Ruminal Characteristics Research Articles

Effects of silage type and inclusion level on ruminal characteristics and feeding behavior of steers fed finishing diets.

Crossbred beef steers fitted with a ruminal cannula were used to study the effects of silage type (BH 8895 corn or AF7401 sorghum) and level of inclusion (10 or 20%) in beef cattle finishing diets on digestibility of nutrients, ruminal kinetics, in vitro methane production, and feeding behavior. A 4 × 6 unbalanced Latin square design was used (6 steers; 363 ± 23 kg; 4 diets: corn silage [CS] or sorghum silage [SS], both at 10 or 20% inclusion, DM basis). Each period consisted of 14 d of adaptation and 7 d of collection. Steers were fed once daily at 1000 h. An additional study evaluated the ruminal degradability of intact ensiled sorghum grain ruminally incubated in 3 steers (547 ± 56 kg BW), using the same hybrids from the main study from 10 laboratory experimental silos. The GLIMMIX procedures of SAS were used for statistical analyses. Steers fed SS had greater NDF intake ( < 0.01) compared with the ones fed CS. The magnitude of the NDF intake change depended on the level of inclusion ( < 0.01), which was 6 and 16% for 10 and 20% inclusion, respectively. Regardless the level of inclusion, CS diets promoted greater ( ≤ 0.01) apparent total tract digestibility of nutrients evaluated (DM, OM, NDF, ADF, hemicellulose, and starch) compared with SS diets. Steers fed SS diets tended to chew 1.1 h/d more ( = 0.07) than steers fed CS diets. The level of inclusion increased ( = 0.02) the chewing time per day by 1.3 h. No major differences were observed in any of the ruminal pH and in vitro gas production variables evaluated for silage type and inclusion level ( ≥ 0.09). The CS-fed steers had 12% greater total VFA concentration and an 18.5% lower ( < 0.01) acetate-to-propionate ratio compared with SS-fed steers. The acetate-to-propionate ratio was 16% greater ( < 0.01) when steers were fed SS compared with when steers were fed CS. The CS samples were more extensively ruminally degraded ( < 0.01) than the SS samples. Greater ( < 0.01) NDF ruminal disappearance was observed in ruminal environments containing 20% silage compared with those containing 10% silage. After 96 h inside the rumen, intact ensiled sorghum grain degradability of DM reached only 51.7%. Replacing CS with SS in beef finishing diets (low roughage inclusion) requires adjustments to balance dietary energy. Sorghum material induced a desirable roughage effect in feeding behavior but also offered the potential for improved regarding fiber digestibility and intact grain ruminal degradability.

CARACTERIZAÇÃO FÍSICO-QUÍMICA E MICROBIOLÓGICA DO FLUIDO RUMINAL E DO CONTEÚDO GASTROINTESTINAL DE BEZERROS HOLANDESES EM ALEITAMENTO ARTIFICIAL CONVENCIONAL OU FRACIONADO

The fractional artificial feeding has allowed provide an adequate amount of milk to calves in the first weeks of life and restrict at weaning, stimulating growth and favoring better adaptation to diets with forage and concentrates. The aim was to evaluate the ruminal characteristics and gastrointestinal microbiota of dairy calves in different feeding systems. Holstein calves were evaluated in randomly assigned to feed milk conventional that consisted of four liters of milk daily for 60 days or fractionated systems, six liters of 6° to 25°, four liters of 26o to 45o and two liters of 46o to 60o days old. At an end of the experimental period, the animals were euthanized, and approximately 15 mL of rumen, abomasum and intestine contents were collected for physicochemical and microbiological analysis to detection of fungi, protozoa and Enterobacteriaceae. Feeding systems did not influence characteristics of color, odor and viscosity of rumen fluid. The analysis of pH and quantification of Enterobacteriaceae, mycelial fungi and yeast showed no significant difference between treatments at the different sites. The Escherichia and Proteus genus were the most frequent for the gastrointestinal tract for both feed system. However, E. coli was significantly more frequent among isolates from the rumen fluid of calves in conventional feeding, which could suggest an imbalance in this ecosystem. Thus the artificial fed milk systems influenced the genus profile of Enterobacteriacea in the rumen and small intestine of calves.

