Chewing and ruminating with various forage qualities in nonlactating dairy cows

This study investigated Italian typical dry forage diets used in the Parmigiano Reggiano PDO (protected designation of origin) area of Italy. The first cutting is typically a mixture of alfalfa and native wild grasses, resulting in a unique forage nutrient content. Alfalfa makes up less than 10% in the first cut because herbicides are not commonly used. Wild grasses are predominant in such conditions, whereas in the subsequent cuts alfalfa content increases as grasses decrease because of agronomical and climatic characteristics. Six multiparous, nonlactating Holstein cows were used in a replicated 3 × 3 Latin square to evaluate 3 different cuttings of alfalfa hay fed as the sole diet source. Eating and ruminating behavior were studied to investigate forage properties related to chewing activity. No differences were found in eating time; however, ruminating time per kilogram of physically effective NDF was greater when cows were fed first-cutting alfalfa than when they were fed the second or fifth cutting, despite similar digestibility and diet particle size of first- and fifth-cutting forage. In vivo digestibility of the diets revealed higher fecal NDF, ADF, and DM digestibility for first- and fifth-cutting hay. A similar trend was observed with the results of the in vitro data, with reduced digestibility for second-cutting forage.