Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Silage”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources

Development of a novel system to estimate protein degradability in legume and grass silages.

Five trials were conducted to develop a system to estimate rumen-undegradable protein (RUP) of legume and grass silages using near infrared reflectance spectroscopy. In situ procedures were the reference method used to determine silage RUP content. Trials 1, 2, and 3 were devoted to improving in situ procedures. In trial 1, alfalfa silage with and without heat treatment was incubated ruminally in 30 cows. The standard deviation of in situ RUP attributable to cow and diet was 0.82 and 3.80 g/10(-1) kg of crude protein (CP) for the unheated and heated alfalfa, respectively. Based on trial 1, it was determined that 8 cows would be required to establish RUP standards. In trial 2, low (13.3 g/10(-1) kg of CP) and high (44.5 g/10(-1) kg of CP) RUP standards were developed using eight ruminally cannulated cows. In trial 3, 11 new RUP standards were developed by mixing trial 2 RUP standards together. The RUP standards were used to employ a calibration curve technique in ruminally cannulated cows. The technique was employed in four ruminally cannulated cows to estimate RUP contents of 121 silages, and RUP values were used for near-infrared reflectance spectroscopic analysis in trial 4. Trial 4 procedures yielded a calibration for RUP content of silages with an R2 of 0.84 and a standard error of calibration of 1.55 g/10(-1) kg of CP. In trial 5, the equation was tested on 300 silage samples. The mean predicted RUP content was 21.8 g/10(-1) kg of CP. Data suggest near-infrared reflectance spectroscopy can predict RUP content of silages.

Animals↗

Effect of feeding macerated alfalfa silage on nutrient digestibility and milk yield in lactating dairy cows.

Five feeding studies were conducted with 141 lactating Holstein cows comparing macerated and control alfalfa silage harvested at two cuttings in each of 2 yr. Overall, silage made from macerated alfalfa contained more ash (suggesting improved soil contamination); greater fiber and lower nonprotein nitrogen (NPN) content suggested greater fermentation in the silo. In a digestion study, two diets were fed containing [dry matter (DM) basis] 72% of either control or macerated second-cutting alfalfa. Apparent digestibility of neutral detergent fiber and acid detergent fiber (ADF) was increased by maceration, and similar changes in digestibility were observed with Yb or indigestible ADF as marker; indigestible ADF was used as a marker in later studies. Lactation trials were conducted with first- and second-cutting alfalfa from each year. In each study, diets were formulated from alfalfa silage plus concentrate based on processed high moisture ear corn; mean compositions were (DM basis): negative control (61% control alfalfa silage), macerated (61% macerated alfalfa silage), and positive control (50% control alfalfa silage). All diets contained 2% crude protein from either roasted soybeans or low-solubles fish meal; soybean meal was added to make the positive control isonitrogenous (but not equal in ruminal undergraded protein). Milk yield was greater on macerated than negative control in two of four trials but not different in the other two trials. Yields of milk and milk components were not different between macerated and positive control in one of four trials. Versus the negative control, milk fat synthesis was depressed on macerated alfalfa in one trial. Overall performance on macerated versus negative control indicated greater apparent digestibility of organic matter (OM), greater yield of milk, protein, and solids not fat, but lower milk fat content. Yields of milk and milk components were greater overall on positive control versus macerated. Estimation of net energy for lactation (NEL) from maintenance, milk yield, and body weight gain indicated that control and macerated alfalfa silage contained, respectively, 1.36 and 1.42 Mcal of NEL of OM, an increase of about 5% due to maceration of alfalfa in these trials.

Animal Nutritional Physiological Phenomena↗

Claviceps cyperi, a new cause of severe ergotism in dairy cattle consuming maize silage and teff hay contaminated with ergotised Cyperus esculentus (nut sedge) on the Highveld of South Africa.