EFFECT OF SUPPLEMENTATION DIETARY DRY FAT ON PRODUCTIVE AND REPRODUCTIVE PERFORMANCE ON EGYPTIAN LACTATING BUFFALOES

The present work was conducted to study the effect of using two levels of dry fat (DF 3 and 5%) supplementation during pre-partum (three months before parturition) and after parturition period (six months after postpartum for Egyptian lactating buffalo-cows on nutritive values, nutrients digestibility, ruminal characteristics, milk yield and its composition, birth weight of their offspring, some reproductive parameters, some blood parameters and economic efficiency. Fifteen buffalo-cows (2-4 lactation seasons) in late pregnancy period were choosed to carry out this experiment. Animals were divided into three equal groups (5 buffaloes in each) and individually fed according to Kearl (1982). Concentrate feed mixture (CFM), berseem hay (BH) and rice straw (RS) were given to animals as a control ration without supplementation (C), while the other two groups received the control ration supplemented with DFat the levels of 3 and 5% dry protected fat as calcium salt of fatty acids (based on DM intake), respectively. The obtained results could be summarized as follows: Supplementing buffalo cows ration DF improved the digestibility of all nutrients (pre and post-partum) and nutritive value which recording: 55.91, 61.37 and 66.87%, TDN at 50 days and 58.40, 64.10 and 70.71%, TDN at 180 days for C, DF3 and DF5, respectively; the respective values of DCP was 7.16, 7.47 and 8.04% for the pre-partum period and 7.32, 7.72 and 8.39% for the post-partum period), respectively. Dry fat treatment led to increases in both birth, weaning weights and total gain of calves, and the highest best weights were occurred with DF5. Actual milk yield was increased as 8.50, 9.30 and 10.50 kg/day for C, DF3 and DF5, respectively and 7% - FCM yield on the same order were 7.92, 9.81 and 12.44 kg/day, with significant differences only due to the addition of DF3 and DF5 compared with C. Dry fat improved the blood contents of, total protein, globulin, and glucose and increased in total lipids, cholesterol and HDL. The periods required for fetal membrane expulsion was significantly (P<0.05) reduced in DF3(9.20 h) and DF5(7.15 h) groups when compared to the C group (10.12 h).Moreover, only C group showed a case of abortion and stillbirth, while treated buffalo - cows of DF delivered 100% healthy calves. Better feed and economic efficiencies were observed with animals fed supplemented DF5. Generally, from the obtained results could be concluded that the supplementation of DF at DF3 and DF5 levels for ration of Egyptian lactating buffalo cows had positive effects on nutritive value, digestibility calves birth weight and milk yield and composition, beside better feed efficiency and reproductive performance as well as improved economic efficiency. The best and the highest results were obtained with the addition of DF5.

1495 Effects of silage type and inclusion level on ruminal characteristics and feeding behavior of feedlot steers

1495 Effects of silage type and inclusion level on ruminal characteristics and feeding behavior of feedlot steers

Methane emissions, ruminal characteristics and nitrogen utilisation changes after refaunation of protozoa-free sheep

Effects of rumen protozoa on ruminal fermentation, methane (CH4) emissions and nitrogen (N) retention were studied in twelve crossbred ewes given an oaten chaff diet. Over 10days sheep were progressively adapted to a diet containing 7% coconut oil distillate to suppress rumen protozoa and then were defaunated using sodium 1-(2-sulfonatooxyethoxy) dodecane (Empicol). Twelve weeks after defaunation treatment, five sheep were inoculated with rumen fluid collected from cannulated sheep to refaunate them and that the effect of re-establishment of rumen protozoa 0, 7, 14 and 21days following refaunation on ruminal fermentation and CH4 emissions was examined in Experiment 1. As a following study (Experiment 2), feed intake was restricted to 1.5×ME requirement for maintenance from day 28 to day 43 when dry matter (DM) digestibility, N retention, fermentation and CH4 emissions were compared between defaunated and refaunated sheep. Sheep were scanned through a computed tomography scanner on day 0 and day 28 to estimate reticulo-rumen (RR) weight and carcass composition. It was concluded that refaunated sheep did not have a higher daily CH4 production (DMP, g CH4/day) than did the defaunated cohort within 21days after refaunation as measured by Greenfeed Emission Monitoring units. Total volatile fatty acid (VFA) concentration and the proportion of propionate in the rumen VFA gradually increased over 21days following refaunation (Experiment 1), while a change towards higher butyrate and lower acetate proportions was observed after 28days (Experiment 2; P<0.05). There was a tendency towards a heavier RR weight (P=0.08) and a higher ratio of RR to liveweight in defaunated sheep 28days after refaunation (P<0.001), but carcass composition was not affected by refaunation status. Experiment 2 showed defaunated sheep had a 7% lower DMP than did refaunated sheep with an established rumen fauna (P<0.05). Apparent whole-tract N and DM digestibility and microbial crude protein supply were not different between defaunated and refaunated sheep, while energy losses in CH4 (MJ/day) and CH4 as a proportion of gross energy intake were both approximately 8% lower in defaunated sheep. The reduced CH4 emissions achieved by defaunation occurred without altering total VFA, apparent whole-tract N and DM digestibility or ADG.

