Consumption Of Silage Research Articles

Effect of Concentrate Level and Feeding Management on Chewing Activities, Saliva Production, and Ruminal pH of Lactating Dairy Cows

Eight ruminally cannulated lactating Holstein cows were used in a double 4 × 4 Latin square to determine the effects of 1) proportion of barley silage [40, 50, and 60% of dry matter (DM)] in the diet, and 2) feeding a total mixed ration (TMR) compared with separate ingredients (SI) on chewing activities, saliva production, and ruminal pH. Although cows fed SI were offered a diet containing 50% silage, they actually consumed a diet containing 43% silage (DM basis). Dry matter intake and milk yield were similar for all diets (18.2kg of DM/d and 27.2 kg/d, respectively). Cows fed the 40% silage TMR spent more time eating than cows fed SI (243 vs. 198 min/d), but rumination time was similar (546 min/d). Eating time was similar among the TMR diets, but rumination time increased from 498 to 516 and 584 min/d as silage in the TMR increased from 40 to 50, and then to 60%, respectively. The secretion of saliva per gram of feed was 4.43, 3.18, and 1.19 ml/g of DM with consumption of silage, TMR, and concentrate, respectively. Resting salivation rate was similar for all diets (101 ml/min). Regardless of the diet, cows secreted 239±17 L/d of saliva, and ruminal pH was below 5.8 for 10 h/d. Results indicated increased chewing time did not increase total daily saliva secretion because increased eating and ruminating saliva was associated with decreased resting saliva. Feeding SI increased the risk of acidosis, because cows ate a higher proportion of concentrate than intended.

Effects of Level of Concentrate Feeding During the Second Gestation of Holstein-Friesian Dairy Cows. 1. Feed Intake and Milk Production

The objective of this experiment was to examine the residual effects of the level of concentrate feeding during the second gestation on performance in the second lactation. Forty-three Holstein-Friesian heifers that calved for the first time at 2 or 3 yr of age were offered diets based on ad libitum consumption of ryegrass silage and either 2 or 7 kg/d of concentrates over the second half of the first lactation. All cows received a low quality diet, based on grass silage and barley straw (60:40 DM basis) for a short (6-wk) dry period. Feeding in the second lactation was based on ad libitum access to grass silage and a flat rate of concentrates (8 kg/d for 120 d; 5 kg/d thereafter). Three-year-old heifers produced more milk than 2-yr old heifers in the first lactation, equivalent to 93kg of fat-corrected milk for each additional month of rearing. Cows given the low level of concentrates produced less milk and gained less weight and body condition, though there was a partial compensation when silage quality improved in late lactation. Forage intake declined as cows approached calving, and cows gained little weight or body condition over the dry period. There was no effect on calf weights. Cows that had received the low level of concentrates in the previous lactation consumed more forage dry matter during the second lactation. Parallel curve analysis showed that 2-yr-old heifers that had received a low level of concentrates produced significantly less milk in the second lactation. The numerically much greater gains of weight and body condition for this group were not statistically significant, owing to large between-cow variation.

In Vitro Digestibility and Preference by Sheep for Silages Made from Whole-Plant Soybeans

Maturity group IV (‘Stafford’) vs group V (‘Bay’) soybean forages were harvested and ensiled at either full bloom (R2), full pod (R4), or full seed (R6) growth stages, with or without a silage inoculant and offered to sheep in a consumption experiment having a balanced incomplete block design. Silage samples were collected at the time of feeding for in vitro total DM digestibility determination. Three sheep were adapted to ensiled R6 Bay silage, then individually offered a selection of four different silages (soybean silage combinations or com silage) daily for 13 d. Quantity of each silage was limited to 50% of the total daily silage consumption. In 1988, the indigestible fraction was higher and digestibility at 18, 24, and 72h was lower from R4 Stafford than from the other cultivar and growth stage combinations (P<.05). In 1989, the indigestible fraction was lower and digestibility higher at 24, 48, and 72h from R2 than R4 and R6 silages (P<.05). Com silage was preferred (P<.05) to any of the soybean silages. Consumption of R6 silage was greater (Ρ<·05) than that 0fR2 and R4 in 1988 and 0fR4 in 1989·Silage consumption was conelated positively (P<.05) with forage DM content; DM yield; molar percentage of isovaleric and valeric acids; and lactic acid, ethanol, and acid-detergent lignin contents and negatively with acetic, propionic, isobutyric, butyric, and total volatile fatty acid concentrations; molar percentage of propionic and isobutyric acids; pH; and N, Ca, and P contents. Delaying ensiling of whole-plant soybeans until the R6 growth stage some-what compromises digestibility of the forage but provides a silage of higher acceptance by sheep.

