UVM Theses and Dissertations
Format:
Print
Author:
Schmitt, Abdon L.
Dept./Program:
Plant and Soil Science
Year:
2008
Degree:
Ph. D.
Abstract:
Pasture-based animal production has assumed in the last decade an outstanding importance all around the world. This fact is mainly related to economic advantages, food security, animal welfare, and ecological issues. Grazing is a dynamic interaction among plant community, animal, soil, and human action. Under intensive pasture, management, the grazier manages animals to achieve optimum production through interaction ofthese components. Knowledge of how ruminants adapt their behavior to cope with pasture management and environmental changes is essential for developing a theoretical framework of factors to understand the pastoral ecosystem. Management methods have been shown to synchronize grazing behavior. Dairy cows learn to anticipate being moved to a fresh paddock after every milking and synchronize their behavior to this prediction. This results in reduction of grazing time and forage intake, especially near reward time. The decline in grazing motivation has been called waiting behavior and is related to instrumental conditioning.
This dissertation reports a research project designed to evaluate effects of alternative paddock management to change grazing habits to minimize waiting behavior, thereby increasing use of the pasture resource. Behavioral budgets and milk yield were used to compare paddock managements on a commercial dairy farm. Two control groups grazed in conventional half-day paddocks. Two treatment groups grazed half-day paddocks that were fenced into two parts, a main (85% of area) and a remaining area (15%). The main area was available to cows when they entered a paddock. The remaining area of fresh forage was offered to them 3 hours before milking. Evaluations of behavioral budgets were done during four daily subperiods (MORNING, AFTERNOON, EVENING, and DAWN), and whole 24-hour daily times. Behavioral and production differences between treatment and control were tested using ANOVA. The magnitude of the difference was evaluated through Tukey-Kramer HSD.
Treatment cows grazed 71 min d⁻¹ more, and had shorter rumination and leisure daily times than control cows (P <0.01). These behavioral adjustments happened on AFTERNOON and EVENING sub-periods, when fresh 15% areas were released to treatment groups. Treatment cows produced 1.0 kg d⁻¹ more milk (P <0.01) than controls. Longer grazing time and higher milk yield were related to better use of the pasture resource and less need of in-barn supplementation. This study showed that simple farm management techniques can positively influence dairy cow performance through environmental friendly use of pasture resources that otherwise would be wasted. Patient observation of livestock and plants is a managerial skill that enables farmers to use management practices better integrated with the whole environment.
This dissertation reports a research project designed to evaluate effects of alternative paddock management to change grazing habits to minimize waiting behavior, thereby increasing use of the pasture resource. Behavioral budgets and milk yield were used to compare paddock managements on a commercial dairy farm. Two control groups grazed in conventional half-day paddocks. Two treatment groups grazed half-day paddocks that were fenced into two parts, a main (85% of area) and a remaining area (15%). The main area was available to cows when they entered a paddock. The remaining area of fresh forage was offered to them 3 hours before milking. Evaluations of behavioral budgets were done during four daily subperiods (MORNING, AFTERNOON, EVENING, and DAWN), and whole 24-hour daily times. Behavioral and production differences between treatment and control were tested using ANOVA. The magnitude of the difference was evaluated through Tukey-Kramer HSD.
Treatment cows grazed 71 min d⁻¹ more, and had shorter rumination and leisure daily times than control cows (P <0.01). These behavioral adjustments happened on AFTERNOON and EVENING sub-periods, when fresh 15% areas were released to treatment groups. Treatment cows produced 1.0 kg d⁻¹ more milk (P <0.01) than controls. Longer grazing time and higher milk yield were related to better use of the pasture resource and less need of in-barn supplementation. This study showed that simple farm management techniques can positively influence dairy cow performance through environmental friendly use of pasture resources that otherwise would be wasted. Patient observation of livestock and plants is a managerial skill that enables farmers to use management practices better integrated with the whole environment.