During December/January 1996/97 typical summer syndrome (hyperthermia and a 30% drop in milk yield) occurred in succession in two Holstein dairy herds (n=240 and n=150 milking cows, respectively) on the South African Highveld. These farms are situated in the midst of the prime maize and dairy farming areas of South Africa where this condition had never been diagnosed before. The individual components of the concentrate on both farms were negative for ergot alkaloids. Endophytic fungi and/or ergot infestation of teff and other grasses fed to the cows were then suspected of being involved, but neither endophytes nor ergot alkaloids could be implicated from these sources. By measuring the serum prolactin levels of groups of sheep (n=5) fed the first farm's total mixed ration (TMR) or its three individual fibre components for a period of 11 days, the source of the ergot alkaloids was identified. A statistically significant decrease in the level of this hormone occurred only in the group on maize silage (which constituted 28% on dry matter base of the TMR). The involvement of the maize silage was further chemically confirmed by the high levels of total ergot alkaloids, predominantly ergocryptine, found by LC-MS in the silage as well as in the TMR (115-975 ppb and 65-300 ppb, respectively). The ergot alkaloid content (mainly ergocryptine) of the maize silage on the second affected farm was 875 ppb. Withdrawal of contaminated silage resulted in gradual recovery of stock on both farms. Nut sedge (Cyperus esculentus and Cyperus rotundus of the family Cyperaceae) has a world-wide distribution and is a common weed in annual crops, and can be parasitized by Claviceps cyperi. Careful examination of the maize silage from both farms revealed that it was heavily contaminated with nut sedge and that it contained minute sclerotia, identified as those of Claviceps cyperi, originating from the latter. Nut sedge was abundant on both farms and it is believed that late seasonal rain had resulted in mature, heavily ergotised nut sedge being cut with the silage. Claviceps cyperi sclerotia, collected on the affected fields in the following autumn contained 3600-4000 ppm ergocryptine. That the dominant alkaloid produced by this particular fungus was indeed ergocryptine, was confirmed by negative ion chemical ionization MS/MS. In one further outbreak in another Holstein herd, teff hay contaminated with ergotised nut sedge and containing 1200 ppb alkaloids, was incriminated as the cause of the condition. This is the first report of bovine ergotism not associated with the Poaceae infected with Claviceps purpureum or endophytes but with the family Cyperaceae and this particular fungal phytopathogen.

Animal Feed↗

Citrus pulp and wheat straw silage as an ingredient in lamb diets: effects on growth and carcass and meat quality.

Twenty "Merinizzata Italiana" lambs were introduced to two experimental diets. Ten animals (five males and five females, control group) received the traditional diet that is supplied by farmers in southern Italy, which comprised of oat hay ad libitum and commercial concentrate. The second group (the same number of lambs, silage group) received citrus pulp and wheat straw silage ad libitum and 70% of the commercial concentrate supplied to the control group. The animals were slaughtered after 80 days of feeding and carcass and some meat quality parameters were measured. No differences were observed for live weight between treatments, and carcass weights were similar for the two diets, but with obvious differences between sexes. Animals on silage produced carcasses with a better muscular conformation and with a lower fatness score (P<0.05). Subcutaneous fat colour was influenced by sex, being lighter in the female carcasses (P<0.05). Dissection of different anatomical parts showed a higher percentage of lean and a lower proportion of fat in silage samples compared to control ones. Ultimate pH was highly affected by sex being higher in the samples from male lambs (P<0.01), but was unaffected by diet treatment. Diet tended to affect meat shear force value which was lower in the silage samples, although, samples from all the animals were extremely tender. Meat from silage samples had a higher water content (P<0.05). Overall, in our experimental conditions, the use of citrus pulp silage seemed to be economically convenient for producing animals with substantially unmodified carcass and meat quality characteristics.

Journal Article↗

Brown midrib-3 corn silage improves digestion but not performance of growing beef steers.