Caracterização físico-química e microbiológica do fluido ruminal e do conteúdo gastrointestinal de bezerros alimentados com silagem de leite de transição

The objective was to evaluate the ruminal characteristics and gastrointestinal microbiota of dairy calves in different milk feeding systems. In an entirely randomized design, 18 Holstein calves at 6 to 59 day of age were used randomly allotted. In the conventional treatment were provided 4 L of milk daily. In the second and third treatments, 2 L of transition milk fermented were administered to 2 L of water or 2 L of milk, respectively. At 60 days of age, it was collected approximately 15 mL of the contents of the tract digestive (rumen, abomasum, and small intestine) and feces after necropsy. The different systems of feeding did not influence the color characteristics, odor and viscosity of the ruminal juice. The pH and quantification of Enterobacteriaceae, mycelium fungi and yeast fungi did not show significant difference between treatments for the different sites studied. Aspergillus spp. was the mycelia fungi most frequent between isolates from gastrointestinal tract for both milk systems. The treatments with transition milk silage, in water or milk, did not influence the physicochemical and microbiological characteristics evaluated, corroborating studies indicate this product can be used as milk replacer for the dairy calves.

Effect of feeding a by-product feed-based silage on nutrients intake, apparent digestibility, and nitrogen balance in sheep.

BackgroundLiterature is lacking on the effects of feeding by-product feed (BF)-based silage on rumen fermentation parameters, nutrient digestion and nitrogen (N) retention in sheep. Therefore, this study was conducted to determine the effect of replacing rye straw with BF-based silage as a roughage source on ruminal parameters, total-tract apparent nutrient digestibility, and N balance in sheep.MethodsThe by-product feed silage was composed of spent mushroom substrate (SMS) (45 %), recycled poultry bedding (RPB) (21 %), rye straw (11 %), rice bran (10.8 %), corn taffy residue (10 %), protected fat (1.0 %), bentonite (0.6 %), and mixed microbial additive (0.6 %). Six sheep were assigned randomly to either the control (concentrate mix + rye straw) or a treatment diet (concentrate mix + BF-based silage).ResultsCompared with the control diet, feeding a BF-based silage diet resulted in similar ruminal characteristics (pH, acetate, propionate, and butyrate concentrations, and acetate: propionate ratio), higher (p < 0.05) ruminal NH3-N, higher (p < 0.05) ether extract digestibility, similar crude protein digestibility, lower (p < 0.05) dry matter, fiber, and crude ash digestibilities, and higher (p < 0.05) N retention (g/d)ConclusionThe BF-based silage showed similar energy value, higher protein metabolism and utilization, and lower fiber digestion in sheep compared to the control diet containing rye straw.

Nitrate but not tea saponin feed additives decreased enteric methane emissions in nonlactating cows.

