Forage-based Diets Research Articles

Digestibility of Buffel grass (Cenchrus ciliaris)-based diets supplemented with four levels of Gliricidia sepium hay in hair sheep lambs

The objective of this experiment was to evaluate the effect of supplementing increasing levels of Gliricidia sepium hay (GS) with different levels of inclusion of Buffel grass (BG) hay on digestibility by hair sheep lambs (2.5 to 3.5 months of age). Eight male lambs were used in a replicated 4 × 4 Latin square design with 21-day experimental periods (n = 4). Animals were fed with BG with different levels of GS: 100% BG (T1, control), 90% BG + 10% GS (T2), 80% BG + 20% GS (T3), and 70% BG + 30% GS (T4). Dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) intakes were not affected by treatments. The intake of crude protein (CP), organic matter (OM), and gross energy was higher (P < 0.05) in those lambs fed with T4 diet than control. NDF and ADF digestibilities were higher (P < 0.05) in T1 than in the other treatments. CP digestibility was higher (P < 0.05) in T4 compared to T1, T2, and T3. The study showed that inclusion of GS up to 30% with BG in forage-based diets of sheep does not affect DM and fiber intake nor influence DM and OM digestibilities but it increases CP intake and reduces NDF and ADF digestibilities.

Influence of fresh forage-based diets and αS1-casein (CSN1S1) genotype on nutrient intake and productive, metabolic, and hormonal responses in milking goats

Polymorphism at the αS1-casein locus (CSN1S1) in goats influences several milk production traits. Milk from goats carrying strong alleles, which are associated with high αS1-casein (αS1-CN) synthesis, has higher fat and casein contents, longer coagulation time and higher curd firmness than milk from goats with weak alleles linked to low αS1-CN content. Nutrition also affects these milk properties; therefore, it is important to better understand the interaction between dietary characteristics and the CSN1S1 genotype in goats. This study aimed to investigate the effect of fresh forage based diet or energy supplement on feeding behavior, milk production, and metabolic and hormonal parameters of Girgentana goats with different genotypes at CSN1S1 loci. From a group of goats genotyped by PCR at the DNA level, 12 were selected because they had the same genotype for αS2-CN, β-CN, and κ-CN but a different genotype for αS1-CN: 6 were homozygous for strong alleles at the CSN1S1 loci (AA) and 6 were heterozygous for a weak allele (AF). Goats of each genotype were allocated to 3 subgroups and fed 3 diets ad libitum in a 3×3 Latin square design. The diets were sulla (Hedysarum coronarium L.) fresh forage, sulla fresh forage plus 800g/d of barley meal (SFB), and mixed hay plus 800g/d of barley meal (MHB). Diet had a stronger effect than CSN1S1 genotype. The SFB diet led to the highest energy intake, dry matter (DM) digestibility, and milk yield. The fresh forage diets (SFF and SFB) increased DM and crude protein (CP) intake, CP digestibility, and milk CN compared with the MHB diet. The diets supplemented with energy (SFB, MHB) reduced milk fat and urea, improved CP utilization for casein synthesis, and limited body fat mobilization, in accordance with a lower level of nonesterified fatty acids and higher levels of glucose and IGF-1. With regard to CSN1S1 genotype, AA goats showed higher CP digestibility and lower free thyroxine hormone and cholesterol levels than AF goats. Significant diet × genotype interactions indicated how AA goats, compared with AF goats, showed higher DM digestibility and milk yield when fed the SFB diet, which had more energy. A reduction in free triiodothyronine hormone occurred in AF goats fed the MHB diet, whereas no differences were observed in AA goats. These results demonstrate how goats with a higher capacity for αS1-CN synthesis exhibit more efficient energy and protein utilization, evident at the digestive level, and better productive responses to high-nutrition diets.

Dosing with Lactipro decreases forage intake and manure output (2013)

High-concentrate diets consisting of cereal grains and grain byproducts have high energy density compared with forage-based diets. To avoid digestive disorders, cattle must be adapted to concentrates, which often entails feeding a series of step-up diets that contain progressively less roughage over a 2- to 3-week period. This allows the microbial population to adapt to fermentation of the starches and sugars that are present in high-concentrate diets. If cattle are not properly adapted to concentrate-based diets, lactic acid, which is produced by opportunistic starch-fermenting bacteria like Streptococcus bovis, can accumulate, predisposing the animal to acidosis. Diets used during the adaptation phase are by nature less digestible than the final finishing diet, which results in increased manure output and suboptimal performance during the adaptation period. Lactipro, a relatively new probiotic drench containing the lactate-utilizing bacteria Megasphaera elsdenii, has been utilized effectively to accelerate the adaptation of cattle from roughages to concentrate-based diets. Our objective was to determine the impact on diet digestibility and manure output in cattle dosed with Lactipro (MS Biotech, Inc., Wamego, KS) and placed directly onto high-concentrate diets without prior adaptation.