The brown midrib-3 (bm3) gene mutation has been incorporated into corn plants to potentially improve fiber digestibility. The objectives of this study were to determine the effect of bm3 corn silage on digestion and performance of growing beef steers and to determine whether limiting intake would further enhance fiber digestibility of bm3 corn silage. A bm3 hybrid and its isogeneic normal counterpart were harvested at three-quarters kernel milk line. Neutral detergent fiber, ADF, and ADL were 4.5, 6.9, and 1.9 units lower, respectively, and DM was 5.4 units higher for bm3 than for normal silage. In Trial 1, eight ruminally fistulated Angus crossbred steers (224 +/- 24 kg) were randomly assigned to a 2 x 2 factorial arrangement of treatments in a replicated 4 x 4 Latin square design. Steers had ad libitum feed access or were restricted to 80% of ad libitum intake of diets containing 86% normal corn silage (Control) or bm3 corn silage (BMCS). The remainder of the diets consisted of soybean meal, urea, monensin, vitamins, and minerals. Dry matter intake was greater (P < 0.01) for steers offered ad libitum access to BMCS than for those with ad libitum access to the Control diet. The BMCS treatment resulted in improved (P < 0.05) apparent total-tract digestibility of DM, OM, NDF, and ADF. Mean concentration of total VFA and molar proportions of acetate were increased (P < 0.05) by feeding BMCS. There tended to be a DMI x hybrid interaction (P = 0.16) for apparent total-tract digestibility of NDF. When diets were offered ad libitum, BMCS increased NDF digestibility by 10.5 percentage units compared with Control, but, when DMI was limited, BMCS increased NDF digestibility by 15.8 percentage units. In Trial 2, 128 steer contemporaries of those used in Trial 1 (245 +/- 13 kg) were offered ad libitum access to BMCS or Control diets as used in Trial 1. After a 112-d treatment period, concentrate in the diet was increased, and all steers were fed a common finishing diet. During the 112-d treatment period, steers receiving BMCS consumed 0.45 kg more DM/d (P < 0.05) and had similar ADG (P > 0.10), compared with those steers receiving the Control silage. This resulted in poorer (P < 0.01) feed efficiency for steers receiving BMCS. Finishing phase and overall performance of the steers was not different (P > 0.10) due to treatment. Although feeding BMCS in growth-phase diets resulted in increased daily DMI and improved digestibility of DM and fiber, it did not result in improved steer feedlot ADG compared with Control silage.

Animal Feed↗

[Effect of the addition of tropical fruits--pineapple (Ananas comosus) and papaya (Carica papaya)--on the production of biological silage from fish].

Microbial Fish Silage was produced from under-utilized fish mixed with juice and waste fruits (pineapple and papaya) at 35 degrees C. Six different products were elaborated as following: A: fish muscle with pineapple juice; B: fish muscle with fruit wastes; C: gutted fish with pineapple juice; D: gutted fish with fruit wastes; E: whole fish with pineapple juice; F: whole fish with fruit wastes. Process development was evaluated by measuring: pH, acidity, non-protein nitrogen, consistency and exudate liquid. Results indicated a slow decrease in pH value and production of acidity during 20 storage days. The addition of fruits to silage did not have any effect on these values. Silage liquefaction or hydrolysis was related to the following parameters: consistency, non-protein nitrogen and exudate liquid. The addition of fruits was related to silage liquefaction or hydrolysis, and it was measured by the consistency. Exudate liquid and non-protein nitrogen increased during storage time. However silage made from whole fish showed highest values in those parameters than other processing conditions. This results suggested that hydrolysis involve first enzymes from guts and second enzymes from muscle and head. Pineapple juice did not contribute to hydrolysis process. Mainly sensory changes in the silage occurs during first 24 hours and they were related to chemical changes. Proximal analysis did not change during silage process and microbial counts indicated the freshness of raw material used i this study.

Animals↗

Effect of sainfoin (Onobrychis viciifolia) silage and hay on established populations of Haemonchus contortus and Cooperia curticei in lambs.

The objective of the study was to examine the effect of dried and ensiled sainfoin (Onobrychis viciifolia) on established populations of Haemonchus contortus (abomasum) and Cooperia curticei (small intestine) in lambs under controlled conditions. Twenty-four parasite naïve lambs were inoculated with a single dose of infective larvae of these parasites 28 days prior to the start of the feeding experiment. Twenty-four days post-infection, 4 days prior to the start of the feeding experiment, animals were allocated to four groups according to egg excretion, live weight and sex. Groups A and B received sainfoin hay and control hay, respectively, for 16 days. Groups C and D were fed on sainfoin silage or control silage for the same period. Feeds were offered ad libitum and on the basis of daily refusals were supplemented with concentrate in order to make them isoproteic and isoenergetic. Individual faecal egg counts on a dry matter basis (FECDM) were performed every 3-4 days and faecal cultures and packed cell volume (PCV) measurements were done weekly. After 16 days of experimental feeding, all animals were slaughtered and adult worm populations were determined. The consumption of conserved sainfoin was associated with a reduction of adult H. contortus (47% in the case of hay, P<0.05; 49% in the case of silage, P=0.075) but had little effect on adult C. curticei. Compared to the controls, H. contortus specific FECDM was reduced by 58% (P<0.01) in the sainfoin hay group and by 48% (P=0.075) in the sainfoin silage group. For both sainfoin feeds FECDM specific to C. curticei were significantly decreased when compared to the control feeds (hay 81% and silage 74%, both tests P<0.001). Our data suggest that different mechanisms were responsible for the reduction in FECDM in response to feeding tanniferous fodder. For H. contortus, the decrease seemed to be due to a nematocidal effect towards adult H. contortus. In contrast for C. curticei, the reduction in FECDM appeared to be a result of a reduced per capita fecundity. For both, hay and silage, an antiparasitic effect could be shown, offering promising perspectives for the use of conserved tanniferous fodder as a complementary control approach against GIN.

