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1.
Two 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. 相似文献
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. 相似文献
2.
J. C. Murdoch 《Grass and Forage Science》1967,22(2):95-99
Experiments with cows and sheep are described in which the voluntary intakes of hay and silage of differing digestibility were determined. The voluntary intake of hay increased consistently with increasing digestibility, but the relationship was not as well defined for silage. The addition of concentrates depressed the intake of hay, and this effect was more marked for hay with a high digestibility than with poorer quality hay. Concentrates appeared to depress the intake of hay by sheep more than by cows, an effect which was again more marked when the hay had a high digestibility value. 相似文献
3.
A study is reported on the voluntary intake and digestibility by sheep of five lines of Cenchrus ciliaris when grown as swards and cut at six different stages of growth. Previous studies with C. ciliaris grown in small rows had shown large differences between these lines in grazing preference by cattle. The ranking order for preference wasline31>10 = 23>30 = 36.
When offered singly to sheep in pens the five lines could be divided into three groups according to their voluntary intakes. Lines 10 and 30 had the highest mean daily intakes of 56·1 and 57·6 g (kg W)-0·75 compared with lines 23 and 36 with low mean intakes of 48·5 and 48·6 g (kg W)-0·75 . Line 31 was intermediate with a mean intake of 543 g (kg W)-0· .
Mean dry matter digestibility of the five lines ranged from 0·577 to 0·597%. Lines 10 and 30 had the lowest digestibility. The difference in intake between the five lines was positively correlated with their proportion of leaf ( r = 0·97). Low-intake lines (23 and 36) also had the highest proportion of seed head.
It was concluded that selection of C. ciliaris on the basis of preference by cattle in a cafeteria study provided no useful guide to voluntary intake when the different lines were grown, cut, dried, chopped and fed separately to sheep. 相似文献
When offered singly to sheep in pens the five lines could be divided into three groups according to their voluntary intakes. Lines 10 and 30 had the highest mean daily intakes of 56·1 and 57·6 g (kg W)-
Mean dry matter digestibility of the five lines ranged from 0·577 to 0·597%. Lines 10 and 30 had the lowest digestibility. The difference in intake between the five lines was positively correlated with their proportion of leaf ( r = 0·97). Low-intake lines (23 and 36) also had the highest proportion of seed head.
It was concluded that selection of C. ciliaris on the basis of preference by cattle in a cafeteria study provided no useful guide to voluntary intake when the different lines were grown, cut, dried, chopped and fed separately to sheep. 相似文献
4.
The results of nineteen digestibility trials with sheep on different silages have been reported. From these data and from the results of forty trials with sheep carried out by Watson (15) it has been shown that Lancaster's method of calculating feed intake (9) can be applied to silages when the crude protein content is within the range studied (9–24% of the dry matter). For silages in this category, no advantage has been found in taking the nitrogen content of the silage dry matter into account in calculating feed intake.
The digestibility of crude protein and Lancaster's'constant'have both been correlated with the crude protein content of the silage dry matter for the fifty-nine trials considered (r = 0.767 and r = 0.452 respectively). Although it has been found unnecessary to take the protein content of silage into account in calculating dry matter intake when feeds containing 9.24% crude protein in the dry matter are used, evidence is presented which indicates that this factor is of considerable importance when herbage of low protein content is fed. The equation, which has been derived from the silage data considered, has been found to be valid when compared with the results of trials with fresh herbage and well preserved hays of low protein content.
The results of this work indicate that Lancaster's method is a suitable one for estimating the feed intake of animals engaged in self feeding of silage, provided the silage has been well preserved. 相似文献
The digestibility of crude protein and Lancaster's'constant'have both been correlated with the crude protein content of the silage dry matter for the fifty-nine trials considered (r = 0.767 and r = 0.452 respectively). Although it has been found unnecessary to take the protein content of silage into account in calculating dry matter intake when feeds containing 9.24% crude protein in the dry matter are used, evidence is presented which indicates that this factor is of considerable importance when herbage of low protein content is fed. The equation, which has been derived from the silage data considered, has been found to be valid when compared with the results of trials with fresh herbage and well preserved hays of low protein content.
The results of this work indicate that Lancaster's method is a suitable one for estimating the feed intake of animals engaged in self feeding of silage, provided the silage has been well preserved. 相似文献
5.