Tea saponin is considered a promising natural compound for reducing enteric methane emissions in ruminants. A trial was conducted to study the effect of this plant extract fed alone or in combination with nitrate on methane emissions, total tract digestive processes, and ruminal characteristics in cattle. The experiment was conducted as a 2 × 2 factorial design with 4 ruminally cannulated nonlactating dairy cows. Feed offer was restricted to 90% of voluntary intake and diets consisted of (DM basis): 1) control (CON; 50% hay and 50% pelleted concentrates), 2) CON with 0.5% tea saponin (TEA), 3) CON with 2.3% nitrate (NIT), and 4) CON with 0.5% tea saponin and 2.3% nitrate (TEA+NIT). Tea saponin and nitrate were included in pelleted concentrates. Diets contained similar amounts of CP (12.2%), starch (26.0%), and NDF (40.1%). Experimental periods lasted 5 wk including 2 wk of measurement (wk 4 and 5), during which intake was measured daily. In wk 4, daily methane emissions were quantified for 4 d using open circuit respiratory chambers. In wk 5, total tract digestibility, N balance, and urinary excretion of purine derivatives were determined from total feces and urine collected separately for 6 d. Ruminal fermentation products and protozoa concentration were analyzed from samples taken after morning feeding for 2 nonconsecutive days in wk 5. Tea saponin and nitrate supplementation decreased feed intake ( < 0.05), with an additive effect when fed in combination. Compared with CON, tea saponin did not modify methane emissions (g/kg DMI; > 0.05), whereas nitrate-containing diets (NIT and TEA+NIT) decreased methanogenesis by 28%, on average ( < 0.001). Total tract digestibility, N balance, and urinary excretion of purine derivatives were similar among diets. Ruminal fermentation products were not affected by tea saponin, whereas nitrate-containing diets increased acetate proportion and decreased butyrate proportion and ammonia concentration ( < 0.05). Under the experimental conditions tested, we confirmed the antimethanogenic effect of nitrate, whereas tea saponin alone included in pelleted concentrates failed to decrease enteric methane emissions in nonlactating dairy cows.

In vivo ruminal degradation characteristics and apparent digestibility of low-quality prairie hay for steers consuming monensin and Optimase.

Seven ruminally cannulated crossbred steers (BW = 720 ± 62 kg) were used in a randomized crossover design (4 periods, each 18 d) to evaluate in vivo rumen characteristics and apparent digestibility of steers consuming low-quality prairie hay and 1 of 4 isonitrogenous protein supplements. Treatments included 1) 40% CP (DM basis) cottonseed meal and wheat middlings-based supplement (Control), 2) a cottonseed meal and wheat middlings-based supplement with slow-release urea and a fibrolytic feed enzyme (Optimase; Alltech, Inc., Nicholasville, KY) designed to replace 30% of plant-based CP provided in the Control (OPT), 3) the Control plus 0.40 mg∙kg BW∙d monensin (Rumensin 90; Elanco Animal Health, Greenfield, IN; MON), and 4) the OPT plus 0.40 mg∙kg BW∙d monensin (COMBO). Steers were allowed ad libitum access to prairie hay (5.0% CP and 76% NDF) and were provided each respective supplement at 0800 h daily at a rate of 1.0 g/kg of BW. Steers were adapted to diets for 10 d before sample collection. Beginning on d 11, DMI was measured and samples were collected to determine apparent digestibility. On d 15 of the 18-d period, rumen fluid was collected 10 times over a 24-h period. Forage DMI was greater ( ≤ 0.02) for steers consuming the OPT compared with steers consuming the MON or COMBO, although forage DMI was not different ( = 0.10) among steers consuming the Control compared with steers consuming the OPT, MON, or COMBO. Steers fed the MON and COMBO had lower ( ≤ 0.05) passage rate compared with steers fed the Control and the OPT. The MON-fed steers had lower ( = 0.01) ruminal pH and increased ( = 0.03) propionate as a percentage of total VFA production. A time × treatment ( = 0.01) interaction was observed for ruminal NH-N due to a rapid (0 to 1 h after feeding) increase followed by a quick (1 to 4 h after feeding) decline in NH-N by steers consuming the OPT and COMBO that was not observed for steers consuming all other treatments. Apparent digestibility of DM ( = 0.01) and NDF ( = 0.03) were improved for steers fed the COMBO supplement compared with steers consuming all other experimental supplements. This work suggests that the OPT may be an effective replacement for a portion of supplemental degradable intake protein in low-quality forage. Further research is necessary to determine if the combination of monensin and the Optimase consistently improves low-quality forage utilization.

