Archived
This content is available here strictly for research, reference, and/or recordkeeping and as such it may not be fully accessible. If you work or study at University of Kentucky and would like to request an accessible version, please use the SensusAccess Document Converter.
Publication Date
1981
Description
Information on feeding value and energy utilization of grass consumed by grazing cattle, especially lactating cows, is limited. It is nearly impossible to perform calorimetric studies with grazing dairy cows. Similar studies indoors often show low intakes of fresh grass and require much labor. Still, in much of the world, cattle graze at least half the year; therefore, knowledge of the feeding value of grass is important for practice. In the Netherlands, each year (1973-1974) each of four permanent pastures in the grazing stage of maturity was cut twice daily and either fed fresh or stored at - 20°C to be fed later to four lactating cows in respiration chambers. Animals were adapted for 7-10 days before a 7-day collection period on fresh grass ad libitum plus 1 kg of concentrates. In a subsequent week, the same grass in the frozen form was used. Digestibility, N, and energy balances were measured to determine energy utilization from grass. In 1977-1979, a total of seven similar calorimetric trials were conducted with four lactating cows fed ad libitum with grass after storage at - 20°C. In some trials, half of the grass dry matter was substituted with concentrates. The grass was fed to dairy cows at production level as well as to wethers near the maintenance level. Because many feed-evaluation systems use sheep digestibility coefficients as their basis, differences in digestibility between sheep and cattle were determined. No differences in intake, digestibility, or energy utilization between fresh and frozen grass could be detected. In the total of 83 energy balances, the digestibility of grass by cattle was high (organic matter 75 %-83 % , energy 71 %-78 % ) but varied between pastures and months. Intake depended mainly on the pasture, the composition of the grass (percentage of DM), and/or the season. Intake varied from 10.2 to 16.0 kg organic matter, but was lowest in the later trials. Despite higher feeding levels of the cattle, cow and wether digestibilities hardly differed, except for trials with extra concen trates in the diet. Utilization for maintenance and milk production of the metabolizable energy from grass agreed fairly well with efficiencies of diets of mixed conserved forage and concentrates, although some results tended to be lower. It was concluded that grass from pastures suited for grazing is highly digestible and efficiently utilized for maintenance and milk production. Increased level of feeding caused ony a minor depression of digestibility in lactating cattle.
Citation
Van Der Honing, Y and Van Es, A.J H., "Energy Balance Studies with Lactating Cows Fed Fresh or Frozen Grass from Pasture Suitable for Grazing" (1981). IGC Proceedings (1977-2023). 12.
(URL: https://uknowledge.uky.edu/igc/1981/section11/12)
Archival?
Archival
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Energy Balance Studies with Lactating Cows Fed Fresh or Frozen Grass from Pasture Suitable for Grazing
Information on feeding value and energy utilization of grass consumed by grazing cattle, especially lactating cows, is limited. It is nearly impossible to perform calorimetric studies with grazing dairy cows. Similar studies indoors often show low intakes of fresh grass and require much labor. Still, in much of the world, cattle graze at least half the year; therefore, knowledge of the feeding value of grass is important for practice. In the Netherlands, each year (1973-1974) each of four permanent pastures in the grazing stage of maturity was cut twice daily and either fed fresh or stored at - 20°C to be fed later to four lactating cows in respiration chambers. Animals were adapted for 7-10 days before a 7-day collection period on fresh grass ad libitum plus 1 kg of concentrates. In a subsequent week, the same grass in the frozen form was used. Digestibility, N, and energy balances were measured to determine energy utilization from grass. In 1977-1979, a total of seven similar calorimetric trials were conducted with four lactating cows fed ad libitum with grass after storage at - 20°C. In some trials, half of the grass dry matter was substituted with concentrates. The grass was fed to dairy cows at production level as well as to wethers near the maintenance level. Because many feed-evaluation systems use sheep digestibility coefficients as their basis, differences in digestibility between sheep and cattle were determined. No differences in intake, digestibility, or energy utilization between fresh and frozen grass could be detected. In the total of 83 energy balances, the digestibility of grass by cattle was high (organic matter 75 %-83 % , energy 71 %-78 % ) but varied between pastures and months. Intake depended mainly on the pasture, the composition of the grass (percentage of DM), and/or the season. Intake varied from 10.2 to 16.0 kg organic matter, but was lowest in the later trials. Despite higher feeding levels of the cattle, cow and wether digestibilities hardly differed, except for trials with extra concen trates in the diet. Utilization for maintenance and milk production of the metabolizable energy from grass agreed fairly well with efficiencies of diets of mixed conserved forage and concentrates, although some results tended to be lower. It was concluded that grass from pastures suited for grazing is highly digestible and efficiently utilized for maintenance and milk production. Increased level of feeding caused ony a minor depression of digestibility in lactating cattle.