G. SWIFT 《Grass and Forage Science》1977,32(4):205-211
An Italian ryegrass (cv. RvP), a tetraploid hybrid ryegrass (Sabrina), and an early heading timothy (Scots), were compared under 3-cut silage plus aftermath, 5-cut early bite-hay-aftermath and 6-cut simulated grazing managements over 2 harvest years 1974–75. Annual nitrogen applications totalled 375 kg ha?1 N for the silage and grazing systems and 325 kg ha?1 for the early bite-hay-aftermath treatment. In 1974, the first harvest year, RvP and Sabrina outyielded Scots timothy. In the dry summer of 1975 the drought tolerance and persistency of Sabrina was superior to RvP, but both grasses gave low yields (approx. 10·0 ha?1 DM under the conservation managements) and showed a marked fall in production compared with the first year, by RvP of 35% and by Sabrina of 25%. Scots timothy in the second year equalled the ryegrass in total DM yield under the hay management system. Over the 2 years RvP and Sabrina gave similar yields, which were 10% better than Scots timothy, under all managements. RvP and Sabrina are equally suitable for silage production, but second and third silage cuts of RvP require shorter regrowth periods than Sabrina for good quality herbage. Sabrina will also provide leafier grazing than RvP. 相似文献
6.
Six castrated male sheep were used in a two-period crossover experiment to investigate the effect of mincing on the voluntary intake and digestibility of a silage. The silage was a high-quality material, containing 68 % digestihle organic matter in the dry matter, prepared from S24 perennial ryegrass cut with a precision chop forage harvester and ensiled with the addition of 2.3 1 t?1 formic acid as preser vative. The median size of particles in the unprocessed silage was 10–20 mm and in the minced silage 2–3 mm. The intakes of dry matter, organic matter and nitrogen for the minced silage were greater than for the unminced material, and for dry matter and organic matter intakes the differences were signi ficant (P<0.01). Mincing was associated, however, with a depression in the digestibility of all three constituents which offset the increase in intake. The intakes of digestible organic matter were 817 g d-1 for the minced silage and 729 g d?1 for the unminced material (P>0.05). Corresponding figures for digestible nitrogen intakes were 208 gd?1and23.0 gd?1 (P>005). It is concluded that with high-quality silage diets there is a physical component in the mechanism for the control of voluntary food intake. It is suggested that for sheep, depressions in the digestibility of dietary constituents are unlikely to occur until silages are chopped to a median particle size of 5–10 mm. 相似文献
7.
D. J. Thomson 《Grass and Forage Science》1971,26(3):149-156
Two experiments were conducted to measure the voluntary intake and digestibility of (a) primary growth and (b) regrowth of diploid (S22) and tetraploid (Tetila tetrone) varieties of Italian rye-grass (Lolium muitifiorum): Sl00 white clover (Trifolium repens) was included as an additional treatment in the second experiment with the re-growth herbage diets. Mature adult wether sheep, housed indoors in digesdhility crates, were fed individually on fresh herbage cut daily from late April to early June (primary growth) and in early Septemher (regrowth). The yield, digestihility, nitrogen and soluble–carhohydrate contents of the two ryegrass varieties were similar during the primary growth stage. Intake-digestibility relationships for the graces were positive, linear and different (P=0.05). The voluntary intake of diploid ryegrass was approximately 14% higher than that of tetraploid ryegrass of the same digestibility. With regrowth herbage the digestibility and voluntary intake of white clover was higher than both the Italian ryegrasses. The digestihility of the regrowth tetraploid was 6% units higher than the diploid variety, but there was no difference in the voluntary intake of digestible organic matter between the varieties at the regrowth stage. The intake of regrowth herbage was higher thaa that of primary growth herhage of similar digestihility. 相似文献
8.
The intake of maize silage by self-fed heifers was measured where access to the silage was limited either by reducing the width of the feed face or by restricting the time allowed for feeding. In the first experiment twenty heifers were allowed 0.4 or 0.2 m feed face per head for 7 h daily. In the second experiment fourteen heifers were allowed 0.5 m feed face per head for 5 or 3 h daily. Intake was measured either by estimating faecal output by the chromic oxide technique and then using the in vitro estimate of silage digestibility to calculate individual intakes, or by using the results of eight individually fed heifers to provide a direct relationship between the chromic oxide concentration of the faeces and total intake, and using this to predict the intake of the self-fed heifers from the concentration of chromic oxide in their faeces. The latter method was found to be the most satisfactory because it took into account the effect of level of feeding on the digestibility of maize silage. Restriction of access to the silage by limiting feed face width (Experiment 1) and time (Experiment 2) significantly reduced intakes by 4 and 7% respectively. In both experiments feeding time was significantly reduced by restriction, but this was partially compensated for by a significant increase in rate of eating. 相似文献
9.
