A field study of a computerized method of grouping dairy cattle

A computer modeling experiment showed that grouping dairy cattle based on requirements of crude protein and net energy per kilogram expected dry matter intake (Grouper) had unique characteristics relative to other grouping systems. The objective of this study was to adapt the computerized Grouper system for practical use by implementing a field trial in commercial dairy herds to determine its managerial benefits and economic merit. Ten cooperating dairy herds participated in the one year trial. Herds were grouped monthly using test day information obtained from the Dairy Records Processing Center, Raleigh, NC and reports mailed to the cooperators. Feed consumption data and a record of cows not placed according to Grouper recommendations were collected during monthly herd visits or by mail. One set of analyses examined trends in Dairy Herd Improvement (DHI) variables through trial duration while another set compared Grouper to a comparable milk production grouping program with all herd test day information grouped with both systems. No significant changes in DHI variables could be attributed to the Grouper system. Grouper retained younger, smaller cows and those with higher fat test in the high group longer and moved older, larger cows and cows with lower fat test into the low group sooner than grouping by milk production. Grouper produced higher intraclass correlations among cows in groups for percent Total Digestible Nutrients (0.59 versus 0.41) and percent crude protein (0.65 versus 0.57) than milk production grouping. Economically, Grouper was significantly more expensive when comparing systems based on average feed cost per cow per day. However, this did not consider increased income or decreased costs associated with the system or account for possible benefits such as better health and higher production resulting from feeding more precisely each individual's nutrient requirements. The Grouper program has been automated to be used through either a dairy records processing center or an individual microcomputer and can be considered a practical management tool to help the dairy manager group cows more efficiently and feed more accurately.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Dairy Science

Department dc:contributor.department

Dairy Science

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1985

Author dc:creator

• Schucker, Brenda Lee

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-11152013-040343

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/45734