Orally dosing steers with Lactipro (Megasphaera elsdenii) decreases the quantity of roughages fed during finishing (2013)

Introduction The cost of roughages is relatively high in comparison to their contribution of nutrients to feedlot diets. Widespread drought has affected roughage supplies in the cattle-feeding regions of the United States, further increasing the cost of roughages for feedlots. Despite their relatively high cost, roughages are incorporated into finishing diets to maintain rumen function and to manage ruminal acidosis. The greatest proportion of roughage is utilized early in the feeding period when cattle are being transitioned from forage-based diets to concentrate-based diets, allowing ruminal microbes to adapt gradually to higher levels of starch and sugars. If cattle are not properly adapted to concentrate-based diets, undesirable lactic acid-producing microorganisms, such as Streptococcus bovis, can rapidly proliferate and produce large excesses of lactic acid in the rumen. This condition can precipitate feedlot acidosis, which can have serious consequences for health and performance of cattle.

Dietary sulfur concentration affects rumen hydrogen sulfide concentrations in feedlot steers during transition and finishing

Angus steers (n = 96; 321 ± 29 kg BW) were used to determine how previous exposure to increased dietary S would affect ruminal hydrogen sulfide concentrations ([H(2)S]) in the feedlot, to investigate the effects of dietary S on ruminal [H(2)S] during transition and finishing, and to determine if dietary S affects the glutathione status of finishing cattle. Steers were strip-grazed on smooth bromegrass (Bromus inermis L.) over a 35 d period and received a dry distillers grains plus solubles (DDGS) supplement at 1% of BW (DM basis) that contained either 0.50% S (LS; n = 4 plots) or the DDGS supplement with an additional 0.30% S from sodium sulfate (0.80% S in supplement; HS; n = 4 plots). On d 36 steers were moved from the pastures to feedlot pens with one-half of the steers on each treatment in the pasture period remaining on the same treatment during the feedlot period and half being switched to the other treatment (n = 6 pens). For the first 10 d in the feedlot, steers were fed hay ad libitum and 1% BW of the DDGS supplement representing their new treatment, followed by transition to finishing diets. Dietary S of transition and finishing diets were 0.2% to 0.3% S for LS and 0.5% to 0.6% S for HS. No interaction between pasture and feedlot treatment was observed (P ≥ 0.50), so data for the feedlot period were pooled by feedlot treatment (n = 12 pens). Rumen [H(2)S] were measured on d 35 of the pasture period and on d 46 while receiving ad libitum hay and supplement at 6 h after the feeding of the supplement and after 7 d on each of the 3 transition diets (d 53, 60, and 67) and on d 93, 126, and 155 of the study after receiving the finishing diet for 26, 59, and 88 d at 6 h after feeding. Ruminal [H(2)S] did not differ between treatment while steers were fed the supplement on forage-based diets. However, ruminal [H(2)S] of HS-fed steers was greater (P < 0.05) than LS-fed steers when transition diets and the finishing diets were fed. Relative to S intake, ruminal [H(2)S] increased disproportionally after 26 d on the finishing diet. This was followed by a decrease in [H(2)S] on d 59 of finishing, although S intake was increased (P < 0.05) compared with d 26 of finishing. It appears that factors other than S intake alone contribute to ruminal [H(2)S]. The amount of glutathione in the liver of steers did not differ (P = 0.47) because of dietary S, but the concentration of oxidized glutathione increased (P = 0.03) in HS-fed compared with LS-fed steers, suggesting that the potential for oxidative stress in cattle fed high-S diets may warrant further investigation.

Swiss diet types for cattle: how accurately are they reflected by the Intergovernmental Panel on Climate Change default values?