R. ANDERSON 《Grass and Forage Science》1982,37(2):139-145
Two areas of an early-heading perennial ryegrass cv. Cropper were harvested by either a precision-chop or a flail harvester at around 50% ear emergence (15 May 1978) and 14d later (29 May). Formic acid (85%) was applied at the rate of 2·2 litres t-1. Mature crossbred wethers were used in a 2 × 2 factorial design to determine the effect of stage of maturity and method of harvesting (chop length) on the in vivo digestibilities of formic acid-treated grass in experiment 1 and formic acid silage in experiment 2. Apparent digestibility coefficients were determined at a fixed level of feeding for both grass and silage and at ad libitum access to feed for silage only. There were no significant differences in the concentrations of crude protein (CP), ether extract (EE), acid-detergent fibre (ADF) or acid-detergent lignin (ADL) in grass or silages of differing chop lengths but the later cut forages had significantly higher ADF and ADL concentrations and lower CP concentrations than the early-cut forages. The ADF and ADL concentrations were also higher in the silages than in the corresponding grasses. In general, the fermentation characteristics of precision-chopped silage were better than for the corresponding flail-cut silage but date of harvest was a more important determinant of quality and the late, flail-cut silage had the highest butyrate and ammonia N concentrations and the highest pH (411) of any treatment. There was a significantly higher intake of precision-chopped as compared with flail-cut silage with both the early-and the late-cut silage but there were no significant differences attributable to stage of maturity (i.e. date of harvest) or significant interaction between chop length and maturity. The slightly increased intake of early harvested, precision-chopped silage as compared with late precision-chopped silage was not significant. Dry matter digestibility (DMD) of the grass decreased at a rate of 0004 units d-1 post 50% ear emergence. The results of experiment 2 indicated a decrease of 0·207 units d-1 in silage fed at a similar level. The late-cut silage (DMD 0·292, mean of both harvesting treatments) thus had a significantly lower digestibility than the corresponding grass (mean DMD 0·247). Chop length had a variable influence on the DMD of both grass and silage fed at a fixed level but treatment differences were non-significant. However, a trend towards higher digestibility of flail-cut as compared with precision-chopped silage was apparent and this became statistically significant when the animals were allowed ad libitum access to feed. This may be a response to the generally lower intake of flail-cut silage. 相似文献
10.
E. Charmley 《Grass and Forage Science》2002,57(1):11-18
Nutritive value and voluntary intake of legumes are generally considered to be higher than those of grasses when ensiled at similar digestibility, although high levels of soluble protein can result in low N utilization by animals and high losses to the environment. The objectives of this experiment were to describe the optimum combination of Westerwolds ryegrass ( Lolium multiflorum Lam. cv. Aubade) and lucerne ( Medicago sativa L. cv. AC Caribou) silages to maximize liveweight gain of steers fed silage, determine chemical components that are important and ascertain whether steers selected the optimum mixture when given a choice. Both silages contained similar concentrations of dry matter (DM), acid-detergent fibre (ADF) and organic acids, but lucerne silage had higher concentrations of N, soluble-N and ammonia-N. Westerwolds ryegrass silage contained more neutral-detergent fibre (NDF). In a 12-week experiment, voluntary intake by Hereford steers was not influenced when the proportion of the two silages was changed from 1 to 0 in 0·25 increments. However, liveweight gain and feed efficiency increased linearly ( P < 0·001) as the proportion of ryegrass silage fed was increased. When preconditioned to either of the two silages, steers showed a significant preference for ryegrass over lucerne ( P < 0·05). When conditioned to a mixture of both silages, no preference was elicited. It is suggested that extensive solubilization and deamination of protein in the lucerne silage may have caused the preference for Westerwolds ryegrass silage and the higher liveweight gains on diets containing higher proportions of Westerwolds ryegrass silage. 相似文献
11.
A comparison was made of the digestibility, voluntary intake and concentration of N in faecal organic matter in castrated male sheep and non-lactating cows offered herbage ad libitum. The sheep ate 22% more herbage DM per kg liveweight than the cows. In general, the sheep and cows digested the organic matter of the herbage to the same extent, although on two occasions significantly higher digestibilities were observed in cows than in sheep. Similar concentrations of N in faecal organic matter in sheep and cows were matched by similar digestibilities of herbage organic matter. Regression equations relating herbage organic matter digestibility to faecal N concentration were not significantly different between sheep and cattle. 相似文献
12.
