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Publication Date
1981
Description
At the VI International Grassland Congress held at Pennsylvania State College in 1952, the late Dr. C.P. McMeekan reviewed the many problems associated with the plant-animal complex. Great stress was placed on the need to measure forage intake accurately as a prerequisite to an under-standing of the plant-animal complex. Progress in the development of more accurate :methods of estimating the forage intake of grazing animals is reviewed, including the introduction of different methods of administering chromic oxide, the esophageal fistula for obtaining samples of selectively grazed material, the in-vitro technique for estimating the digestibility of the forage eaten, and the use of grazing behavior and bite-size data. Many different methods of measuring forage intake are available, but none of these has a high degree of accuracy. The absence of accurate methods of measuring forage intake has led to use of other approaches to study the plant-animal complex. The existence of a critical bite size below which intake will be depressed is considered. It is shown that the critical bite size will be achieved only when the yields of desired forage exceed about 1,000 kg/ha. Grazing animals pxefer green leaf, and in many cases Tejection of the stem and dead material is so great that only green leaf should be considered when determining if sufficient forage is available for the grazing animal to achieve the critical bite size. In mixed pasture, animals will tend to prefer certain species, and the yield of these species will determine whether maximum voluntary intake of forage will be achieved. The possibilities of using fertilizers to change this preference rating in favor of a plant of higher nutritive value is discussed, together with problems associated with the low intake of the stem fraction. It is concluded that major advances have been made in our knowledge of the plant-animal complex and that most of these advances have been achieved without using accurate methods of measuring the forage intake by animals. This progress was achieved by bringing together the skills of many different disciplines, and there is a continuing need for individual scientists who have trained in both the plant and the animal sciences.
Citation
Minson, D J., "Forage Quality: Assessing the Plant-Animal Complex" (1981). IGC Proceedings (1981-2023). 2.
(URL: https://uknowledge.uky.edu/igc/1981/plenary/2)
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Forage Quality: Assessing the Plant-Animal Complex
At the VI International Grassland Congress held at Pennsylvania State College in 1952, the late Dr. C.P. McMeekan reviewed the many problems associated with the plant-animal complex. Great stress was placed on the need to measure forage intake accurately as a prerequisite to an under-standing of the plant-animal complex. Progress in the development of more accurate :methods of estimating the forage intake of grazing animals is reviewed, including the introduction of different methods of administering chromic oxide, the esophageal fistula for obtaining samples of selectively grazed material, the in-vitro technique for estimating the digestibility of the forage eaten, and the use of grazing behavior and bite-size data. Many different methods of measuring forage intake are available, but none of these has a high degree of accuracy. The absence of accurate methods of measuring forage intake has led to use of other approaches to study the plant-animal complex. The existence of a critical bite size below which intake will be depressed is considered. It is shown that the critical bite size will be achieved only when the yields of desired forage exceed about 1,000 kg/ha. Grazing animals pxefer green leaf, and in many cases Tejection of the stem and dead material is so great that only green leaf should be considered when determining if sufficient forage is available for the grazing animal to achieve the critical bite size. In mixed pasture, animals will tend to prefer certain species, and the yield of these species will determine whether maximum voluntary intake of forage will be achieved. The possibilities of using fertilizers to change this preference rating in favor of a plant of higher nutritive value is discussed, together with problems associated with the low intake of the stem fraction. It is concluded that major advances have been made in our knowledge of the plant-animal complex and that most of these advances have been achieved without using accurate methods of measuring the forage intake by animals. This progress was achieved by bringing together the skills of many different disciplines, and there is a continuing need for individual scientists who have trained in both the plant and the animal sciences.
