Differences In Voluntary Intake Research Articles

Effect of pelleting crop residues on feed intake and digestibility in Djallonke sheep in North-sudanian zone of Burkina Faso

The effect of pelleting fodder on voluntary feed intake and digestibility in sheep was tested with sorghum straw and cowpea haulm in two forms (chopped and granulated). Twenty-four (24) sheep, of 18 to 24 months old, Djallonké breed were divided into 4 groups of 6 sheep following a random complete block device with four (04) treatments as follows: R1= 50% chopped sorghum straw + 50% chopped cowpea haulms, R2 = Granulated feed 1 (50% sorghum straw + 50% cowpea haulms), R3 = 50% chopped sorghum straw + 50% maize bran and R4 = Granulated feed 2 (50% chopped sorghum straw + 50% maize bran). Six (6) sheep per group underwent the intake trial, then consecutively five (5) sheep per group were retained and housed in digestibility cages for the digestibility test. The voluntary intake of dry matter varied from 417.5 g/d for ration 3 to 600.5 g/d for ration 2. In terms of nutrient intake, ration 1 (75. 26g) records the highest intake of crude protein, followed by ration 2 (70.15g). There is no difference in voluntary intake within rations with forage chopped (R1 and R3) and pellet rations (R2 and R4). The digestibilities of DM and OM are lower with R2, followed by R4; on the other hand, R1 and R3 showed the best levels of digestibility. The crude protein digestibility value is higher for R1 than for the others. The grounding and pelleting of forage did not improve the intake and digestibility of the rations. Additional studies are needed, especially on the size of ground feed, in order to better elucidate the nutritional value of pelleted fodder.

Effect of exogenous fibrolytic enzymes supplementation on nutrient intake and digestibility in Black Bengal kids

The present study was carried out to evaluate the effect of supplementation of exogenous fibrolytic enzymes (EFE) to the Total Mixed Ration (TMR) at two different levels on intake, nutrient digestibility and nutrient availability in Black Bengal kids. A digestibility trial was conducted on 15 post-weaned Black Bengal kids divided into three groups. Control (T0) group was fed ad lib. TMR was prepared from concentrate mixture and green fodder @ 40: 60 on DM basis. T1 and T2 groups were supplemented with EFE cellulase and xylanase @ 8000 and 16000 IU/kg TMR DM and 12000 and 24000 IU/kg TMR DM, respectively. The study revealed significantly higher digestibility of nutrients, i.e. DM, OM, EE, NDF, ADF, hemicellulose, cellulose and total carbohydrates in both enzyme supplemented groups than the control group. However, the digestibility of CP, cellulose and hemicellulose was significantly higher only in T2 group than the control. There was no significant difference between two enzyme supplemented groups in terms of digestibility of different nutrients except for CP which was significantly higher in T2 than T1. The difference in voluntary intake of DM and OM were non-significant but the intake of CP, DCP and TDN were higher in enzyme supplemented groups. Similarly, TDN, DE and ME content of the diet were also higher in two enzyme supplemented groups than control. However, there was no significant difference between T1 and T2 in terms of nutrient availability and intake. Based on the present study, supplementation of EFE @ cellulase 8000 and xylanase 16000 IU/ kg DMwas found to be optimum for improving the nutrient digestibility and availability in Black Bengal kids, which may further improve the productive and reproductive performance of the animals.

Digestibility and palatability of Virginia fanpetals (Sida hermaphrodita R.) silage in sheep.

