Nutritional Requirements
A grazing system needs to meet the nutritional requirements of the livestock. Animals require water, energy, protein, vitamins and minerals. These nutrients are used to meet the requirements for reproduction, body growth, wool or hair growth, lactation, and general body maintenance. Environmental conditions, such as hot and cold weather, can increase maintenance requirements. An animal's priorities for nutrition are maintenance, lactation, growth (young animals) and reproduction. Consequently, reproduction is the first to go and the last to return in cases of inadequate nutrition.
Forage Quality And Intake
Forage sources vary in nutrient content and nutrient availability (digestibility). As forage plants mature, energy availability and protein content decrease. Forage intake decreases as nutrient availability or digestibility decreases. Intake of forages accounts for over 75% of the differences observed in animal performance between various forages.
Ideally, the livestock manager would like the forage plants to have a high leaf area compared to stems. Leaves are more digestible than stems. Livestock will selectively graze leaves and petioles, before grazing stems. Leaves also decline more slowly in digestibility than stems. In a rotational grazing system, regrowth will be more leafy and thus maintain higher digestibility longer.
Monitoring The Animals
Producers can monitor the effectiveness of the nutrition program in the longterm by herd performance records. In the short term, it can be monitored by keeping an eye on the "amount of milk in the bucket" and by monitoring the flesh or body condition score of the livestock.
Dairymen can quite easily assess changes in forage quality by reading the dipstick in the bulk tank. Body condition changes can be a more reliable guide than body weight for evaluating the day-to-day nutrition status of beef cows or ewes. This system also had an advantage compared to body weight in that scales or corrals are not needed for body condition evaluation. Body condition scoring tools are available at your County Extension Office.
Monitoring The Forage
Accurately measuring pasture nutritional value involves collecting samples for laboratory analysis. Sample close to where animals graze, not spots that are avoided. With rotational grazing, taking random samples in the pasture will work better than with continuous grazing system. Most feeds should be placed in a sealable container and frozen prior to mailing. County Extension offices have bags and forms for forage samples. Extension personnel can recommend the most appropriate analysis to be conducted at the laboratory.
Admittedly, the information from the laboratory may be "after the fact" since the samples are taken when or near the time the animals are actually grazing the forage. However, such information will give you a base to start evaluating forage quality. A combination of grazing management experience and laboratory analyses will allow you to make better day-today estimates of forage quality and determine if there is a need for supplementation.
Forage Quality And Intake
Forage sources vary in nutrient content and nutrient availability (digestibility). As forage plants mature, energy availability and protein content decrease. Forage intake decreases as nutrient availability or digestibility decreases. Intake of forages accounts for over 75% of the differences observed in animal performance between various forages.
Ideally, the livestock manager would like the forage plants to have a high leaf area compared to stems. Leaves are more digestible than stems. Livestock will selectively graze leaves and petioles, before grazing stems. Leaves also decline more slowly in digestibility than stems. In a rotational grazing system, regrowth will be more leafy and thus maintain higher digestibility longer.
Monitoring The Animals
Producers can monitor the effectiveness of the nutrition program in the longterm by herd performance records. In the short term, it can be monitored by keeping an eye on the "amount of milk in the bucket" and by monitoring the flesh or body condition score of the livestock.
Dairymen can quite easily assess changes in forage quality by reading the dipstick in the bulk tank. Body condition changes can be a more reliable guide than body weight for evaluating the day-to-day nutrition status of beef cows or ewes. This system also had an advantage compared to body weight in that scales or corrals are not needed for body condition evaluation. Body condition scoring tools are available at your County Extension Office.
Monitoring The Forage
Accurately measuring pasture nutritional value involves collecting samples for laboratory analysis. Sample close to where animals graze, not spots that are avoided. With rotational grazing, taking random samples in the pasture will work better than with continuous grazing system. Most feeds should be placed in a sealable container and frozen prior to mailing. County Extension offices have bags and forms for forage samples. Extension personnel can recommend the most appropriate analysis to be conducted at the laboratory.
Admittedly, the information from the laboratory may be "after the fact" since the samples are taken when or near the time the animals are actually grazing the forage. However, such information will give you a base to start evaluating forage quality. A combination of grazing management experience and laboratory analyses will allow you to make better day-today estimates of forage quality and determine if there is a need for supplementation.