Effect of elemental nano-selenium on feed digestibility,rumen fermentation,and purine derivatives in sheep

The objective of this experiment was to study the effect of elemental nano-selenium (NS) on feed digestibility, rumen fermentation, and urinary purine derivatives in sheep. Eight male ruminally cannulated sheep (42.5 ± 3.2 kg of body weight, BW) were used in a replicated 4×4 Latin square experiment in four 20 day periods. Depending on treatment designation, sheep were fed the basal diet supplemented with 0 (control), 0.3, 3 and 6 g of nano-Se/kg dry matter (DM). Ruminal pH (range of 6.68–6.80) and ammonia N concentration (range of 9.95–12.49 mg/100 mL) was decreased (P<0.01), and total VFA concentration (range of 73.63–77.72 mM) was increased linearly (P<0.01) and quadratically (P<0.01) with increasing nano-Se supplementation. The ratio of acetate to propionate was linearly (P<0.01) and quadratically (P<0.01) decreased due to the increasing of propionate concentration. In situ ruminal neutral detergent fiber (aNDF) degradation of Leymus chinensis and crude protein (CP) of soybean meal were linearly (P<0.01) and quadratically (P<0.01) improved by feeding nano-Se. Similarly, nutrients digestibility in the total tract and urinary excretion of purine derivatives were also quadratically (P<0.01) changed by increasing nano-Se supplementation. The present results indicated that nano-Se supplementation in basal diet improved rumen fermentation and feed utilization. Nano-Se could also stimulate rumen microbial activity, digestive microorganisms or enzyme activity. The optimum dose of nano-Se was about 3.0 g/kg dietary DM in sheep.     

Effects of Brosimum alicastrum and Lysiloma latisiliquum mixtures on voluntary intake, nutrient digestibility and nitrogen balance in sheep fed tropical pastures

Effects of supplementing tree foliage mixtures on voluntary intake, apparent digestibility and N balance was evaluated using Pelibuey sheep fed low quality diets. Five treatments were examined in a 5 × 5 Latin square design, which consisted of a basal diet of grass (Sorghum halepense) hay supplemented with Brosimum alicastrum (B) and Lysiloma latisiliquum (L) at the following rates (g DM/kg diet): B264, L0; B198, L66; B132, L132; B66, L198 and B0, L264. Additionally, an in situ degradability evaluation was completed with two ruminally cannulated cows. Neutral detergent fibre (NDF), acid detergent insoluble N (ADIN), lignin(sa) and total phenols (TP) were higher (P<0.01) in L. latisiliquum versus B. alicastrum. Daily intake (g/kg LW^0.75/day) of DM (from 98 to 73) and OM (from 88 to 66) decreased quadratically (P<0.01), whereas CP (from 8.0 to 5.6) and ME (from 7.7 to 5.2, MJ/sheep/day) reduced linearly (P<0.01), as L. latisiliquum increased in the diet. Apparent digestibility of DM (from 0.486 to 0.445), OM (from 0.511 to 0.458) and CP (from 0.417 to 0.198) decreased linearly (P<0.01) and was associated with a low ruminal in situ CP degradability of L. latisiliquum. The decrease in N intake and digestibility induced lower (P<0.01) N retention (from 2.7 to 0.1 g/sheep/day). Although the incremental substitution of B. alicastrum with L. latisiliquum negatively affected intake, rumen degradation, digestibility and N balance, results indicate that this foliage mixture, but with no more than 132 g DM/kg diet of L. latisiliquum, could be used as a supplementation strategy to sheep fed low quality forage without negative effects on voluntary intake.     

