Dry Matter Intake Digestibility Research Articles

Influence of different sources of zinc and protein supplementation on digestion and rumen fermentation parameters in sheep consuming low-quality hay

This experiment studied the effect of ZnCl2 or ZnSO4 included into a protein supplement on dry matter intake (DMI), DM digestibility (DMD) and rumen fermentation parameters in sheep consuming low-quality native pasture hay (NPH) as a basal diet. Four ruminally fistulated Corriedale weathers (31±4kg BW) were randomly assigned to a 4×4 latin square design, and received NPH ad libitum in the following treatments: (1) Control (CON) mineral mix only, (2) protein supplement (PROT), (3) PROT+ZnCl2 (CZProt) and (4) PROT+ZnSO4 (SZProt). All supplements were fed at the rate of 150ganimald−1. The Zn concentration in CZProt and SZProt was 460ppm for a total intake of 100ppm daily as a proportion of total diet. The NPH contained 5.3 and 77.4 of CP and NDF as % of DM respectively. Protein supplements were isonitrogenous (30% CP) with barley grain, wheat middlings and sunflower meal as main components. Mean NPH intake and total DMI were not affected by protein supplementation or Zn addition to the diet. DM digestibility as well as DDMI (digestible DMI) increased 31 and 37% respectively for SZProt compared to CON (P<0.05). Sampling hour affected most rumen variables with the exception of butyric and total volatile fatty acids (VFA; P<0.05). A treatment by sampling hour interaction (P<0.05) was only found for ruminal ammonia-N (NH3-N) concentration. At time intervals of 2, 4, 8 and 12h, [NH3-N] was much lower in CON than in protein supplemental treatments (P<0.05). A trend was observed for increased NH3-N concentration in SZProt (39.76mgdL−1) vs. CZProt (29.25mgdL−1) at 4h (P=0.0897). The rumen pH was not affected by treatments; the lowest values found 12h after feeding were 6.2. Zinc, particularly from SZProt, seems to modulate [NH3-N] by sustaining higher concentrations during the 24h period. A clear effect on major VFA was not observed. The inclusion of 100ppm of Zn, and source could differentially affect animal response to protein supplementation and utilization of low quality roughages by affecting some rumen fermentation patterns.

Somatotropin supplementation decreases feed intake in crossbred dairy goats during the early phase of lactation

Recombinant bovine somatotropin (rbST) has been shown to increase milk yield in dairy goats, especially during late lactation. The galactopoietic effect of rbST appears to derive mainly from the partitioning of nutrients to the mammary gland. Previously, this effect has been shown to coincide with an increase in feed intake. To test whether rbST has concomitantly an effect on milk yield and feed intake during the early lactation period, ten crossbred dairy goats during the peri-parturition period were selected and divided into two groups of five animals each. Two consecutive injections of sesame oil or rbST were performed at day 7 and 22 post-parturition (PP-7 and PP-22). Dry matter intake (DMI), water intake (WI) and milk yield of the individual animals were measured throughout the experiment. Blood was collected daily from day 6 post-parturition (PP-6) and throughout the first rbST injection period. Milk yield from the rbST supplemented group was slightly higher than the control group during the second rbST supplementation. Supplementation with rbST decreased significantly DMI per body weight. DMI digestibility from the second rbST injection did not differ between the treatments. The concentration of plasma IGF-1, insulin and glucose increased within 24h after rbST injection. Importantly, plasma leptin also increased after rbST supplementation and this preceded the feed intake effect of rbST supplementation. The present results suggest that rbST induces a decrease in feed intake in dairy goats during early lactation, which relates to increase in the concentration of plasma leptin and in combination with galactopoietic effects of rbST, IGF-1 and insulin.

English

Thirty two, 6 to 8 weeks old rabbits of mongrel origin, balanced for sex and weighing averagely 0.92 kg were allotted to four dietary treatments in a complete randomized design (CRD) with 8 rabbits per treatment. The diets contained groundnut haulms (GH) at 40, 50, 60 and 70% levels of inclusion with a crude protein content of 16%. The rabbits were fed for eight weeks with 6 weeks of preliminary feeding and 2 weeks of faecal collection. Data collected were subjected to analysis of variance (ANOVA). The results obtained indicated an increase in feed conversion ratio (FCR), acid detergent fiber digestibility (ADFD), crude protein digestibility (CPD) and feed cost (=N=) / kg weight gain (FC/WG), and a decrease in dry matter intake (DMI), dry matter digestibility (DMD), daily weight gain (DWG), crude protein digestibility (CPD) and digestible dry matter intake (DDMI) with increasing fibre level. There was a significant difference (P<0.01) among the mean values for acid detergent fibre intake (ADFI) and digestible acid detergent fibre intake (DADFI) indicating that these variables were affected by fibre levels. All the rabbits fed on the four diets gained weight. Taking into consideration feed cost and the availability of grains as a limiting factor to increase animal production, it can be concluded that GH, a potential crop residue can be included in the diet of growing rabbits at up to 70% level, since this did not cause any significant deleterious effect on the growth and performance of the rabbits. Key words: Groundnut haulms, growth, performance, rabbits.