Excretion patterns of solute and different-sized particle passage markers in foregut-fermenting proboscis monkey (Nasalis larvatus) do not indicate an adaptation for rumination

Behavioral observations and small fecal particles compared to other primates indicate that free-ranging proboscis monkeys (Nasalis larvatus) have a strategy of facultative merycism (rumination). In functional ruminants (ruminant and camelids), rumination is facilitated by a particle sorting mechanism in the forestomach that selectively retains larger particles and subjects them to repeated mastication. Using a set of a solute and three particle markers of different sizes (<2, 5 and 8mm), we displayed digesta passage kinetics and measured mean retention times (MRTs) in four captive proboscis monkeys (6–18kg) and compared the marker excretion patterns to those in domestic cattle. In addition, we evaluated various methods of calculating and displaying passage characteristics. The mean±SD dry matter intake was 98±22gkg−0.75d−1, 68±7% of which was browse. Accounting for sampling intervals in MRT calculation yielded results that were not affected by the sampling frequency. Displaying marker excretion patterns using fecal marker concentrations (rather than amounts) facilitated comparisons with reactor theory outputs and indicated that both proboscis and cattle digestive tracts represent a series of very few tank reactors. However, the separation of the solute and particle marker and the different-sized particle markers, evident in cattle, did not occur in proboscis monkeys, in which all markers moved together, at MRTs of approximately 40h. The results indicate that the digestive physiology of proboscis monkeys does not show typical characteristics of ruminants, which may explain why merycism is only a facultative strategy in this species.

Effects of feeding yeast (Saccharomyces cerevisiae), organic selenium and chromium mixed on growth performance and carcass traits of hair lambs

Yeasts and organic minerals are used in diets to improve health, productive performance and some carcass characteristics of ruminants and non-ruminants. Thirty-two lambs (Pelibuey×Katahdin; BW=(30.55±1.67) kg; n=8) were used in a 56-d feeding experiment to study the effects of different levels of live yeast (Saccharomyces cerevisiae; yeast), selenium (Se) and chromium (Cr) mixed (Se-Cr), and a mixture of yeast-Se-Cr on growth performance and carcass traits. Animals were stratified by body weight (BW) and randomly assigned to one of four treatments: 1) control group (0.0 g kg−1 yeast); 2) yeast (1.50 g kg−1 dry matter intake (DMI) d−1); 3) Se-Cr premix (1.5 mg kg−1 DMI d−1 for each mineral); and 4) yeast-Se-Cr mixture. There were no treatment effects on final BW; whereas lambs fed Se-Cr or yeast-Se-Cr had higher (P<0.05) DMI than animals supplemented with only yeast. Average daily gain (ADG), gain:feed ratio, chop area, dorsal fat and carcass yield were similar (P>0.05) among treatment groups. In conclusion, supplementation with yeast, Se-Cr mixed or yeast-Se-Cr did not improve ADG, final BW, back fat content and carcass yield of growing of Pelibuey×Katahdin lambs. Supplementation with Se-Cr and yeast-Se-Cr increased DMI, and approximately 250 g ADG animal−1 d−1 was produced with no negative effects on growth and health of the animals.

Does sugar cane ensiled with calcium oxide affect intake, digestibility, performance, and microbial efficiency in beef cattle?

Two trials were conducted to evaluate how calcium oxide (CaO) as an additive in sugar cane silage affects animal performance and diet digestibility. Experiment 1 included 35 crossbred steers (Holstein×Nellore) with an average body weight (BW) of 350±18.3kg, which were distributed across a randomized block design with five treatments and seven replicates. The five treatments consisted of sugar cane ensiled with four different levels of CaO (0, 5, 10, and 15g/kg; fresh basis) and a standard diet of corn silage. The forage concentrate ratio was 50:50 and was formulated to be isonitrogenous (120g/kg DM). The dry matter intake (DMI) was measured daily and individually. Indigestible acid detergent fiber (iADF) was used as an internal marker to estimate apparent nutrient digestibility. There was a quadratic positive effect (P=0.013) of the CaO levels on DMI (gDM/kgBW), organic matter (OM; P=0.032), and non-fiber carbohydrates (NFC; P=0.014) intake. The average daily gain (ADG) of steers that were fed corn silage diets was similar (P=0.11) to that of those fed sugar cane silage with 5g/kg of CaO. There was a positive linear effect of the percentage of CaO on the apparent total digestibility of DM (P=0.012), OM (P=0.001), crude protein (CP; P=0.022) and neutral detergent fiber (aNDF; P=0.015) of the diets. In Experiment 2, four ruminally and abomasally cannulated Nellore steers (184±10.2kgBW) were used with a 4×4 Latin square design to evaluate the effect of CaO levels on apparent total and ruminal digestibility of nutrients, ruminal characteristics, and microbial efficiency. The four treatments were composed of the same sugar cane silage diets used in Experiment 1. The aNDF intake decreased linearly (P=0.032) as the percentage of CaO increased. There was a linear positive effect of the percentage of CaO on the apparent total digestibility of DM (P=0.036), OM (P=0.007), CP (P=0.042), and aNDF (P=0.025). There were no effects of CaO levels on the ruminal pH values (P=0.52), ammonia concentration (P=0.22), or microbial efficiency (P=0.283). Adding CaO to sugar cane silage reduces the silage fiber. However, the addition of more than 5g/kg CaO to sugar cane at ensiling does not improve silage intake and animal performance. Additionally, the use of 15g/kg of CaO in sugar cane at ensiling decreases diet intake and growth of beef cattle.