Two experiments were carried out to evaluate propionic acid-treated hay as a feed for sheep in which eighteen ewes (experiment 1) and eighteen ewe lambs (experiment 2) were fed ad libitum on hay only. At feeding, the propionic acid-treated hays had higher D-values and water-soluble carbohydrate concentrations, but a lower dry matter concentration, than the untreated hays. The voluntary feed intake and liveweight gain of the sheep fed on two acid-treated hays and on an untreated hay in experiment 1 were similar. In the second experiment an acid-treated moist hay was eaten in greater amounts by the sheep and liveweight gains were greater than on the corresponding untreated hay, but were not significantly different from those of sheep fed on field-cured hay. 相似文献
13.
R. J. WILKINS 《Grass and Forage Science》1970,25(2):125-130
Perennial ryegrass was conserved by ensiling, or by dehydration, grinding and pelleting. the two resultant feeds were given ad lib. to wether sheep, either separately or in different proportions. Pellets were consumed in greater quantities than the silage, but were lower in digestibility. There was a rectilinear relationship between the percentage of pellets in the ration consumed and organic-matter digestibility, but a curvilinear relationship between the percentage of pellets and organic-matter intake. Silage intake was little affected by the feeding of pellets until more than 40% of the ration consisted of pellets. The increase in total intake with an increase in pellets above 60% was small, with the result that intake of digestible organic matter was highest when 65% pellets was fed. the results suggest that dried-grass pellets may be a useful supplement for silage rations. 相似文献
14.
An experiment was conducted over 3 years (1983-85) to assess the performance of Holcus lanatus German Commercial and cv. Massey Basyn compared with Lolium perenne cv. Perma on a gley soil under sheep grazing in the Scottish uplands. All grasses were sown together with Trifolium repens cv. Grasslands Huia. The swards were rotationally grazed at similar herbage allowances. During the first harvest year, the swards were grazed hard to a low mass (500 kg DM ha−1 ). In the second harvest year, post-grazing herbage masses of 500 and 1000 kg DM ha−1 were compared.
Perma ryegrass had a higher level of herbage production than both H. lanatus cultivars in the first and second harvest years after sowing and hence had a greater number of sheep grazing days. The ryegrass sward consisted of 25% more green sown grass (85 cf. 60%) but 12% less white clover (4 cf. 16%) compared with both H. lanatus cultivars in the establishment and first harvest years. The persistence of all three grasses was poor although ryegrass had a higher presence (36%) than either Massey Basyn (22%) or German Commercial (13%) at the end of the. second harvest year.
At a similar herbage allowance, there were no significant differences in the herbage intake and liveweight gain of sheep. Ryegrass had a higher organic matter digestibility and lower neutral and acid detergent fibre and lignin contents than either of the H. lanatus cultivars.
In the second harvest year, although herbage production was greater at the higher herbage mass, there was no difference in the proportion of sown grass.
It was concluded that ryegrass is a superior grass to H. lanatus on upland soils with high N status, moderate P status and a high pH. 相似文献
Perma ryegrass had a higher level of herbage production than both H. lanatus cultivars in the first and second harvest years after sowing and hence had a greater number of sheep grazing days. The ryegrass sward consisted of 25% more green sown grass (85 cf. 60%) but 12% less white clover (4 cf. 16%) compared with both H. lanatus cultivars in the establishment and first harvest years. The persistence of all three grasses was poor although ryegrass had a higher presence (36%) than either Massey Basyn (22%) or German Commercial (13%) at the end of the. second harvest year.
At a similar herbage allowance, there were no significant differences in the herbage intake and liveweight gain of sheep. Ryegrass had a higher organic matter digestibility and lower neutral and acid detergent fibre and lignin contents than either of the H. lanatus cultivars.
In the second harvest year, although herbage production was greater at the higher herbage mass, there was no difference in the proportion of sown grass.
It was concluded that ryegrass is a superior grass to H. lanatus on upland soils with high N status, moderate P status and a high pH. 相似文献
15.
Two experimental populations of Italian ryegrass selected for high and low magnesium content were established as swards, harvested fresh daily and offered to sheep. Chemical analysis of the crops showed a 44% higher Mg and a 22% higher Ca concentration in the high-Mg selection but no significant differences between the selections for the other minerals.
