Studies of grazing and nursing behavior in Angus crossbred cattle

In this experiment, grazing and nursing behavior of approximately 30 cow/calf pairs was examined in two years. Sires of the Polled Hereford x Angus cows had been selected for above (+) or below (-) average expected progeny difference for yearling weight and maternal weaning weight. Calves were sired by Angus bulls of United States (US) or New Zealand (NZ) origin. Observations from dawn to dusk were conducted on five days each year, spaced throughout lactation. All nursing episodes were recorded, and every ten minutes it was noted whether each cow and calf was or was not grazing. Periods of maximum grazing activity were early in the morning and late in the afternoon. The growth genotype of the cow did not affect her grazing time. Calves of maternal (+) cows grazed longer than calves of maternal (-) cows (P< 0.10), and their grazing time was not affected by the growth genotype of their dams. In year 1, US-sired calves spent 3% more time grazing than NZ-sired calves; whereas in year 2, NZ-sired calves grazed 4% longer than US-sired calves (interaction P <.10). Also in year 1, NZ-sired calves tended to graze during several intervals of time while US-sired calves tended to graze in longer continuous bouts. This tendency was reversed during the second year (interaction P<.10). As the grazing season progressed, time spent by calves grazing increased from < 20% to approximately 60%. Cows with (+) genetic merit for maternal weaning weight were nursed a similar number of times per day as cows with (-) genetic merit. Sire origin likewise did not affect nursing behavior.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Animal Science

Department dc:contributor.department

Animal Science

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1992

Author dc:creator

• Ngassa, Tchatchoua

Statement dc:rights

• In Copyright

Licence dc:rights.uri

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

Language dc:language.iso

en

Dc Identifier Other

etd-09292009-020057

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/44911