Carbon footprint in different beef production systems on a southern Brazilian farm: a case study

The carbon footprint (CF) of beef production is one of the most widely discussed environmental issues within the current agricultural community due to its association with climate change. Because of these relevant and serious concerns, the beef cattle industry is under increasing pressure to reduce production or implement technological changes with significant consequences in terms of beef marketing. The goals of this study were to evaluate the CF per 1 kg of live weight gain (LWG) at the farm gate for different beef production systems in the southern part of Brazil. Aberdeen Angus beef-bred cattle were assigned to one of seven categories: natural grass; improved natural grass; natural grass plus ryegrass; improved natural grass plus sorghum; cultivated ryegrass and sorghum; natural grass supplemented with protein mineralised salt; and natural grass supplemented with protein-energetic mineralised salt. Monte Carlo analysis was employed to analyse the effect of variations of dry matter intake digestibility (DMID), total digestible nutrients (TDN) and crude protein (CP) parameters in methane (CH4) enteric, CH4 manure, nitrous oxide (N2O) manure and N2O N-fertiliser. The method used was a comparative life cycle assessment (LCA) centred on the CF. The CF varied from 18.3 kg CO2 equivalent/kg LWG for the ryegrass and sorghum pasture system to 42.6 kg CO2 equivalent/kg LWG for the natural grass system, including the contributions of cows, calves and steers. Among all grassland-based cattle farms, production systems with DMID from 52 to 59% achieved the lowest CO2 emissions and the highest feed conversion rate, thereby generating lower CH4 and N2O emissions per production system. Because the feed intake and feed conversion rate are one of the most important production parameters in beef cattle production with an obvious risk of data uncertainty, accurate feed data, which include quantity and quality, are important in estimates of CF for LWG. The choice of adequate feeding strategies to mitigate greenhouse gas (GHG) emissions may result in better environmental advantages.

A meta-analysis of the effect of dietary fat on enteric methane production, digestibility and rumen fermentation in sheep, and a comparison of these responses between cattle and sheep

The objective of this study was to investigate the effect of dietary fat supplementation on methane production, digestibility and rumen fermentation in sheep by means of a meta-analysis, and subsequently to compare the results with response in cattle. A dataset was constructed compiling data from ten published publications containing 41 dietary treatments and 259 observations on sheep. Fat supplementation decreased methane production (expressed as g/day, g/kg dry matter (DM) intake, g/kg digestible DM intake, % of gross energy intake) linearly (P<0.05; R2=0.49 to 0.78). Inclusion of fat did not (P=0.21) affect DM intake. However, digestibilities of DM (P=0.04; R2=0.24) and neutral detergent fiber (P=0.09; R2=0.16) reduced linearly with increasing fat concentrations. Conversely, fat digestibility increased quadratically (P=0.03; R2=0.65) with increasing fat contents. Total volatile fatty acids and acetate percentage in rumen fluid were not altered (P>0.10) by dietary fat supplementation. Percentage of propionate increased linearly (P=0.06; R2=0.17), while butyrate percentage (P=0.06; R2=0.21), acetate to propionate ratio (P=0.05; R2=0.22) and ammonia concentration (P=0.02; R2=0.39) in rumen fluid decreased linearly with increasing fat concentrations. Supplementation of fat had greater suppressive effects on methane production expressed as digestible DM intake in sheep than cattle, but had similar responses on digestibility and rumen fermentation. In conclusion, low concentration of fat in the diet may decrease methane emission without adversely affecting rumen fermentation; but it may lower fiber digestibility at high concentrations.