In Switzerland, a considerable part of the country is mountainous. Forage-based diets dominate, as crop production and feed import are limited. Long winter periods require large amounts of conserved feeds. This results in diet types where the current Intergovernmental Panel on Climate Change (IPCC) default values for enteric and manure-derived methane may not be fully appropriate. In 10 experiments carried out in Switzerland, methane emission data were obtained from various forage-based diet types. This included enteric (open-circuit respiratory chambers) and manure-derived methane (various techniques). In dairy cows and suckler cow–calf pairs, the methane-conversion rate (Y m, methane energy, % of gross energy intake) was 7.1% (5.9–8.0) and 8.1% (7.8–8.5), respectively (IPCC default value: 6.5%). In fattening bulls, Y m increased from 4.5% to 5.4% during fattening (default: 6.5%). In the slurry of fattening bulls and dairy cows, the methane-conversion factor (% of maximum slurry-methane emission potential realised) was 0.9% and 5.3% on average when incubated at 14 and 27°C (means of 7 and 14 weeks storage), respectively (default: 15% and 48%). Accordingly, IPCC default values overestimate enteric methane emissions of Swiss forage-based fattening bulls and underestimate those of suckler beef cow–calf pairs. For dairy cows, Y m remained within the current uncertainty range given by IPCC.

Weight loss resistance: A further consideration for the nutritional management of obese Equidae

Evidence-based, weight loss management advice is required to address equine obesity. Changes in body mass (BM), body condition score (BCS), heart (HG) and belly circumference (BG), direct (ultrasonographic) and indirect (D(2)O dilution, bioelectrical impedance analysis [BIA]) measures of body fat as well as indices of insulin resistance (IR) were monitored in 12 overweight (BCS ≥ 7/9) horses and ponies of mixed breed and gender for 16 weeks. Animals were randomly assigned to two groups (Group 1, n=6, BCS 7.6/9 ± 0.6, 489 ± 184.6 kg; Group 2, n=6, BCS 8.1/9 ± 0.6, 479 ± 191.5 kg). Daily dry matter intake (DMI) was restricted to 1.25% BM as one of two, near-isocaloric (DE ∼0.115 MJ/kg BM/day), forage-based diets (Group 1, 0.8% BM chaff-based feed: 0.45% BM hay; Group 2, 1.15% BM hay: 0.1% BM nutrient-balancer). Statistical modelling revealed considerable between-animal heterogeneity in proportional weight losses (0.16-0.55% of Week 1 BM weekly). The magnitude of weight loss resistance (WLR) or sensitivity to dietary restriction was independent of diet or any measured outset variable and was largely (65%) attributed to animal identity. Predicted rates of weight loss decreased over time. BCS and BIA were poor estimates of D(2)O-derived body fat%. Reciprocal changes in depths of retroperitoneal and subcutaneous adipose tissues were evident. Changes in BG were associated with losses in retroperitoneal fat and BM (r(2), 0.67 and 0.79). Indices of IR improved for 9/12 animals by Week 16. For obese animals, weight loss should be initiated by restricting forage DMI to 1.25% BM. Subsequent restriction to 1% BM may be warranted for WLR animals.

Supplementation of increasing amounts of linseed oil to dairy cows fed total mixed rations: Effects on digestion, ruminal fermentation characteristics, protozoal populations, and milk fatty acid composition

The effect of linseed oil (LO) supplementation on nutrient digestibility, forage (i.e., timothy hay) in sacco ruminal degradation, ruminal fermentation characteristics, protozoal populations, milk production, and milk fatty acid (FA) profile in dairy cows was investigated. Four ruminally cannulated, primiparous lactating cows were used in a 4×4 Latin square design (28-d periods). They were fed a total mixed ration (50:50 forage:concentrate (F:C) ratio [dry matter (DM) basis] without supplementation (control, CTL), or supplemented (wt/wt; DM basis) with LO at 2, 3, or 4%. Supplementation with LO had no effect on DM intake (19kg/d) and apparent total-tract digestibility of nutrients (organic matter, neutral detergent fiber, acid detergent fiber, starch, and gross energy). Ruminal pH, ammonia, and total volatile FA concentrations were not changed by LO supplementation to diets. Extent of changes in volatile FA pattern and effective ruminal degradability of DM of timothy hay were minor. Neither the total numbers nor the genera distribution of protozoa was changed by the addition of increasing amounts of LO to the diet. Milk yield increased linearly (26.1, 27.3, 27.4, and 28.4kg/d for CTL to LO4, respectively) as the amount of LO added to the diet increased. Milk fat content was not affected by LO supplementation, whereas milk protein content decreased linearly with increasing amounts of LO in the diet. Milk fat proportions of several intermediates of ruminal biohydrogenation of polyunsaturated FA (i.e., trans-10 18:1, trans-11 18:1, cis-9,trans-11 18:2, trans-11,cis-15 18:2, and cis-9,trans-11,cis-15 18:3) increased linearly with LO addition to the diet. The proportion of cis-9,cis-12 18:2 decreased linearly (2.06, 1.99, 1.91, and 1.83% for CTL to LO4, respectively) as the amount of LO in the diet increased. Milk fat content of cis-9,cis-12,cis-15 18:3 increased as the level of LO in the diet increased up to 3% but no further increase was observed when 4% of LO was fed (0.33, 0.79, 0.86, and 0.86% for CTL to LO4, respectively). A similar quadratic response to LO supplementation was also observed for cis-5,cis-8,cis-11,cis-14,cis-17 20:5 and cis-5,cis-7,cis-10,cis-13,cis-16 22:5. The results of the present study show that LO can be safely supplemented up to 4% in forage-based diets of dairy cows to enrich milk with potential health beneficial FA (i.e., n-3 FA) without causing any detrimental effects on rumen function, digestion, and milk production.