Effects of isobutyrate on rumen fermentation, lactation performance and plasma characteristics in dairy cows

The objective of this study was to evaluate effects of isobutyrate supplementation on rumen fermentation, lactation performance and plasma characteristics of dairy cows. Twenty multiparous second filial generation (F2) cows of a cross between Chinese Jinnan Yellow and Holstein cows at 148 ± 4.5 days in milk and 22.3 ± 0.81 kg milk production were used in a replicated 4 × 4 Latin square experiment. The treatments were: control (without isobutyrate), low (LIB), medium (MIB) and high (HIB) isobutyrate supplementation of 20, 40 and 60 g per cow per day, respectively. Experimental periods were 30 days with 15 d of adaptation and 15 d of data collection. Dry matter (DM) intake was not affected by increasing isobutyrate supplementation, but milk yields were highest for the 40 g/d isobutyrate supplementation level, where proportion of milk fat, true protein and lactose were minimized. Ruminal pH (6.38–6.24) and ammonia N (13.8–11.1 mg/100 ml) were linearly (P<0.01) decreased, whereas total VFA concentration (124–131 mM) increased at a decreasing rate with increasing isobutyrate supplementation. The ratio of acetate to propionate increased linearly (P<0.01) from 2.77 to 4.43 as isobutyrate supplementation increased due to the increase in acetate production and decrease in propionate production. Digestibilities of OM in the total tract increased linearly (P<0.01) as isobutyrate supplementation increased, digestibilities of DM and EE were highest for the 40 g/d isobutyrate supplementation level, digestibilities of CP, aNDF and ADF increased at a decreasing rate with increasing isobutyrate supplementation. Plasma concentrations of glucose and growth hormone linearly (P<0.03) increased, whereas concentrations of non-esterified fatty acids linearly (P<0.01) decreased. Results indicate that supplementation of this diet with isobutyrate changed the rumen fermentation pattern towards acetate production, improved digestion and modified plasma concentrations of glucose and growth hormone. This suggests that isobutyrate stimulated digestive microorganisms or enzymes in a dose-dependent manner with the optimum isobutyrate dose at about 40 g per cow per day in terms of improved digestion.     

Effects of malic acid on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in steers

The objective of this study was to evaluate the effects of malic acid (MA) supplementation on rumen fermentation, urinary excretion of purine derivatives (PDs) and whole gastro-intestinal tract feed digestibility in steers. Eight ruminally cannulated Simmental steers (465 ± 13 kg) were used in a replicated 4 × 4 Latin square design. The treatments were: control (without MA), LMA (MA-low), MMA (MA-medium) and HMA (MA-high) with 0.0, 7.8, 15.6 and 23.4 g MA per kg dry matter (DM), respectively. Diets consisted of corn stover and concentrate (60/40, DM basis). DM intake was approximately 9 kg per day, which was 90% of ad libitum intake including 5.4 kg corn stover and 3.6 kg concentrate. Ruminal pH (range of 6.91 to 6.56), ratio of acetate to propionate (range of 3.88 to 3.25), ammonia N (range of 9.03 to 6.42 mg/100 ml) and lactate (range of 91.25 to 76.31 mg/100 ml) decreased linearly as MA supplementation increased, whereas total volatile fatty acid (VFA) concentration (range of 55.68 to 61.49 mM) linearly (P < 0.05) increased with increase in MA supplementation. In situ ruminal neutral detergent fiber (aNDF) degradation of corn stover was improved but the crude protein (CP) degradability of concentrate mix was decreased with increasing the dose of MA. Urinary excretion of PDs was quadratically (P < 0.01) changed with altering MA supplementation (67.88, 72.74, 75.81 and 73.78 mmol/day for control, LMA, MMA and HMA, respectively). Similarly, digestibilities of DM, organic matter (OM), NDF and acid detergent fiber (ADF) in the total tract were also quadratically increased with increasing MA, and no differences in terms of CP and ether extract digestibility were observed. The results indicate that MA supplementation has the potential to improve rumen fermentation and feed digestion in beef cattle. The MA stimulates the digestive microorganisms or enzymes in a quadratic response. In the experimental conditions of this trial, the optimum MA dose was 15.6 g MA per kg DM.     