The aim of the current study is to evaluate Virginia fanpetals silage based on an apparent digestibility and palatability test performed on six adult rams. Alfalfa silage was used as standard forage for comparison. Virginia fanpetals samples were harvested in the bud-formation stage and alfalfa samples were harvested in the late bud stage. Virginia fanpetals silage had a crude protein (CP) content of 176 g kg dry matter (DM), a neutral detergent fiber (NDF) content of 378 g kg DM, and a lignin content of 42.8 g kg DM. Virginia fanpetals silage had higher acidity (pH of 4.30) and was characterized by intense lactic acid fermentation compared with alfalfa silage (80 % vs. 51 % of the total acids). The digestibility coefficient of Virginia fanpetals silage was as follows: for DM it was 0.707, for organic matter (OM) it was 0.724, for CP it was 0.861, and for NDF it was 0.609. In comparison with alfalfa silage, Virginia fanpetals silage was characterized by higher apparent digestibility of nutrients, but a significant difference was noted only for CP. The voluntary intake of Virginia fanpetals silage was significantly higher than that of alfalfa silage (1427.4 vs. 954 g DM). The greatest differences in voluntary intake were observed 0–2 and 8–12 h after feeding. Virginia fanpetals silage had a chemical composition similar to that of alfalfa, but it was characterized by a more desirable fermentation pattern and higher digestibility, and it was more willingly consumed by rams. The present findings indicate that Virginia fanpetals silage can be fed to sheep.

Whole-grain cereal voluntary intake and preference in Japanese quail (Coturnix coturnix japonica)

Japanese quail (Coturnix coturnix japonica) usually fed on ground or pelleted balanced feeds, while whole grains are supplied in alternative systems. Voluntary intake and preference of four whole-grain cereals (durum wheat, bread wheat, triticale and barley) were assessed in Japanese quails. Two experiments were performed: (i) a trial with five batches of six randomly selected quails (three males, three females) allocated to each treatment consisting of one cereal or a balanced feed (control) in the voluntary intake experiment; and (ii) a trial with four bird batches receiving simultaneously the four cereals in the preference experiment. Three repetitions of each trial were performed. When feedstuffs were provided as a sole feed, voluntary feed intake differed, being the highest in quails fed the balanced feed (20.0 g/d), intermediate for durum wheat (15.0 g/d), bread wheat (15.8 g/d) or triticale (15.6 g/d), and the lowest for barley (12.1 g/d). Voluntary intake did not differ between sexes. Positive correlations existed between voluntary feed intake and live weight of quails, being the highest and very strong for the balanced feed, moderate for durum and bread wheat and barley, and weak for triticale. The preference trial showed that quails preferred durum wheat (7.1 g/d), triticale (4.0 g/d), bread wheat (3.0 g/d) and barley (0.3 g/d) in descending order, independently of sex. Positive correlations existed between daily feed intake and live weight of birds for durum and bread wheat. Strong positive correlation existed between bird live weight and total intake when the four cereals were available simultaneously. Differences in voluntary intake and preference among whole-grain cereals should be take into account when used to feed quails.

Sows’ preferences for different forage mixtures offered as fresh or dry forage in relation to botanical and chemical composition

Providing forage to feed-restricted pregnant sows may improve their welfare by reducing their high feeding motivation. The aim of this study was to determine sows’ preferences for four forage mixtures cultivated in Canada. Forage mixtures were compared when offered either fresh or dry. The four forage mixtures were composed of different proportions and species of legumes (alfalfa (Alf) or red clover (Clo)) and grasses (tall fescue (F) and/or timothy (T)): (1) Alf-F, (2) Alf-F-T, (3) Clo-T and (4) Clo-F-T. Voluntary intake was measured, and preference tests were carried out for two experiments: one in spring for fresh forages ( n = 8) and the other in autumn for hays ( n = 8) with different sows housed in individual pens and fed a concentrated diet meeting their nutritional requirements for maintenance and foetal growth. Voluntary intake was measured by offering each forage mixture separately (one forage mixture/day) during 90 min according to a 4 × 4 Latin square design replicated four times. During preference tests, all six combinations of two forage mixtures were offered once (one combination/day) for 45 min to each sow. Individual forage intake was measured, and feeding behaviour was observed. Forages were analysed for botanical and chemical composition. Difference in voluntary intake among the four forage mixtures was determined using a variance analysis followed by Tukey tests for post hoc comparisons. In preference tests, differences between the two forage mixtures offered were determined using a paired Student’s t test, and the most ingested forage mixture was considered the preferred one. Results from both experiments revealed clear preferences for some forage mixtures when offered either fresh or dry. Forage mixtures with a greater proportion of legumes (AlfT and CloT) were preferred over forage mixtures with a higher proportion of grasses (AlfFT and CloFT). The AlfFT and CloFT forage mixtures contained at least 30% of fescue; therefore, the greater preference for the AlfT and CloT forage mixtures could also be due to the absence of fescue. Sows preferred forages with low DM and NDF concentrations and high CP and non-structural carbohydrates concentrations. Based on results from previous studies, the preferences seen in the present study are most likely due to the greater proportion of legumes, although an effect of tall fescue in preference cannot be excluded. Therefore, offering forages with a high proportion of legumes would be a good strategy to maximise both fresh and dry forage intake in pregnant sows.