Effects of increased dietary sulfur on beef steer mineral status, performance, and meat fatty acid composition

Ninety-six crossbred yearling steers (321 ± 29 kg BW) were used to determine the effects of feeding cattle a high S diet on pasture before receiving a high S diet in the feedlot. Steers were blocked by BW, allocated to 2.4-ha bromegrass (Bromus inermis L.) pastures (n = 4 plots per treatment), and supplemented at 1% BW with either low S dried distillers grains with solubles (DDGS; 0.34% total diet S; LS) or LS DDGS with additional S (0.47% total diet S; HS) from NaSO(4) for 36 d. On d 37, steers moved into the feedlot where one-half remained on the previous S treatment and the other half switched treatments, resulting in 4 treatments (LS-LS, LS-HS, HS-LS, HS-HS; LS: 0.2 to 0.3% total diet S, HS: 0.5 to 0.6% total diet S; n = 6 feedlot pens per treatment). During the pasture period, forage mass offered, grazing residual mass, and in vitro digestible DM of forage did not differ among treatments (P > 0.40), and ADG did not differ (LS: 1.6 kg · d(-1), HS: 1.7 kg · d(-1), P = 0.54). Plasma Mg measured on d 35 was decreased by ≈ 5% in response to increased dietary S during the pasture period (P = 0.05), though no effect on plasma Mg was observed during finishing (P > 0.15). Plasma Cu concentrations on d 155 were ≈ 15% less (P = 0.02) in HS vs. LS steers, and d 155 liver Cu concentrations were ≈ 51% less in HS vs. LS steers (P = 0.01). Increased dietary S during the feedlot period decreased ADG by ≈ 10% (P = 0.01) and tended to decrease HCW by ≈ 5% (P = 0.06) compared with LS steers. Steers receiving the HS diet had increased stearic acid (C18:0) and heptadecanoic acid (C17:0; P = 0.04 and 0.01, respectively) percentages in rib facings collected at slaughter. Exposing cattle to greater S diets (0.47% S) during a forage-based diet did not influence later performance on high S feedlot diets (0.5 to 0.6% S); however, cattle fed high dietary S on pasture had greater fat cover at slaughter (P = 0.01), suggesting S may have influenced lipid metabolism.

A meta-analysis evaluation of supplementing dried distillers grains plus solubles to cattle consuming forage-based diets

Data from 20 (13 pasture grazing and 7 confinement-fed) forage-based growing studies utilizing 790 steers and heifers supplemented dried distillers grains (DDGS) were analyzed using mixed models to determine the response to supplementing different levels of DDGS on gain and forage intake. Thirty-eight treatment means (442 cattle) were from grazing cattle supplemented DDGS (range: 0.00 to 1.03% BW/d). Twentyeight treatment means (348 cattle) were from confinement-fed cattle supplemented DDGS (range: 0.00 to 1.27% BW/d). Outcomes of interest were the effect of DDGS intake on forage intake (confinement studies), final BW, and ADG. In pasture grazing studies, final BW increased linearly (P < 0.01) and tended to increase quadratically (P = 0.07) with increasing DDGS supplementation. Daily gain increased linearly (P < 0.01) with increased DDGS supplementation. Results from confinement-fed studies indicate that final BW (P < 0.01) and ADG (P < 0.01) increased quadratically with increasing DDGS supplementation. Intakes measured in the confinement studies suggest that increasing DDGS supplementation increases total DMI (P < 0.01) quadratically, even though forage intake decreases (P < 0.01) quadratically with increased DDGS supplementation. Results from all studies indicate that increasing DDGS supplementation increases ADG and final BW, and supplementation of DDGS replaces some forage in forage-based diets fed to growing cattle.

