Evaluation of controlled release devices for administration of chromium sesquioxide using fistulated grazing sheep. 2. Variation in rate of release from the device

1990 ◽  
Vol 41 (5) ◽  
pp. 977 ◽  
Author(s):  
EP Furnival ◽  
KJ Ellis ◽  
FS Pickering
Keyword(s):  
Controlled Release ◽  
Dry Matter ◽  
Statistical Correlation ◽  
Faecal Output ◽  
Merino Sheep ◽  
Coefficients Of Variation ◽  
Release Device ◽  
Flow Through ◽  
The Mean ◽  
Release Devices

Merino sheep fitted with rumen cannulae and varying in liveweight, grazed Phalaris aquatica pastures with high and low dry matter mass. One or more controlled release devices were tethered inside the rumen and attached to its cannula. The position of the plunger within the controlled release device was recorded every 2 or 3 days for periods of up to 19 days, and the mean rate of plunger movement was calculated. Faecal output and flow of rumen digesta were measured concurrently in two experiments. Rate of plunger movement was measured in 152 devices and found to be substantially constant over time, but significant differences in mean rate of plunger movement were observed between formulation type, between sheep and between pastures varying in herbage mass. Coefficients of variation between sheep ranged from � 6 to �14%, and differences between pasture means ranged from 1 to 14%. Some of this variation was associated statistically with faecal output; assuming a linear relationship, a change in dry matter output of 100 g/day was associated with a change in plunger rate of 0.05 mm/day or about 6% of the mean rate. Liquid flow through the rumen was the rumen variable which had the highest statistical correlation with the rate of plunger movement.

Evaluation of controlled release devices for administration of chromium sesquioxide using fistulated grazing sheep. 1. Variation in marker concentration in faeces

1990 ◽  
Vol 41 (5) ◽  
pp. 969 ◽  
Author(s):  
EP Furnival ◽  
JL Corbett ◽  
MW Inskip
Keyword(s):  
Controlled Release ◽  
Circadian Variation ◽  
Grab Sampling ◽  
Once Daily ◽  
Gelatin Capsules ◽  
Faecal Output ◽  
Release Device ◽  
Daily Sampling ◽  
Release Devices ◽  
Representative Samples

A group of 10 sheep grazed as a single flock; five were dosed with chromium sesquioxide (Cr2O3) using an experimental controlled release device, and five were dosed twice a day with gelatin capsules. Total faecal output was collected from each sheep over a period of 13 days, and in addition, a sample was taken twice daily from the rectum (grab sample). In a second experiment total faeces were collected every 2 h for 24 h. Total faecal output was compared with estimates of faecal output calculated from the quantity of Cr2O3 in the dose, and the concentrations in representative samples and in grab samples of faeces. An examination was made of the biases in the estimates from these two types of samples for the controlled release devices and for the gelatin capsules. Use of the controlled release devices significantly reduced circadian variation in the Cr2O3concentration in faeces, compared with twice daily dosing with gelatin capsules. Consequently variability was lower and biases in estimates of faecal output were relatively small. Once daily grab sampling from sheep with controlled release devices produced more reliable estimates of faecal output than twice daily sampling from sheep with gelatin capsules.

The influence of various factors on some methods of estimating fibre and follicle population density in the skin of Merino sheep. I. Methods of delineating area of natural skin

1958 ◽  
Vol 9 (2) ◽  
pp. 237 ◽  
Author(s):  
HB Carter ◽  
HN Turner ◽  
MH Hardy
Keyword(s):  
Population Density ◽  
Body Region ◽  
Skin Area ◽  
Sampling Errors ◽  
Density Estimates ◽  
Merino Sheep ◽  
Coefficients Of Variation ◽  
Biopsy Punch ◽  
The Mean ◽  
Influence Measurement

Many factors may influence measurement of skin area for estimation of fibre or follicle population density. This paper analyses the influence of method of delineation (hairpin calliper, Hardy clipper, or Carter biopsy punch), type of sheep (wrinkled or plain), body region, and sheep individuality on the mean density estimated and on the error of estimation. With either a biopsy punch or a 1 in.2 hairpin calliper in the midside region, sampling errors of the order of 8–11 per cent. were found for density estimates in a series of field observations on Merino and Corriedale ewes, with between-sheep coefficients of variation ranging from 13 to 18 per cent.