Milk production from grass silage diets: the relative importance of the amounts of energy and crude protein in the concentrates

AbstractTo identify the separate and combined effects of energy and crude protein (CP) from concentrates on responses to concentrate feeding, 42 multiparous Friesian cows were given fixed amounts of concentrates with primary growth grass silage (194 g CP per kg dry matter (DM)) ad libitum for weeks 4 to 22 of lactation. A basal treatment of 3 kg DM per day of a standard concentrate (197 g CP per kg DM) was compared with 6 kg DM per day of the same concentrate (doubling energy and CP intake), 6 kg DM per day of a low-protein concentrate (106 g CP per kg DM) (doubling energy intake alone), or 3 kg/day of a high-protein concentrate (383 g CP per kg DM) (doubling CP intake alone). Results are presented in terms of main effects as interactions were not significant except for energy apparent digestibility. Silage intake was reduced by energy but increased by CP; in consequence extra energy from concentrates increased digestible energy (DE) intake but reduced CP intake and concentration whereas extra CP from concentrates increased not only DE intake but also CP intake and concentration. The ratio of the responses to CP compared with the responses to energy were 1·7 for milk yield, 0·9 for fat yield, 3·2 for protein yield and 1·4 for lactose yield. Energy reduced milk protein concentration and tended to increase milk fat concentration whereas CP had the opposite effect. The efficiency of converting food nitrogen to milk nitrogen was unaffected by extra CP but was increased, from 0·195 to 0·229, by extra energy. The poor response in milk protein yield and the reduction in its concentration with extra energy reflected the lower CP intake due to the reduced silage consumption. The experiment emphasizes the importance of concentrate CP supply in stimulating silage intake and yields of all milk constituents for diets containing fairly small amounts of concentrates.

Persian clover and maize silage. II. Effects of variations in clover and silage consumption on the productivity of dairy cows at various stages of lactation

Four experiments, involving 62 animals, were undertaken to establish the effects of variations in Persian clover (Trifolium resupinaturn) and maize (Zea mays) silage consumption on the productivity of dairy cows at various stages of lactation. The research was specifically designed to exclude the effects of the substitution of one feed for another on the responses obtained. Feeding maize silage to cows fed 7-8 kg DM day-1 of Persian clover in early lactation resulted in marginal responses of 1.3-1.4 kg of milk per kg DM of supplement. As level of feeding increased, whether due to additional Persian clover or maize silage, returns to maize silage diminished. In late lactation, 0.9 kg of extra milk was produced from each additional kg DM of maize silage eaten. All of these responses were greater than expected and approached those reported for the use of high energy concentrates. However, there were two exceptions to this general conclusion. Firstly, at very low levels of Persian clover (4.0 kg DM/cow day-1), a protein deficiency prevented responses in milk as more maize silage was offered. Secondly, it was demonstrated that maize silage starch was also important to achieving good responses in milk yield. With only 5% grain in the maize silage in one experiment in mid lactation, the return to extra feeding was only 0.7 kg of milk/kg DM, which was below that obtained in both early and late lactation. The relationships of rumen parameters to differential feeding were variable. Ammonia concentration and acetate proportion both decreased as maize silage intake increased. Of the faecal variables measured, nitrogen concentrations were variable while lignin concentrations were negatively related to maize silage intake, and starch contents showed strong positive correlations.

