Roughage Level Research Articles

Influence of dietary roughage level and Megasphaera elsdenii on feedlot performance and carcass composition of thin cull beef cows fed for a lean market.

One hundred forty-four cull cows (body condition score = 2.10 ± 0.61; BW = 456 ± 47 kg) were organized into a 2 × 2 factorial design (48 pens, 12 pens/treatment, and 3 cows/pen) to evaluate the effect of dietary roughage level and oral drenching of Megasphaera elsdenii NCIMB 41125 (M. elsdenii culture; Lactipro Advance; MS Biotec Inc., Wamego, KS) on performance and carcass characteristics. Cattle were finished over a 42-day realimentation period, and aggressively stepped up over a 10-day period to either a high roughage finisher (HRF; 25% roughage) or a low roughage finisher (LRF; 10% roughage). Within diet, cattle were administered no probiotic or 100 mL of M. elsdenii culture (M. elsdenii NCIMB 41125, 2 108 cfu/mL) on day 0. No diet × probiotic interactions were detected (P ≥ 0.15), suggesting that the magnitude of the response was not influenced by the concentrate level of the diet. The main effect of diet triggered several significant responses. Decreasing roughage level tended to improve average daily gain (ADG) by 9.7% (0.26 kg, P = 0.08), while decreasing dry matter intake (DMI) by 0.9 kg (P = 0.09), provoking a 19.7% enhancement of feed efficiency (0.036 units, P < 0.01). However, interim data revealed declines of performance parameters among both diets with a significant difference between treatments only documented during the final phase of the realimentation period. During the final 14 days, LRF posted a 0.68 kg increase in ADG (P = 0.05) and a 2.0 kg decrease in DMI (P = 0.01), translating to improved feed efficiency (0.054 units, P = 0.03). This suggests that increasing the caloric density of finishing diets may help offset the regression of performance typically observed following a compensatory gain. No carcass traits were impacted by either diet or M. elsdenii culture (P ≥ 0.08). Overall, oral drenching of M. elsdenii culture tended to augment ADG (0.26 kg, P = 0.08) and carcass ADG (0.20 kg, P = 0.10). Implying that M. elsdenii culture was effective at alleviating the acidosis risk prompted by the rapid step-up period employed in the trial and may help capitalize on the narrow timeline of compensatory gain in cull cow realimentation.

Effect of roughage-to-concentrate ratios combined with different preserved tropical forages on the productive performance of feedlot lambs

Abstract This study proposes to investigate the production performance of lambs fed diets containing different roughage sources and formulated with different roughage-to-concentrate ratios (R:C). A total of 108 castrated male Santa Ines lambs aged 3–6 months, at an average body weight of 26.1 kg ± 5.6 kg were used. The experiment was set up as a randomized block design with a 2 × 3 factorial arrangement represented by two R:C ratios (400:600 or 600:400 g/kg, dry matter basis) and two roughage sources [transvala grass (Digitaria decumbens Stent cv. Transvala) hay or sorghum (Sorghum bicolor) silage], or a combination of the two sources. Six diets were tested, namely, Diet 1–400 g/kg hay +600 g/kg concentrate; Diet 2–400 g/kg silage +600 g/kg concentrate; Diet 3–200 g/kg hay +200 g/kg silage +600 g/kg concentrate; Diet 4–600 g/kg hay +400 g/kg concentrate; Diet 5–600 g/kg silage +400 g/kg concentrate; and Diet 6–300 g/kg hay +300 g/kg silage +400 g/kg concentrate. The concentrate was composed of ground corn, soybean meal, urea and a mineral mixture. The diets with the lower R:C ratio (400:600 g/kg DM) provided the highest intakes of dry matter and other nutritional components as well as increased animal performance and carcass yield parameters. Better feed efficiency was observed in the lambs fed the silage-containing diets. In conclusion, the tested roughage sources can be used in lamb diets, and the roughage level of 400 g/kg DM maximizes feed efficiency in lambs. When using hay in the diet formulation, higher weight gain rates are achieved with a R:C ratio of 400:600 g/kg; for diets formulated with silage, in turn, the recommended R:C ratio for increased weight gain is 600:400 g/kg. Thus, depending on the availability of roughage, the producer may choose one of the sources and associate it with the most adequate proportion of concentrate to maximize the performance of feedlot lambs.