Chemical fat in the musculature of the sheep carcass

1973 ◽  
Vol 80 (2) ◽  
pp. 219-224 ◽  
Author(s):  
W. J. Pryor ◽  
G. H. Warren
Keyword(s):  
Hind Limb ◽  
Dry Matter ◽  
Mean Value ◽  
Fat Content ◽  
Muscle Group ◽  
Intercostal Muscle ◽  
Merino Sheep ◽  
Acid Lactone ◽  
The Mean ◽  
Muscle Groups

SummaryForty merino sheep of mixed ages including lambs, ewes, wethers and rams were slaughtered and dissected. The chemical fat content often muscle groups in each sheep was measured directly and the mean value for the musculature of the whole carcass calculated.A characteristic pattern of chemical fat deposition was shown with the intercostal muscle group and the abdominal group being consistently highest in fat content, the shin and hind-limb muscles lowest and other intermediate. The pattern of growth of intramviscular fat was consistent with differences in activity of the muscle groups in the maintenance of posture. It was postulated that variations in fat content in muscle groups are affected by differences in blood flow.A highly significant relationship was established between dry matter and chemical fat content for each of the muscle groups. The regression was characteristic for each muscle group, and differed for most groups.Regressions between individual muscle group fat and that of total musculature fat revealed that no group was consistently the best predictor of the total carcass musculature fat though there was considerable difference between the groups. It was concluded there is no group which could be used for prediction purposes commercially.In a group of 14 other ewes subjected to weight loss up to 30%, and half of which were implanted with resorcylic acid lactone, no discernible effects on muscle group fat content were revealed.

Using molasses as an alternative to controlled release devices for administering n-alkane markers to cattle

2003 ◽  
Vol 76 (3) ◽  
pp. 471-480 ◽  
Author(s):  
R. E. Hendricksen ◽  
C. Gazzola ◽  
M. M. Reich ◽  
R. F. Roberton ◽  
D. J. Reid ◽  
...  
Keyword(s):  
Controlled Release ◽  
Block Design ◽  
Extended Period ◽  
Control Treatment ◽  
Delivery Methods ◽  
Dry Matter Digestibility ◽  
Release Device ◽  
Randomized Complete Block Design ◽  
The Individual ◽  
Release Devices

AbstractAn experiment was conducted to determine if molasses could be successfully used to administer dotriacontane (C32) and hexatriacontane (C36) n-alkane markers to steers and to compare this method with a commercially available intra-ruminal controlled release device (CRD). The experiment was conducted over two similar periods (runs) using 24 Brahman crossbred steers in each run to study the effect of marker delivery methods and tropical grass hay diets in a randomized complete block design with three replicates. All steers were housed individually in partially covered pens, received one of two buffel-grass hays (B20: 20-week regrowth; 0·72 g nitrogen (N) per 100 g and B8: 8-week regrowth; 1·11 g N per 100 g) and one of four marker delivery treatments (control: no marker; 200 mg/day of C32 and C36 n-alkanes from a CRD or offered three times (Ms ✕ 3) or five times (Ms ✕ 5) a day in molasses). Voluntary intake (VI) and dry matter digestibility (DMD) for diets differed (P < 0·001) with B8 greater than B20. There was no difference among marker treatments for VI but the control treatment had greater, unexplained and possibly spurious, DMD than the Ms ✕ 3 marker treatment. Although the recovery of n-alkanes was variable (0·84 to 1·05) adjacent odd- and even-chain n-alkanes were similar with no differences (P > 0·05) due to marker treatment or diet. The CRD supplied a consistent marker dose between 6 and 18 days after insertion. Deviation from the 24-h mean faecal concentration seldom varied more than 0·03 for the individual markers and 0·05 for C31/C32 and C33/C32 ratios for all treatments. Over all the n-alkanes studied, the between-day variation was less than the within-day variation. For instance, the average of subsamples taken at 06:00 h and 18:00 h was within proportionately 0·05 of the 10-day mean concentration for 0·38 and 0·25 of records for C32 and C36 markers, respectively. It was concluded that molasses containing C32 and C36 n-alkane markers and given either three or five times daily was as accurate as the commercial CRD in administering n-alkane markers to steers and provides a method of delivering n-alkanes over an extended period in grazing studies.