Abomasum↗

Growth of Escherichia coli O157 in poorly fermented laboratory silage: a possible environmental dimension in the epidemiology of E. coli O157.

Laboratory silages, inoculated with either c. 1000 cfu g-1, an atoxigenic Escherichia coli O157 or a toxigenic E. coli O157 isolate, were made in plastic bags which permitted limited aerobic spoilage. Replicate bags of each treatment were opened at weekly intervals after incubation at 20 degrees C. In all silages the fermentation was slow and aerobic spoilage with visible moulding ocurred at the tie ends after 7 d. In all the aerobically spoiled silages Enterobacteriaceae reached over 107 cfu g-1 within 1 week. The E. coli in control silages increased from barely detectable levels to 104 cfu g-1 within 13 d; over the same period both strains of E. coli O157 increased from 103 to 107 cfu g-1. The increases in the poorly fermented interior of the silage bags were initially similar but declined slightly as the pH fell. It is suggested that faecal contamination of grass followed by poor silage management may be a factor in the persistence of E. coli O157 carriage in ruminants.

Animals↗

The importance of the form of nitrogen on microbial protein synthesis in the rumen of cattle receiving grass silage and continuous intrarumen infusions of sucrose.

1. In a 4 x 4 Latin square design experiment, four cattle were given grass silage in two meals per d to satisfy maintenance energy requirements. In addition, sucrose (170 g/kg silage dry matter (DM] was infused intraruminally at a constant rate with no nitrogen supplementation; with the infusion intraruminally of either casein (23 g/kg silage DM) or urea (8 g/kg silage DM); or with soya-bean meal (64 g/kg silage DM) fed in two equal portions. 2. Samples of duodenal digesta representative of a 24 h period were obtained using chromium-EDTA and ytterbium acetate for flow estimation and 35S as a marker of microbial N entering the small intestine. Samples of rumen fluid were also taken for estimation of rumen pH and concentrations of ammonia-N and volatile fatty acids. Estimates of apparent organic matter (OM) and N digestibility and of the rates of silage DM and N disappearance from porous synthetic-fibre bags incubated in the rumen were also made. 3. The N supplements had no significant effects on rumen pH, concentrations of volatile fatty acids, their molar proportions or the disappearance of DM or N from porous synthetic-fibre bags. N supplementation increased rumen ammonia-N concentrations (urea, P less than 0.05; casein, soya-bean meal, not significant). 4. N supplementation had no significant effects on the digestion of OM, acid-detergent fibre or soluble carbohydrate. 5. Infusion of casein increased the quantities of total non-ammonia-N (not significant) and microbial N (P less than 0.05) entering the small intestine daily and the efficiency of rumen microbial N synthesis (not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

Fat and protein metabolism in growing steers fed either grass silage or dried grass.

Cattle fed grass silage diets have been reported to have high carcass fat:protein ratios. The effect of grass silage and dried grass diets, fed at different levels of intake to ensure a range of equivalent metabolisable energy intakes (MEI) from 1 .1 x metabolisable energy requirement for maintenance to ad libitum, on fat and protein metabolism in twenty-four Hereford x Friesian steers was investigated. After about 84 d of dietary treatment rates of whole-body fat and protein metabolism were measured, as were rates of lipogenesis in omental, perirenal and subcutaneous adipose tissue. Carcass composition was determined. Animals fed silage had greater (P<0 .001) carcass fat:protein ratios than animals fed dried grass at equivalent levels of MEI. Animals fed silage had lower (P<0 .001) rates of protein gain. Rates of leucine entry and oxidation were lower (P<0 .001) in animals fed silage, but there was no dietary difference in the rate of whole-body protein synthesis. There was no dietary difference in the rate of carcass fat gain, but rates of lipogenesis in perirenal adipose tissue were significantly (P=0 .007) higher in animals fed silage. There was no dietary difference in the rate of palmitate and glycerol entry or palmitate oxidation. There were no interactions between MEI and diet, indicating that increments of energy were utilised with the same efficiency from both diets. It was concluded that the high carcass fat:protein ratios of young growing steers was due to limited rates of protein accretion and not to elevated rates of carcass fat accretion.