The effect of feeding animals ad libitum vs. at maintenance level on the in vivo digestibility of mown herbage from two permanent grasslands of different botanical composition

AbstractThe aim of this experiment was to study the effect of feeding level (FL) on the digestibility of unconserved forage obtained from two permanent grasslands cut at three different dates during the first cycle of growth. Forage was offered to Texel sheep (wethers), at maintenance level and at ad libitum level. Differences in voluntary intake (VI) between grasslands were also tested. Organic matter digestibility (OMD) measured at ad libitum level and at VI was 13% higher on harvested forage from grassland rich in forbs (GRF) than grassland rich in grasses (GRG) at early herbage growth stages, but these differences were no longer found at later maturity stages. In GRF, there were no differences for OMD, at either FL at the young growth stages, but at the end of the cycle the OMD obtained at ad libitum level (0·56) was higher than that at maintenance level (0·50). However, in GRG, at an early stage of forage maturity, OMD at ad libitum level (0·67) was lower than that at maintenance level (0·70), but this difference was no longer found at the end of the growth cycle. In conclusion, the effect of FL on the digestibility of unconserved forage from permanent grasslands depends on the type of grassland. These differences are mainly explained by the different botanical composition of the grassland types.

Orchardgrass Ley for Improved Manure Management in Wisconsin: II. Nutritive Value and Voluntary Intake by Dairy Heifers

Confinement dairy feeding operations in the Upper Midwest could benefit from using a wider range of forages than alfalfa (Medicago sativa L.) and corn silage (Zea mays L.). A short‐term ley of orchardgrass (Dactylis glomerata L.) (OG) frequently treated with manure, was compared with corn silage (CS) in a 2 × 2 factorial trial conducted across 3 yr at two locations in Wisconsin. Nutrients were applied as either manure (M) or fertilizer (F) to meet crop N needs. Weighted on the basis each cut contributed to the total annual yield of OG, concentrations of crude protein (163 g kg−1) and 48‐h neutral detergent fiber (NDF) digestibility (657 g kg−1 NDF) were suitable for incorporation into the diets of dairy cows (Bos taurus) and replacement heifers. Tissue concentrations of P and K were 3.7 and 32.0 g kg−1, respectively. High tissue concentrations of P can help with soil‐test P drawdown, and reduce purchases of supplemental dietary P. Although heavy manuring resulted in high tissue K, especially in late‐season cuts, K concentrations were not significantly greater in the hay‐production years relative to the seeding year in either M or F. Based on results with 483 ± 37.6 kg Holstein heifers, there were no differences in voluntary intake by heifers offered commercially fertilized compared to manured OG hays. These results indicate that an OG ley system could be part of a larger alfalfa–corn silage rotation, providing confinement dairies with an alternative forage option, and additional manuring opportunities during summer months.

