The Effect of Amount Offered on Selection and Intake of Barley Straw by Goats

Author(s):  
R.A. Waned ◽  
E. Owen

The conventional method of measuring ad libitum intake of roughages involves offering sufficient (usually in chopped form) to ensure that 15 to 20% is left at the end of the feeding period (Blaxter et al 1961). Earlier experiments (Waned and Owen, 1986) with goats and sheep fed long roughages ad libitum (allowing 20% of feed offered to be refused) showed both species to be capable of selective feeding, in that refusals had a lower nutritive value than feed offered. The latter study and that of Glbb and Treacher (1976) with grazing sheep, suggested that selection and hence intake of roughage would increase if the amount offered (and hence refusal rate) was increased.To test this hypothesis two experiments were conducted with housed (16 hours light, 8 hours dark), individually penned Saanen castrate goats ranging in weight (15 to 65 kg) and age (6 to 30 months). Animals were fed restricted amounts of concentrates (15 g dry matter (DM) per kg M0.7S daily) and long barley straw ad libitum.

1973 ◽  
Vol 24 (6) ◽  
pp. 939 ◽  
Author(s):  
SC Valentine ◽  
DC Brown

Formaldehyde-treated silage, formic acid-treated silage, formaldehyde-formic acid-treated silage, untreated silage, and lucerne hay were made from a lucerne sward and offered to Merino wethers. The formaldehyde was applied at a rate of 0.9 % of the weight of the dry matter and formic acid at 0.5 % of the fresh weight of the lucerne. Formaldehyde-treated silage and formaldehyde-formic acid-treated silage had significantly lower concentrations of ammonia nitrogen and total and individual organic acids than untreated silage. Formic acid-treated silage had a similar degree of fermentation to untreated silage, but more acetic acid and less lactic acid were produced than in untreated silage. However, when formic acid was applied in combination with formaldehyde, the ensiling fermentation was inhibited more than when formaldehyde was applied alone. There was some apparent protection of protein by the formaldehyde treatment. Treatment with formic acid significantly increased the in vivo digestibility of both nitrogen and dry matter, but did not increase ad libitum intake or wool growth by sheep offered this silage. Compared to untreated silage, treatment with formaldehyde significantly reduced the in vivo digestibility of nitrogen, produced a non-significant increase in intake, and significantly increased wool growth. The treatment of lucerne with both formaldehyde and formic acid significantly increased in vivo digestibility of dry matter, ad libitum intake, and wool growth compared with untreated silage. The treatment of lucerne with a mixture of formaldehyde (0.9% of the dry matter) and formic acid (0.5% of the fresh weight) was a suitable method of controlling the ensiling fermentation in order to increase the ad libitum intake of lucerne silage by sheep and their subsequent wool production. However, the intake and wool production of sheep offered such silage was still significantly less than that of sheep offered lucerne hay.


1973 ◽  
Vol 53 (2) ◽  
pp. 257-263 ◽  
Author(s):  
G. PELLETIER ◽  
E. DONEFER

Three yearling Cheviot × Suffolk ewes and three Columbia wethers were confined in metabolic cages and fed ad libitum fresh and dried marrow-stem kale (Brassica oleracea var. acephala D.C.) harvested in mid- and late October. Chemical analyses of the forages indicated no marked effects on any of the plant constituents due to drying or advancing maturity. Digestibility measurements demonstrated that marrow-stem kale (MSK) was a highly digestible material with an average dry matter digestibility of 78%. The fresh forages had higher (P < 0.05) dry matter and gross energy digestibility values than the dried form. Dry matter digestibility coefficients were higher (P < 0.05) for late October as compared with the earlier harvest. A trend toward higher (P > 0.05) voluntary intake values due to drying maturity was observed with an average relative intake of 80%. The nutritive value index averaged 65, thus indicating a digestible energy intake similar to a high-quality (legume) forage.


1985 ◽  
Vol 36 (3) ◽  
pp. 483 ◽  
Author(s):  
JK Egan ◽  
PT Doyle

Six mature Merino sheep received three treatments in a randomized block design experiment. The treatments were: chopped oaten hay diet at 90% of ad libitum intake without urea (L); the ciet offered at the same level as for L with urea infused into the rumen at 11.5 g kg-1 dry matter intake (LU); and the diet offered at 90% of the ad libitum intake achieved with urea infused at 11.5 g kg-1 dry matter intake (HU). Sheep given HU consumed 37% more (P < 0.01) organic matter (OM) than those fed L or LU, but the apparent digestibility of OM did not vary (59.2-61.8%) between treatments. The addit onal food consumption was associated with c. 20% increase (P < 0.05) in the weight of OM in the reticulorumen and significantly higher (by 10-35%; P < 0.05) fractional outflow rates of most dietary and microbial constituents of digesta. The fractional digestion rate of potentially digestible plant cell walls was not affected by urea, but the flow of microbial non-ammonia nitrogen from the abomasum was enhanced (L, 7.0; LU, 8.2; HU, 12.5 g day-1; P < 0.05). The results of this study suggest that the stimulatory effect of urea upon food intake was associated with the provision of additional microbial protein for digestion in the intestines, rather than changes in the rate or extent of organic matter fermentation in the reticulorumen.