Performance, carcass, and meat characteristics of beef steers finished on 2 different forages or on a high-concentrate diet

In response to potential changes in consumer demand, the utility of different forage-based systems as finishing programs should be evaluated. Performance and carcass characteristics of yearling steers that grazed monocultures of endophyte-free tall fescue or alfalfa or fed a high-concentrate (feedlot) diet were evaluated. Steers fed a feedlot diet gained more and reached a final endpoint sooner than those grazing tall fescue or alfalfa. Forages were not limiting in terms of mass produced and nutritive value. Despite the greater nutritive value of alfalfa compared with tall fescue, no differences in performance and hence productivity per unit of land were detected. No difference (P > 0.05) in ADG was detected between steers grazing (alfalfa and tall fescue, 0.93 and 0.98 kg, respectively) when compared with those in the feedlot or finished in drylot (1.32 kg). Beef produced on a forage-based diet was leaner and had acceptable organoleptic characteristics. Backfat and ribeye area were greater (P < 0.05) in the carcasses of steers that grazed alfalfa compared with fescue (7.6 vs. 4.0 mm and 66.7 vs. 57.5 cm2, respectively). However, the fat was more yellow (P < 0.05) than the fat of those on tall fescue, indicating a possible effect of the carotenoids that might be present in greater concentration in alfalfa. Forage-fed beef is a niche market that is growing rapidly in the United States. Forage finishing steers on tall fescue or alfalfa is a viable alternative for beef cattle producers interested in meeting the demand for this product.

Characterization of the longissimus lumborum transcriptome response to adding propionate to the diet of growing Angus beef steers

Development of management paradigms that enhance the rate of gain and qualitative characteristics of beef carcass development has the potential to impact production and nutrient use efficiency but also mitigate losses to the environment. We used eight Black Angus beef steers (272.5 ± 17.6 kg initial body wt) fed a forage-based pelleted diet alone (n = 4) or supplemented with sodium propionate included (n = 4) for 42 days. High-quality RNA was extracted from the longissimus lumborum and subjected to transcriptome sequencing using RNA-seq technology. Trimmed reads were aligned to the bovine reference genome (Btau4.0, release 63) and uniquely mapped reads from control and propionate treatment groups were subject to further analysis using edgeR. Candidates were filtered to account for multiple testing and differentially expressed genes (153 at a false discovery rate of <5%) were analyzed using Gene Ontology (GO) analysis (GOseq) to select terms where enrichment had occurred. Significant GO terms included regulation of cholesterol transport, regulation of sterol transport, and cellular modified amino acid metabolic process. Furthermore, the top four identified gene networks included lipid metabolism, small molecule biochemistry, carbohydrate metabolism, and molecular transport-related categories. Notably, changes in lipid metabolism specific genes reflect both increased oxidative and lipid synthetic capacities. Metabolism-related gene changes are reflective of expected enhancements in lean tissue accretion patterns exhibited in steers where high ruminal propionate relative to other short chain fatty acids is observed. Propionate feeding induced increased N retention in rapidly growing Angus cattle, and the observed alterations in LL tissue lipid metabolism-related gene networks are consistent with enhanced cell formation and function (protein synthesis, and lipogenic vs. lipolytic activities).

Gene expression in the arcuate nucleus of heifers is affected by controlled intake of high- and low-concentrate diets1