222 Effect of corn stalk inclusion rate on performance and rumination behavior in beef steers

Abstract Coarse roughage, such as corn stalks, in feedlot diets aids in the formation of a fibrous mat within the rumen. The fibrous mat supports rumen health, buffers pH, and reduces acidosis risk in cattle consuming high-concentrate diets. Excess roughage can increase physical fill, thus lowering the animal’s ability to consume enough energy for efficient growth. The objective of this experiment was to quantify feedlot growth performance, rumination, ruminal pH and carcass quality and yield outcomes of cattle consuming a finishing diet with increasing levels of roughage. Fifty-one steers (initial BW = 295 + 11 kg) were randomly allocated to 1 of 3 dietary treatments; 5% (5CS; n = 18), 10% (10CS; n = 17), or 15% (15CS; n = 16) corn stalks (DM basis) in a steam-flaked-corn based finishing diet. Steers were fitted with a sensory collar that recorded rumination (min/d) and one-half of the steers (n = 27) received a rumen bolus that continuously monitored pH. The experiment was conducted using a randomized complete block design. Data were analyzed using a mixed model; treatment was a fixed effect and block was a random effect. As CS inclusion increased, we observed increased DM intake (P = 0.01; 7.7, 8.2, and 8.5 kg/d, respectively), decreased gain efficiency (P &lt; 0.01; 0.18, 0.16, and 0.14 kg/kg DM, respectively), and a tendency for decreased ADG (P = 0.09; 1.34, 1.33, and 1.22 kg/d, respectively). Ruminal pH was highest (P &lt; 0.01) for 15CS (6.28) and similar for 5CS and 10CS (6.10). Steers spent more time ruminating (P &lt; 0.01) when consuming the 10CS diet (361 min/d) and least with 5CS diet (279 min/d). Increasing CS to 15% decreased rib fat thickness (P = 0.01), decreased calculated YG (P = 0.02), and decreased marbling score (P &lt; 0.01) compared with the 5CS and 10CS treatments. Feeding excess corn stalks (≥ 15%) may prevent adequate energy intake, thus diminishing feedlot growth performance and carcass merit.

How did Lofgreen and Garrett do the math?

Lofgreen and Garrett introduced a new system for predicting growing and finishing beef cattle energy requirements and feed values using net energy concepts. Based on data from comparative slaughter experiments they mathematically derived the California Net Energy System. Scaling values to body weight to the ¾ power, they summarized metabolizable energy intake (ME), energy retained (energy balance [EB]), and heat production (HP) data. They regressed the logarithm of HP on ME and extended the line to zero intake, and estimated fasting HP at 0.077 Mcal/kg0.75, similar to previous estimates. They found no significant difference in fasting HP between steers and heifers. Above maintenance, however, a logarithmic fit of EB on ME does not allow for increased EB once ME is greater than 340 kcal/kg0.75, or about three times maintenance intake. So based on their previous work, they used a linear fit so that partial efficiency of gain above maintenance was constant for a given feed. They show that with increasing roughage level efficiency of gain (slope) decreases, consistent with increasing efficiency of gain and maintenance with greater metabolizable energy of the feed. Making the system useful required that gain in body weight be related to EB. They settled on a parabolic equation, with significant differences between steers and heifers. Lofgreen and Garrett also used data from a number of experiments to relate ME and EB to estimate the ME required for maintenance (ME = HP) and then related the amount of feed that provided that amount of ME to the metabolizable energy content of the feed (MEc), resulting in a logarithmic equation. Then they related that amount of feed to the net energy for gain calculated as the slope of the EB line when regressed against feed intake. Combining the two equations, they estimate the net energy for maintenance and gain per unit feed (Mcal/kg dry matter) as a function of MEc: 0.4258 × 1.663MEc and 2.544–5.670 × 0.6012MEc, respectively. Finally, they show how to calculate net energy for maintenance and gain from experiments where two levels of a ration are fed and EB measured, where one level is fed and a metabolism trial is conducted, or when just a metabolism trial is conducted—but results are not consistent between designs.