Influence of the addition of fish meal to diets of roughage or roughage and concentrate on the consumption and live-weight gain of growing cattle

Two feeding trials were carried out to evaluate the influence of the addition of fish meal (F) to diets based on two tropical roughages of different nutritive value supplemented or not with a rumen degradable concentrate (C), on the intake and live-weight (LW) gain of growing cattle. A factorial 2 × 2 arrangement was used with the following treatments: zero or 300 g day −1 F supplementing diets of roughage or roughage plus 1.0 kg day −1 C. Twenty 190 kg Brahman × Holstein animals were used in each experiment over 12 or 11 week periods with basal diets of fresh forage or sorghum silage. The consumption of forage and silage in control treatments without supplements were 25.8 and 15.1 g kg −1 LW, the crude protein (CP) contents were of 81 and 69 g kg −1 dry matter (DM) and DM disappearances in nylon bags at 48 h (DMD48h) were of 579 and 400 g kg −1 DM. The N degradability of concentrate and fish meal were 0.88 and 0.36. Another two trials were carried out with rumen-fistulated animals to evaluate the influence of these supplements on some parameters of rumen digestion. It was found that forage DMD48h was slightly decreased and its rate of digestion in nylon bags was reduced ( P < 0.05) with F, but not with C. In the feeding trials F slightly increased ( P > 0.05) silage intake and decreased forage consumption, and the LW gain responses to this supplement varied with the quality of the roughage. They were higher with the silage of lower quality than with the forage, with increments of 0.33 and 0.16 kg day −1, respectively. These responses were very similar for each roughage given alone or supplemented with concentrate. LW gain was appreciably increased by F and C in both trials ( P < 0.01), but the magnitude of the responses per unit supplement was different between sources and roughages. LW gain increments were 50 and 108 g per 100 g F with forage and low quality silage, and 33 per 100 g C with both roughages. These results indicate that LW gain response to fish meal is very large with low quality tropical forages, and as its quality improves this response is appreciably reduced and tends to be similar to those obtained with concentrates based in degradable sources of nitrogen.

Epidemiologie investigation of a silage-associated epizootic of ovine listeric encephalitis, using a new Listeria-selective enumeration medium and phage typing

Summary The role of silage feeding in the origin of an epizootic of encephalitic listeriosis in a sheep flock was investigated by use of a new direct Listeria-selective isolation and enumeration medium, in combination with serotyping and phage typing. The silage contained high numbers (about 106 cells/g) of a L monocytogenes strain indistinguishable with respect to serovar and phagovar from that isolated from the brains of sick sheep. These results provided unambiguous bacteriologic evidence of the epidemiologic link between silage consumption and listeriosis in ruminants.

Some factors related to the voluntary intake of silage by individual dairy cows housed as a group during two winter-feeding periods

ABSTRACTThe consumption of grass silage by each individual cow in a group housed during two consecutive winter-feeding periods was continuously recorded. During the first winter, one of two concentrates, containing high starch or high fibre, were offered on a sliding scale and half the cows were injected with bovine somatotropin (bST). During the second winter, one of two concentrates, containing high or low rumen-undegradable protein were offered at a flat rate ivith two-thirds of the cows receiving bST. The cows injected with bST had significantly greater yields of milk but their consumption of silage was similar to that of cows not treated with bST. The type of concentrate offered had no significant effect on silage consumption. Although there were significant variations in the consumption of silage from day to day, there were highly significant variations in consumption attributable to individual cows. This individuality of intake persisted in a consistent manner throughout a feeding period and could not be explained on the basis of milk production, body weight, age or parity. In 24 of the cows which were used in both years, their individual intakes for the two periods were significantly correlated. The possibility that this individuality may be of economic importance is discussed.

PERFORMANCE OF BEEF STEERS FED GRASS SILAGE WITH OR WITHOUT SUPPLEMENTS OF SOYBEAN MEAL, FISH MEAL AND BARLEY

Forty crossbred beef steers were used in a 112-d experiment to study the effect of fish meal (FM, 300 g d−1), soybean meal (SBM, 320 g d−1), barley (B, 2 kg d−1) and B plus FM (2 kg + 300 g d−1) supplementation of grass silage on the performance of growing cattle. The growth rate of steers fed silage was 0.83 kg d−1 and this was increased by 0.15, 0.12, 0.27 and 0.36 kg d−1 by supplements of FM, SBM, B and B + FM. Silage dry matter (DM) intake averaged 2.13% of body weight. Protein supplementation had no effect on silage intake. B and B + FM supplementation increased total DM intake (P &lt; 0.01), but decreased silage consumption by 14% (P &lt; 0.05). Key words: Cattle, grass silage, soybean meal, barley, growth, fish meal

