Comparisons of Two Different Systems of Feeding Dairy Cows for Three Consecutive Lactations

Abstract

Comparisons between group-fed ]=Iolsteins receiving complete feeds and Holsteins receiving corn silage and concentrates were studied for three consecutive lactations. The cows were randomly allotted to one of four treatment groups. All cows were housed in a free-stall barn, kept on concrete, bunk fed, and parlor milked. Cows in Groups I and IV received high and medium levels of concentrate and ad libitum corn silage. Cows in Groups II and III were fed complete feeds, ad libitum, with 60:40 and 70:30 concentrate: roughage ratios. Total digestible nutrients and dry matter consumptions were computed from daily intakes. Milk yields were based on weekly weights; monthly tests were run on fat, solids-not-fat, and protein. Three lactation averages ranged from 6,601 to 6,967 kg milk; 234 to 246 kg fat; 3.4 to 3.6% milk fat; 8.3 to 8.5% solids-not-fat and 3.1 to 3.3% protein. Differences between groups for milk, fat, and protein production, dry matter and total digestible nutrient intakes were not statistically significant. Based on these data approximately 0.5 kg total digestible nutrient is required to produce 1.0 kg milk by high-producing cows for total lactations. Complete rations and concentrate:silage rations are very similar in their abilities to maintain milk, fat, and protein production. Group-feeding and total confinement do not appear to be detrimental to herd life or health of dairy cows.