Effect of Protein and Mineral Improvement on the Performance of Growers Goats

The current trials were initiated to help the goat keepers improve the nutritional status of grower goats with other alternative supplements offered by available cotton and mucuna seeds and locally made mineral lick. The performances of the growers such as growth rate of 12 months, weight at one year and mortality rate at postweaning stage of 3 to 12 months were measured. The results showed that treatment effect on dry matter intake by growers was significant. The growers fed the seeds consumed significantly more dry matter than those fed sole palm frond. Treatment effect on digestible dry matter intake was highly significant. The mean digestible dry matter intake by growers in the period of 8 to 12 months ranged between 25.8 g in the control and 39.1 g/kg 0.75 /day in the mucuna seed without salt lick group. Treatment effect was highly significant. The growers fed diets supplemented with the seeds showed higher growth rate than those in the control. The growers fed diets supplemented with the seeds showed higher weight at one year compared to the control. The mean weight at one year varied from 12.0 kg in the growers fed the seed to 14.6 kg in treatments with mineral lick. Use of these sources of protein could help the household in providing feed for their goats especially in the dry season and also in increasing the size of household flocks.

Feed Utilization of Lactating Does and Pre-weaning Performances of Kids in Republic of Benin

This trial aims at finding out the effect of supplementing the lactating does basic diet (palm frond, with mucuna seed and cotton seed these seeds and a locally made mineral lick on the pre-weaning performances of the kids. Lactating does that kidded in each treatment were used in the experiment which was conducted in farm conditions. The lactating goats was divided into six groups of 5 to 6 animals per groups. The treatments as six different diets: T1 was the control, (palm frond) which is the feed usually offered by the farmers. The experimental diets were T2, T3; T4, T5, T6; with were the control plus the seeds and the mineral lick (T1). The does and the kids were weighed monthly during the pre-weaning stage of the kids (0 to 90 day). The means of growth rate and of weight at weaning were estimated per treatment using individual performance of the animals in each treatment. The seeds improvement on dry matter intake, digestible dry matter and crude protein intake by the lactating does was significant (P<0.05). A non-significant increase was observed with the salt lick in T2, T4 and T6. The seeds improvement on growth rate of lactating does was highly significant (P<0.05). The growth rate of kids sucking milk from does fed the seeds improved significantly (P<0.5). The mortality rate was lower (10% to 13%) in treatments with the seed plus salt lick. The mortality rate decreased slightly with the salt lick in T2, T4 and T6.

How does the suppression of energy supplementation affect herbage intake, performance and parasitism in lactating saddle mares?

Agroecology opens up new perspectives for the design of sustainable farming systems by using the stimulation of natural processes to reduce the inputs needed for production. In horse farming systems, the challenge is to maximize the proportion of forages in the diet, and to develop alternatives to synthetic chemical drugs for controlling gastrointestinal nematodes. Lactating saddle mares, with high nutritional requirements, are commonly supplemented with concentrates at pasture, although the influence of energy supplementation on voluntary intake, performance and immune response against parasites has not yet been quantified. In a 4-month study, 16 lactating mares experimentally infected with cyathostome larvae either received a daily supplement of barley (60% of energy requirements for lactation) or were non-supplemented. The mares were rotationally grazed on permanent pastures over three vegetation cycles. All the mares met their energy requirements and maintained their body condition score higher than 3. In both treatments, they produced foals with a satisfying growth rate (cycle 1: 1293 g/day; cycle 2: 1029 g/day; cycle 3: 559 g/day) and conformation (according to measurements of height at withers and cannon bone width at 11 months). Parasite egg excretion by mares increased in both groups during the grazing season (from 150 to 2011 epg), independently of whether they were supplemented or not. This suggests that energy supplementation did not improve mare ability to regulate parasite burden. Under unlimited herbage conditions, grass dry matter intake by supplemented mares remained stable around 22.6 g DM/kg LW per day (i.e. 13.5 kg DM/al per day), whereas non-supplemented mares increased voluntary intake from 22.6 to 28.0 g DM/kg LW per day (13.5 to 17.2 kg DM/al per day) between mid-June and the end of August. Hence total digestible dry matter intake and net energy intake did not significantly differ between supplemented and non-supplemented mares during the second and third cycles. In conclusion, supplementing lactating mares at pasture should not be systematic because their adaptive capacities enable to increase herbage intake and ensure foal growth. Further research is needed to determine the herbage allowance threshold below which supplementation is required.