Influence of husbandry on the transfer of radiocaesium from feed to milk during the winter that followed the chernobyl reactor accident

The release of activity from the Chernobyl nuclear reactor resulted in deposition of radionuclides throughout the UK in early May 1986. Since that time, the transfer of radiocaesium from feed to milk has been followed at two farms that differ in both location and husbandry practice. This paper concerns the winter of 1986/87, when activity concentrations in milk increased because of the consumption of silage prepared earlier in the year. Silage-to-milk transfer coefficients have been estimated which suggest that, when incorporated into prepared silage, radiocaesium from Chernobyl is less available for transfer to cows' milk than soluble caesium-134 applied directly onto pasture. The measured activity concentrations in milk have been compared with those predicted by the NRPB model FARMLAND; despite differences between the husbandry practice assumed in the model and those observed in practice, the model provides an adequate radiological assessment of the feed-cow-milk pathway after an accidental release of radioactivity.

Effects of supplemental silage on forage intake and utilization by steers grazing wheat pasture or bermudagrass.

Seven trials were conducted to determine the effects of increasing amounts of silage (corn, wheat or sorghum) on forage intake, gastrointestinal tract fill, fecal output and ruminal flow and degradation of forage by cattle grazing wheat pasture or bermudagrass. In each of 3 yr, 24 steers grazed a common wheat or bermudagrass pasture and were randomly allocated to four treatments (0, .35, .70 or 1.05 kg silage DM.100 kg body weight-1.d-1). Intake and ruminal flow of forage were measured by feeding a single pulse dose of Yb-labeled forage followed by collection of fecal samples for 4 to 5 d and fitting Yb concentrations to a one-compartment, age-dependent model. Ruminal digestion kinetics of wheat forage were estimated in situ using eight ruminally cannulated steers fed 0 or .55 kg sorghum silage DM.100 kg body weight-1.d-1. Supplemental silage decreased wheat forage (P less than .10) and bermudagrass (P less than .01) intake linearly. However, total forage intake of bermudagrass plus silage increased linearly (P less than .05). Each kilogram of added silage DM decreased DM intake of wheat forage by .66 +/- .25 and of bermudagrass by .63 +/- .17 kg. Flow and turnover of wheat forage or bermudagrass were not altered (P greater than .15) by supplemental silage. Silage consumption increased extent of ruminal degradation of wheat forage DM (P less than .05; 63.1 vs 52.5%), indicating a positive associative effect of silage on wheat forage utilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Food intake in sheep following intraruminal infusion of extracts from lucerne silage with particular reference to organic acids and products of protein degradation

SummarySheep were infused intraruminally with iso-osmotic solutions of saline, organic acids or lucerne silage extracts with or without additional acids and products of protein degradation found in silage. The post-ingestive effects of silage constituents on food intake were assessed by measuring the voluntary consumption of high dry matter silage over a 20 h period following feeding. In Expt 1, three different silage extracts each depressed food intake up to 4 h following feeding. In Expt 2, one of these extracts, to which 40 g of γ-amino butyric acid (GABA) was added, depressed intake up to 4 h following feeding; with the further addition cf 10 g α-amino butyric acid (AABA) and 28 g amines to this extract, intake was enhanced within 0·5 h but depressed from 4 to 8 h following feeding. In Expt 3, infusion of organic acids alone did not significantly depress food intake relative to saline, nor was there a discernible effect on food intake when graded levels of nitrogenous constituents from silage were added to the infusates. In Expt 4, infusion of an extract, to which only AABA and four other amines were added, depressed cumulative intake up to 8 h following feeding and had a more pronounced effect on food consumption than infusion of the extract with these constituents together with GABA. It was concluded that soluble constituents in silage can inhibit intake but no single constituent is primarily responsible.

