Abstract: A method of formulating dairy cow rations based on the amounts of ruminally available protein (RAP) and carbohydrates (RAC) in the total daily ration, which includes both grain and forage components. Quantities necessary for determining RAP and RAC values are obtained from conventional chemical analysis and in situ techniques. Statistical analysis of experimentally obtained data showed optimized lactation response is obtained from a total daily ration containing RAP and RAC in the ranges of about 10.5-12.5% and 35.0-45.0%, respectively. Other important nutritional factors such as microbial synthesis and feed escape protein were also shown to be optimized by total daily rations containing RAP and RAC levels within or near the lactation optimization ranges.

Abstract: A novel method of determining the portion of a given dairy cow feedstuff which is attributable to non-structural carbohydrates is disclosed. The method includes the steps of analytically determining the percentages of crude protein, lipid and ash in the dry matter concentration of a first feed sample, and in the neutral detergent fiber which has been separated from the soluble matter of a second sample of the same feed, and subtracting the amounts of crude protein, lipid and ash in the neutral detergent fiber from the respective amounts of the same substances in the original sample. The three difference figures are totaled and subtracted from the percentage of the second sample represented by neutral detergent solubles, i.e., 100 minus neutral detergent fiber, thereby providing an accurate indication of the percentage of non-structural carbohydrate in the feedstuff.

Abstract: A novel method of formulating dairy cow rations based on regulation of the content of non-structural carbohydrates and neutral detergent fiber in the total daily ration, including both forage and grain portions, is disclosed. Feedstuffs analyzed to determine the percentages of non-structural carbohydrate and neutral detergent fiber contained thereby were fed in various proportions to test groups of cows under controlled conditions, and to commercial herds under actual field conditions to determine the effects, if any, on milk production by varying the proportion of the total daily ration constituted by non-structural carbohydrates. Also, the proportion of non-structural carbohydrates to neutral detergent fiber in the ration was calculated and compared with milk production levels. It was established that milk production was optimized when the total daily ration, including at least one grain and one forage, consists of between about 30% and 45% non-structural carbohydrates, depending upon forage type.