Influence of calcium oxide level and time of exposure to sugarcane on in vitro and in situ digestive kinetics

These experiments were carried out to evaluate, using in vitro and in situ techniques, the effects of three inclusion levels of calcium oxide (0, 5, and 10 g/kg of sugarcane fresh matter) and four exposure times (0, 24, 48, and 72 h) of sugarcane to calcium oxide on the chemical composition and digestive kinetic parameters of sugarcane. The treatments were arranged in a 3 by 4 factorial design. Freshly-cut sugarcane (whole plant) was treated with calcium oxide and separated into 12 piles inside a barn to prevent direct exposure to sunlight, rain, and wind. Every day, before and after animal feeding, the calcium oxide was proportionally hand-mixed with approximately 150 kg of freshly-cut sugarcane to make up the dietary treatments. The lowest (Ti) and greatest (Ts) temperature and pH of the treated sugarcane piles were measured immediately before and after sampling, respectively. The ether extract (EE) and DM were not affected (P>0.05) by either exposure time or inclusion level. However, CP increased linearly (P=0.01) and OM decreased linearly (P<0.0001) as the exposure time and calcium oxide inclusion level increased. Interactions between inclusion level and exposure time on DM, OM, CP, EE, Ti, and Ts were not observed. However, significant interactions were detected for non-fibre carbohydrate (NFC), neutral detergent fibre (aNDF), and pH. A quadratic effect of exposure time on the Ti and Ts was observed (P=0.001 and P=0.001, respectively). The maximum temperature was reached with approximately 51 h of exposure time. Calcium oxide positively affected the insoluble potentially digestible fraction of sugarcane DM and aNDF (P=0.001 and P=0.001, respectively), and the indigestible fraction of sugarcane aNDF (P=0.001). Interactions between inclusion level and exposure time on soluble and indigestible fractions of sugarcane DM (P=0.0001 and P=0.01, respectively) were found. However, no interactions (P>0.27) were found between inclusion level and exposure time on aNDF digestive kinetic parameters. The fractional digestion rate (kd) of sugarcane DM and aNDF was not influenced by treatments (P>0.05). The mean values of kd for sugarcane DM and aNDF were 0.0235 and 0.0215/h, respectively. The gas production kinetics parameters were not affected (P>0.05) by treatments. In conclusion, the inclusion of calcium oxide improved the in situ potentially digestible fraction of sugarcane DM and aNDF; however, it did not influence the fractional digestion rate. No effects were observed on the in vitro digestive kinetic parameters.     

Effect of organic zinc supplementation on growth, nutrient utilization and mineral profile in lambs

To study the efficacy of organic zinc (Zn) supplementation on growth, nutrient utilization and mineral profile as compared to inorganic source [zinc sulphate (ZnSO₄)], 18 Muzaffarnagari male lambs of 11.30 ± 0.45 kg mean body weight (4–5 months of age) were divided into three groups of six animals in each in a randomized block design. Lambs in the control group were fed a standard total mixed ration (TMR) consisted of 60 kg/100 kg of concentrate mixture (CM) and 40 kg/100 kg of wheat straw. CM was consisted of 300 g/kg crushed maize grain, 270 g/kg soybean meal, 400 g/kg wheat bran, 20 g/kg mineral mixture (without Zn) and 10 g/kg common salt. Animals in the experimental groups were additionally supplemented with 20 mg Zn/kg of diet either through inorganic (ZnSO₄) or organic [Zn-methionine AA complex (Zn-meth)] sources. Experimental feeding was done for a period of 150 days including a 6 days metabolism trial. The intake of dry matter (DM), organic matter (OM), crude protein (CP), digestible CP and total digestible nutrients and digestibility of DM, OM, CP, ether extract, neutral detergent fibre and hemicellulose were comparable (P>0.05) among the three groups. However, digestibility of cellulose and acid detergent fibre was significantly (P<0.05) higher in Zn-meth group as compared to control group. Though the balance of calcium was adversely affected (P<0.01) in both the Zn supplemented groups, but it was significantly higher in Zn-meth group compared to ZnSO₄ group. While apparent absorption and retention of nitrogen, phosphorus, copper, iron and manganese were similar (P>0.05) among different groups, retention of Zn (P<0.05) as well as its concentration in the serum (P<0.01) were highest in Zn-meth group, followed by ZnSO₄ group and lowest in the control group, suggesting higher bioavailability of Zn from Zn-meth as compared to ZnSO₄. Average daily gain of the lambs and feed conversion efficiency were also significantly (P<0.05) higher in Zn-meth group as compared to control and ZnSO₄ groups, suggesting a positive role of organic zinc supplementation on the performance of lambs.     