1988 ◽  
Vol 47 (1) ◽  
pp. 105-110 ◽  
Author(s):  
P. K. Bhargava ◽  
E. R. Ørskov ◽  
T. K. Walli

AbstractExperiments were made to study the proportion, chemical composition, and rumen degradability of the morphological components of barley straw (Corgi variety) and to study the selection of these components by sheep. The proportions in the harvested straw dry matter (DM) as leaf blade, leaf sheath, stem and chaff were 128, 314, 500 and 58 g/kg DM, respectively. The different components of straw on analysis proved to have very different concentrations of nitrogen and neutral-detergent cellulase digestibility. The leaf blades had the highest and the stems the lowest values. The degradabilities of DM in the components and in the whole straw were determined by measuring DM loss from samples incubated in nylon bags for various periods in the rumen of sheep. Responses were measured using the mathematical model p = a+b (1–e−ct) where p is DM loss, (a+b) potential degradability, c the rate constant of DM loss and t is the time of incubation. DM losses decreased in the order leaf blades > leaf sheath > whole plant > chaff > stems. Leaf blades also had the highest potential degradability and rate of degradation.In another trial, five sheep were offered unchopped barley straw ad libitum. There were five treatment periods in which sheep were allowed to leave uneaten proportionately 0·2, 0·3, 0·4, 0·5 and 0·7 of the straw on offer for assessing the animal's selection of the morphological components of that straw. The amount of leaf blade in the material consumed increased in largely a linear (P < 0·01) fashion with the amount of excess allowance. The proportion of stem eaten varied conversely. The selection of leaf sheath was less apparent. Little stem was consumed until the proportion of leaf blade in the food available decreased below proportionately 0·4. The practical significance of the study is discussed.


2008 ◽  
Vol 15 (3) ◽  
pp. 235 ◽  
Author(s):  
P. PURSIAINEN ◽  
M. TUORI

The effect of replacing wilted grass silage (GS) with pea-barley intercrop silage (PBS) on feed intake, diet digestibility and milk production was studied with 8 multiparous Ayrshire-cows in a replicated 4 × 4 Latin square experiment. Proportion of PBS was 0 (PBS0), 33 (PBS33), 67 (PBS67) or 100 (PBS100) % of silage dry matter (DM). The DM content was 559 and 255 g kg-1 for GS and PBS. Crude protein content was 131 and 170 g kg-1 DM, respectively. Pea-barley silage was more extensively fermented than GS with total fermentation acid content of 120 vs. 12 g kg-1 DM. Silage was fed for ad libitum intake and supplemented with on the average 13 kg concentrate per day. Silage DM intake was 9.2 (PBS0), 9.7 (PBS33), 9.0 (PBS67) and 7.1 (PBS100) kg per day (Pquadr. < 0.05). The energy corrected milk yield [30.3 (PBS0), 29.8 (PBS33), 30.3 (PBS67), 31.3 (PBS100) kg per day] was not significantly affected by the treatment. Milk protein concentration decreased linearly (P < 0.05) in response to feeding PBS. It is concluded that PBS can replace up to two thirds of wilted, moderate quality GS in the feeding of dairy cows because in this experiment pure pea-barley silage reduced silage intake.


1978 ◽  
Vol 91 (2) ◽  
pp. 483-486 ◽  
Author(s):  
E. R. Ørskov ◽  
D. A. Grubb

SUMMARYMilled barley straw, either untreated or treated with 70 g of NaOH/kg straw was supplemented with four levels of urea, namely 0, 6, 12 or 18 g/kg and fed ad libitum to young sheep. For the untreated straw, dry-matter intakes were (g/day) 423, 451, 441 and 463, while the digestibility of organic matter was 458, 467, 490 and 483 g/kg, respectively. For the treated straw, the intakes of dry matter were 355, 402, 531 and 567 g/day and the digestibility of organic matter was 423, 480, 589 and 628 g/kg respectively.The different responses to urea supplementation of treated and untreated straw are discussed in relation to a new system of estimating protein requirements for ruminants put forward by the Agricultural Research Council.