scholarly journals Estimation of faecal output, digestibility, and intake using a controlled release capsule of alkanes in early and late lactation dairy cows fed two levels of concentrate

2004 ◽  
Vol 84 (2) ◽  
pp. 277-289 ◽  
Author(s):  
D. R. Ouellet ◽  
H. V. Petit ◽  
D. M. Veira ◽  
E. Charmley
Keyword(s):  
Controlled Release ◽  
Dairy Cows ◽  
Key Words ◽  
Dry Matter ◽  
Faecal Output ◽  
Lactation Stage ◽  
Using Data

Thirty-two dairy cows (663 ± 70; kg of BW ± SD) were allotted to a 2 × 2 factorial arrangement of treatments to evaluate the controlled release alkane capsule (CRC; C32 and C36) to estimate digestibility and dry matter (DM) intake in early and late lactation for diets based on low (LC, 30%) or high (HC, 60%) proportions of concentrate. Cows were dosed orally with a CRC into the rumen and digestibility was measured by total collection and estimated from the ratios of alkanes in the diet and faeces. Recoveries of endogenous (C31 and C33) and exogenous (C32 and C36) alkanes were higher and lower, respectively, for LC compared with HC. The effects of diet and the interaction between diet and lactation stage were well estimated (P < 0.05) when measured released rates of C32 and C36 were used to estimate DM digestibility although estimation with both alkanes indicated an effect of lactation stage, which was not observed when using data of measured DM digestibility. The faecal ratio of C31/C32 or C33/C32 showed no diet effect on DM intake estimation while measured DM intake was 22.6% higher for cows fed HC than for those fed LC. In conclusion, estimation of DM intake was inadequate although digestibility of DM was estimated from alkanes contained in the CRC. Key words: Dairy cows, alkane, intake

Evaluation of techniques for estimating the yield of irrigated pastures intensively grazed by dairy cows. 1. Visual assessment

1984 ◽  
Vol 24 (126) ◽  
pp. 300 ◽  
Author(s):  
CR Stockdale
Keyword(s):  
Dairy Cows ◽  
Dairy Cow ◽  
Dry Matter ◽  
Sampling Technique ◽  
Visual Assessment ◽  
Sampling Procedure ◽  
Double Sampling ◽  
Assessment Technique ◽  
Coefficients Of Variation ◽  
The Mean

A visual assessment technique was evaluated for estimating pre- and post-grazing pasture yields in experiments in which dairy cows rotationally graze irrigated pastures. Visual assessment, when associated with the harvesting of standard quadrats, accounted for 62.3 and 68.4% of the variability in pre- and post-grazing yield, respectively. The mean residual standard deviations associated with the pre- and post-grazing regressions were 490 and 395 kg dry matter/ha and, when the variable yields were taken into account, these represented coefficients of variation of 15.6 and 19.0%, respectively. By using the coefficient of variation as the criterion for precision, pre-grazing regressions were significantly more precise than post-grazing regressions. In practice, visual assessment by a double sampling procedure can be used to estimate pre- and post-grazing yields in dairy cow grazing experiments where herbage intakes and growth rates are required, provided sufficient readings are taken to allow an acceptable level of precision. It is suggested that about ten standards are required to formulate a calibration regression regardless of whether or not the pasture to be assessed has been grazed. Although the double sampling technique may be suitable for research purposes, it has been demonstrated that the completely subjective eye appraisal, often used by farmers and their advisers for feed budgeting, can result in many incorrect assessments. A more objective technique needs to be developed for this purpose.