Effect of breed and age on the voluntary intake and the micromineral status of non-pregnant sheep: 1. Estimation of voluntary intake

Twenty-four sheep were used to test breed and age differences in voluntary intake (VI). The sheep were divided into four groups of six animals each: Suffolk mature ewes (SM), Suffolk yearlings (SY), Rambouillet mature ewes (RM), and Rambouillet yearlings (RY). The animals grazed alternatively two mixed pastures containing Trifolium repens latum, Lolium perenne and Pennisetum clandestinum from 07:00 to 16:30 hours and remained penned overnight. Voluntary intake was estimated using chromic sesquioxide (1 g per sheep) as an external marker, administered in two gelatin capsules, one before and one after grazing, during 65 days. Faecal grab samples were collected directly from each animal for three consecutive days beginning on Day 7 of the experiment and at 14-day intervals until Day 65 (sampling times=5). Hand-plucked samples of forage were used to estimate in vitro dry matter digestibilities (IVDMD), which were used with estimates of fecal output to calculate intakes (per animal and per kg of metabolic body weight (kg 0.75)). The data were analyzed as a completely randomized design in a factorial arrangement with repeated measurements. Voluntary intake, expressed both per animal and per kg 0.75, showed a breed×age interaction ( P<0.001). Suffolk mature ewes had the greatest daily VI (1.88 versus 1.26 kg DM/animal for the other three groups) because they were the heaviest animals, but their VI/kg 0.75 (0.071 kg DM/day) was not different ( P>0.05) from that of RY (0.063 kg DM/day), which were smaller, younger animals. Suffolk yearlings and RM had similar VI/kg 0.75 (0.057 and 0.051 kg DM/day, respectively), not different from that of the RY. Intakes showed a cubic trend ( P<0.001) with time, possibly because of changes in IVDMD and climatic conditions. The lower intake, yet better gains of RM and RY indicate a greater ability to thrive under conditions of average pasture quality. High forage availability did not result in greater forage consumption. The information on VI was later used to assess the micromineral status of the sheep in the experiment.

A comparison of the effects on voluntary intake by sheep of either dietary or intra-ruminal addition of silage juices

AbstractTwo silages were made from a regrowth of perennial ryegr ass following a 24-h wilt using either 2·5 l/t (LF) or 5·5 l/t (HF) of Add Safe (an aqueous solution of ammonium tetraformate, Trouw Nutrition, Cheshire, UK). Composition of silages LF and HF respectively were for dry matter (DM, g/kg) 205, 217; crude protein (g/kg DM) 106, 104; digestible organic matter (g/kg DM) 665, 692, pH 3·8, 3·9; lactic acid (g/kg DM) 103, 84; neutralizing value (meq/kg DM) 1051, 892; acetic acid (g/kg DM) 18·4, 14·0. Experiment A measured the intakes of the two silages using 12 Scottish Blackface wether lambs (mean live weight 25 kg) using a cross-over design with periods of 21 days. Intakes (g DM per day) were significantly greater (P &lt; 0·05) for silage HF (329) than for LF (268). Experiment B measured the voluntary intakes of dried silage residues following juice extraction using the same protocol as for experiment A, except that only six lambs were used. There were no significant differences in composition or intake (P &gt; 0·05) of the dried residues from the two silages. Experiment C used a 5 × 5 Latin-square design to measure the effects on voluntary intake of adding juices from the two silages to unmolassed sugar-beet nuts (SBN) pre-feeding or administered directly into the rumen in two discrete doses per day. Sheep on treatments LED and HFD received juices added to SBN (1·5 l/kg) and water added into the rumen in equal volume to the juice consumed with the previous day’s SBN. Treatments LFR and HFR received water added to the SBN (1·5 l/kg) and juice into the rumen in equal volume to the water consumed with the previous day’s SBN. The control treatment (W) was water added both to the SBN and into the rumen. Total mean daily intakes (g/day) were 1930,1954,1296, 2034 and 1703 (s.e.d. 179) for treatments LED, HFD, LFR, HFR and W respectively. Treatment LFR gave significantly lower mean daily intakes (P &lt; 0·05) than all other treatments. Values for pH, volatile fatty acids and ammonia in the rumen fluid were not significantly affected by treatment (P &gt; 0·05). Differences in voluntary intake for the two silages made from the same crop using different ensilage methods were attributed to differences in the silage liquid and volatile phases and not to the non-volatile solid phase. The effects of juice composition on intake were greater when added directly to the rumen than when added to the diet suggesting that effects on taste or smell were relatively unimportant.