1999 ◽  
Vol 68 (1) ◽  
pp. 211-215 ◽  
Author(s):  
J. E. Velasquez ◽  
E. Owen ◽  
F. L. Mould

AbstractA 28-day experiment with 12 9-month-old cattle (275 kg initial weight, M1), used a 2 × 2 arrangement of treatments to compare the effect of doubling the ad-libitum quantity of long barley straw offered daily (25 or 50 g dry matter (DM) per kg M1) and sex/genotype (Limousin × Friesian steers or Friesian heifers) on intake and selection. All animals received a protein concentrate at 20 g DM per kg M10·75 per day. Prior to the experiment the cattle had grazed for 6 months and were given no pre-experimental change-over period. On day 1 animals were weighed (M1), allocated to treatment and penned individually. Animals were weighed on day 28 (M2). Doubling the amount offered did not affect straw intake (g DM per kg M3 per day; M3 = mean of M1 and M2) during days 22 to 28 (steers: 17·9, 17·2; heifers 14·3, 13·3; s.e. 0·50) but increased the proportion (g DM per kg DM offered) refused (steers: 258, 635; heifers: 412, 721; s.e. 22). During days 22 to 28, at each level of offer (25, 50), refused straw contained (g DM per kg DM) less leaf-plus-sheath than offered straw (25 g steers: 251, 430, s.e. 16·7; 50 g steers: 393, 450, s.e. 19·7; 25 g heifers: 304, 420, s.e. 7·2; 50 g heifers: 405, 446, s.e. 9·6). The sex/genotype effect on intake was attributed to differences in growth potential. Straw intakes increased significantly over the first 14 days, but there were no differences between days 15 to 21 and days 22 to 28. It is concluded that an excess-feeding strategy, involving a doubling of the ad libitum amount of barley straw offered did not result in growing cattle consuming more straw, in contrast to published results with sheep and goats. However, the cattle did show a limited ability to selectively consume leaf-plus-sheath in preference to stem but the improvement in diet digestible organic content (estimated in vitro) was presumably insufficient to stimulate intake.


Author(s):  
Md. Shahiduzzaman ◽  
E. Owen

Calcium hydroxide (Ca(OH)2) is widely available in Third World countries because of extensive limestone deposits. Previous studies (reviewed by Owen et al 1984) have shown Ca(OH)2-treated straw to be prone to mouldiness and low intakes. Urea was added to Ca(OH)2 in the present study to inhibit mould and supply nitrogen. Two experiments are reported which investigated the amounts of Ca(OH)2 and urea required for improving intake and digestibility of barley straw in sheep.Forty Suffolk x Mule store lambs (20 castrates, 20 ewe lambs) aged 8 months were used to measure intake and digestibility of 5 straws (Table 1) in a randomized block experiment, with blocking according to weight and sex. Animals were fed restricted concentrates (Table 1) and ad libitum straw (allowing refusals of 25% of intake) over a period of 35 days, with collection of faeces over the last 8 days. For treatment, straw was chopped, mixed with chemical solutions (Table 1) in a concrete mixer, and “ensiled” for 60 days (September & October) at 500 g dry matter (DM) per kg, in plastic bags contained in 45-gallon oil drums. Straw was aerated for 3 days before feeding. Untreated straw was simply chopped before feeding.


1995 ◽  
Vol 46 (8) ◽  
pp. 1579 ◽  
Author(s):  
JF Perez ◽  
J Gasa ◽  
C Castrillo ◽  
JA Guada

Rates of passage of liquid and particulate markers (Co-EDTA, Cr mordanted fibres and Yb) were measured in ewes at late pregnancy, lactation and non-breeding status. Animals were given ammonia treated barley straw ad libitum supplemented daily with 250 and 550 (pregnancy), 550 and 850 (lactation) and 250, 550 and 850 (non-breeding) g of concentrate. The effect of the reproductive state was analysed only on ewes fed on 550 g of concentrate. Lactating ewes showed a higher voluntary straw intake (970 g/day) than pregnant or non-breeding ewes (720 and 790 g/day respectively), but there were not significant differences in the OM digestibility (OMD) among reproductive states. Increasing concentrate supplementation promoted significant decreases in the voluntary intake of straw, associated with an enhanced OMD ( P < 0.05). Fractional outflow rates (FOR/h) were higher in pregnant and non-breeding than in lactating ewes, although differences were only significant ( P < 0.01) for Chromium derived values. Ewes given 250 g of concentrate showed lower ( P < 0.05) FOR than those given 550 and 850 g/day. Results support the idea that in ruminants fed on low quality roughages, voluntary dry matter intake is mainly restricted by rumen capacity, although the energy status of the animals might influence the extent of this restriction.


1976 ◽  
Vol 16 (82) ◽  
pp. 656 ◽  
Author(s):  
H Jeffery

Three experiments were conducted in which the amount of feed offered to caged sheep was varied. Fresh kikuyu grass (Pennisetum clandestinum) was fed in one experiment and hays in the other two. Within each experiment a significant correlation between dry matter digestibility and liveweight occurred; no differences were detected between the slopes found with the various diets (slope = 0.34 per cent increase in digestibility per kg liveweight). Up to 60 per cent more kikuyu grass was offered to sheep than they could consume. Over this range a significant positive correlation was found between the ratio of the unconsumed to consumed feed and digestibility. This result indicates that great care should be exercised if the results of sheep digestibility experiments are used to interpret field data.


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