The Use of Chromic Oxide in the Measurement of Individual Feed Intake in Cattle Fed on Silage and Barley

1970 ◽  
Vol 12 (1) ◽  
pp. 71-80 ◽  
Author(s):  
J. M. Wilkinson ◽  
J. H. D. Prescott
Keyword(s):  
Diurnal Variation ◽  
Feed Intake ◽  
Dry Matter ◽  
Live Weight ◽  
Chromic Oxide ◽  
Faecal Output ◽  
Grass Silage ◽  
The Mean ◽  
Ad Libitum ◽  
Mean Concentration

SUMMARY1. Three experiments are reported in which chromic oxide, administered as a component of shredded paper at 09·00 and 16·30 hr daily, was used in the estimation of the faecal output of steers fed on silage and barley.2. Four Friesian steers of 160 kg live weight were used in experiment 1. They were fed on grass silage ad libitum with controlled allowances of concentrate supplement. ‘Absolute’ recovery of Cr2O3 in total collections was 85–91%, though it was apparent that some faeces may have been lost from the total collections. ‘Relative’ recovery in grab samples was 97%.3. Diurnal variation in Cr2O3 excretion was investigated in experiment 2 with four yearling Friesian steers. Faeces were sampled in three 24-hr periods at each natural defaecation. A significant and consistent diurnal variation was observed, with the lowest concentration of Cr2O3 occurring during the night. Concurrent grab samples taken at 09.15 and 17.00 hr over four days gave estimates of cr2O3 in the faeces which were 16·27% higher than the mean concentration for the three 24-hr sampling periods.4. Day-to-day variation in the Cr2O3 content of grab samples was examined in experiment 3 with eight yearling Friesian steers. Four steers received 3·63 kg/head per day of barley supplement and four received 1·81 kg. Both groups were offered silage of 25% dry matter ad libitum. Faeces were sampled per rectum twice daily at 09.15 and 17.00 hr over four-day sampling periods. The degree of day-to-day variation was small and tended to be random.

Factors influencing the release rate of alkanes from an intra-ruminal, controlled-release device, and the resultant accuracy of intake estimation in sheep

2002 ◽  
Vol 53 (6) ◽  
pp. 681 ◽  
Author(s):  
H. Dove ◽  
R. W. Mayes ◽  
C. S. Lamb ◽  
K. J. Ellis
Keyword(s):  
Controlled Release ◽  
Release Rate ◽  
Feeding Frequency ◽  
Release Rates ◽  
Castrate Male ◽  
Once Daily ◽  
Faecal Output ◽  
Factors Influencing ◽  
Herbage Intake ◽  
Release Devices

Two experiments were conducted to evaluate factors influencing the release rate of octacosane (C28) and dotriacontane (C32) synthetic alkanes from controlled-release devices (CRD) inserted into the rumen of sheep, and the resultant accuracy of alkane-based estimates of herbage intake. In the first experiment, estimates of the rate of release of alkanes from CRD suspended in the rumen of 7 rumen-fistulated ewes were obtained by directly measuring the rate of CRD plunger travel. In the second experiment, CRD were administered orally to 24 castrate male sheep to evaluate the effects of level of feeding (1200 v. 600 g DM/day), frequency of feeding (continuous v. once-daily), and number of CRD inserted (1 v. 2) on temporal trends in faecal alkane concentrations and ratios and on the accuracy of estimation of intake. In both experiments, animals were also dosed orally, once daily with paper pellets containing 56 mg hexatriacontane (C36). In Expt 1, linear alkane release from the CRD commenced after a lag period of 2-3 days, at mean rates of 40.1 mg/day (C28) and 41.7 mg/day (C32), close to the desired rates of 40 mg/day. There was no evidence of curvilinearity, and differences in release rate between sheep were small (CV 4.1%). Alkanes attributable to the CRD appeared in faeces after 2-3 days and reached plateau concentrations by 6-7 days. Data are presented to indicate that the release rate was not affected by the removal of CRD from the rumen for measurement, and that the release rates in fistulated (Expt 1) and intact sheep (Expt 2) were similar. In Expt 2, there was no effect of level of feeding on CRD release rates and faecal alkane concentrations were consistent with the differences in faecal output caused by feeding level. As a result, the accuracy with which known intakes were estimated was unaffected by level of feeding. Similarly, there were no effects of feeding frequency on the accuracy of estimated intake, implying that in this study, feeding frequency had no effect on CRD release rates. The administration of 2 CRD to half the animals in this experiment increased faecal concentrations of C28 and C32 and the synthetic : herbage alkane ratios associated with these alkanes [e.g. faecal C32 : tritriacontane (C33)] but these changes were not significantly different from those expected from the release rates estimated in Expt 1. As a result, the accuracy with which known intakes were estimated was not influenced by the number of CRD administered. In both experiments, once-daily dosing with C36 alkane resulted in a more rapid rise in faecal C36 concentrations and faecal C36 : pentatriacontane (C35) ratios to maximal levels (3-4 days), compared with alkanes derived from the CRD (6-7 days), but thereafter, faecal C36 concentrations were much more variable, especially in the fistulated sheep. As a result, intake estimates based on the C36 : C35 alkane pair significantly over-estimated known intakes by 13% (Expt 1) and 8% (Expt 2). Data are presented to indicate that C36 alkane functioned satisfactorily as a faecal output marker and, with C32 : C33 estimates of intake, provided accurate estimates of herbage digestibility. The results indicate that intra-ruminal controlled-release devices provide a satisfactory means of delivering an accurate, daily dose of alkanes for the estimation of herbage intake, faecal output, and digestibility in sheep.