Effects of free-choice hay and straw bedding on digestion of nutrients in 7-week-old Holstein calves

ABSTRACT Objective Bedding with long straw improves animal health and performance but could affect digestibility measurements if calves consume the bedding. Feeding hay with calf starters is common practice; however due to the limited capacity of the young calf’s rumen, high levels of roughage can lead to decreased DMI, digestibility, and ADG. The objectives of this study were to evaluate the effect of long-straw bedding and free-choice hay on nutrient digestibility in calves less than 2 mo old. Materials and Methods Sixteen calves (45.4 ± 1.18 kg of BW, 3 d of age) were bedded on long wheat straw or on rubber mats and fed diets with or without free-choice, long-grass hay. Calves were fed a 25% CP, 17% fat milk-replacer powder at 0.66 kg of DM 2 times per day for 35 d and then 0.33 kg of milk replacer 1 time per day for 7 d. Milk replacer was diluted to 14% DM. Calves were fed free-choice textured starter and water for the entire 56-d trial. Hay was 5.4% CP and 62.8% NDF (DM basis). Digestibility was estimated on d 47 to 51 using acid insoluble ash in feeds and feces as an internal marker. Results and Discussion Hay intake varied and reduced the digestion of dietary DM, OM, CP, and fat by calves. As hay intake increased, digestion of OM decreased linearly. Implications and Applications Long wheat straw as bedding did not change estimates of digestion in young calves consuming coarse, textured starter, whereas moderate- to low-quality hay intake reduced digestion.

BEEF SPECIES-RUMINANT NUTRITION CACTUS BEEF SYMPOSIUM: Energy and roughage levels in cattle receiving diets and impacts on health, performance, and immune responses1.

Transition of newly received feedlot cattle from a forage- to grain-based diet is challenging, and the appropriate roughage level in receiving diets is debatable. Nutritionists must consider the paradox of dietary transition and roughage level to mitigate ruminal acidosis, yet concomitantly low feed intake presents difficulty in achieving nutrient requirements when metabolic demand is increased due to inherent stress and disease challenge during the receiving period. Previous research suggests that performance is improved at the expense of increased morbidity for newly received cattle consuming diets with less roughage and greater starch concentration. The clinical signs of bovine respiratory disease (BRD) and acute acidosis are analogous; therefore, it is probable that acidotic cattle are incorrectly diagnosed with BRD in both research and production settings. Additional research efforts have attempted to elucidate alterations in microbial populations and digestion, physiological response to inflammatory challenge, and immunological response to infectious bovine rhinotracheitis virus challenge in cattle consuming diets of various roughage levels. Furthermore, our understanding of the rumen microbiome is improving rapidly with culture-independent assays, products such as direct-fed microbials are available, and increased availability and use of fibrous byproduct ingredients requires further attention. Beef cattle nutritionists and producers should consider that the health benefit of receiving diets containing greater levels of roughage and lower energy may not compensate for the reduction in performance compared with feeding receiving diets with lower roughage and greater energy.

273 Roughage levels in receiving diets and impacts on animal health and transition to a high-grain diet.

273 Roughage levels in receiving diets and impacts on animal health and transition to a high-grain diet.

Roughage levels impact on performance and carcass traits of finishing Nellore cattle fed whole corn grain diets.

This study was carried out to evaluate the effects of chopped hay levels in high-concentrate diets with whole corn grain (WCG) on performance and carcass traits of finishing Nellore cattle. One hundred and eight 24-month-old Nellore intact males (453±75kg) were fed one of three WCG-based diets that differed in roughage level: without roughage (WCG), with 5% chopped hay included (WCG5), or with 12% chopped hay included (WCG12) in a block design (based on initial body weight) for 86days. Animals fed WCG5 or WCG12 had significantly improved on final body weight, dry matter intake, average daily gain, feed efficiency, hot carcass weight, and dressing percentage when compared to those fed WCG. The Longissimus muscle area (P=0.1108), backfat thickness (BFT; P=0.6089), and rump fat thickness (P=0.1798) were not affected by roughage levels. Therefore, using WCG diets without roughage negatively affects the performance of feedlot Nellore cattle but does not affect carcass traits and does lead to the minimum BFT required by the industry.

566 Isolation of Fusobacterium necrophorum , Trueperella pyogenes , and Salmonella enterica from ruminal, ileal, and colonic epithelial tissues of finishing beef steers receiving different levels of dietary roughage with and without tylosin

566 Isolation of Fusobacterium necrophorum , Trueperella pyogenes , and Salmonella enterica from ruminal, ileal, and colonic epithelial tissues of finishing beef steers receiving different levels of dietary roughage with and without tylosin

Effects of fibre digestibility and level of roughage on performance and rumen fermentation of finishing beef cattle.