Effects of increasing crude protein concentrations on performance and carcass characteristics of growing and finishing steers and heifers

A 2 × 3 factorial design was utilized to ascertain the effects of three dietary crude protein (CP) concentrations on performance, carcass characteristics, and serum urea nitrogen (SUN) concentration in steers and heifers. Animals were blocked by gender (n = 9) and body weight (BW; n = 3/gender), randomly assigned to a diet containing 110, 125 or 140 g/kg dietary CP (n = 6), subjected to a growing period of 56, 84 or 112 d, depending on start BW, and a finishing period of 84 d. Animals were weighed and bled at 28 d intervals and daily dry matter intake (DMI), average daily gain (ADG), and gain to feed (G:F) were calculated and SUN was analyzed as a repeated measure throughout the study. Following slaughter, carcass data was collected for hot carcass weight (HCW), dressing percent (DP), kidney, pelvic and heart fat (KPH), 12th rib backfat (BF), loin muscle (LM) area, marbling score (MS), and yield grade (YG). Growing steers and heifers were programmed to gain 1.02 and 0.91 kg/d, respectively. Therefore, heifers consumed less than steers and steers gained more than heifers (P<0.01) with no differences in feed efficiency. Dietary CP treatment did not effect DMI, but did result in a quadratic (P=0.04) increase in ADG; thereby quadratically (P=0.06) and linearly (P=0.08) increasing final BW, and G:F, respectively. Finishing heifers consumed and gained less than steers (P<0.01), had lighter HCW (P<0.01) and greater DP (P=0.01) and LM area (P=0.01) than steers. DMI (P=0.02), ADG (P=0.05), HCW (P=0.08), and DP (P=0.06) reacted quadratically with increasing dietary CP. HCW (P=0.02) increased linearly with increasing dietary CP. G:F, KPH, BF, LM area, MS and YG was not affected by dietary CP concentration and G:F, KPH, BF, MS, and YG did not differ between genders. However, there was a gender × dietary CP interaction (P=0.01) for G:F. Steers were the most efficient at 125 g/kg dietary CP, while heifers were most efficient at 140 g/kg dietary CP. Gender had no effect on SUN concentrations, but SUN increased linearly (P<0.01) with increasing dietary CP concentrations. In conclusion, quadratic responses in DMI and ADG indicate that a 125 g/kg dietary CP concentration is optimal for either steers or heifers during the finishing period.     

The effects of xylanase supplementation on performance, characteristics of the gastrointestinal tract, blood parameters and gut microflora in broilers fed on wheat-based diets