Intake and digestibility by sheep, in situ disappearance in cannulated cows, and chemical composition of crabgrass hayed at two moisture concentrations and treated with a non-viable Lactobacillus–lactic acid additive

Crabgrass (Digitaria ciliaris [Retz.] Koel.) is a high-quality warm-season annual that can be used as hay, but field curing time may be lengthy compared with other forages. A 1.6-ha field of common crabgrass was divided into 12 plots (8.25m×50m) that were used in a randomized complete block design with a 2×2 factorial treatment arrangement to determine the effects of a non-viable Lactobacillus–lactic acid additive and moisture concentration at baling on heating characteristics and pre- and post-storage chemical composition. Half of the plots within each block were treated with 0.081ml/mg dry matter (DM) of a solution containing 110g lactic acid/kg and non-viable Lactobacillus acidophilus at the time of mowing (T) and half were not treated (U). Within T and U plots, half were baled in small square bales at 163g moisture/kg DM (L) and half at 251g moisture/kg DM (H) of moisture. Six bales per plot were selected at random, weighed, and stored in separate insulated 6-bale stacks. Core samples were taken from 3 bales initially and 3 bales post-storage. Initial bale moisture concentrations were greater (P<0.05) and initial neutral-detergent fiber (NDF) concentrations were lower (P<0.05) from H vs. L. Post-storage concentrations of NDF and acid-detergent insoluble N (ADIN; g/kg DM and g/kg N), were greater (P<0.05) from H vs. L. Dry matter intake in sheep was unaffected (P>0.05) by either treatment, but DM digestibility and digestible DM intake were both positively affected (P<0.05) by the spray treatment. In addition, DM digestibility was also affected (P<0.05) by moisture, with H>L. In situ DM disappearance was largely affected by spray treatment×moisture interactions (P<0.05). The immediate soluble fraction and effective ruminal disappearance were greater (P<0.05), and the undegraded portion in the rumen was less (P<0.05) for HT compared to HU, indicating a positive relationship between applied spray treatment and digestibility of high-moisture crabgrass. Treating crabgrass with the additive at mowing may not affect forage chemical composition, but may improve digestibility in hay baled at elevated moisture levels.

Grain excretion by goats fed whole or processed cereals with various roughages

Despite cereal grains being grown on 5 continents where goats are kept, there is little information on the excretion of whole cereal grains when fed to goats. We determined the effects of various dietary treatments on whole grain and starch loss in the faeces of Angora goats. In Experiment 1 there were 4 replicates of the factorial design: (a) 2 grain types (barley, oats); (b) whole grain or processing (milled barley or rolled oats); (c) 2 roughage qualities (Persian clover hay, barley straw); and (d) 2 feeding levels (level 1, 150g/d of grain, 250g/d of roughage; level 2, 250g/d of grain, ad libitum roughage). In Experiment 2, which immediately followed Experiment 1, and aimed to detect carry over effects of previous feeding of barley straw and grain processing, feed levels were either 650g/d grain or 400g/d grain with 550g/d Persian clover hay. Data were analysed by ANOVA. In Experiment 1, processing had no effect on digestible dry matter intake. The number of whole grains lost per 100g of fresh faeces and whole grains loss as the % of grain dry matter intake were affected by an interaction between processing and roughage quality. Whole grain fed with Persian clover hay had greater grain loss than all other diets. Whole grain loss was greater with whole grain than with processed grain. Level of feeding had no effects on grain loss. In Experiment 2, more whole grains were lost in fresh faeces when fed with Persian clover hay than when fed without hay, an effect of previous feeding with barley straw reduced whole grain excretion, and more barley grains were lost than oat grain. Faecal starch was affected, with higher levels when whole barley grain was fed, particularly with Persian clover hay, or when previously fed barley straw at a high level. Feeding grain at 650g/d did not increase grain or starch excretion. Whole grains represented a small loss of grain dry matter intake in faeces, averaging 0.8% with a maximum recorded of 2.6%. Faecal concentration of the whole grains may be altered by grain size and the digestibility of the roughage component of the diet. In this study an additional cost of 3% for processing grains would not have provided economic benefits.