The objective was to evaluate effects of neutral detergent fibre (NDF) digestibility and level of fresh sugarcane on intake, body fatness, carcass characteristics, and rumen kinetics and fermentation of beef cattle. Forty-eight Nellore young bulls were used in a complete randomized block design with a 2×2 factorial arrangement of treatments. Eight rumen-cannulated Nellore steers were used in a replicated 4×4 Latin square design. Two sugarcane genotypes divergent for stalk NDF digestibility (NDFD) were used. Experimental diets were formulated with 20 or 40% of sugarcane on a dry matter (DM) basis. High-NDFD genotype associated with the lower level of roughage in the diet promoted greater DM intake, resulting in greater body gain. Sugarcane with high-NDFD increased final body weight, hot carcass weight, and back-fat thickness. Animals receiving the genotype with high NDFD had greater rump-fat thickness only with 40% sugarcane in the diet. Animals receiving the low-NDFD genotype at 20% of the diet had lower NDF passage rate. Rumen pH was greater for diets with greater NDF content. There was greater proportion of butyrate in the rumen of animals receiving diets with greater NDF content. In conclusion, high-NDFD sugarcane increased final body and carcass weight, HCW, and fat thickness. When associated with lower inclusion of roughage in the diet, it can also increase DM intake and body weight gain of beef cattle.

Effects of Dietary Starch and Crude Protein Levels on Milk Production and Composition of Dairy Cows Fed High Concentrate Diet

Effects of two dietary levels of starch and crude protein on performance of dairy cow fed low roughage level (70:30 concentrate to roughage) were investigated. Twenty eight Holstein cows were randomly assigned to one of four dietary treatments in a 2 x 2 factorial arrangement. Factors were two dietary level of starch (14% and 22%) and crude protein (15% and 18%). Wheat straw was used as sole roughage source. The study was continued 6 weeks. Dry matter intake was not affected (P&gt;0.05) by the dietary treatments in the study. Milk and protein yield (kg/d) were higher (P

Detection of heat produced during roughage digestion in ruminants by using infrared thermography

The present study aimed to establish the relationship of infrared thermography (IRT) with fermentation dynamics in ruminants, and to initiate the development of a method that allows associating these images with the heat produced during feed digestion. The experiment was conducted at APTA, Brazil. Twenty-four Jersey heifers (mean liveweight of 221.25 ± 59.41 kg) were subjected to the following treatments: 30R (30% corn silage and 70% concentrate), 50R (50% corn silage and 50% concentrate) and 70R (70% corn silage and 30% concentrate) in a Latin square design. The diet (corn silage + concentrate) was offered at 3% of liveweight from 0800 hours to 1400 hours. Infrared images were collected from the whole body on the left and right sides, from the eyes, from the left foreleg on the cranial and caudal side, and from the forehead. IRT images were taken at 2-h intervals for 12 h (from 0600 hours to 1800 hours) and 24 h (0600 hours of the following day) after the beginning of feeding and so on. Physiological parameters were obtained at the same time as the IRT were taken. Ruminal parameters were collected after 4 h of feeding. The thermograms of the right (P &lt; 0.001) and left flank (P &lt; 0.001) differed among sampling times, with an increase in temperature until 1400 hours and a reduction thereafter. The temperatures on the right (P = 0.037) and left (P = 0.017) flank were higher in animals consuming the 50R diet and lower in those consuming the 70R diet. When the 50R diet was offered, the heifers exhibited higher dry-matter intake (P &lt; 0.001), neutral detergent fibre (P &lt; 0.001), non-fibrous carbohydrates (P &lt; 0.001) and total digestible nutrients (P &lt; 0.001). A decrease in the concentrations of butyric acid (P = 0.042), isobutyric acid (P = 0.001), isovaleric acid (P = 0.019) and ammonia nitrogen (P = 0.001) in the rumen fluid of heifers was observed with an increasing dietary roughage level. Infrared thermography was able to detect differences in the body temperature of animals associated with different fibre proportions in the diets. However, the magnitude of these differences was small and further research is needed to investigate the application of IRT to the detection of possible differences in the body temperature of ruminants as part of the digestive process.