Rumination activity of dairy cows in the 24 hours before and after calving

Monitoring rumination behavior serves multiple purposes in feeding and herd management of dairy cows. The process of calving is a major event for cows, and a detailed understanding of alterations in behavioral patterns of animals in the time around calving is important in calving detection. The objective of this study was to describe the short-term changes in rumination patterns in dairy cows immediately before and after parturition. In total, 17 cows were fitted with rumination sensors that were able to monitor rumination time, number of rumination boli, and number of rumination jaw movements. Rumination time was decreased in the last 4h antepartum and in the first 8h postpartum. Cows stopped ruminating 123±58min (mean ± standard deviation) before calving and resumed ruminating 355±194min after calving. The number of rumination jaw movements and boli per day were decreased in the 24-h period postpartum. Rumination rate, the number of rumination jaw movements per rumination minute, and the number of boli per rumination minute changed little around calving. The calving event primarily influenced the duration and frequency of various rumination characteristics but not rumination intensity. Among detected characteristics, rumination time showed the greatest potential for monitoring of calving events.

Effect of reducing dietary forage in lower starch diets on performance, ruminal characteristics, and nutrient digestibility in lactating Holstein cows

This experiment evaluated the effect of feeding a lower starch diet (21% of dry matter) with different amounts of forage (52, 47, 43, and 39% of dry matter) on lactational performance, chewing activity, ruminal fermentation and turnover, microbial N yield, and total-tract nutrient digestibility. Dietary forage consisted of a mixture of corn and haycrop silages, and as dietary forage content was reduced, chopped wheat straw (0–10% of dry matter) was added in an effort to maintain chewing activity. Dietary concentrate was adjusted (corn meal, nonforage fiber sources, and protein sources) to maintain similar amounts of starch and other carbohydrate and protein fractions among the diets. Sixteen lactating Holstein cows were used in replicated 4×4 Latin squares with 21-d periods. Dry matter intake increased while physically effective neutral detergent fiber (peNDF1.18) intake was reduced as forage content decreased from 52 to 39%. However, reducing dietary forage did not influence milk yield or composition, although we observed changes in dry matter intake. Time spent chewing, eating, and ruminating (expressed as minutes per day or as minutes per kilogram of NDF intake) were not affected by reducing dietary forage. However, addition of chopped wheat straw to the diets resulted in greater time spent chewing and eating per kilogram of peNDF1.18 consumed. Reducing dietary forage from 52 to 39% did not affect ruminal pH, ruminal digesta volume and mass, ruminal pool size of NDF or starch, ruminal digesta mat consistency, or microbial N yield. Ruminal acetate-to-propionate ratio was reduced, ruminal turnover rates of NDF and starch were greater, and total-tract digestibility of fiber diminished as dietary forage content decreased. Reducing the dietary forage content from 52 to 39% of dry matter, while increasing wheat straw inclusion to maintain chewing and rumen function, resulted in similar milk yield and composition although feed intake increased. With the lower starch diets in this short-term study, the minimal forage content to maintain lactational performance was between 39 and 43%.

