HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hohenboken, W. D. Articles by Cundiff, L. V. Search for Related Content PubMed Articles by Hohenboken, W. D. Articles by Cundiff, L. V.

Partitioning Lactation TDN Consumption in Herefords between Maintenance, Gain and Milk Production^1,2,3

University of Wisconsin, Madison, 53706 and U.S. Department of Agriculture

Abstract

Kilograms TDN consumed during 245 first, second or third lactations of twin Hereford cows were partitioned between that for maintenance of body weight, weight change (DW) and milk (MP) and butterfat (BF) production. Partial regression coefficients of TDN on calving weight (CW), DW, MP and BF were used to adjust TDN to average CW and zero DW, MP and BF. Although adjusted TDN was called TDN for maintenance (TDNM), it more nearly reflected differences among cows in overall efficiency of feed use.

For first through third parities, respectively, MP averaged 949, 1,063 and 1,184 kg, BF averaged 33, 37 and 41 kg, TDN averaged 1,268, 1,364 and 1,430 kg, DW averaged 46, 27 and 32 kg and CW averaged 432, 483 and 496 kilograms.

TDNM/CW/day was 0.0089, 0.0090 and 0.0085 kg for first through third parities, values somewhat higher than 0.0065 frequently recommended for mature dairy cattle. Percentages of TDN partitioned between maintenance, weight change and MP, respectively, were 72, 7 and 21%, 76, 4 and 20%, and 71, 6 and 23% for first through third parities, respectively. Over the entire experiment values were 73% for maintenance, 6% for weight gain and 21 % for milk production. Gross lactational efficiency averaged 13% while net lactational efficiency averaged 59%.

Estimates of the power of CW with which TDNM varied were 0.69±.09, 0.55±.08 and 0.61 ±.05 for first through third parities and 0.61 ±.05 pooled over the entire experiment.

Partial regression coefficients presented relating TDN requirement to CW, DW, MP and BF should aid in predicting feed levels required to support various levels of performance.

¹ Published with the approval of the Director, Wisconsin Agricultural Experiment Station. Data were obtained from research conducted in cooperation with the Animal Science Research Division, A.R.S., U.S.D.A., as part of North Central Regional Project NC-1, Improvement of Beef Cattle Through Breeding Methods.

² Partial support from Tri-State Breeders Cooperative, Westby, Wisconsin, is gratefully acknowledged.

³ Paper No. 1443 from the Laboratory of Genetics and No. 584 from the Department of Meat and Animal Science.

⁴ Assistant Professor of Animal Science, Oregon State University, Corvallis 97331.

⁵ Beef Cattle Research Branch, Animal Science Research Division, A.R.S., Lincoln, Nebraska 68503.