Skip to main content
ARS Home » Research » Publications at this Location » Publication #140728
Title: MILK PRODUCTION IN FOUR DIVERGENT BIOLOGICAL TYPES GRAZING COMMON BERMUDAGRASS OR ENDOPHYTE INFECTED TALL FESCUE

Author
item SANDELIN, B - UNIV ARKANSAS
item BROWN, JR., A - UNIV ARKANSAS
item BROWN, MICHAEL
item JOHNSON, Z - UNIV ARKANSAS
item BAUBLITS, R - UNIV ARKANSAS

Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2002
Publication Date: 1/23/2003
Citation: SANDELIN, B.A., BROWN, JR., A.H., BROWN, M.A., JOHNSON, Z.B., BAUBLITS, R.T. MILK PRODUCTION IN FOUR DIVERGENT BIOLOGICAL TYPES GRAZING COMMON BERMUDAGRASS OR ENDOPHYTE INFECTED TALL FESCUE. AMERICAN SOCIETY OF ANIMAL SCIENCE SOUTHERN SECTION MEETING. 2003. v. 81 (Suppl. 2):Abstract p. 3.

Interpretive Summary: Abstract Only.

Technical Abstract: Milk yield and quality were measured on four divergent biological types resulting from Angus, Brahman, and reciprocal cross cows grazing either common bermudagrass or endophyte-infected tall fescue. Data were collected over a 4 yr period to evaluate the effect of biological type and forage on milk production traits. The growth curve parameters of mature weight (A) and rate of maturing (k) were estimated for 121 cows using the growth curve model as described by Brody. Cows were assigned to one of four biological types: genetic potential for large mature size-late maturing (LL, A > 570 kg, k < 0.047 %, n = 35), large mature size-early maturing (LE, A > 570 kg, k <= 0.047 %, n = 19), small mature size-late maturing (SL, A <= 570 kg, k < 0.047 %, n = 25), and small mature size-early maturing (SE, A <= 570 kg, k >= 0.047 %, n = 42). Milk yield was estimated by milking machine, and milk fat, protein, and somatic cell counts were evaluated in a commercial laboratory. Monthly measurements were made beginning on day 61 of lactation and continued for five months. Data were averaged over month within year, and also reported as monthly estimates averaged over year. Included in the final models for milk yield and quality traits were the independent variables of forage, biological type, biological type x forage and residual error. Somatic cell counts were transformed using natural logarithms prior to analysis. Biological type was a significant (P < 0.10) source of variation for average milk yield, average milk protein and average somatic cell count. Forage was a significant source of variation for average milk production and average butterfat percentage (P < 0.05). The cows grazing bermudagrass had higher (P < 0.01) milk yields and butterfat percentage than their counterparts grazing endophyte-infected fescue. These results suggest that biological type and forage have varying effects on milk production traits.