Effect of herbage type and level of intake on the release of chromic oxide from intraruminal controlled release capsules in sheep

Abstract

Controlled release capsules (CRC) provide for the continuous uniform release of chromic oxide (Crp3) into the rumen and so offer an improved means of estimating feed intake in grazing animals. Two experiments were conducted with sheep to measure the effect of herbage type and level of herbage intake on the pattern of Crp3 release from CRC. In Experiment 1, differences in CRC plunger travel within and between rumen-fistulated sheep, fed lucerne chaff indoors over 42 days at an allowance equivalent to 1.1 maintenance (M), were not significant. The relationship between plunger travel and time was almost perfectly linear (P < 0.001),but a slight reduction in the rate ofplunger displacement became more pronounced while the animals were at grazing between Day 43 and Day 100. Chromium (Cr) release from Day 3 to Day 42 averaged 62 ± 1 (mean ± SE) mg Cr/day, In Experiment 2, rumenfistulated and intact wethers, housed indoors, were offered ryegrass, white clover, ryegrass-white clover

Differential response to stocking rates and feeding by two genotypes of Holstein-Friesian cows in a pasture-based automatic milking system

“…Cows were orally dosed with gelatin capsules containing 10 g of Cr 2 O 3 , once daily for 10 days at 0700 h. Fecal grab samples were taken once daily for the last 5 days of the dosing period. Fecal samples were dried at 55°C in a forced air oven and ground through a 1 mm screen for analysis of Cr concentration (Parker et al, 1989) by atomic absorption spectroscopy (model 3110; PerkinElmer, Waltham, MA, USA). During the period of DMI determination, additional composite samples of pasture (above a 5 cm height, approximately), PMR and concentrates were collected, processed and analyzed for CP, NDF, ADF and 48-h IVTD, as described previously.…”

Evaluation of the feeding value of Aries HD perennial ryegrass(Lolium perenne).I. Performance of lactating ewes in spring

“…Errors in faecal output can arise from variation in chromium concentration, release rates of Cr 2 O3 from the capsules, and by assay variation (Parker et al 1990a(Parker et al , 1990b. However, the use of a slow release capsule can ensure a uniform release of Cr2O3 into the rumen and reduced diurnal variation in faecal chromium concentration compared with daily dosing (Parker et al 1989). A chromium release rate from a similar experiment (Bluett et al 1997) was used to estimate intake, because the release rate is often dependent on the particular forage and animal being tested (Burns et al 1994).…”

“…Herbage intake was measured during peak lactation from 23 September to 3 October, using intraruminal slow release chromium sesquioxide (Cr2O3) capsules (Captech New Zealand Ltd, Auckland) as described by Parker et al (1989). Chromium capsules were orally administered to each ewe on 16 September.…”

Partial replacement of corn grain with calcium salts of fatty acid in the concentrate fed to grazing primiparous and multiparous dairy cows

“…Pasture DMI was estimated in seven cows and four heifers in each treatment using an indigestible faecal marker (Cr 2 o 3 ) that was dosed as controlled-release capsules of captec® (Nufarm Ltd, Auckland, New Zealand) after 45 days in milk (Parker et al 1989). Cows were dosed with capsules 7 days prior to start of faecal sampling to allow for a steady-state release of cr 2 o 3 .…”

“…Cows were dosed with capsules 7 days prior to start of faecal sampling to allow for a steady-state release of cr 2 o 3 . Faecal grab samples were collected after milking during 7 days and then analysed for cr using an atomic absorption spectrophotometer (Parker et al 1989). Faecal cr concentration was used to calculate total faecal output using the equation:…”