during both classified as high MUNBV other low MUNBV. Low had more mastications per bite over day (P < 0.01) a one-unit decrease resulting 0.07 bites mastication first two bouts, well temporal distribution bouts compared cows. A resulted 0.11 ± 0.02 increase bout composition. Ingestive has large impact on physical features ingesta thereby rumen function. results indicate that same forage apply strategies terms oral processing meal pattern. These present potential explanatory variables phenotypical observed