The aim of this study was to investigate the effects of xylanase supplementation on performance, characteristics of the gastrointestinal tract, blood parameters and gut microflora in broilers fed on wheat-based diets. The experimental diets consisted of a wheat-based diet supplemented with 0 or 1 g/kg enzyme preparation (xylanase activity was 1218 U/g). The diets were fed between 7 and 49 days of age. Enzyme supplementation (ES) improved (P<0.05) growth performance and feed conversion efficiency. The addition of enzyme to a wheat-based diet reduced the relative weights of the duodenum, jejunum, pancreas (P<0.05) and colon (P<0.01) in 21-day-old broiler chickens. Enzyme preparation reduced digesta viscosity in the proventriculus and jejunum of 21-day-old broiler chickens (P<0.05) and in colon of 49-day-old broiler chickens (P<0.05). The pH of the digesta in the crop, duodenum and jejunum was increased (P<0.05) in 21-day-old broiler chickens and was reduced in the caecum of 49-day-old broiler chickens (P<0.05) with enzymes. There was no significant difference between the two experimental groups in counts of lactobacillus and coliform bacteria in the caecum. Enzyme supplementation increased the concentration of blood insulin-like growth factor I (IGF-I) (P<0.01) of 21-day-old broilers, triiodothyronine (T₃) and insulin (P<0.05) at 49 days. ES reduced the concentrations of blood thyroxine (T₄) (P<0.01) and uric acid (P<0.05) at 49 days, but had no effect on glucose concentration (P>0.05). In conclusion, ES can improve performance and digestive parameters and can change some blood parameters in broiler chickens fed a wheat-based diet.     

Effects of Fermenten supplementation to beef cattle

Two experiments were conducted to evaluate a commercially available supplemental N source for beef cattle (Fermenten^®; Church & Dwight Co., Inc., Princeton, NJ, USA). The first experiment evaluated kinetics of in vitro NH₃-N release using batch cultures of rumen fluid incubated with: control (no N added), soybean meal, urea, and Fermenten^®. Ammonia-N was measured at 0, 0.5, 2, 4, 6, 8, 12 and 24 h after incubation began. A treatment by time interaction (P<0.01) occurred in which, during the initial 2 h, Fermenten^® cultures had the highest (P<0.01) NH₃-N but, from 4 to 24 h, the highest (P<0.01) NH₃-N concentrations were with urea-incubated cultures. The total increase in NH₃-N concentrations from 0 to 24 h of incubation was less for Fermenten^® (P<0.01) than for the soybean meal and urea. The second experiment assessed effects of Fermenten^® supplementation on growth, blood parameters, voluntary forage intake and reproductive performance of beef heifers. Sixty heifers, stratified by initial body weight (BW), were randomly allocated to one of two treatments that consisted of iso-nitrogenous grain-based supplements containing either Fermenten^® (72 g/kg, as-fed) or urea (9.7 g/kg, as-fed). Supplements were offered three times weekly at a rate of 2.4 kg of dry matter per heifer daily. Shrunk BW was measured on days 0 and 112 for calculation of daily body weight gain. Body volume measurements were completed on days 0, 28, 56, 84 and 112, whereas pelvic area was assessed on days 0, 56 and 112. Blood samples were collected on days 28, 56, 84 and 112 for analysis of metabolites and hormones. On day 56, 2 heifers, which were randomly selected from each pasture, were placed in individual feeding stations for 26 days to determine treatment effects on voluntary forage intake. On day 112, all heifers were grouped by treatment and exposed to bulls for 60 days. Fewer heifers offered the Fermenten^® supplement attained puberty (P<0.05) and became pregnant during the study compared to heifers fed urea (0.60 and 0.93, respectively; P<0.01). Addition of Fermenten^® to batch cultures of rumen fluid rapidly increased NH₃-N concentrations, whereas further increases occurred in a slower and steady rate. Beef heifers fed a supplement containing Fermenten^® had similar growth and development, but inferior reproductive performance, than heifers fed a supplement containing urea.     

