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Full-Text Articles in Physical Sciences and Mathematics

An Analysis Of The Dry Matter Intake And Rate Of Live-Weight Gain Of Growing Cattle Fed Forage Diets, J G. Buchanan-Smith Sep 2024

An Analysis Of The Dry Matter Intake And Rate Of Live-Weight Gain Of Growing Cattle Fed Forage Diets, J G. Buchanan-Smith

IGC Proceedings (1993-2023)

The intake and rate of live-weight gain of 500 growing steer calves fed experimental forage diets in 7 trials were compared with corresponding values predicted using the Na1ional Research Council (NRC) model (1984). The cattle were predominantly weaned calves and most of the experimental diets were alfalfa-grass silage, either unsupplemented or supplemented with various protein sources, but some diets were based on maize silage or maize grain. The feeding period evaluated in this study ranged between the first 84 and 147 days when protein accretion rate in the cattle would be relatively high. Dry matter intakes were overpredicted by the …


Simulating The Impact Of Global Warming On Regional Pasture Production Environment, P J. Vickery, M J. Hill, E P. Furnival Sep 2024

Simulating The Impact Of Global Warming On Regional Pasture Production Environment, P J. Vickery, M J. Hill, E P. Furnival

IGC Proceedings (1993-2023)

Global warming scenarios predict increases in temperatures, evaporation and summer rainfall in the northern two-thirds of Australia. Pasture production models can be combined with spatial climate data in a geographic information system to predict net primary production from pastures. We used a pasture-sheep production model for a phalaris-white clover pasture together with interpolated climatic data to predict the outcome of increases in temperature, evaporation and summer rainfall for net primary production (NPP) from pastures in northern NSW. NPP was predicted to rise in winter due to elevated temperatures, to decline slightly In spring due to increased evaporation, and to change …


Raster Map For Prediction Of Heading Date Of Timothy By Nonparametric Dvr Method, T Saigusa, K Nakashima, N Noshiro, M Tsutsumi Jun 2024

Raster Map For Prediction Of Heading Date Of Timothy By Nonparametric Dvr Method, T Saigusa, K Nakashima, N Noshiro, M Tsutsumi

IGC Proceedings (1993-2023)

A system for making a raster map for predicting the heading date of timothy (Phleum pratense L.) at first cutting for every 1km2 plot was developed to supply information for smooth harvest of forage of good quality in a dairy farming area of Hokkaido. Daily mean air temperature for every 1km2 plot was estimated with data from a network of meteorological observatories and data base of the Japan Meteorological Agency. Day length could be calculated from latitude and calendar day. Using these two environmental factors, heading date of timothy at first cutting for each area was predicted by nonparametric DVR …


Ruminal Fill Effect Of Forages: Prediction And Relationship With Voluntary Intake, R Baumont, A Barlet, J Jamot Feb 2024

Ruminal Fill Effect Of Forages: Prediction And Relationship With Voluntary Intake, R Baumont, A Barlet, J Jamot

IGC Proceedings (1993-2023)

Voluntary dry matter intake (VDMI) and rumen fill were measured on sheep fed with 18 forages ranging from wheat straw to lucerne hay. In vivo fill effect (IVFE i.e. rumen DM pool divided by VDMI), in situ degradability, cell-wall composition, pepsin-cellulase digestibility and in vitro gas production were determined. In situ estimated fill effect (ISFE) was calculated as the retention time of insoluble potential degradable and undegradable fractions using a constant rate of passage. ISFE and IVFE were highly correlated (r2=0.89) but ISFE values were lower than IVFE values because in situ degradability does not integrate comminution time of …


Effects On Intake Of Supplementing Low-Quality Roughage With Protein-Rich Feeds, J.J. M.H. Ketelaars, G A. Kaasschieter, M Kane Feb 2024

Effects On Intake Of Supplementing Low-Quality Roughage With Protein-Rich Feeds, J.J. M.H. Ketelaars, G A. Kaasschieter, M Kane

IGC Proceedings (1993-2023)

Intake responses of ruminants to supplementation with protein-rich concentrates or legume hays have been related to the ratio of nitrogen (N) content and organic matter digestibility (OMD) of the basal feed. Marginal intake effect of supplements, i.e. change of organic matter intake (OMI) from the basal feed per unit OMI from supplement, decreased on average from 1.7 to 0 and -0.8 g. g-1 at N/OMD of 0.010, 0.016 and > 0.030 g. g-1, respectively. Marginal effect of supplements defined as change of total digestible organic matter intake (DOMI) per g DOMI from supplement was 2.5, 1 and 0.3 g. g-1 for …


A Simple Vegetation Criterion (Ndf Content) May Account For Diet Choices Of Cattle Between Forages Varying In Maturity Stage And Physical Accessibility, Cécile Ginane, R. Baumont Jun 2023

A Simple Vegetation Criterion (Ndf Content) May Account For Diet Choices Of Cattle Between Forages Varying In Maturity Stage And Physical Accessibility, Cécile Ginane, R. Baumont

IGC Proceedings (1993-2023)

The management of extensively grazed pastures requires an understanding and prediction of the diet choices of herbivores grazing on vegetation that is qualitatively (maturity stage) and quantitatively (biomass, sward height) heterogeneous. The Optimal Foraging Theory (OFT, Stephens & Krebs, 1986), bases its predictions on the relative energy intake rate (EIR) of forages. However, as EIRs are difficult to assess at pasture and are subject to wide intra- and inter-individual variations, another vegetation criterion was sought (accessibility, quality), by-passing the animal's influence, to predict cattle diet choices quantitatively.


A Simple Vegetation Criterion (Ndf Content) May Account For Diet Choices Of Cattle Between Forages Varying In Maturity Stage And Physical Accessibility, Cécile Ginane, R. Baumont Mar 2023

A Simple Vegetation Criterion (Ndf Content) May Account For Diet Choices Of Cattle Between Forages Varying In Maturity Stage And Physical Accessibility, Cécile Ginane, R. Baumont

IGC Proceedings (1993-2023)

The management of extensively grazed pastures requires an understanding and prediction of the diet choices of herbivores grazing on vegetation that is qualitatively (maturity stage) and quantitatively (biomass, sward height) heterogeneous. The Optimal Foraging Theory (OFT, Stephens & Krebs, 1986), bases its predictions on the relative energy intake rate (EIR) of forages. However, as EIRs are difficult to assess at pasture and are subject to wide intra- and inter-individual variations, another vegetation criterion was sought (accessibility, quality), by-passing the animal's influence, to predict cattle diet choices quantitatively.