It was hypothesized that a high-concentrate diet fed during early calfhood alters the expression of genes within the arcuate nucleus that subserve reproductive competence. Beef heifers (n = 12) were weaned at approximately 3 mo of age, and after acclimation, were allocated randomly to 1 of 2 nutritional groups: 1) High Concentrate/High Gain (HC/HG), a high concentrate diet fed to promote a gain of 0.91 kg/d; or 2) High Forage/Low Gain (HF/LG), a forage-based diet fed to promote a gain of 0.45 kg/d. Experimental diets were fed under controlled intake for 91 d. At the end of 91 d, heifers were slaughtered by humane procedures, blood samples were collected, brains were removed, liver weights were determined, and rumen fluid was collected for VFA analyses. Tissue blocks containing the hypothalamus were dissected from the brains, frozen, and cut using a cryostat, and frozen sections were mounted on slides. Tissue from the arcuate nucleus (ARC) was dissected from sections for mRNA extraction. Microarray analysis was used to assess genome-wide transcription in the ARC using a 60-mer oligonucleotide 44K bovine expression array. The ADG was greater (P < 0.001) in heifers fed the HC/HG diet than in heifers fed the HF/LG diet. At slaughter, mean propionate to acetate ratios in the ruminal fluid and liver weight as a percentage of BW were increased (P < 0.005) in HC/HG compared with HF/LG heifers. Mean serum concentrations of insulin (P < 0.05) and IGF-1 (P < 0.005) were greater, and leptin tended to be greater (P = 0.1) in HC/HG heifers compared with HF/LG heifers. Approximately 345 genes were observed to be differentially expressed in the HC/HG group with approximately two-thirds of the genes exhibiting increased expression in the HC/HG group. Genes exhibiting decreased expression in the HC/HG group included agouti-related protein and neuropeptide Y, products of which are known to regulate feed intake and energy expenditure. Functional annotation of enriched Gene Ontology terms indicates that a number of biological processes within the hypothalamus are affected by consumption of high-concentrate diets, including those related to control of feed intake, regulation of cellular metabolic processes, receptor and intracellular signaling, and neuronal communication. In summary, dietary treatments shown previously to accelerate the timing of pubertal onset in heifers increased ruminal propionate, promoted enhanced metabolic hormone secretion, and altered gene expression in the ARC.

Increasing protein supply to pregnant beef cows when energy is limited does not improve cow or calf performance (2012)

Introduction Preand postpartum deficiencies of metabolizable protein have been identified as potentially limiting to productivity of beef cows and calves. Pre-partum supplementation of forage-based diets with ruminally undegraded protein has increased weight gain and breeding performance in prior studies, but the level of ruminally degraded protein fed was not known. Feeding adequate ruminally degraded protein to beef cows maximizes the productivity of microbes in the rumen, so any benefits shown in prior work could have been attributed to increased ruminal fermentation.

Effect of propolis product on digestibility and ruminal parameters in buffaloes consuming a forage-based diet

This study evaluated the Propolis product (LLOS) effects on feed intake, dry matter (DM) and nutrients total digestibility, rumen characteristics and microbial efficiency in buffaloes fed a roughage based diet (70% Cynodon spp hay and 30% concentrate). Using a 4×4 latin square design, four crossbred buffalo (Murrah x Jafarabadi) steers (519.0±13.0 kg body weight - BW), were fed four treatments with three LLOS concentrations: Control (no LLOS), LLOS B3+ (0.272 mg/g flavonoid chrysin equivalents), LLOS C1 (0.092 mg/g flavonoid chrysin equivalents), and LLOS C1+ (0.184 mg/g flavonoid chrysin equivalents). Diet formulation was 60% total digestible nutrient (TDN) and 11% crude protein (CP). No difference was observed in DM intake among experimental diets (P>0.05). Steers fed LLOS C1 had greater (P<0.05) coefficients of digestibility for DM (67.2 vs 62.7%), organic matter (OM) (68.1 vs 63.7%), neutral detergent fibre (NDF) (61.7 vs 56.6%), total carbohydrates (TCHO) (67.7 vs 63.2%) and TDN (66.1 vs 62.8%) compared to animals fed the control diet. LLOS C1 provided greatest (P<0.05) short chain fatty acids (SCFA) production (141.89 vs 129.15 µM/mL) and butyric production (16.15 vs 14.05 µM/mL) compared to control. The lowest rumen pH (6.65; P<0.05) was observed in steers fed diets with LLOS C1. No difference (P>0.05) was observed for ammoniacal nitrogen (N-NH3), solid and liquid passage rate and microbial efficiency among treatments. In this study LLOS C1 improved forage diet efficiency in buffalo steers.

Feed consumption, diet digestibility and mineral utilization in captive blackbuck (Antelope cervicapra) fed different levels of concentrates