Acetates↗

The impact of the quality of silage on animal health and food safety: a review.

This paper reviews the microbiological aspects of forage preserved by ensilage. The main principles of preservation by ensilage are a rapid achievement of a low pH by lactic acid fermentation and the maintenance of anaerobic conditions. The silage microflora consists of beneficial micro-organisms, i.e. the lactic acid bacteria responsible for the silage fermentation process, and a number of harmful micro-organisms that are involved in anaerobic or aerobic spoilage processes. Micro-organisms that can cause anaerobic spoilage are enterobacteria and clostridia. Clostridium tyrobutyricum is of particular importance because of its ability to use lactic acid as a substrate. Silage-derived spores of C. tyrobutyricum can cause problems in cheese making. Aerobic spoilage of silage is associated with penetration of oxygen into the silage during storage or feeding. Lactate-oxidizing yeasts are generally responsible for the initiation of aerobic spoilage. The secondary aerobic spoilage flora consists of moulds, bacilli, listeria, and enterobacteria. Mycotoxin-producing moulds, Bacillus cereus, and Listeria monocytogenes in aerobically deteriorated silage form a serious risk to the quality and safety of milk and to animal health.

Animal Welfare↗

[Food intake of dairy cows and heifers in late pregnancy during feeding of maize silage].

The influence of restricted (covering requirements) or ad libitum supply of maize silage in late pregnancy on feed intake was tested in two experiments with totally 51 dairy cows with several calvings (V1, V2 and in one experiment with 14 heifers (V3). Experimental time were the last 8 weeks before the expected calving date and was equivalent to the dry period of the cows. With adjusted feeding for energy requirement as a restricted supply the cows in V1 and V2 consumed 5.73 vs. 5.64 kg DM maize silage/animal and day, with ad libitum supply the intake of maize silage was substantial higher with an average of 9.65 vs. 9.85 kg DM/animal and day. With adjusted feeding for energy requirement as a restricted supply the heifers in V3 consumed 4.77 kg DM maize silage/animal and day. With ad libitum supply, however, the daily maize silage intake of heifers was substantial more with 7.00 kg DM/animal. With ad libitum feeding the mean daily intake of maize silage was unchanged in the weeks 8 to 3 before calving and decreased very strong in the cow experiments (V1, V2) in the last two weeks before calving and in the heifers experiment (V3) in the last week before calving. With restricted feeding the intake of maize silage was nearly unchanged until calving, only the cows in V1 showed a slight decrease in the last week before calving. With ad libitum feeding of maize silage in late pregnancy until 2 weeks before calving the cows and heifers reached a net energy intake of about 80 vs. 62 MJ NEL/day, which corresponded to 160% (V1, V2) vs. 135% (V3) of the energy requirement. The overconsumption for the crude protein was slighter with 120 to 140% of requirement.

Animals↗

[The effect of starch-rich single feed on the digestibility and the energy content of corn silage in cattle and sheep].

Different starch components were added to rations with maize silage measuring the influence of the supplements on the digestibility and energy content of maize silage in cattle (n = 36) and sheep (n = 36). The starch-rich components maize, wheat, barley, oat, cassava meal and potato starch were added to the total rations on average of 33%. All supplements were ground (sieve of 2.5 mm); additionally, wheat was added in extruded or crushed form. All rations including the control ration without starch components were supplemented with soybean meal to an average crude protein content of 12.4% DM. The mean starch content of the total rations was 42% DM. The supplementation of maize silage with the different starch components increased the digestibility of the organic matter of all rations on average only slightly from 77% to 78% in cattle, while the mean digestibility in sheep raised from 74% to 79% more pronounced. However, the influence of the different starch components on the digestibility was similar for both ruminants. The supplementation with the ground, crushed or extruded wheat, with barley and with oats impaired the digestibility of the crude fibre of the total ration and of the maize silage, respectively. Therefore, the digestibility of the organic matter of maize silage was reduced and the energy content decreased by about 6% in comparison to the control ration without starch supplementation. However, the supplementation with maize, cassava meal or potato starch had no negative effects on the digestibility and energy content of maize silage.

