A Field Study of Grouping Cows by Nutrient Requirements for Feeding

• Published in: Journal of dairy science Vol. 71; no. 3; pp. 870 - 878
• Main Authors: Schucker, B.L., McGilliard, M.L., James, R.E., Stallings, C.C.
• Format: Journal Article
• Language: English
• Published: Champaign Elsevier Inc 01.03.1988; Am Dairy Sci Assoc; American Dairy Science Association
• Subjects: ALIMENTACION DE LOS ANIMALES; ALIMENTATION DES ANIMAUX; ANIMAL FEEDING; ANIMAL POPULATION; BESOIN NUTRITIONNEL; BOVIN LAITIER; COMPUTER SOFTWARE; COWS; DAIRY CATTLE; GANADO DE LECHE; LOGICIEL; NECESIDADES DE NUTRIENTES; NUTRITIONAL REQUIREMENTS; POBLACION ANIMAL; POPULATION ANIMALE; PROGRAMAS DE ORDENADOR; VACA; VACHE
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(88)79630-7

A field study was designed to evaluate the practicality of a system of grouping cows based on nutrient requirments for concentrations of CP and TDN. This cluster system was computerized and implemented in 10 commercial dairy herds feeding total mixed rations. Grouping recommendations based on DHIA records were provided for 12 mo. The final modified computer program was applied in retrospect to the 12 mo of production records of the herds. The cluster procedure, when compared with a milk only grouping with all other constraints identical, placed in the high groups cows 7 mo younger and 16kg lighter, requiring .9% more TDN and .6kg less DM. The cluster system placed in the low groups cows 9 mo older and 22kg heavier, requiring 1.2% less TDN concentration and .8kg more DM. Intragroup correlations for the cluster and milk systems were .59 and .41 for TDN, .65 and .57 for CP, and .19 and .48 for intake of DM, indicating that cows in clustered groups were more homogeneous in nutrient requirements than cows grouped by milk. Analysis of predicted feed cost per cow per day indicated similar feed costs for each grouping system.