Energy metabolism and methane production in llamas, sheep and goats fed high- and low-quality grass-based diets

This study aimed to test whether the digestive and metabolic characteristics of pseudo ruminants provide superior ability to utilise low-quality diets compared to true ruminants. A total of 18 mature, non-pregnant, non-lactating female animals, including six llamas (Lama glama), six Danish Landrace goats and six Shropshire sheep, were used in a crossover design study. The experiment lasted for two periods of three weeks. Half of the animals were fed either high-quality grass hay (HP) or low-quality grass seed straw (LP) during each period. Animals were placed in metabolic cages during the last 5 d, and gaseous exchange was measured by open-circuit indirect calorimetry for 22 h. Metabolisable energy for maintenance (MEm) and fasting energy expenditure (FEExp) were estimated by regression approach. Dry matter (DM) intake per kg0.75 was substantially reduced in llamas and sheep, but not in goats, on the LP compared to HP diet. Llamas had lower daily energy expenditure (324 kJ · kg−0.75) than sheep (416 kJ · kg−0.75) and goats (404 kJ · kg−0.75) on the LP diet. Llamas in comparison with sheep and goats had lower methane emission (0.83 vs 1.34 and 1.24 l · d−1 · kg−0.75, p < 0.05), lower MEm (328 vs 438 and 394 kJ · d−1 · kg−0.75, p < 0.05) and lower FEExp (246 vs 333 and 414 kJ · d−1 · kg−0.75, p < 0.05), respectively. In conclusion, llamas had lower basal metabolic rate and hence maintenance requirements for energy.

Consumo, digestibilidade dos nutrientes e características ruminais de cordeiros alimentados com níveis crescentes de concentrado em ambiente tropical no Vale do Alto Guaporé - MT

The objective was to evaluate the use of concentrate in the diet of lambs on intake and total digestibility coefficient (DC) of nutrients, ruminal characteristics, rectal and body temperature. It was used four lambs without breed defined (SRD), entire, with average body weight (BW) of 19.3 ± 2.07 kg using a Latin square design, 4 x 4. The animals were housed in metabolism cages and were fed twice a day with diet consisting of corn silage and concentrate at a ratio of 20, 40, 60 and 80% dry matter in the diet, composite of corn grains and soybean meal. Leftovers were measured daily and the feces were collected through bags. Data from variables studied were submitted to ANOVA and regression analysis at 5% probability. The increasing levels of concentrate in lamb diets affected (P&lt;0.05) of linear form decreasing the intake of NDF, ADF and quadratic of DM, OM, CP, EE, NFC and TCH intake. There was no effect (P&gt;0.05) of concentrate levels on digestibility coefficient of DM, OM, EE, NDF, ADF, NFC and TCH. However, the digestibility coefficient of CP showed a quadratic effect (P&lt;0.05). The pH and ammonia nitrogen showed a quadratic effect (P&lt;0.05) for the time after feeding. The rectal and body temperature of lambs was not affected (P&gt;0.05) by dietary concentrate. It can be concluded that 38% of concentrate in diets of lambs favors the maximum dry matter intake, organic matter and crude protein. The digestibility coefficient of the nutrients, except for protein, are not altered with the addition up to 80% concentrate in diet for lambs, as well as, this does not affect the pH and ammonia nitrogen concentration of ruminal fluid, rectal and body temperature.

Effect of a non-forage fiber of red bean hulls on ruminal mat characteristics, chewing activity and milk production in dairy cows

The evaluation of red bean hulls (RBH) as a non-forage fiber source on ruminal mat formation, chewing activity and milk production was determined using two experiments. In experiment 1, four non-lactating, rumen-cannulated Holstein cows were offered a control diet of 60.1% forage, and an RBH diet of 51.6% forage and 9.4% RBH. Although the neutral detergent fiber (NDF) intake was higher with the RBH diet than the control diet, the physically effective NDF (peNDF) intake was lower. The rumination period tended to be longer with the RBH diet than with the control diet and the ruminal mat was formed even when the RBH diet was consumed. Ruminal fermentation parameters were not affected by treatment. In experiment 2, 40 lactating cows were fed a control diet of 53.4% forage or an RBH diet of 50.3% forage and 8.1% RBH. Dry matter intake, chewing activity and milk production were not affected by diet. Cows sorted against NDF in the control diet, but not in the RBH diet. It is concluded that normal ruminal function can be maintained because the ruminal mat was stratified and rumination activity was not reduced even when a low peNDF diet that contained RBH was given to dairy cows.