Blood and rumen contents were sampled throughout the feeding period and voluntary intake, digestibility and mineral balances for Na, K, Mg, Ca and P were determined. Magnesium intake, apparent availability and retention were significantly greater with the high-Mg selection. There were no significant differences in the plasma-mineral concentrations and all were within the normal range. Rumen fluid from animals fed the high-Mg selection had a higher proportion of soluble Mg and a higher Na:K ratio in the supernatant liquor. 相似文献
Blood and rumen contents were sampled throughout the feeding period and voluntary intake, digestibility and mineral balances for Na, K, Mg, Ca and P were determined. Magnesium intake, apparent availability and retention were significantly greater with the high-Mg selection. There were no significant differences in the plasma-mineral concentrations and all were within the normal range. Rumen fluid from animals fed the high-Mg selection had a higher proportion of soluble Mg and a higher Na:K ratio in the supernatant liquor. 相似文献
16.
Comparison of the fermentation quality and nutritive value of sulphuric and formic acid-treated silages fed to beef cattle 总被引：2，自引：0，他引：2
S. J. KENNEDY 《Grass and Forage Science》1990,45(1):17-28
Five experiments were carried out in the years 1980-1983 and 1986 to study the effect of treating grass at ensiling with sulphuric acid (850 g kg?1) and formic acid (850 g kg?1) additives alone, and in mixtures with or without formalin on the preservation of grass, in vivo digestibility in sheep, in-silo loss, intake and performance of finishing cattle. Primary growth grass was ensiled in experiments 1 (3–4 June 1980), 2 (12-15 June 1981) and 3 (31 May-2 June 1982), primary regrowth grass in experiment 4 (1-2 August 1983) and secondary regrowth grass in experiment 5 (7-10 October 1986). During the ensiling period within each experiment, approximately 60 t of unwilted, double-chopped, additive-treated or untreated grass was packed into covered concrete-walled 60-t capacity silos. The dry matter (DM) contents of the ensiled grass in experiments 1, 2 and 5 ranged from 155-180 g kg?1 and were lower than those recorded in experiments 3 and 4 (214 g kg?1). With the exception of grass ensiled in experiment 2, where water-soluble carbohydrate (WSC) contents were low, at 104 g kg?1 DM, grass in all other experiments contained relatively high WSC contents ranging from 140-154 g kg?1 DM. In experiments 1, 3 and 4 all silages were well-preserved. However, in experiment 2 the 450 g kg?1 sulphuric acid-treated and formic acid-treated silages displayed significantly lower pH, buffering capacity (Bc) and ammonia nitrogen contents than the untreated silage. In experiment 5, the sulphuric acid-treated and formic acid-treated silages displayed significantly lower pH, Bc, ammonia nitrogen, butyrate and volatile fatty acid (VFA) contents than the untreated silage. Each of the silages was offered daily with various levels of a supplementary concentrate for approximately 70-d periods to twelve animals of mixed breed in experiments 1, 3, 4 and 5 and to fifteen animals in experiment 2. All animals weighed between 380-470 kg at the start of the experiments. In experiments 1, 2 and 3 there were no significant differences between silages for any of the intake or animal performance parameters. In experiment 4, cattle fed the formic acid-treated silage displayed significantly higher silage DM intakes and daily liveweight gains than those fed the sulphuric acid-treated and untreated silages; in experiment 5, cattle fed the formic acid-treated silage displayed significantly higher silage DM intakes than those fed the untreated silage. It was concluded that formic acid was a more effective silage additive than sulphuric acid. Increasing the level of supplementation significantly decreased silage DM intakes in cattle in experiments 3 and 4, and significantly increased daily liveweight gains and daily carcass in cattle in experiments 1, 3 and 4. 相似文献
17.