Circadian variation in composition of duodenal and ileal digesta from pigs fitted with T-cannulas

1986 ◽  
Vol 43 (1) ◽  
pp. 133-140 ◽  
Author(s):  
H. Graham ◽  
P. Åman
Keyword(s):  
Gastrointestinal Tract ◽  
Crude Protein ◽  
Dry Matter ◽  
Circadian Variation ◽  
Live Weight ◽  
Sampling Period ◽  
Coefficients Of Variation ◽  
The Mean ◽  
Dietary Components ◽  
Composite Samples

ABSTRACTCircadian variation in the composition of digesta was examined in pigs fitted with replaceable T-cannulas in the proximal duodenum and terminal ileum. The pigs were fed twice daily with a cereal-based diet containing Cr2O3, as a marker. Digesta were collected hourly for 16 h following morning feeding (pig live weight (LW) 25 and 65 kg) or as a 12-h composite collection (pig LW 45 kg), and analysed for pH, dry matter (DM), ash, crude fat, crude protein, starch, neutral-detergent fibre (NDF) and Cr2O3,.No statistically significant differences were found in the composition of digesta from pigs weighing 25 or 65 kg LW. Calculated relative to Cr2O3, recoveries in 12-h composite samples of duodenal and (ileal) digesta were 1·19 (0·34) for DM, 1·28 (0·31) for crude protein, 0·97 (0·05) for starch and 0·93 (0·79) for NDF. Composition of both duodenal and ileal digesta varied considerably during the sampling period and was particularly influenced by giving food. Between-hour coefficients of variation for the samples taken hourly were, in general, greater at the duodenum (mean 017) than at the ileum (mean 0·11), while mean within-hour (between pigs) coefficients of variation (0·19 and 0·18, respectively) were greater than those between hours. The Cr2O3 marker generally followed the flow of dietary matter through the gastrointestinal tract, although there was an indication of a partial separation of NDF from other dietary components in the stomach. Composition of the 12-h composite samples of digesta did not differ from that of the mean of the samples taken hourly for 16 h.

Stochastic homogenization and macroscopic modelling of composites and flow through porous media

2002 ◽  
pp. 337-378 ◽  
Author(s):  
Jozef Telega ◽  
Wlodzimierz Bielski
Keyword(s):  
Porous Medium ◽  
Random Distribution ◽  
Flow Through Porous Media ◽  
Macroscopic Models ◽  
Linear Elastic ◽  
Multi Scale ◽  
Convergence Method ◽  
Flow Through ◽  
The Mean ◽  
Random Porous Medium

The aim of this contribution is mainly twofold. First, the stochastic two-scale convergence in the mean developed by Bourgeat et al. [13] is used to derive the macroscopic models of: (i) diffusion in random porous medium, (ii) nonstationary flow of Stokesian fluid through random linear elastic porous medium. Second, the multi-scale convergence method developed by Allaire and Briane [7] for the case of several microperiodic scales is extended to random distribution of heterogeneities characterized by separated scales (stochastic reiterated homogenization). .

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