The effect of dietary fats on methane emissions, and its other effects on digestibility, rumen fermentation and lactation performance in cattle: A meta-analysis

The objective of this study was to investigate the effects of fats in diets of cattle on methane emissions, and associated impacts on digestibility, milk yield and composition, and rumen fermentation by using meta-analysis. For this purpose, a dataset was constructed compiling data from 29 experiments (27 publications) containing 105 dietary treatments arising from 1339 observations in cattle. Fat supplementation decreased methane production (expressed as g/day, g/kg dry matter (DM) intake, g/kg digestible DM intake, g/kg milk, % of gross energy intake) linearly (P<0.01) with moderate degree of relationship (R2=0.38 to 0.63). Fatty acids C12:0 and C18:3 had marked inhibitory effect on methanogenesis compared with other fatty acids in diets. Methane emissions were not considerably affected by total concentration of saturated fatty acid, but were depressed (P<0.05) by total concentrations of mono- and poly-unsaturated fatty acids in diets. Among other nutrient composition of diets, only non-fibrous carbohydrate content affected the response of fats on methane suppression. Methane yield was influenced by the interaction of fatty acid composition and neutral detergent fiber content of diets. Fats showed a quadratic response (P=0.03) on DM intake, although the relationship was very low (R2=0.15). The digestibilities of DM (R2=0.30) and neutral detergent fiber (R2=0.51) reduced linearly (P<0.01) with increasing fat concentrations. Conversely, fat digestibility increased quadratically (P=0.04; R2=0.53) with increasing fat contents. Milk yield increased quadratically (P<0.01; R2=0.41) with increasing fat supplementation. Milk production reached plateau levels within a range of 3.9–6.0% fat concentrations, and then decreased with increasing fat concentrations. Total volatile fatty acids and acetate percentage in rumen fluid were not altered (P>0.10) by fats, but percentage of propionate increased linearly (P=0.03) with increasing fat concentrations in diets. Fats tended to decrease percentage of butyrate (P=0.10) and acetate to propionate ratio (P=0.07) linearly, but degrees of relationship were very low. From this analysis, it can be concluded that fats with high concentrations of C12:0, C18:3 and polyunsaturated fatty acid up to 6% of dietary DM should, in general, be considered when developing effective feeding strategies for methane mitigation without compromising the productivity in dairy cattle.

A note on suitable laboratory stover quality traits for multidimensional maize improvement

A total of 10 maize stovers from two open pollinated varieties (OPV's), four hybrids (one grown in two different seasons, Kharif and summer) and at two different locations and two parental lines were tested for a range of laboratory fodder quality traits and for in vivo digestibility and voluntary feed intake in sheep. Laboratory stover fodder quality traits measured were nitrogen (N), neutral (NDF) and acid detergent (ADF) fiber, acid detergent lignin (ADL), in vitro organic matter digestibility (IVOMD) and metabolisable energy (ME) content. Highly significant (P<0.0001) differences among the stovers were observed for all laboratory fodder quality traits and for dry matter digestibility (DMD), dry matter intake (DMI) and digestible dry matter intake (DDMI) with DMD (%) DMI (g/d) and DDMI (g/d) ranging from 53 to 65, 325 to 635 and 194 to 382, respectively. The total amount of stover refused (DMR) by the sheep did not differ significantly (P=0.67) among the stovers, however when DMR was expressed relative to DMI significant differences (P=0.0007) were observed. Laboratory fodder quality traits most closely correlated to the in vivo measurements were ADF with r=−0.83, r=−0.92 and r=−0.93 for DMD, DMI and DDMI, respectively, and ME with r=0.77, r=0.94 and r=0.94 for DMD, DMI and DDMI, respectively. Applying statistical cross-validation procedures where the predicted values were not used for the development of the regression equations (“blind-predictions”), DMD, DMI and DDMI could be predicted by ADF with resulting R2 for good-of-fitness between observed and predicted values of 0.46, 0.76 and 0.79, respectively. Similarly DMD, DMI and DDMI could be predicted by ME with resulting R2 for good-of-fitness between observed and predicted values of 0.40, 0.83 and 0.83, respectively.

Nutrient and cell wall fraction digestibility of growing WAD ewe fed Mexican sunflower leaf meal (MSLM) based diets