Effect of dietary roughage level on chewing activity, ruminal pH, and saliva secretion in lactating Holstein cows

Increasing dietary roughage level is a commonly used strategy to prevent subacute ruminal acidosis. We hypothesized that high-roughage diets could promote chewing activity, saliva secretion, and hence more alkaline to buffer rumen pH. To verify the hypothesis, 12 multiparous Holstein cows in mid lactation were randomly allocated to 4 treatments in a triplicated 4 × 4 Latin square experiment with one cow in each treatment surgically fitted with a ruminal cannula. Treatments were diets containing 40, 50, 60, or 70% of roughage on a DM basis. Increasing dietary roughage level decreased DM, CP, OM, starch, and NEL intake, increased ADF intake, and decreased milk yield linearly. Intake of NDF was quite stable across treatments and ranged from 7.8 to 8.1 kg/d per cow. Daily eating time increased linearly with increased roughage level. The increase in eating time was due to increased eating time per meal but not number of meals per day, which was stable and ranged from 8.3 to 8.5 meals per day across treatments. Increasing dietary roughage level had no effect on ruminating time (min/d), the number of ruminating periods (rumination periods per d), and chewing time per ruminating period (min/ruminating period). Ruminating time per kilogram of NDF intake and total chewing time per kilogram of ADF intake were similar across treatments (57.4 and 183.8 min/kg, respectively). Increasing dietary roughage level linearly increased daily total chewing time; linearly elevated the mean, maximum, and minimum ruminal pH; and linearly decreased total VFA concentration and molar proportion of propionate in ruminal fluid. Saliva secretion during eating was increased, the secretion during rumination was unaffected, but the secretion during resting tended to decrease with increased dietary roughage level. As a result, total saliva secretion was not affected by treatments. In conclusion, the results of the present study did not support the concept that high-roughage diets elevated ruminal pH through increased salivary recycling of buffering substrates.

Effect of halophyte Salicornia bigelovii Torr and graded levels of dietary crude protein on feed performance and carcass traits of camels

The objective of this study was to evaluate the effect of source of roughage and crude protein level on feeding performance and carcass traits of Majaheem camels (Camelus dromedarius). Forty-eight male calf-camels weighing 203.3±5.1 kg were equally assigned to a 2 × 3 factorial arrangement of two sources of roughage (Rhodes grass hay and dry salicornia biomass) and three dietary crude protein levels (12, 14.5, and 17%); the feeding trial lasted for 18 weeks. The results showed that slaughter and hot carcass weights, average daily gain, dry matter intake, feed efficiency, and separable fat from 9th-11th rib joint increased as the crude protein in the diets increased from 12 to 14.5%, whereas increasing crude protein to 17% resulted in no further changes. Slaughter weight, average daily gain, hot carcass weight, rib eye area, and separable lean did not differ between Rhodes grass and salicornia diets, but salicornia-fed camels had higher dry matter intake and produced heavier kidney fat and separable fat weights than camels fed Rhodes grass diets. It is suggested that the inclusion of salicornia biomass as a roughage ingredient up to 25% in the diet containing not greater than 14.5% crude protein can be utilized without adverse effect on feeding performance of calf-camels.

Effects of wet distillers grains with solubles in diets based on steam-flaked corn containing moderate or high roughage levels on nutrient digestibility in feedlot cattle and in vitro fermentation

ABSTRACT Previous research with roughage and wet distillers grains with solubles (WDGS) concentrations in feedlot diets based on steam-flaked corn has not extensively evaluated measurements of digestibility. Two experiments were conducted to evaluate the effects of concentrations of alfalfa hay (AH) and WDGS on apparent total-tract nutrient digestibility by finishing cattle and in vitro fermentation characteristics. In both studies, treatments were arranged in a 2 × 3 + 1 factorial and consisted of diets based on steam-flaked corn including AH (6 or 12% of DM) and WDGS (15, 30, or 45% of DM), and a control diet without WDGS that contained 9% AH. In Exp. 1, 56 beef steers (initial BW = 395 ± 7 kg) were used in a randomized complete block design and fed for 28 d. Intakes of DM, OM, NDF, ADF, and CP were greater (P ≤ 0.048) by steers fed 12 versus 6% AH. Increasing the dietary concentration of WDGS increased NDF, ADF, and CP intakes (P ≤ 0.046), and an AH × WDGS interaction (P ≤ 0.02) was detected for starch intake. Digestibility of DM and OM was greater for control steers than for the average of all treatments containing WDGS (P

