Improving management techniques in southeastern beef cattle production
Studstill, Matthew Wilson
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Two experiments were conducted to improve common management techniques on beef cattle operations. Experiment 1 analyzed beef heifers for pre-breeding measurements that relate to reduced time to conception and positive pregnancy outcome. Odds of pregnancy increased by 15% for every 2.5 cm increase in hip height, and by 20% for every one month increase in heifer age at the start of the breeding period. Hip height was not associated with conception during the first 35 days (P = 0.204) but after 35 days the hazard rate for conception increased by 15% for every 2.5 cm increase in hip height (P = 0.005). Experiment 2 studied the effect on ruminal kinetics in vitro when feeding forages varying in nutritive value in association with common supplementation strategies. The objective of this experiment was to measure the change in DM, NDF and ADF digestibility of two forage species (‘Kentucky 31’ tall fescue and ‘Tifton 85’ bermudagrass) over seven time points (0, 3, 6, 12, 18, 24, and 48 h). These forages were subjected to harvesting intervals typical of production systems that graze cattle or produce hay in Georgia. Samples of harvest data was subjected to NIR spectroscopy to determine quality. Forages were stratified by RFQ, in order to create three quality categories: high (HIG), median (MED), and poor (LOW). The various qualities were paired with common supplementation strategies: no supplementation control (CON), liquid molasses urea (LIQ), and corn gluten feed (CGF). Regression analysis showed an increase (P < 0.01) in IVDMD, total gas production, neutral detergent fiber digestible (NDFD) and acid detergent fiber digestible (ADFD) with increased incubation time. Diets that consisted of the HIG treatment had the greatest (P < 0.001) IVDMD, NDFD and ADFD compared to the AVG treatment which was intermediate between LOW and HIG treatments. However, effect of supplementation differed between varieties of forage. Poor quality tall fescue supplemented with CGF had greater (P < 0.05) DMD compared to CON and LIQ treatments.