After a previous 84-d performance phase on growing WAD ewe, Studies was conducted using sixteen West African dwarf (WAD) ewe-lambs weighing between 17.50 and 17.88kg on a basal diet of Panicum maximum were allotted into 4 treatment groups A, B, C and D of 4 replicates each. The MSL replaced Wheat bran (WB) gravimetrically at 0, 15, 30 and 45%. Treatment A served as control. The experiment lasted for one week. Digestibility was determined using a 6-d total fecal collection. Ewes were given ad libitum access to feed and water. Parameters measured were voluntary dry matter intake (VDMI), which comprised concentrate dry matter intake (CDMI) and grass dry matter intake (GDMI), Apparent Digestibility Coefficients of DM, CP, NDF, ADF, ADL, Organic matter (OM) and Energy . Data were analyzed using descriptive statistics and ANOVA .The VDMI (g/d) varied from 392.30 - 695.00, CDMI (g/d) varied from 181.80 - 536.80 and GDMI (g/d) varied from 130.65 - 215.95 for ewe-lambs. Apparent Digestibility Coefficients of NDF, ADF, ADL, organic matter (OM) and Energy were similar. Approximately 75.5 ±1.1% of the VDMI came from the supplement. Diets containing 15% MSLM was superior to others for CDMI (181.80 – 536.80 g/day), CP intake (17.72 – 32.40 g/day/kgW 0.75 ), Digestible DMI (49.45 - 80.68 g/day/kgW 0.75 ) and Digestible CPI (13.68 - 27.16 g/day/kgW 0.75 ) while GDMI (130.65 – 215.95 g/day) for diets containing 30% and 45% MSLM were significant (p < 0.05). Inclusion of up to 45% Mexican Sunflower Leaf in the diets of growing ewe to replace Wheat bran was adequate.

Eating a high fiber diet during pregnancy increases intake and digestibility of a high fiber diet by offspring in cattle

Experiences early in life influence preferences for the forages which animals eat as adults, but little is known about how such experiences affect forage intake and digestibility. We hypothesized that experience with high fiber (HF) diets in utero enables cattle to better utilize HF diets by enhancing intake and digestibility of HF diets. We exposed cows to either HF or low fiber (LF) diets from October 20 until parturition on March 15. The HF diet was primarily ammoniated wheat straw (AWS), while the LF diet was mainly grass hay (700g/kg orchardgrass and 300g/kg meadow bromegrass). The two diets were iso-net energy (NEm), isonitrogenous, and similar in mineral and vitamin contents, but they varied 10-fold in neutral detergent soluble carbohydrates. Following weaning, the 8mo old calves from mothers fed HF or LF diets during pregnancy were fed AWS and a high fiber supplement, and dry matter (DM) intake and digestibility were measured during the last half of a 40d experiment (i.e., 26d adaptation, 14d measured DM intake, 5d measured DM digestibility). Intake (5.6 versus 5.3kg/d; P=0.04) and digestibility (545 versus 523g/kg; P=0.03) of AWS were higher for calves fed HF than for those fed LF diets. As a result, digestible DM intake of AWS was higher for HF than LF (3.1 versus 2.8kg/d; P<0.01). Calves fed HF diets ate more straw as a proportion of their diet than did calves fed LF (733 versus 723g/kg; P=0.05). Total digestible DM intake (i.e., AWS+supplement) was higher for calves fed HF than LF diets (4.7 versus 4.4kg/d; P<0.01), as was total diet DM digestibility (613 versus 600g/kg; P=0.07). Calves were weighed at the conclusion of the DM intake and digestibility measurement periods, and then fed an AWS/processed wheat middlings diet for an addition 28d to determine daily gain. Collectively, increases in intake and digestibility affected body weight gains such that HF diet fed calves numerically gained more than LF fed calves even during this short period (0.45 versus 0.41kg/d; P=0.13). Higher DDM intake is likely important for pregnant cows and their offspring which winter for many months under extensive range conditions on dormant forages where their NEm requirements are marginally satisfied. These effects on offspring, further magnified by experiences with their mothers early in life, make cows and their progeny better adapted to using dormant forages during winter.

Short term consumption of Havardia albicans tannin rich fodder by sheep: Effects on feed intake, diet digestibility and excretion of Haemonchus contortus eggs

