Estimation of Forage Dry Matter Intake in Lactating Dairy Cows Using a Deuterium Oxide Dilution Technique

Li, Jinghua; Odwongo, Willie O.; Conrad, H.R.

doi:10.3168/jds.s0022-0302(85)81142-5

Cited by 2 publications

(2 citation statements)

References 17 publications

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“…The biological half-life of water determined in the lactating goats in this series of experiments was similar to values for lactating ewes (Foot et al, 1979) but lower than for lactating dairy cattle (Odwongo et al, 1984 andWoodford, Murphy and Davis, 1984;Rogers, Odwongo and Conrad, 1985). As would be expected WTO was related to both milk production and DMI.…”

Section: Discussionsupporting

confidence: 77%

A two-pool model of tritiated water kinetics to predict body composition in unfasted lactating goats

et al. 1988

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1988). A two-pool model of tritiated water kinetics to predict body composition in unfasted lactating goats. ABSTRACTA two-pool model of tritiated water kinetics was investigated as a means of partitioning total body water into empty body water and gut water in 17 lactating goats. Empty body water, gut water and total body water were of a similar magnitude to, and highly correlated with, a rapidly equilibrating tritiated water pool, a more slowly equilibrating pool and the sum of these two pools, respectively.Empty body fat was poorly correlated with both live weight and empty body weight (R 2 = 0-42 and 0-51, respectively). However, there was a strong inverse relationship between the water and fat contents of the empty body. Consequently, empty body fat was accurately predicted by a multiple regression equation which included both empty body weight and empty body water as independent variables (R 2 = 0-97). Substitution of these variables with estimates derived from tritiated water kinetics still resulted in a high correlation (R 2 = 0-88). Tritiated water kinetics offered little improvement over live weight alone in the prediction of empty body protein, empty body ash or fat-free empty body.

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Section: Discussionsupporting

confidence: 77%

A two-pool model of tritiated water kinetics to predict body composition in unfasted lactating goats

et al. 1988

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“…However, there is potential for dietary moisture content to vary considerably and collecting representative samples of vegetation could be dif®cult, especially with the incidence of rain or heavy dew. Potential restrictions on the use of 3 H 2 O, due to its radioactivity, could be avoided by using 2 H 2 O instead (Rogers et al 1985). Despite the number of estimates of energy expenditure made in free-ranging herbivores by thè double-labelled water' method, which involves measuring the turnover rates of 2 H and 18 O in the body-H 2 O pool (Nagy et al 1999), the potential to use the 2 H data to estimate dietary intake has not been exploited.…”

Section: Intake Estimates Based On Turnover Ratesmentioning

confidence: 99%

Measurement of dietary nutrient intake in free-ranging mammalian herbivores

Mayes¹,

2000

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The nutrient intakes of mammalian herbivores depend on the amount and the nutrient content of the plant species and plant parts which they eat. We review the merits of oesophageal-®stulated (OF) animals, microhistological procedures, stable C-isotope discrimination and plant cuticular-wax markers as methods for estimating diet composition and intake in both ruminant and non-ruminant herbivores. We also brie¯y discuss methods based on grazing behaviour measurements or on H 2 O or Na turnover, and methods for estimating supplement or soil intake. Estimates of intake in ruminants are often based on separate measurements of faecal output and herbage digestibility. We review this approach and emphasize that, under some circumstances, the applicability of in vitro digestibility estimates based on OF extrusa is questionable. We discuss how plant-wax marker patterns can be used to check whether OF and test animals are consuming similar diets, but also emphasize that a major advantage of the use of plant-wax markers is that this approach may obviate altogether the need for OF animals. Estimates of total herbage intake can be partitioned into the intakes coming from different plant species and=or parts, provided diet composition can be measured. Diet composition estimates based on C-isotope discrimination have the major disadvantage that they cannot be taken to species level. By contrast, microhistological methods can identify many plant species in extrusa, digesta or faeces, but often a large proportion of plant fragments remains unidenti®able. Plant-wax hydrocarbons show great promise as markers for estimating diet composition and intake. However, we suggest that to be applicable in complex plant communities there is a need with this method either to recruit a wider range of wax markers (e.g. alcohols, sterols, fatty acids) or to use it in combination with other methods. We suggest that, in turn, this generates an urgent need for research on statistical aspects of the combined use of markers or methods, in relation to the error structures of the data or methods being combined and the standard errors of the resultant estimates of diet composition and intake. We conclude by discussing the extension of intake and=or diet Abbreviation: OM, organic matter.

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Estimation of Forage Dry Matter Intake in Lactating Dairy Cows Using a Deuterium Oxide Dilution Technique

Cited by 2 publications

References 17 publications

A two-pool model of tritiated water kinetics to predict body composition in unfasted lactating goats

A two-pool model of tritiated water kinetics to predict body composition in unfasted lactating goats

Measurement of dietary nutrient intake in free-ranging mammalian herbivores

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