INTERACTION OF EXERCISE AND CONCENTRATION ON OVERALL ACCEPTANCE OF A SPORTS BEVERAGE IN OLDER PEOPLE 1608

To determine the interaction of exercise and beverage concentration on overall acceptance (OA) and perception of flavor characteristics in older people, we exposed older men (n=7) and women (n=17) (72.2±5.8 yrs.) to five concentrations of a powdered sports beverage (SB). Beverages were 10%, 50%, 100%, 150%, and 200% of the control (100%) concentration and randomly sampled in both sedentary (SE) and post-exercise (PE) conditions. SE consisted of sampling all five beverages in a single session. Subjects then performed 40 min of aerobic exercise on mini-trampolines (65-70% of predicted maximal HR reserve) on 3 days per week for 4 weeks. Immediately after each of the last five exercise sessions, one of the five SB's was provided ad libitum and 19 sensory and perceptual attributes were rated by self-report on category and visual analogue scales. There were no differences in OA scores among the five SB's in the SE condition. While exercise increased ratings of tiredness, thirst, and mouth dryness (p<0.05), there were no differences in voluntary intake among SB's. In this older group, thirst and fluid intake were not related. The largest positive shift for OA was for the 50% SB at PE(5.9±1.5) compared to SE (4.8±1.9). OA appeared to peak at the 150% SB in PE, but had a broader range of acceptability. Hedonic measures of sweetness and flavor favored the 150% SB after exercise. As a measure of discriminability, ANOVA F-ratios for sweetness and flavor strength were greater in the PE than in the SE condition, but for aftertaste, were lower in PE than in SE. Our data indicate that in older people, exercise may modify the ability to discriminate individual attributes of flavor and broaden the range of acceptable SB concentrations. Although thirsty, our older subjects had a limited fluid intake even though most SB's were reported to be acceptable as fluid rehydration alternatives.

Voluntary intake and kinetics of degradation and passage of unsupplemented and supplemented pastures from semiarid lands in grazing goats and sheep

Interspecies differences in voluntary intake and fractional rates of passage and degradation of digesta in goats and sheep grazing on semiarid lands in the south-east of Spain were studied following a 2 (animal species) × 3 (period of the year, i.e., phenological state) × 3 (feed supplementation) factorial design. The animals were on a semi-extensive management system and were fed, from early spring to late summer, pasture unsupplemented or supplemented (88 g DM/animal/d) with barley grain or with barley grain plus urea. The voluntary intake met the energy (ME) requirements for maintenance in goats but not in sheep. The voluntary intake of organic matter of pasture (POMI) was significantly (P < 0.05) affected by the phenological state of the pasture and significantly reduced by supplementation (P < 0.05). The total organic matter intake (TOMI) remained unchanged. Goats had significantly (P < 0.05) faster fractional rates of passage of digesta from the rumen than sheep. Neither the phenological state nor the supplementation affected the particle outflow rate. The fractional rate of degradation of both dry matter (DM) and crude protein (CP) seemed to be slightly higher in goats than in sheep, whereas it was unaffected by supplementation. Effective degradability (Ed) of DM both in goats and sheep decreased from early spring to late summer.

Effect of palatability on voluntary feed intake by sheep. II. The effect of altering the palatability of a wheaten hay on long-term intake and preference