This experiment determined the short term effect of feeding Havardia albicans (HA) tannin rich fodder on voluntary feed intake (VFI), dry matter digestibility (DMD), digestible DM intake (DDMI) and fecal excretion of Haemonchus contortus eggs by hair sheep. Polyethylene glycol (PEG) was used to identify possible roles of tannins on the results. Hair sheep lambs (12.6±3.33kg body weight (BW)) without browsing experience and raised free of gastrointestinal nematode infections were maintained in metabolic cages. There were 5 experimental groups with 3 of them infected with H. contortus (350L3/kg BW): Group IC: infected and fed a tannin free diet (n=8), Group IHA: infected and fed fresh HA fodder alone (n=5) and Group IHA+PEG: similar to IHA plus PEG (n=5). Two groups remained free of infection and were fed fresh HA fodder either alone (NIHA) (n=5) or with PEG (NIHA+PEG) (n=5). Sheep were assigned to the experimental groups when the H. contortus infection was patent (i.e., day 25 post-infection). The HA fodder was fed daily at 14g DM/kg BW) for 7d as part of the diet after a 5d of adaptation. A concentrate feed containing 150g/kg crude protein (CP) and 10.1MJ/kg DM of metabolizable energy, and sugar cane molasses, were used to meet requirements for a BW gain of 100g/d. Infected sheep (IHA) had higher HA consumption than non-infected (NIHA) (P<0.05). Such differences in HA fodder consumption due to infection did not occur between PEG supplemented groups. As a result, VFI of the NIHA group was lower than the other groups (P<0.05). Sheep fed HA had a lower DMD and DDMI compared to controls and use of PEG did not have an impact. Short term consumption of HA fodder reduced fecal egg excretion by 58.8% in the IHA versus the IC group (P<0.01). Such a reduction in egg excretion did not occur in the IHA+PEG group. Results show that sheep infected with H. contortus may increase consumption of tannin rich foliage in spite of negative effects on digestibility of the foliage. Such an increase in foliage consumption reduced fecal excretion of nematode eggs and these effects were blocked by PEG.

Effects of dietary carbohydrates on rumen epithelial metabolism of nonlactating heifers

Ruminal wall metabolism was studied in nonlactating heifers by altering the carbohydrate (CHO) digestion site between rumen and intestine. The CHO digestion site was estimated from in situ and total-tract digestibility of control (CONT) diets and diets supplemented with corn (CRN), barley (BARL), or soy hulls (SOYH). Ruminal epithelial metabolism regulating gene expression, morphology, and nutrient delivery was assessed from a combination of rumen volatile fatty acid (VFA) concentration, biopsies for papilla morphology, and expression of putative metabolic regulatory genes encoding enzymes that facilitate VFA utilization. Digestible dry matter and CHO intake were 25 and 45% higher, respectively, in the supplemented diets than in CONT diets. Fiber supplementation increased the intestinal and decreased ruminal CHO digestion. Ruminal nonfiber CHO digestibility was 10% lower in CRN than with the high rumen-degradable supplement. The CONT heifers had lowest total ruminal VFA and highest acetate concentration relative to the other treatments. Total VFA concentration in BARL and CRN diets tended to be higher than in SOYH. The SOYH diet tended to reduce papilla dimension relative to CRN and BARL. The CRN diet tended to increase papilla surface area relative to BARL and SOYH. Gene expression of propionyl-coenzyme A carboxylase was higher in CRN and BARL than in SOYH diets, and tended to be higher in CRN than in BARL and SOYH diets. Lactate dehydrogenase and butyryl coenzyme A synthase gene transcripts tended to be higher in CONT than in the supplemented treatments. Thus, rumen epithelial expression of genes involved in VFA metabolism and ruminal wall-structure development are influenced by other regulatory mechanism that is not directly affected by local signals. The in situ methods used are a useful tool for differentiating ruminal from extraruminal nutrient supply.

Digestive utilization of ozone-exposed forage by rabbits (Oryctolagus cuniculus)

A mixture of common Southern Piedmont (USA) grassland species (Lolium arundinacea, Paspalum dilatatum, Cynodon dactylon and Trifolium repens) was exposed to O3 [ambient (non-filtered; NF) and twice-ambient (2X) concentrations] and fed to individually caged New Zealand white rabbits (Oryctolagus cuniculus) in a digestibility experiment. Forages and feed refusals were analyzed for concentrations of total cell wall constituents, lignin, crude protein, and soluble and hydrolyzable phenolic fractions. Neutral detergent fiber and acid detergent fiber digestibility by rabbits were significantly lower for 2X than NF forage. Decreased digestibility could not be attributed to lignin concentrations, but was associated with increased concentrations of acid-hydrolyzable and saponifiable phenolics. Exposure of forage to elevated O3 resulted in decreased digestible dry matter intake by rabbits. Elevated O3 concentrations could be expected to have a negative impact on forage quality, resulting in decreased nutrient utilization by mammalian herbivores in Southern Piedmont grasslands under projected future climate scenarios.