Effects of superovulation, arachidonic acid or endometrium on release of prostaglandins and synthesis of proteins by bovine trophoblast

This study was conducted in vitro to examine factors that may regulate prostaglandin release by bovine trophoblast and endometrial slices. Trophoblastic tissues and endometrial slices were recovered from superovulating and normally-ovulating cattle on day 16 or 20 of pregnancy and incubated for 24 h. Release of PGF_2^α and 13,14-dihydro-15-keto-PGF_2^α (PGMF), and incorporation of [¹⁴C]-leucine into proteins were quantified and expressed per μg DNA, which gives a measure of cellular activity. Activity of trophoblastic tissue for synthesizing protein was decreased (P<.05) and for releasing PGMF was increased (P<.05) on day 20 compared to day 16 of pregnancy. Neither supercovulation nor day of pregnancy altered trophoblastic activity for releasing PGF_2^α. Supercovulation increased (P<.05) endometrial release of PGF_2^α. Endometrial release of PGF_2^α was less (P<.05) on day 20 than on day 16 of pregnancy. When arachidonic acid (0, 100, 200 or 400 μg) was added at the start of incubation, trophoblastic release of PGF_2^α changed (P<.05) quadratically with dose of arachidonic acid. When arachidonic acid was added 8 h after the start of incubation, triphoblastic release of PGF_2^α increased linearly (P<.01) with dose of arachidonic acid. Adding arachidonic acid to incubation medium did not affect trophoblastic or endometrial protein synthesis. Endometrial slices suppressed (P<.05) trophoblastic protein synthesis and release of PGF_2^α. Apparently, endometrium can modulate trophoblastic release of prostaglandins and synthesis of proteins in vitro, and trophoblastic tissue from supercovulated cattle 16 or 20 days pregnant can be used to study trophoblastic synthesis of prostaglandins and proteins.     

Methane emission by goats consuming diets with different levels of condensed tannins from lespedeza

Twenty-four yearling Boer × Spanish wethers (7/8 Boer; initial body weight (BW) of 34.1 ± 1.02 kg) were used to determine effects on methane (CH₄) emission of dietary levels of a condensed tannin (CT)-containing forage, Kobe lespedeza (Lespedeza striata; K), and a forage very low in CT, sorghum-sudangrass (Sorghum bicolor; G). Treatments were dietary K levels (dry matter (DM) basis) of 1.00, 0.67, 0.33, and 0 (100, 67, 33, and 0 K, respectively). Forages were harvested daily and fed at approximately 1.3 times maintenance metabolizable energy requirement. The experiment lasted 21 days, with most measures on the last 8 days. The CT concentration was 0.3 and 151 g/kg DM in G and K, respectively. DM intake was similar among treatments (i.e., 682, 675, 654, and 648 g/day; S.E. = 30.0) and gross energy (GE) digestibility increased linearly (P<0.05) with decreasing K (0.472, 0.522, 0.606, and 0.666 for 100, 67, 33, and 0 K, respectively). CH₄ emission changed quadratically (P<0.05) with decreasing K (10.9, 13.8, 17.6, and 26.2 l/day; 32, 42, 57, and 88 kJ/MJ GE; 69, 81, 94, and 133 kJ/MJ digestible energy for 100, 67, 33, and 0 K, respectively). In vitro CH₄ emission by incubation of ruminal fluid for 3 weeks with a medium for methanogenic bacteria and other conditions promoting activity by methanogens also was affected quadratically (P<0.05) by K level (7.0, 8.1, 9.2, and 16.1 ml for 100, 67, 33, and 0 K, respectively). The total bacterial count of ruminal samples was similar among K levels, but the number of total protozoa increased linearly (P<0.05) as K declined (8.3, 11.8, 15.6, and 27.1 × 10⁵ ml⁻¹ for 100, 67, 33, and 0 K, respectively). The CT-containing forage K decreased CH₄ emission by goats regardless of its feeding level, although the effect per unit of K increased with decreasing K. Forage type (i.e., legume versus grass) may have contributed to the effect of K on CH₄ emission, but most of the change appeared attributable to CT, which appeared to directly impact activity of methanogenic bacteria, although alterations of protozoal activity could have been involved. These findings suggest that relatively low dietary levels of CT could be employed to lessen CH₄ emission without a marked detrimental effect on other conditions such as total tract protein digestion.     