A feeding trial was conducted to know the level of concentrates in the diet of Antelope cervicapra at which diet digestibility and mineral utilization were optimum. Fifteen blackbucks (25-33 kg BW) were distributed into three groups of five each. Fresh oat (Avena sativa) and berseem (Trifolium alexandrinum) fodders were offered ad libitum to all the animals. In addition, animals in groups II and III received concentrate mixture at the rate of 0.5 and 1% of BW, whereas animals in group I received no concentrates. As the level of concentrates increased, consumption of fodder decreased resulting in decreased consumption of neutral detergent fibre (NDFom), acid detergent fibre (ADFom), hemicellulose and cellulose. However, overall total dry matter (DM) and organic matter (OM) intake was not significantly different between the groups. Digestibility of DM, OM and gross energy (GE) increased while that of NDFom and ADFom decreased with increased level of concentrates in the diet. Intake of P, Zn, Cu and Mn increased with increased level of concentrate supplementation; however, consumption of Ca and Fe followed the reverse trend. Absorption of P and Zn increased with increased level of concentrate supplementation. Serum concentration of Zn increased when concentrate was supplemented at the rate of 0.5% BW beyond which there was no further improvement. Increasing the level of concentrates in the diet was resulted in increased serum glucose and cholesterol levels. Forage-only diet was inadequate in supply of energy, P and zinc. Supplementation of concentrates at the rate of 0.5% BW was able to meet the requirement of these nutrients. Supplementation at the rate of 1% BW supplied energy and P in excess of requirement. It was concluded that the feeding of concentrates to the captive blackbuck fed forage-based diets should be restricted to 0.5% of BW.

Feeding value of field pea as a protein source in forage-based diets fed to beef cattle.

Three studies were conducted to evaluate the feasibility of field peas as a protein source in diets for beef cattle. In the first study, 4 cultivars of field pea were incubated in situ to determine rate and extent of CP disappearance. Results indicate that field pea cultivars vary in CP content (22.6, 26.1, 22.6, and 19.4%, DM basis for Profi, Arvika, Carneval, and Trapper, respectively). Soluble protein fraction ranged from 34.9% for Trapper to 54.9% for Profi. Degradable CP fraction was greater (P = 0.01) for Trapper compared with the other cultivars, and no differences (P ≥ 0.25) were observed among Profi, Arvika, and Carneval. Rate of CP degradation differed (P ≤ 0.03) for all cultivars, with Profi being the greatest and Trapper the smallest (10.8, 10.0, 8.1, and 6.3 ± 1.4%/h for Profi, Carneval, Arvika, and Trapper, respectively). Estimated RDP was not different (P = 0.21) for all 4 cultivars. In the second study, 30 crossbred beef steers (301 ± 15 kg) were individually fed and used to evaluate effects of field pea processing (whole, rolled, or ground) on steer performance. Diets contained 40% field pea grain. Growing steers consuming whole field pea had greater ADG (P = 0.08) than those consuming processed field pea (1.69, 1.52, and 1.63 ± 0.05 kg/d, for whole, rolled, and ground, respectively). However, DMI (kg/d and as % of BW) and G:F were not different (P ≥ 0.24). In the third study, 35 individually fed gestating beef cows (694 ± 17 kg) were used to evaluate the use of field pea as a protein supplement for medium quality grass hay (9.3% CP). Treatments consisted of whole field peas at 1) 0 g (CON), 2) 680 g (FP680), 3) 1,360 g (FP1360), and 4) 2,040 g (FP2040), and 5) 1,360 g of 74% barley and 26% canola meal (BCM). Total intake (forage + supplement) of gestating beef cows increased with increasing field pea level (linear, P = 0.01; supplemented vs. nonsupplemented, P = 0.01). In summary, protein quantity and rate of ruminal protein degradation vary across sources of field peas used in this study. Additionally, because of source variability, nutrient analysis and animal requirements should be considered when field pea is incorporated into beef cattle diets. Processing field pea does not improve performance of growing steers. Supplementation of field pea to gestating cows consuming medium-quality grass hay increased total DMI. Overall, our data indicate field pea can be used in a wide variety of beef cattle diets.

Effects of form of leftover khat (Catha edulis) on feed intake, digestion, and growth performance of Hararghe Highland goats

