Effect of supplementation on performance and reproduction of lactating beef cows grazing lush spring pasture

K. Doungkamchan, M. S. Jarboe, L. M. Shoup, W. T. Meteer, W. P. Chapple, D. W. Shike

Research output: Contribution to journalArticlepeer-review


Our objectives were to use 230 Angus × Simmental beef cows in a 2-yr experiment to determine the effects of supplementation on cow BW and BCS, first-service AI conception rate, and blood metabolites (nonesterified fatty acids, BHBA, and BUN). Cows (110 in yr 1 and 120 in yr 2) were randomly assigned to 1 of 2 treatments: control or supplement (SUPP). There were 3 replicates per treatment each year, and both treatments grazed clover–tall fescue pasture in early spring. The supplement contained 45% ground corncobs, 45% soybean hulls, and 10% dry molasses (DM basis), and 1.81 kg/cow per d was offered to cows fed SUPP starting 10 d before breeding. Forage samples were collected as groups were rotated to new pastures. Throughout the grazing season, forage CP decreased (P < 0.01), whereas ADF and NDF increased (P < 0.01). Day-18 BUN concentration in yr 2 tended to be decreased (P = 0.10) in cows fed SUPP compared with control cows. Concentration of BHBA for cows fed SUPP tended to be greater (P = 0.07) compared with control cows; however, nonesterified fatty acids did not differ (P = 0.80). There was no difference (P ≥ 0.44) in final BW and BCS nor was there any difference (P ≥ 0.35) in AI conception and overall pregnancy rate. In conclusion, a high-fiber, low-protein supplement did not affect BW or BCS or significantly improve first-service AI conception rate and overall pregnancy rate in cows grazing lush, early-spring pasture.

Original languageEnglish (US)
Pages (from-to)798-804
Number of pages7
JournalProfessional Animal Scientist
Issue number6
StatePublished - Dec 1 2016


  • beef cow
  • cool-season pasture
  • excess protein
  • reproduction
  • supplementation

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology


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