Double enrichment of chicken eggs with conjugated linoleic acid and n-3 fatty acids through dietary fat supplementation

Yolk fat fatty acid (FA) concentrations, sensory quality and firmness of eggs and laying hen performance were evaluated with respect to the combined inclusion in the diet of conjugated linoleic acid (CLA), high n-3 oil sources and high-oleic sunflower oil (HOSO). Nine diets were arranged factorially, with three levels of n-3 FA supplementation (2.9, 3.7 and 4.5 g/kg) from three different sources (two fish oils highly concentrated in eicosapentanoic (EPA) or docosahexanoic acid (DHA) and one algae oil with a very high-DHA content) in diets added with fixed amounts of CLA (2.5 g/kg) and HOSO (30 g/kg). A commercial feed with no CLA, n-3 or HOSO added, and another one containing 4.5 g/kg of high-DHA fish oil but not CLA or HOSO were also formulated. An increase in n-3 FA supplementation had little effect on proportions of CLA, monounsaturated FA, saturated FA or total polyunsaturated FA in yolk fat, but increased (P<0.005) long-chain n-3 FA and decreased (P<0.001) long-chain n-6 FA. An increment of dietary n-3 FA also impaired linearly (P<0.001) egg acceptability by consumers. An increment in the proportion of DHA with respect to total n-3 FA from 0.28 to 0.96 increased yolk concentrations of DHA (P<0.001) and total n-3 FA (P<0.01), but decreased (P<0.001) concentrations of EPA and docosapentanoic acid FA. Current data indicate that addition of HOSO to diets supplemented with moderate amounts of CLA and n-3 FA allows the production of double enriched eggs while maintaining sensory quality for consumers at acceptable levels.     

Effect of ruminally protected fat on in vitro fermentation and apparent nutrient digestibility in buffaloes (Bubalus bubalis)

Experiments were conducted to evaluate effects of supplementation of calcium salts of long chain fatty acids (Ca-LCFA) as a rumen inert fat (PF) on in vitro fermentation and apparent nutrient digestion in adult buffaloes fed wheat straw based diets. For the in vitro fermentation study, five total mixed rations (TMR) consisting of a concentrate mixture (CM), green Sorghum bicolor, WS and supplemented without (C) or with 30 g/kg dry matter (DM) rice bran fatty acid oil (RBO) (30 RBO) or 20 g/kg RBO + 10 g/kg PF (20 RBO/10 PF) or 10 g/kg RBO + 20 g/kg PF (10 RBO/20 PF) or 30 g/kg PF in the DM in the ratio of 340:50:580:30 were prepared. The in vitro DM degradability (IVDMD), TN, trichloro acetic acid precipitable N (TCA-N), non-protein N (NPN) and ammonia N (NH₃-N) were similar among groups. Within the fat supplemented groups, total volatile fatty acid (TVFA) concentration increased linearly (P=0.025) with PF supplementation. Apparent nutrient digestibility was determined on 20 adult buffaloes divided into five equal groups fed CM supplemented without (C) or with 300 g RBO (30 RBO) or 200 g RBO + 100 g PF (20 RBO/10 PF) or 100 g RBO + 200 g PF (10 RBO/20 PF) or 300 g PF (30 PF) along with limited green S. bicolor and WS maintaining forage: concentrate ratio of 650:350. Fat supplementation had no effect on the DM intake and apparent digestibilities of DM, organic matter (OM), crude protein (CP), total carbohydrate (TCHO) and neutral detergent fiber (aNDF). Within fat supplemented groups, inclusion of PF increased digestibilities of DM, OM, ether extract (EE), TCHO, aNDF and ADF. Supplemental fat also increased the digestible energy (DE) and metabolizable energy (ME) content of the diet, which also increased linearly with PF supplementation. All buffaloes were in positive N, Ca and P balances. We conclude that 200–300 g supplemental PF in the form of Ca-LCFA can be included in straw based diets fed to buffaloes to increase its energy density without adversely affecting DM intake and digestibility.     