The effect of either an increase or a decrease in palatability on both long-term intake and preference for a wheaten hay was studied using two groups of sheep. Quantitative assessments of palatability confirmed that it was possible either to increase the palatability of 17 mm length hay by treating it with a combination of butyric acid plus monosodium glutamate or to decrease the palatability of 6 mm length hay by treating it with MgO. The voluntary intake of hay treated with butyric acid plus monosodium glutamate was 10% higher than that of the untreated hay when offered singly to sheep over 25 days. The increase in intake of the treated hay was associated with an increase in the apparent fractional rate of digestion in the rumen. There was no difference in voluntary intake between hay treated with MgO and untreated hay, even though there was a reduction in the apparent digestibility of the treated hay. The addition of MgO resulted in a decrease in the apparent fractional rate of digestion in the rumen which was compensated for by an increase in rumen digesta load. The palatability of a forage did affect its long-term preference, as determined by offering treated and untreated forages together in separate containers for 25 days. The sheep demonstrated a preference for hay treated with butyric acid plus monosodium glutamate (77 cf. 23%) and an aversion to hay treated with MgO (23 cf. 77%). The results indicated that palatability had little effect on the voluntary intake of a wheaten hay when it was offered as the sole forage to sheep. However, when offered a choice between forages, animals consumed significantly more of the more palatable forage.

Intake and digestibility by wethers as influenced by forage morphology at three levels of forage offering1,2

Animals on pasture do not always have the opportunity for ad libitum consumption. Our objectives were to determine effects of intake level on digestibility of 12 grass hays, and to relate differences in intake and digestibility to proportions of leaf blade, leaf sheath and stem. In each of two periods, 24 wethers were offered one of 12 hays at three consecutive levels of feeding: (L1) ad libitum, allowing 15% refusal; (L2) restricted to 100% of hay consumed ad libitum by individual wether during L1; and (L3) 1.8% of BW on a DM basis. Hays offered included two sorghum-sudan, four barley, four oat and two pearl millet. Hays were similar in NDF concentration but differed in morphological composition Organic matter intake averaged 1.99 +/- .04, 1.79 +/- .04 and 1.52 +/- .01% of BW for L1, L2 and L3, respectively. Organic matter digestibilities averaged 71.8 +/- .55 72.4 +/- .60 and 72.3 +/- .65% for L1, L2 and L3, respectively. Intake SEM within hays were lower with restricted intakes (L3), whereas the opposite was observed for the SEM for digestibility. Forage morphological composition within feeding level influenced intake and digestibility by altering diet selection capabilities of wethers. Wethers did not consume equal NDF amounts, ranging form .95 to 1.47% of BW, because hays differed in morphological composition. Ash-free ADF and 72% sulfuric acid lignin were higher (P less than .01) in stem than in blade or sheath. In vivo digestibilities measured under restricted feeding conditions were related more closely (P less than .05) to in vitro estimates of digestibility than were digestibilities measured under ad libitum conditions (r = .72, .79 and .85 for L1, L2 and L3, respectively). This study demonstrates that variation in morphological characteristics of forages may account for part of the difference in voluntary intake of forages of similar chemical composition. New knowledge in this area will be valuable in developing improved forage quality prediction procedures.

Voluntary consumption and digestion of diets high in endophyte-infected fescue by growing Holstein steers.

Holstein steers (112 to 258 kg BW) were fed diets high in endophyte-infected fescue (80 to 100%) in 15 latin square experiments to determine the relationships among BW, forage composition, voluntary consumption and digestion. Fescue DM intake (kg/d) increased linearly (P less than .05) with increasing BW (-.513 + .0275 BW; R2 = .69). Regressing log fescue intake (DM) on log BW resulted in a BW exponent of 1.1034 (R2 = .66) but did not account for any more variation in intake than the simple regression did. The percentage NDF in fescue was not related (P greater than .10) to fescue intake (kg/d) and was correlated only slightly with fescue intake as a percentage of BW (r = -.13; P less than .10). Adding the percentage of fescue in the diet or NDF in the fescue to the regression of DM intake on BW did not increase explained variation. Organic matter intake (kg) and digestibility (%) were not related (P greater than .10). Based on standardized partial regression coefficients, differences in voluntary intake accounted for 60% of the variation in the total quantity of OM digested, whereas differences in digestibility accounted for 40%. In conclusion, ingestibility of endophyte-infected fescue hay in relation to changing BW did not vary greatly. Concentrations of chemical constituents such as NDF and ADL in fescue were poorly correlated with feed consumption and digestibility.

