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Accueil du site → Master → Etats Unis → 2020 → GRAZING PATTERNS, DIET QUALITY, AND PERFORMANCE OF COW- CALF PAIRS GRAZING SHORT GRASS PRAIRIE USING CONTINUOUS OR HIGH STOCKING DENSITY GRAZING STRATEGIES

West Texas A&M University (2020)

GRAZING PATTERNS, DIET QUALITY, AND PERFORMANCE OF COW- CALF PAIRS GRAZING SHORT GRASS PRAIRIE USING CONTINUOUS OR HIGH STOCKING DENSITY GRAZING STRATEGIES

Fritzler, Larry Dale

Titre : GRAZING PATTERNS, DIET QUALITY, AND PERFORMANCE OF COW- CALF PAIRS GRAZING SHORT GRASS PRAIRIE USING CONTINUOUS OR HIGH STOCKING DENSITY GRAZING STRATEGIES

Auteur : Fritzler, Larry Dale

Université de soutenance : West Texas A&M University

Grade : Master of Science (MS) 2020

Résumé partiel
Two experiments were performed at the WTAMU Nance Ranch (Canyon, TX) to compare different grazing strategies. The first measured differences in intensity of defoliation among species when cattle were allotted the same mean daily herbage allowance but with different stocking densities and grazing period lengths on reclaimed farmland dominated by old world bluestem (Bothriocloa ischaemum L.). Eighty-seven cows were randomly assigned to four treatment herds from January 12 – February 13, 2018. Fifty-nine mature cows (567 kg ± 10.8 kg, std. dev.) were stocked to achieve a target mean daily herbage allowance of 68 kg standing biomass . hd-1 . day-1 for the grazing period allotted among four replicates of the continuous grazing treatment. Another 28 cows received the same daily herbage allowance, but moved daily in small paddocks among four replicates, consecutively. Paddock size was determined each day by standing biomass in the area to be used to achieve an herbage allowance of 68 kg standing biomass . hd-1 . day-1. Botanical composition of standing herbage was measured before and after completion of the study in order to measure herbage disappearance by species. At the end of the grazing season, a nearest-plant step point transect was used to measure severity of defoliation by species between treatments. Total standing herbage at the beginning and end of the grazing season was not different (p>0.05) between treatments. Neither herbage removal nor proportional weight remaining were different (p>0.05) between treatments for any species measured. The before and after index (BAI) was used to estimate the relative change in standing biomass (BAIweight) or composition (BAIcomp) by weight for individual species in the plant community.

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