Effects of Silage pH on Voluntary Intake of Corn Silage and Alfalfa Haylage

Effects of forage pH on voluntary intake of corn silage and alfalfa haylage were evaluated. Four (140kg) Holstein steers were in a 4×4 Latin-square design with 15-day experimental periods in Trial 1. Treatments consisted of 1) fresh whole corn plant frozen at harvest, 2) fresh whole corn plant acidified with hydrochloric acid to the pH of corn silage, 3) corn silage, and 4) corn silage neutralized with sodium bicarbonate to the pH of fresh whole corn plant. Addition of acid to fresh whole corn plant reduced pH from 5.20 to 3.66 and organic matter intake .29 to 3.62 kg/day. Neutralization of corn silage acidity increased pH from 3.86 to 5.94 and organic matter intake .49 to 4.23 kg/day. In Trial 2, 16 Holstein heifers (290kg) were fed one of the following treatments in an 8-wk experiment: 1) control corn silage, 2) corn silage plus added water, and 3) corn silage plus 7.0% sodium bicarbonate solution in amount identical to amount of water in 2. Water and sodium bicarbonate solution were added at 25 kg/100kg of silage prior to feeding. Addition of water depressed intake of organic matter 1.16kg to 6.64 kg/day. Addition of sodium bicarbonate increased silage pH to 7.11 versus 3.79 for control and increased organic matter intake .59 kg/day over animals fed water plus silage. In Trial 3, 16 Holstein heifers (250kg) were fed in an 8-wk experiment haylage neutralized with 0, 1.f, 3.0, or 4.5.% sodium bicarbonate (dry matter). Silage pH increased from 4.48 in the controls to 5.78 at the highest addition of sodim bicarbonate. Sodium bicarbonate increased intake of organic matter in a linear response with the greatest increase (1.08 kg/day) at 4.5% sodium bicarbonate. Forage pH affects voluntary consumption of corn silage and alfalfa haylage, and neutralizing free acid with sodium bicarbonate increased intake.

The face fly (Diptera: Muscidae): effect on holstein milk secretion.

Three switchback-design field trials were conducted in which we compared milk quantity and quality between herds of Holstein cows, one protected from face flies, Musca autumnalis De Geer, and the other exposed to face flies. Cows were between the peak and the middle of lactation, fed and milked similarly, and grazed on adjacent pastures while alternately protected from or exposed to face flies during three 10-day penods. Data concerning face fly numbers, and milkweights and silage consumption were taken for each cow daily; milk samples for chemical analysis were taken each second or third day. With one exception, the results for each trial showed that average milkweight values did not differ between exposed and protected cows, despite marked differences in face fly numbers. Further, no consistent differences were observed in percentage of milkfat, percentage of protein, percentage of nonfat solids, or somatic cell counts. Silage consumption and silage conversion efficiency were also similar for protected and exposed herds. We therefore conclude that exposure to greater numbers of face flies resulted in little, if any, effect on milk secretion.

Effects of Silage pH on Voluntary Intake of Corn Silage

We evaluated effects of silage pH on corn silage intake. Sixteen Holstein heifers (292kg) were fed control corn silage during a 2-wk preliminary period. This was followed by an 8-wk experimental period in which animals were fed silage neutralized with 0, 2, 4, or 6% sodium bicarbonate (dry matter) added prior to feeding with corresponding pH's 3.72, 4.46, 5.62, and 8.05. Organic matter intake was increased 1.0 and 1.2 kg/day by addition of 2 and 4% sodium bicarbonate versus controls whereas 6% sodium bicarbonate reduced intake .7 kg/day. An equation developed to predict organic matter intake from silage pH was: Y = −3.20 + 3.92 (pH) −.35 (pH)2 with coefficient of determination .66. This equation predicted maximum organic matter intake at pH 5.6. It appears that silage pH is a factor that affects voluntary consumption of corn silage and that pH 5 to 6 is optimum, whereas silage pH above and below may reduce intake.

Nutrient intake and efficiency of calf production by two-breed cross cows.