Performance and economic viability of feedlot sheep fed different levels of roughage, concentrate, and water

The aim of this study was to evaluate performance and economic viability of producing sheep fed different levels of roughage, concentrate, and water. Forty Santa Inês crossbred sheep with an average initial weight of 18.85 ± 2.80 kg and an average age of 5.0 ± 2.0 months were distributed in a completely randomized design with a 2 × 2 factorial arrangement composed of two proportions of roughage and concentrate (30:70 and 70:30) and two levels of water supply (ad libitum, and 50% restriction), with 10 replicates. Water restriction had a negative effect (P0.05) feed conversion or feed conversion. Total weight gain, average daily gain, feed conversion, and feed efficiency were influenced by the proportions of roughage and concentrate. In conclusion, the diet with 70% roughage, associated with a water restriction of 50%, reduced the uptake of energy and protein, compromising the animal performance. The combination of the diet plus concentrate and water restricted to 50% of the free consumption provides a better cost-benefit ratio.

Prospects of complete feed system in ruminant feeding: A review.

Effective utilization of available feed resources is the key for economical livestock rearing. Complete feed system is one of the latest developments to exploit the potential of animal feed resources in the best possible way. The complete feed is a quantitative mixture of all dietary ingredients, blended thoroughly to prevent separation and selection, fed as a sole source of nutrients except water and is formulated in a desired proportion to meet the specific nutrient requirements. The concentrate and roughage levels may vary according to the nutrient requirement of ruminants for different production purposes. The complete feed with the use of fibrous crop residue is a noble way to increase the voluntary feed intake and thus animal’s production performance. In this system of feeding, the ruminant animals have continuous free choice availability of uniform feed mixture, resulting in more uniform load on the rumen and less fluctuation in release of ammonia which supports more efficient utilization of ruminal non-protein nitrogen. Feeding complete diet stabilizes ruminal fermentation, thereby improves nutrient utilization. This feeding system allows expanded use of agro-industrial by­products, crop residues and nonconventional feeds in ruminant ration for maximizing production and minimizing feeding cost, thus being increasingly appreciated. However, to extend the concept extensively to the field and make this technology successful and viable for farmers, more efforts are needed to be taken.

Effects of various roughage levels with whole flint corn grain on performance of finishing cattle1

Performance responses to steam flaking flint corn as well as to the addition of roughage to finishing diets composed of whole flint corn were evaluated. Ninety-six Nellore bulls were stratified by initial BW (373 ± 11 kg) and randomly allotted to 16 feedlot pens (6 bulls/pen) in a randomized complete block design with 4 replicates/treatment. Dietary treatments for the 86-d feeding trial consisted of (DM basis) 1) 78.8% steam-flaked flint corn with 6% sugarcane bagasse and 0.20% urea, 2) 85% whole flint corn without sugarcane bagasse, 3) 81.9% whole flint corn with 3% sugarcane bagasse and 0.10% urea, and 4) 78.8% whole flint corn with 6% sugarcane bagasse and 0.20% urea. All diets contained 15% (DM basis) of a pelleted protein, mineral, and vitamin supplement. Compared with whole flint corn grain, flaking of flint grain decreased ( < 0.01) DMI but did not alter ADG ( = 0.86), so G:F was increased ( = 0.02). Although steam flaking did not alter final BW and carcass characteristics ( > 0.47), it increased energy content of the diet ( < 0.03) and total tract starch digestibility ( < 0.01). In addition, flaking increased ( < 0.01) NEg of flint corn when compared with whole corn. Increasing the roughage content of WC-based diets resulted in quadratic ( < 0.02) responses in DMI, NEm and NEg intakes, ADG, and final BW but had no effect ( > 0.47) on G:F or on observed energy content of the diet. In summary, steam flaking of flint corn when fed in diets containing 6% sugarcane bagasse decreased DMI by 17% but increased G:F by 20% and NEg of corn calculated from feedlot performance by 23%; these responses markedly exceed those typically observed with dent corn grain. Moreover, adding 3% sugarcane bagasse to a flint whole corn grain diet optimized feedlot performance of Nellore bulls.