An evaluation of tree legumes on an acid ultisol in South Sumatra, Indonesia

SummarySeventeen tree species (16 legumes and Eucalyptus saligna) were grown for 4 years on an Ultisol of pH 4·5 at Nakau, South Sumatra, Indonesia. Leaf and wood yields were recorded seven times during the 4-year period and mineral and plant quality measurements were made on leaf samples from the first harvest taken 2 years after transplanting. At this time, leaf and wood yields were highest from Acacia mangium but the yield of this species declined over time. Highest leaf production was recorded for Cassia siamea over the 4-year period.Mineral analyses of leaf indicated N, K, Ca and Mg to be adequate for animal production in all species. P was below the critical level for animals in all species and Na levels were adequate only in Acacia mangium and Acacia auriculiformis.Plant quality measures (ADF, NDF, lignin) suggest marked differences could be expected in potential feed value between species through differences in voluntary intake and digestibility.

Nutritive value of willow (Salix sp.) for sheep, goats and deer

SummaryVoluntary intake and apparent digestibility of tree willow (Salix matsudana Χ alba) and of osier willow (Salix viminalis) were measured with male sheep and goats and voluntary intake only with male deer. Both willow species had been selected for extremely rapid growth, and were grown in coppices on high fertility soil. In a first experiment spring primary growth of both willows was fed to sheep, goats and deer in early summer, whilst in a second experiment summer regrowth (i.e. secondary growth) of osier willow was fed to sheep and goats in autumn.Although the ratio of readily fermentable to structural carbohydrate (0·51–0·70) and total N concentration (18–24 g/kg D.M.) in primary growth of the willows was less than normally found in high quality fresh temperate forages, the values were similar to those of many dried forages normally used as supplements. Averaged over sheep and goats, voluntary intake of digestible D.M. was 22% less for osier than for tree willow, this being associated with higher concentrations of lignin (197 ν 182 g/kg D.M.) and of condensed tannin (66 ν 29 g/kg D.M.) in the osier willow. The lower digestible dry-matter intake was attributable to both lower voluntary intakes and lower digestibility of the D.M. (0·57 ν 0·64). Both voluntary intake and apparent digestibility of secondary growth willow were lower than that of primary growth.When expressed as functions of the amount required for maintenance, voluntary metabolizable energy intake of goats was approximately double that of sheep, both for primary growth (2·2 ν 1·1) and for secondary growth (1·8 ν. 0·7) willow. This was attributable to consistently higher voluntary D.M. intakes/kg W0'6 by goats, and to a trend for higher digestibility than sheep, which attained significance in Expt 2but not in Expt 1. The ratios of dry-matter intake/kg W075 per day for sheep: deer: goats fed primary growth willow were 1·0:1·5:1·9, with deer thus being intermediate between the other two species. There were no differences in voluntary intake (g/kg W0·75 per day) of sheep, goats and deer fed a high quality lucerne hay.It was concluded that willows grown during spring and summer could adequately be used as supplementary feed during summer droughts and that willow could be used most effectively if fed to goats, followed by deer, with sheep being the least efficient. Tree willow is a preferred choice to the osier willow used here, and it was further concluded that like Lotus pedunculatus, high concentrations of lignin and condensed tannin, both of which are produced by the same biochemical pathway, are likely to be limiting nutritive value of the more leafy osier willow.

