Diet Digestibility, Rate of Passage, and Eating and Rumination Behavior of Jersey and Holstein Cows

Abstract

Diet digestibility and rate of passage, eating and ru- mination behavior, dry matter intake (DMI), and lacta- tion performance were compared in 6 Jersey and 6 Hol- stein multiparous cows. Cows were fed gestation diets according to body weight (BW) beginning 7 wk before expected calving and ad libitum amounts of a lactation diet postpartum. Diet digestibility and rate of passage were measured in 5-d periods at wk 5 prepartum and wk 6 and 14 of lactation. Eating and ruminating behav- ior was measured over 5-d periods at wk 5 and 2 prepar- tum and wk 2, 6, 10, and 14 of lactation. Milk yield and DMI were higher in Holsteins, but milk energy output per kilogram of metabolic BW (BW0.75) and intake ca- pacity (DMI/kg of BW) did not differ between breeds. Holsteins spent longer ruminating per day compared with Jerseys, but daily eating time did not differ be- tweenbreeds.Jerseysspentmoretimeeatingandrumi- nating per unit of ingested feed. The duration and num- ber of meals consumed did not differ between breeds, but the meals consumed by Jerseys were distributed more evenly throughout each 24-h period, providing a more regular supply of feed to the rumen. Feed passed throughthedigestivetractmorequicklyinJerseyscom- pared with Holsteins, suggesting particle breakdown and rumen outflow were faster in Jerseys, but this may also reflect the relative size of their digestive tract. Neutral detergent fiber digestibility was greater in Jer- seys, despite the shorter rumen retention time, but di- gestibility of dry matter, organic matter, starch, and N did not differ between breeds. Utilization of digested N for tissue retention was higher at wk 5 prepartum and lower at wk 14 of lactation in Jerseys. In contrast to numerous published studies, intake capacity of Jerseys wasnothigherthanthatofHolsteins,butinthepresent study, cows were selected on the basis of equal expected