Effect of flint corn processing method and roughage level on finishing performance of Nellore-based cattle1

This study was conducted to evaluate the effects of flint corn processing method (CPM) and level of NDF from roughage (rNDF) on performance, carcass characteristics, and starch utilization by finishing Nellore-based cattle fed high-concentrate, flint corn-based diets. In this study, 112 Nellore type bulls (initial BW 384.07 ± 29.53 kg and 24-36 mo of age) were individually fed using Calan gates or individual pens. The animals were used in a randomized complete block design in a 2 × 4 factorial arrangement with 2 CPM, high-moisture flint corn (HMC) or finely ground dry flint corn (FGC), with 1 of 4 levels of rNDF, 3, 8, 13, and 18% (DM basis), using sugarcane silage (SS) as roughage. Bulls were adapted to the finishing diet over a 21-d period and fed for a total of 81 d. Fecal starch (FS) concentration was determined on d 46 and 74 of the feeding period. There was a quadratic effect of rNDF on final BW ( < 0.01) and ADG ( = 0.01). Optimal concentrations of rNDF were estimated using the first derivative of second order polynomials, indicating that final BW and ADG were maximized with 13.3 and 13.0% rNDF, respectively. An interaction was observed between CPM and rNDF ( = 0.05) for DMI, with peak DMI occurring at 11.3 and 13.7% rNDF with FGC and HMC, respectively. Cattle fed HMC had 13.9% greater G:F ( < 0.01) compared with those fed FGC (0.172 vs. 0.151, respectively). There were quadratic effects of rNDF on HCW ( = 0.04) and ME intake ( < 0.01); heaviest carcass weights were estimated, in both cases, to be achieved with 12.8% rNDF. A quadratic effect of rNDF for renal, pelvic, and inguinal fat weight ( = 0.04) was observed, with a peak estimated to occur at 12.6% rNDF. An interaction between CPM and rNDF also was observed for FS ( < 0.05). Bulls fed FGC with 3% rNDF had greater FS content, and FS linearly decreased as concentration of rNDF increased. For bulls fed HMC, FS was 3.0% of DM and was unaffected by rNDF in the diet. Lower FS from bulls fed HMC suggests that availability of starch from flint corn was greater than that of FGC. For Nellore-based cattle fed a flint corn-based diet containing SS and 8% whole lint cottonseed, performance was optimized with 12.8% rNDF. In the absence of cottonseed addition to diets, optimal performance would be expected with about 14.5% rNDF.

Effect of Roughage to Concentrate Ratio in the Diet on Milk Production and Fatty Acid Profile of Milk in Crossbred Cows

Eighteen crossbred dairy cows were divided into three groups of six each and fed on rations containing different roughage: concentrate (R: C) ratios for a period of 60 days to investigate their effect on milk production and its fatty acid composition. The roughage (berseem hay: Trifolium alexandrinum) to concentrate ratio was 50: 50, 60: 40 and 70: 30 in treatments T1, T2 and T3, respectively. DM intake decreased (P<0.05) with the increase in the level of roughage in the diet. Digestibility of DM, CP, EE, NFE and OM showed a significant (P<0.05) decrease whereas digestibility of CF and ADF increased significantly (P<0.05) with the increase in the ratio of roughage to concentrate. Increasing R: C ratio significantly (P<0.05) decreased milk production but production of 4% FCM was not affected by roughage level. Milk fat concentration decreased (P<0.05) by 6.30 and 3.78% in T1 and T2, respectively as compared to T3. Increasing R: C ratio had no significant effect on milk lactose, protein, TS, SNF, MUN, Ca and P levels. Milk cholesterol in treatment T3 was lower by 13.35 and 8.27% as compared to T1 and T2, respectively. The concentrations of TLCFA, TUFA, MUFA and PUFA in milk increased with the increase in roughage level in the diet whereas TSFA level was reduced. PUFA content of milk fat increased by 141.75% in T3 over T1. Total CLA production in T3 was increased by 50.92% over T1. Results of the present study indicated that cows producing 12–14 kg of milk/d could be best maintained on a dietary regimen of 70% good quality roughage and 30% concentrate to have maximum production beneficial fatty acids with lesser cholesterol without compromising milk yield.