Animal Feed↗

[The effect of size reduction of corn silage on feed intake, milk production and milk composition of cows].

In three experiments (E1, E2, E3) maize silage of different physical structure and of different stage of maturity at harvest were fed to 24 (E1), 36 (E2) or 28 (E3) dairy cows. The cows were fed individually over an experimental period of five or six weeks. The maize silages had a mean DM content of 28% (E1), 32% (E2) or 36% (E3). At the stage of harvest, the stovers and the cobs had a mean DM content of < 22% (E1, E2) or 27% (E3), 40% (E1), 46% (E2) or 57% (E3), respectively. The maize was harvested with a chopping length of 4 and 8 mm (E1, E3) and of 6 and 8 mm (E2), without corn cracking (E1) or with and without corn cracking (E2, E3). The daily feed ration consisted of ad libitum offered maize silage, 1.7 kg DM hay, soya bean meal (E2, E3) and concentrate. The different chopping length of 4 mm, 6 mm or 8 mm had no effect on the maize silage intake in E1 and E2. In E3 the daily maize silage intake increased by about 1.2 kg DM per cow at a chopping length of 4 mm in comparison to 8 mm, whereas only the treatment with the combination of 4 mm chopping length and corn cracking showed a significant increase in DMI. The corn cracking improved the milk yield significantly (E2) or in a tendency (E3) at 2.0 kg (E2) or at 1.6 kg (E2), while the variation of chopping length had no effect on milk yield. The different physical structure did not influence the milk fat content with mean values of 4.65% (E1), 4.15% (E2) and 4.10% (E3), respectively. The milk protein content decreased in E2 feeding maize silage with a chopping length of 8 mm and corn cracking; but in E1 and E3 no effect was seen on protein content with mean values of 3.66% (E1) or 3.51% (E2).

Animals↗

Inhibition of proteolysis in alfalfa silages using heat at harvest: effects on digestion in the rumen, voluntary intake and animal performance.

The effects of proteolysis on digestion and animal performance were studied using heat to inhibit proteolysis at ensiling. Alfalfa (Medicago sativa) was ensiled either after wilting for 24 h (control; C) or after heating (100 degrees C) in a crop dehydrator for 2 min (heated; H). In Exp. 1, eight wethers, cannulated in the rumen and duodenum, were given the silages to determine the effects of heat treatment of alfalfa on the digestion of silage. In Exp. 2, growing lambs had ad libitum access to the silages to determine the effects of heat treatment on intake, animal performance and body composition. Heat treatment inhibited protease activity; protein N accounted for 33.5 and 61.3% and ammonia N 15.5 and 5.1% of total N in C and H silages, respectively. Heat treatment reduced mean post-feeding ruminal ammonia N concentration (P less than .05), ruminal pH (P less than .05) and the acetate: propionate ratio (P less than .001) in ruminal fluid. Heat treatment increased duodenal flow of non-ammonia N (P less than .05) and amino acids (P less than .05), the amount of N absorbed (P less than .05) in the small plus large intestine and also increased the efficiency of microbial protein synthesis (P less than .05). In Exp. 2, although intake and gain were higher (P less than .001) for H-fed than for C-fed lambs, there were no differences (P greater than .05) in empty body composition. The results indicated that inhibition of proteolysis by heat treatment at ensiling can increase utilization of silage N within the rumen, increase voluntary intake and result in a higher rate of gain by lambs fed alfalfa silage.

Animal Feed↗

Composition of formaldehyde- and formic acid-treated alfalfa and orchardgrass silages harvested at two maturities and their effects on intake and growth by Holstein heifers.