Pure swards of S22 Italian ryegrass, H.1 hybrid ryegrass, S170 tall fescue, S48 timothy, S215 meadow fescue and Germinal cocksfoot were each harvested at several stages of maturity during first growth in the spring, and in the subsequent regrowths. Each batch of herbage was fed to sheep in a digestion trial under conditions of voluntary intake. Results from the first growth herbages showed the expected fall in digestibility with increasing maturity. However, the digestibility of S22, H.1, S170 and S48 began to fall well before ear emergence, whereas the digestibility of Germinal fell only slowly up to the time of ear emergence, as had been found previously with S24 and S23 ryegrass and S37 cocksfoot. The rate of fall of digestibility in H.1 and S48 (0.4 units/day) also appeared to be lower than with the perennial ryegrasses and cocksfoot (0.5 units/day). The monthly regrowths within each herbage were of similar digestibility, but the mean digestibility of regrowths differed between herbages, being highest for S215 and lowest for Germinal and S170. The grasses with highest digestibility in the early Spring, in particular S22 ryegrass, were not, however, always the most digestible in the subsequent regrowths. The numbers of sheep fed on each herbage were insufficient to show whether there were significant differences in voluntary intake between different herbage species of the same digestibility. It is suggested that an intake/digestibility relationship, based on data from more animals, should be developed for each herbage species. Only if different relationships are found can it be concluded that factors other than level of digestibility have an effect on intake. 相似文献
18.
A series of trials was carried out in which barn-dried hay and silage were fed to young fattening cattle with or without supplementary barley. Liveweight-gains on silage and barn-dried hay alone were too low to provide an adequate finish during winter feeding. Liveweight-gains on hay alone were always higher than those obtained on silage alone, the difference being more marked in lighter animals. There was a marked response to supplements of 3 and 4 lb (1.4 and 1.8 kg) of barley, the response being significantly greater in silage-fed cattle than in those fed on barn-dried hay. There was some evidence of growth compensation with the introduction of a barley supplement to cattle on silage diets, but there was no such response in those fed on hay. Compensatory growth was not accompanied by improved digestibility or N retention. 相似文献
19.
The effects of harvest date of timothy on the chemical composition of herbage and silage, and on the voluntary intake, liveweight gain and feed conversion efficiency by finishing lambs, were evaluated. The herbage was harvested and ensiled on three dates: 16 June (before heading), 20 June and 26 June. The silages were analysed for chemical composition and degradation characteristics by an in vitro gas production (GP) technique with end-point measurements (72 h) of degradability of organic matter (OM) and neutral-detergent fibre (NDF). There were clear effects of later dates of harvest increasing the concentration of NDF, and reducing the degradability of OM and NDF, and the rate of GP, of silages made from this herbage. The silages were fed ad libitum to lambs in a feeding experiment using a Latin square design. Later harvest dates decreased the voluntary intake of silage, liveweight gain and feed conversion efficiency. Lambs fed the early-cut silage had a liveweight gain of 152 g d−1 and those fed the silage harvested 10 d later had a liveweight gain of 76 g d−1 . Changes in the chemical composition of herbage and silage and in in vitro degradation characteristics of silages with later harvests were associated, to a large extent, with the reduction in voluntary intake and liveweight gain of lambs. 相似文献
20.
Guilherme Lobato Menezes Alan Figueiredo de Oliveira Frederico Patrus Ananias de Assis Pires Lúcio Carlos Gonçalves Rafael Araújo de Menezes Pamella Grossi de Sousa Paulo Henrique Arruda de Medeiros Matheus Morais de Pinho Ângela Maria Quintão Lana Vânia Eloisa de Araújo Diogo Gonzaga Jayme 《Grass and Forage Science》2023,78(1):1-22
The effects of different additives on farm-scale silage quality and beef cattle performance are inconsistent. This study aimed to carry out a systematic review and meta-analysis to evaluate the efficacy of chemical and microbial additives to silage on beef cattle performance. Systematic searches were performed using databases and scientific journals, and 42 articles were selected. Data for all variables were grouped into subgroups according to the additive type. For dry matter intake and average daily gain, the data were also grouped by forage type due to greater comparison numbers. The treatment mean differences and 95% confidence intervals (p < 0.05) were analysed using a random-effects model. The use of homo- and heterofermentative microbial inoculant mixtures and chemical additives (Ch) increased the average daily gain of beef cattle fed maize/sorghum silage. Homofermentative microbial inoculant (Ho), Ch, and a mixture of microbial inoculant and chemical additives also increased the average daily gain of beef cattle fed temperate grasses. Only Ch increased dry matter intake. Ch increased feed efficiency, and Ch and Ho increased carcass weight. The evaluated additives improved the silage fermentation process mainly via pH and ammonia nitrogen reduction. Overall, this meta-analysis demonstrated that silage additives improved the ensiling process and beef cattle performance, with better results with Ch use. Due to the aerobic stability and microbiological profile analyses being carried out more in laboratory-scale silos, more studies are needed to determine these silage parameters after opening the silo at the farm scale. 相似文献