Soybean as supplement of growing cattle on tropical pasture: effects on intake, digestibility and animal performance

&lt;p&gt;An indoor trial was conducted with weaning heif­ers (experiment 1). Raw whole soybean (RSB), whole soybean heated with steam (SHSB) and extruded whole soybean (EXSB) were given as supplements at 0.7% of live weight (LW). One group was the control, with no supplement. All supplements increased total dry matter (DM) intake and did not affect hay intake. RSB was the most degradable crude protein (CP) source. Total digestive tract digestibility was not affected by treatments, except for apparent CP digestibility. Because total DM intake increased in supplemented animals, all supple­ments increased intake of digestible DM, organic matter (OM) and CP over the control. In another assay (experiment 2) a performance trial was conducted with forty weaned heifers. The same supplements used in experiment 1 were used. Heifers supplemented with EXSB gained the highest and had better apparent feed efficiency. Apparent feed efficiency was similar to those observed in protein supplementation, suggesting that some increase in DM intake from pasture may have occurred. RSB had the poorest apparent feed efficiency which agreed with the numerical lower OM intake observed in experiment 1. All supplemented heifers had higher gain, hip height change, thoracic perimeter and body condition score change than the control group.&lt;/p&gt;

Levels of ground corn supplied to beef heifers at pasture during the rainy season: productive performance, intake, digestibility and microbial efficiency

The objective was to evaluate the effect of four levels of ground corn supply on nutritional parameters, microbial synthesis efficiency and growing performance of beef heifers, at the rainy season. For such, 28 crossbred yearling heifers, with initial age of 16-17 months and initial weight of 255 ± 31.0 kg were distributed into five paddoks of B. decumbens, of 2.0 ha each, with average potentially digestible DM availability of 2,377.0 kg/ha. For each one of the lots, one of the following supplements was daily supplied: mineral mix exclusively or with ground corn at levels 0.25, 0.50, 0.75 or 1.00 kg/day. The experiment was arranged in completely randomized design with five treatments (supplements), five repetitions for the groups receiving exclusive mineral mix or mineral mix plus corn on the level of 0.50 kg/day and six repetitions for those receiving the other supplements. There was a response of 0.092 kg of weight gain for every 1 kg of ground corn supplied to the animals, and no substitution effect was verified on the dry matter intake of pasture. The increase in ground corn levels increased metabolizable energy intake, which is explained by the crescent linear effect on digestible dry matter intake, on apparent digestibility of dry matter and organic matter as well as on the levels of total digestible nutrients of the diet consistent with the increase in intake of the most digestible ingredient, ground corn. In the same way, there was a positive linear effect for apparent digestibility of neutral detergent fiber. The supplementation provided linear positive effect on the flow of microbial nitrogen compounds (MICN) for the small intestine, and did not affect the microbial synthesis efficiency. The supply of energetic supplement for beef heifers, at pasture, during the rainy season increases the use of the forage and consequently, weight gain.

Flaccidgrass Forage Mass and Canopy Characteristics Related to Steer Digesta Kinetics and Intake

ABSTRACT‘Carostan’ flaccidgrass (Pennisetum flaccidum Griseb.) has potential as a perennial, warm‐season grass for pastures. This 2‐yr study examined digesta kinetics, dry matter intake (DMI), and diet of steers as related to canopy characteristics. Steers (Bos taurus L.) were continuously and variably stocked at canopy heights of Short (15 to 20 cm), Medium (30 to 40 cm), and Tall (45 to 55 cm) with forage mass (FM) of 1245, 2600, and 3585 kg ha−1, respectively (linear; p &lt; 0.01). Neither mean retention time nor passage rate of either liquid or digesta phases were altered by FM. Fecal output increased linearly (p = 0.04) from Short to Tall (0.643 to 0.739 kg 100 −1 kg body weight [BW]) indicating a possible variation in DMI. However, DMI and digestible DMI (based on leaf in vitro dry matter disappearance [IVDMD]) were similar among FM (mean = 1.99 and 1.29 kg 100−1 kg BW). Leaf composed 24.3% of the three canopies and was not altered by FM. Stem increased linearly (p = 0.01) from 40.1 to 53.1% with height whereas dead tissue declined linearly (p = 0.06) from 34.8 to 23.4%. Steers selected diets (1 yr data), regardless of FM, similar in IVDMD (mean = 713 g kg−1) and neutral detergent fiber (NDF) (mean = 486 g kg−1). In general, steer digesta kinetics were not influenced by FM as animals adjusted grazing behavior to result in similar responses. Flaccidgrass canopies were flexible and no particular optimum FM was detecting for an optimum diet. The influence of FM on pasture productivity (regrowth after defoliation) requires additional study.