Alfalfa and orchardgrass herbages were each harvested at two maturities (May 22 to 25 vs June 5 to 7) in primary growth and directly ensiled with 5 kg of a mixture of 30% formic acid and 25% formaldehyde per metric ton of fresh herbage in upright conventional silos. Alfalfa silage contained less NDF (71%) and more N (150%) and hot-water-insoluble N (117%) than orchardgrass silage did. Major differences between silages were that orchardgrass contained 20.4 percentage units more NDF and 1.10 percentage units less N than alfalfa. The NDF increased 104% and total N decreased to 86% with advancing maturity. Twenty-eight yearling Holstein heifers (223 kg BW) were given ad libitum access to the four silages with trace mineral salt, and growth rate was measured in a 119-d period. Daily DE intake was 297 kcal/kg.75 BW for heifers fed alfalfa silage compared with 202 kcal/kg.75 BW for heifers fed orchardgrass silage. Daily gain was 992 g for heifers fed alfalfa compared with 661 g for heifers fed orchardgrass. Gross efficiency, or gain per unit of DE, was similar for heifers fed orchardgrass and alfalfa. Rate of gain was primarily a function of ad libitum intake of DE. Heifers fed alfalfa had greater plasma essential amino acid concentrations (122%) than those fed orchardgrass did. Late alfalfa produced greater ADG than orchardgrass harvested 2 wk earlier.

Amino Acids↗

Voluntary feed intake, acid-base balance and partitioning of urinary nitrogen in lambs fed corn silage with added sodium bicarbonate or sodium sesquicarbonate.

An experiment with growing lambs was designed to test the hypothesis that alterations in blood acid-base status would influence intake of corn silage. Six wethers (29 kg) were fed a diet of corn silage (36% DM, 8% CP) supplemented with 1.25% urea and .2% sulfur. At feeding time, sodium bicarbonate (NaHCO3) and sodium sesquicarbonate (NaSC) were added to the silage at levels of 0, 2% or 4% of diet DM. The treatments were arranged as a 2 x 3 factorial, and the study was conducted as a 6 x 4 incomplete latin square with four 17-d periods. Voluntary intake of OM was not different (P greater than .05) between NaHCO3 (1,008 g/d) and NaSC (1,041 g/d). There was no significant interaction between type of buffer (NaHCO3 or NaSC) and level of buffer on any of the variables measured. The progressive increase in buffer load did not alter feed intake (P greater than .05), although there was a quadratic response (P less than .05) in urine pH and a linear increase (P less than .01) in blood HCO3- 2 h after feeding. There was no evidence that lambs fed corn silage experienced metabolic acid stress. Urinary excretion of ammonia and urea were indicative of changes, although not pronounced, in ammoniuria and ureapoiesis in response to bicarbonate loading. This study implies that corn silage imposes no "acid stress" on lambs and, consequently, that there is no nutritional benefit in adding buffers to corn silage for sheep.

Acid-Base Equilibrium↗

Effect of replacing alfalfa silage with high moisture corn on nutrient utilization and milk production.

Twenty-four multiparous lactating Holstein cows were blocked by days in milk and assigned to treatment sequences in a replicated 4x4 Latin square with 21-d periods. The four diets, formulated from alfalfa silage plus a concentrate mix based on ground high moisture ear corn, contained [dry matter (DM) basis]: 1) 20% concentrate, 80% alfalfa silage (24% nonfiber carbohydrates; NFC), 2) 35% concentrate, 65% alfalfa silage (30% NFC), 3) 50% concentrate, 50% alfalfa silage (37% NFC), or 4) 65% concentrate, 35% alfalfa silage (43% NFC). Soybean meal and urea were added to make diets isonitrogenous with equal nonprotein N (43% of total N). Intake of DM and milk yield indicated that adaptation was complete within 7 d of changing the diets within the Latin square. There were linear increases in apparent digestibility of DM and organic matter, and a linear decrease in neutral detergent fiber (NDF) digestibility with increasing dietary NFC. Solutions of significant quadratic equations yielded estimated maxima for intake of DM, organic matter, digestible organic matter, and NDF at, respectively, 37, 38, 43, and 27% dietary NFC. There were linear increases in yields of milk, protein, lactose, and solids not fat with increasing dietary NFC. Feed efficiency (milk/DM intake) yielded a quadratic response with a minimum at 27% dietary NFC. Maxima for milk fat content, fat yield, and fat-corrected milk yield were estimated to occur at, respectively, 30, 34 and 38% dietary NFC. In this short-term trial, maximal DM intake and fat-corrected milk yield indicated that the optimum concentrate for cows fed high moisture ear corn plus alfalfa silage as the only forage was equivalent to 37 to 38% dietary NFC; however, yields of milk, protein and solids not fat were still increasing at 65% dietary concentrate (43% NFC).

Animal Nutritional Physiological Phenomena↗