In situ degradability and selected ruminal constituents of sheep fed with peanut forage hay

Because legumes are a very important feed source for ruminants, the aim of this study was to evaluate the ideal inclusion level of hay Arachis pintoi cv. Belmonte in sheep diets by measuring the dry matter intake (DMI), concentration of volatile fatty acids, ammonia–nitrogen concentration, ruminal pH and the in situ degradability of dry matter (DM) and crude protein (CP). In the experiment with four sheep, a 4 × 4 Latin Square design was used with four periods and four treatments (0%, 30%, 60% and 100% Arachis replacing grass hay). Significant interactions were observed between treatments and sampling times for ammonia–nitrogen and acetate, propionate and butyrate concentration and the acetate:propionate ratio. The ruminal pH and total volatile fatty acids concentration were not affected by interaction between treatments and sampling time. The degradation of DM and CP was similar, rising with the increasing content of Arachis, showing a linear effect. The treatment containing 60% of Arachis showed best results, with good levels of daily weight gain and higher ruminal concentrations of volatile fatty acids. The legume showed high levels of CP, high digestibility and appropriate levels of fibre, with excellent standards of degradation and ruminal characteristics. The use of the legume Arachis for ruminants is a promising option of nutrient supply to meet production demands of these animals.

Effects of dietary level of selenium and grain on digestive metabolism in lambs

The objective was to evaluate the effect of different levels of selenium with two levels of grain corn in the diets on ruminal, postruminal, and total tract digestion of nutrients, ruminal fermentation characteristics, and selenium balance in lambs. A split-plot design was used in four periods with repeated Latin square using eight Suffolk &amp;times; Dorset male lambs with four levels of selenium (sodium selenite, Na&lt;sub&gt;2&lt;/sub&gt;SeO&lt;sub&gt;3&lt;/sub&gt;), without adding selenium, 0.3, 0.6, and 0.9 mg of selenium/kg dry matter (DM) with 70 and 50% of corn grain in the diet. The four selenium levels affected organic matter as follows: starch, neutral detergent fibre, nitrogen and selenium excretion; selenium ruminal digestion; organic matter, neutral detergent fibre, nitrogen and selenium postruminal digestion; and organic matter, neutral detergent fibre, nitrogen and selenium total tract digestion (P &amp;lt; 0.05). Starch and organic matter flow decreased with 0.6 and 0.9 mg of selenium with the 70% grain diet (P&amp;nbsp;&amp;lt; 0.05). Selenium flow increased linearly with selenium levels (P &amp;lt; 0.01) with both levels of grain. Selenium supplementation increased linearly selenium concentration in ruminal fluid (P &amp;lt; 0.01), but did not affect other ruminal characteristics. Also, selenium absorption and retention was increased by selenium concentrations (P&amp;nbsp;&amp;lt; 0.01). The apparent absorption of selenium increased (31%, P &amp;lt; 0.01) with the 70% grain diet. In conclusion, the high content of nonstructural carbohydrates improved the availability of selenium and 0.9 mg of selenium/kg &lt;br /&gt;DM improved the absorption and availability of selenium. &amp;nbsp;

Conspecific body weight, food intake, and rumination time affect food processing and forage behavior

Much research has been directed at the chemical characteristics of plants that influence forage digestibility but there is less investigation into relationships between chewing and foraging in herbivores. The role of body size on forage processing, via chewing, and ingestive behavior is poorly understood in spite of associations between conspecific body size of ruminants and botanical and nutritional composition of their diets. I examined the implications from a relationship between body weight and absolute forage intake (kg/day) and no relationship between body weight and rumination time (h/day) on chewing behavior and feeding time (h/day). Cattle were selected as the model species because the diets presented offered benefits to digestion from increased chewing and because of the number of studies that measured body weight, daily food intake, dietary nutritional characteristics, feeding time, and rumination characteristics on the same individuals. Data were extracted from 24 studies of cattle (n ≤ 74). Absolute food intake scaled allometrically (0.75) with body weight but rumination time was unrelated to body weight, meaning smaller animals had more rumination time for a unit weight of ingesta. Correspondingly, small cattle chewed the weight-specific ingesta more and fed longer than large animals, probably because of a reduction in time of rumen turnover. These findings might be revealing as to how differences in digestion and foraging are associated with body size among conspecific animals of wild ruminant species.