Individual consumption of total digestible nutrients (TDN) was measured on 105 two-breed cross cows (Hereford X Angus reciprocal crosses, HA; Simmental X Angus, SA; Simmental X Hereford, SH; Brown Swiss X Angus, BA; Brown Swiss X Hereford BH; Jersey X Angus, JA and Jersey X Hereford, JH) and their three-breed cross calves managed in drylot. Cows were 4 to 6 yr of age and mated to Charolais or Limousin bulls. Cows remained in the drylot for a period of approximately 1 yr (from weaning one year to weaning the next year). Ad libitum consumption of corn silage was allowed for about 4 h each day and fixed amounts of grain and protein supplement were fed as needed. Calf creep feed was provided during the latter portion of lactation. Compared with the average weight of HA cows (454 kg), SA cows were 7% heavier, SH, BA and BH cows were similar, while JH and JA cows were 15 and 22% lighter in weight, respectively. Total intake of TDN by cow and calf for the 365-d drylot period was greatest for the SA group (2,309 kg), exceeding that of the HA group by 11.2%. The JA group consumed 7.2% less than HA, while other groups were similar to HA in TDN intake. Daily intake of TDN for the 365-d period, expressed as a percentage of cow weight and cow weight .75, was highest for the smaller J crosses. The ratio of 365-d TDN intake to 205-d calf weight, a measure of weaning efficiency, averaged 10.0 kg/kg for JH, BH and SH, 10.5 kg/kg for HA and BA and 10.9 kg/kg for JA and SA. When TDN intake was adjusted for cow weight change, crossbred cow group was not a significant source of variation for kg TDN/205-d calf weight.

Utilization of alkali-treated grain. 3. Utilization by steers of NaOH-treated and rolled barley in silage-based diets

In the first of three experiments, silage constituted 33 or 66% of the dry matter of complete diets, barley being the other component. The barley was either rolled, or treated with 30 g NaOH/kg dry matter. In two further treatments, the NaOH-treated barley was given in separate feeds, while silage was offered ad libitum. The diets were offered ad libitum to 32 Hereford cross steers from 325 kg live weight to slaughter at 450 kg live weight. Growth rate increased and feed conversion ratio decreased as the precentage of barley in the diet increased, but were significantly poorer with NaOH-treated than with rolled barley owing to the significantly lower digestibility of dry matter, organic matter and starch in diets containing NaOH-treated grain. In the second experiment, the effect on digestibility of increasing the NaOH added to the barley used in the mixed diets was investigated with steers. The results showed that the level of NaOH application had to be greater when NaOH-treated barley was used in mixed feeds than when it was used as the sole feed. The optimum rate of application in silage based diets was in the region of 45 g NaOH/kg dry matter. In the third experiment, forty Hereford cross steers were allocated to one of four treatments and were fattened from 325 to about 450 kg live weight. They were given (dry matter basis) 50% silage and 50% of barley, either rolled (RM) or treated with 45 g/kg NaOH (CM), mixed together, or they were given the silage alone until they had eaten the allocated quantity and then the allocated barley; the barley was either rolled (RS) or treated with 30 g/kg of NaOH (CS). The same quantities of silage and grain were given to all steers. The steers fed on silage and grain separately took, on average, 125 days to consume the feed (70 days for consumption of silage), but had similar carcass weights to the steers given mixed diets, which consumed their feed in 91 days. The growth rates for treatments RM, CM, RS and CS, respectively, were 1.15, 1.20, 0.89 and 0.78 kg/day, the food consumption was 737, 741, 728 and 741 kg dry matter and the final carcass weights were 256, 253, 247 and 252 kg. There were no significant differences between steers receiving the diets containing rolled or NaOH-treated barley.