Khat (Catha edulis) is a lucrative cash crop in many African countries and other areas of the world. Leftover khat can be used as a feedstuff for ruminants, although seasonal production limits the extent of utilization. Practical methods of feed conservation to preserve nutritional value would be beneficial. Thus, a study was conducted to investigate effects of feeding different forms of leftover khat on intake, digestion, and growth performance of a tropically adapted indigenous goat genotype of eastern Ethiopia. Twenty-four (six per treatment) individually housed Hararghe Highland yearling male goats with an initial body weight of 18±0.4kg were used in an on-station experiment, and 32 similar yearlings with an initial body weight of 19±0.4kg were employed under on-farm conditions. The on-farm experiment occurred at two villages, with four farmer groups (two farmers per group co-managing animals) per village. Four animals in each farmer group were subjected to each of the four different treatments. Experiments were 90 days in length, with inclusion of a subsequent 10-day period on-station to determine digestibility. Khat in fresh, dry, and silage forms was fed at 1.5% body weight (dry matter; DM), whereas control animals did not receive khat. Animals on-station consumed grass hay ad libitum and those on-farm grazed/browsed surrounding areas. Grass hay DM intake on-station was greater (P<0.05) without than with khat (528, 358, 387, and 368g/day; SE=20.3), although total DM intake was increased by feeding khat regardless of form (528, 649, 622, and 639g/day for control, fresh, dry, and silage, respectively; SE=22.9). Digestibility of organic matter was increased (P<0.05) by feeding each form of khat (62.3%, 75.7%, 75.2%, and 72.4% for control, fresh, dry, and silage, respectively; SE=1.63). Nitrogen balance was increased by fresh and ensiled khat (P<0.05) (−0.54, 2.07, 0.80, and 0.86g/day for control, fresh, dry, and silage, respectively). Average daily gain (ADG) was increased by khat regardless of form on-station (13, 49, 33, and 39g; SE=4.6), and on-farm ADG was less for control than for fresh and dry forms (P<0.05) (32, 56, 47, and 42g for control, fresh, dry, and silage, respectively SE=2.0). The ratio of ADG:DM intake on-station was lower for control than for fresh (P<0.05) and silage (P<0.05) (26, 76, 54, and 61g/kg for control, fresh, dry, and silage, respectively; SE=7.6). In conclusion, feeding leftover khat to Highland goats consuming low to moderate quality forage-based diets can increase growth performance. Khat can be preserved for use as a feedstuff throughout the year by drying or ensiling without marked effect on performance.

Fatty acid profile and oxidative stability of the perirenal fat of bulls fattened on grass silage and maize silage supplemented with tannins, garlic, maca and lupines

Carcass fat composition of cattle fed a forage-based diet might be inferior with maize silage compared to grass-silage based systems. This was quantified using complete diets with concentrate. To test whether supplements may influence carcass fat properties as well, the maize-silage diet was additionally supplemented either with Acacia mearnsii tannins, garlic, maca or lupines, feeds rich in secondary metabolites. The perirenal fat of 6 × 6 bulls fed these six diets was analysed for fatty acid profile and shelf life. The n−6/ n−3 ratio was always higher than 11 with the maize silage treatments and 2 with grass silage. The supplements did not affect the occurrence of biohydrogenation intermediates, including rumenic acid. Shelf life, being twice as long with maize compared to grass silage, was either unaffected or tended to be impaired, especially with supplementary garlic. Overall, supplementation was not efficient in improving carcass fat properties of maize-silage fed bulls.

Effect of dried distillers' grain, soybean meal and grain or canola meal and grain-based supplements on forage intake and digestibility

Van De Kerckhove, A. Y., Lardner, H. A., Yu, P., McKinnon J. J. and Walburger, K. 2011. Effect of dried distillers' grain, soybean meal and grain or canola meal and grain-based supplements on forage intake and digestibility. Can. J. Anim. Sci. 91: 123–132. Four ruminally cannulated beef heifers (72 wk of age) were individually fed a basal ration of 75% ground barley straw and 25% ground bromegrass hay [total digestible nutrients=46.3, crude protein (CP)=7.5 (% dry matter (DM))]. Heifers were supplemented with either (1) no supplement (CONT); (2) dried distillers' grains plus solubles [70:30 wheat:corn blend; dried distillers' grains plus solubles (DDGS)]; (3) commercial range pellet (COMM); or (4) barley grain and canola meal (BAR+CM). Forage intake, apparent total tract digestibility, passage rate, rate and extent of forage degradation, rumen pH and rumen ammonia nitrogen were measured. Forage intake, passage rate, and apparent total tract digestibility of DM, neutral detergent fiber, and acid detergent fiber were unaffected (P&gt;0.41) by treatment. Apparent total tract digestibility of CP was increased (P=0.02) with supplements as compared with CONT, but did not differ (P&gt;0.05) among DDGS, COMM, and BAR+CM. Ruminal pH was not affected (P=0.20) by treatment, but rumen ammonia-N was increased (P&lt;0.01) with all three supplements. Potentially degradable and undegradable forage fractions were decreased (P&lt;0.02) and there was a tendency (P=0.06) for the rate of forage DM degradation to increase with supplementation. Supplementing forage diets with either DDGS, grain-soybean-canola- or grain-canola-based supplements did not increase the intake or digestibility of a forage-based diet. More research, however, is required to study the feasibility of feeding these supplements at greater levels with forage-based beef cattle diets.