The intake and feeding value for young beef cattle of two cultivars of tetraploid Italian ryegrass when grazed or conserved by artificial dehydration or ensilage

AbstractTwo experiments were carried out to determine whether the differences in intake and feeding value previously shown between two grass cultivars when offered to ruminants as chopped artificially dehydrated (dried) material could also be demonstrated when the grasses were offered in other forms. Two cultivars of tetraploid Italian ryegrass (Lolium multiflorum), Sabalan and Tetila, were established in the same field in 1975. In 1976 they were grazed and conserved (two cuts of primary growth) as dried material or as silage.The composition of the herbage selected at pasture and conserved showed higher concentrations of normal detergent fibre and acid detergent fibre in the dry matter for Tetila than for Sabalan, but differences between cultivars in digestibility were small. In both grazing and winter feeding trials differences in voluntary intake between the two cultivars were not significant, but at pasture young beef cattle spent less time grazing and tended to spend more time ruminating on Tetila than Sabalan. There was no measure of animal performance at pasture but liveweight gain was 15% higher for Sabalan than Tetila when both were offered to young beef cattle as the sole feed of dried grass or of silage. The voluntary intakes of the three forms of feed were very similar, which in part reflected a similarity in digestibility. However, gains were lower for calves given silage than those given dried grass. This may have been due to a lower efficiency in the utilization of the nitrogeneous components of silage for tissue growth than those of dried grass.

Soaking of complete fattening rations high in poor roughage 1. The effect of moisture content and spontaneous fermentation on nutritional value

SUMMARYThe effect of three moisture concentrations (10, 50 and 75%) and of four fermentation conditions (none, 24 hr aerobic, and 24 and 48 hr anaerobic) on the nutritive value of two complete fattening diets containing 25 and 45% poor roughage, was examined in three digestion and nitrogen balance trials, each of Latin square design, in cattle.Fermentation increased the lactic acid and volatile fatty acid concentrations of the feed, decreased its pH and the crude fibre content, and caused losses of dry matter.There were non-significant differences in voluntary intake between the dry and soaked diets. The apparent digestibility of dry and organic matter, crude protein, nitrogen-free extract and crude fibre was non-significantly improved by added moisture. There were no consistent differences in nitrogen retention.The average metabolizable energy values (ME) observed for both diets were 6% higher than those calculated. There were no significant differences in the apparent digestibility of gross energy or in ME value between treatments of different moisture content.The fluctuations in pH of rumen liquor during the day differed markedly when the animals received different levels of roughage. These differences were greater when the feed was allowed to ferment. Soaking of feed resulted in a significant increase in the concentration of propionic acid in the rumen liquor, and a non-significant decrease in that of acetic acid. Consequently the C2/C3ratio was significantly lower on the moist feed treatments.There were no consistent differences in concentration of ammonia in the rumen liquor, or of urea in the blood.

THE VOLUNTARY INTAKE AND DIGESTIBILITY BY SHEEP OE LEAF AND STEM FRACTIONS OF LOLIUM PERENNE

ABSTRACTThe leaves of tropical grasses are eaten in larger quantities than stems of similar DM digestibility. To determine whether the same fact applied to a temperate grass, studies were made with leaf and stem fractions of Lolium perenne. The leaves of L. perenne had a 20% higher voluntary intake than the stems, white the DM digestibilities were only slightly higher (67·3%ν. 64·8%). The leaves also had a larger surface area/g, a higher initial (12 h) fermentation rate in vitro, larger content of pepsin‐soluble DM, and a smaller energy require ment to grind I g DM in a laboratory mill compared with the stems.The difference in voluntary intake between the leaves and stems of L. perenne was smaller than that for a number of tropical grasses.

The pepsin soluble dry matter of leaf and stem fractions of grasses in relation to voluntary intake by sheep

The level of pepsin soluble dry matter (PSDM) was determined on leaf and stem fractions derived from five grasses each cut at three stages of growth. The voluntary intake and dry matter digestibility of all grass fractions had been previously determined with sheep. Mean PSDM for leaf and stem were similar (23.0 v. 23.4 per cent) despite large differences in voluntary intake (57.8 v. 39.6 g/kg W0.75 )and similar dry matter digestibility (52.6 v. 55.8 per cent). For all grass fractions the correlation between voluntary intake and PSDM was r = 0.26, P &gt; 0.05. This poor relation was partly caused by a significant difference between the leaf and stem populations. It was concluded that PSDM was an unreliable guide for predicting the voluntary intake of grasses when compared at similar stages of growth.