Nutritional studies with sheep fed conserved ryegrass. 2. Silage supplemented with dried grass or barley

SummaryGrass silage (21.0 % D.M.) was given ad libitum to sheep together with supplements of rolled barley, dried-grass pellets or dried-grass wafers at 12 and 25 g organic matter (OM)/kg0·75.Intake of silage was greater with supplement at 12 g/kg0·75 but total intake of OM and digestible organic matter (DOM) increased with increasing supplement. Intake of OM was higher with the pellet supplement than with other supplements. Intake of DOM, however, did not differ between the pellet and barley treatments, but was lower with wafers.Concentrations of ammonia and total volatile fatty acids and the molar proportions of butyric and higher volatile fatty acids were higher when silage was supplemented with barley than with dried grass. Mean rumen retention times of silage and of supplement were highest in the barley-supplemented treatments. Dried-grass wafers were retained longer than dried-grass pellets. Supplement treatments did not differ significantly for eating and ruminating times, rumen fluid volume and pH, digestion rate in the rumen and nitrogen retention.At the low supplement rate silage consumption may have been controlled by factors associated directly with the silage, whereas at the high rate intake was limited either by physical factors or by the potential energy demand of the animals.

Brown-Midrib Corn Silage for Lactating Dairy Cows

Brown midrib-3 mutant (low lignin) corn silage and its normal genetic counterpart were fed to more cows longer than in most trials. Twenty lactating Holstein cows (10 per ration group) were group fed corn silage (brown midrib-3 or normal) ad libitum, 2.25kg alfalfa hay/head and grain at 1 kg/3kg milk produced daily through 12 wk. Cows averaged 6 wk postpartum at the start of the trial. Chemical composition was similar for the two silages. Silage and total intakes of dry matter were similar, although intakes tended to be larger for cows fed the mutant corn silage. Milk production and its composition were similar (25.0 and 25.5kg milk/day, 3.79 and 3.88% fat, 2.99 and 3.03% protein, and 12.44 and 12.42% total solids for cows fed brown midrib-3 and normal silages). Cows fed the ration of mutant corn gained more weight than those fed the normal corn silage ration. Apparent digestibilities of nutrient constituents were 1 to 10 percentage units higher for the brown midrib-3 ration. Utilization of nitrogen from the two rations was similar. Concentrations of total volatile fatty acids and butyrate were greater in rumen contents of cows fed the normal ration. Rumen pH and ammonia were similar. Glucose and urea nitrogen concentrations in serum did not differ between treatments. The slightly greater consumption and digestibility of silage made from the brown midrib-3 mutant of corn were reflected in increased weight gains rather than in increased milk production.

EVALUATION OF WHOLE PLANT FABABEAN FORAGE IN RUMINANT RATIONS

Feeding trials were conducted to evaluate nutritive value of whole plant fababean (FB) silages. A growth trial with dairy heifers resulted in higher consumption (P &lt; 0.05) of FB silage than a grass-legume (GL) silage, with no difference (P &gt; 0.05) in average daily gain (ADG). Lactating Holstein cows were fed four diets, 1-GL + high grain (HG) (control diet), 2-direct cut FB (33% DM) + HG, 3-wilted FB (37% DM) + HG and 4-wilted FB + medium grain (MG), in a Lucas design. Consumption of the direct cut FB silage was higher (P &lt; 0.05) than that of grass silage, and reducing the level of grain feeding from 56 to 43% of the diet resulted in an increase (P &lt; 0.05) in FB silage consumption. Wintering calves were fed five silages (1-FB, 2-GL, 3-barley-clover (BC), 4-corn or 5-barley) plus 1 kg grain supplement for 93 days. Calves receiving FB or GL silage consumed more (P &lt; 0.05) DM than animals on the other treatments. In trial 2, beef calves were fed four silages (early FB, frosted FB, corn or GL) or two types of dehydrated cubes (FB or allalfa). Frosted FB silage have a higher (P &lt; 0.01) ADG compared with the other treatments. Intakes of DM were similar for both FB silages and alfalfa cubes but higher than in GL or corn silage treatments. Feed efficiency ratio was smaller (P &lt; 0.05) for frosted FB than GL silage or dehydrated cubes and similar to the early FB and corn silages. Finishing steers were fed three silages (FB, GL or corn) free choice plus a barley supplement at 1% of body weight. Total DM intake and ADG were higher (P &lt; 0.01) for steers receiving FB silage than for those fed the GL or corn silage. Energy digestibility of FB silage as measured by sheep digestion trials over 2 crop yr and three silage samples was 69.4% ± 2.3, and digestible energy content of FB was similar to that of corn silage.