Rumen degradable nitrogen requirements for optimum microbial protein synthesis and nutrient utilization in sheep fed on finger millet straw (Eleucine coracana) based diet

Studies were conducted to determine the rumen degradable nitrogen (RDN) requirement levels for optimum microbial protein synthesis and nutrient utilization in Nellore rams fed on finger millet straw (FMS) based diet. Thirty six Nellore sheep were randomly divided into four groups of nine animals each using the balanced completely randomized design. Animals in all the groups were fed finger millet straw as a basal roughage and groundnut cake (GNC) was offered daily in two equal halves in the morning (8.00 AM) and evening (4.00 PM) as RDN source. The animals in group I (GI) were fed with ad libitum FMS. Animals in group II, III and IV (GII, GIII, and IV) were offered GNC @ 12.4, 16.6, and 21.1 g RDN/kg digestible organic matter (DOM) along with FMS. The daily total dry matter (DM) and organic matter (OM) intakes linearly increased (P<0.05) with increasing level of RDN supplementation while there was no difference in total DM and OM intake/kg W^0.75 among different experimental groups. The digestibility coefficients of DM (P<0.001), OM (P<0.001), crude protein (CP) (P<0.001), ether extract (EE) (P<0.001), neutral detergent fibre (NDF) (P<0.01) and acid detergent fibre (ADF) (P<0.03) increased quadratically with increasing level of RDN supplementation from GI to GIV. The purine derivatives (PD) excretion, microbial purine absorption and microbial nitrogen supply (MNS g/day) linearly increased (P<0.001) as the level of RDN supplementation increased. There was no difference in nitrogen capture efficiency (NCE) and microbial nitrogen to total urinary nitrogen ratio (MN:UN) among the RDN supplemented groups. This study indicated that 12 g RDN/kg digestible organic matter intake (RDN g/kg DOMI) or 18 g RDN/kg OM apparently digested in the rumen (RDN g/kg DOMR) may be adequate for optimum microbial protein synthesis and digestibility of nutrients, there by improved plane of nutrition in sheep fed on finger millet straw based diet.     

Effects of soybean hulls inclusion on intake, total tract nutrient utilization and ruminal fermentation of goats fed spineless cactus (Opuntia ficus-indica Mill) based diets

A study was conducted to evaluate soybean hulls (SH) as a replacement of tifton bermudagrass hay (TH) in diets of goats containing high levels of spineless cactus. Ten mature bucks (five ruminally fistulated) were used in a 5 × 5 Latin square experiment with 21-day periods. Soybean hulls replaced 0, 250, 500, 750 and 1000 g/kg of TH in the experimental diets. All diets contained 600 g/kg spineless cactus (dry matter basis). Intakes of dry matter (DM), organic matter (OM) and non-fiber carbohydrates and chewing activities decreased linearly (P < 0.01) as the level SH in the diet increased. In vivo digestibility of DM, OM and neutral detergent fiber increased linearly (P < 0.01) as the level of SH in the diet increased. Addition of SH linearly increased (P < 0.05) N retention without affecting microbial N supply (g/kg of digestible OM intake) to the small intestine. Ruminal pH and NH₃-N decreased linearly (P < 0.05) while total volatile fatty acid (VFA) concentration increased linearly (P < 0.05) as proportion of SH in diets increased. It was concluded that inclusion of SH in cactus-based diets had a negative impact on intake and chewing activities but improved total tract nutrient utilization by goats. Replacing TH with SH resulted in a concentrate type ruminal fermentation (i.e., low ruminal pH and high VFA concentration).     

Influence of level of zilpaterol chlorhydrate supplementation on growth performance and carcass characteristics of feedlot lambs

Forty-eight Pelibuey × Katahdin (38.8 ± 0.67 kg) crossbred male lambs were used in a 32-day feeding trial (four pens per treatment in a randomized complete block design), to evaluate the influence of zilpaterol (β₂-agonist) supplementation level on growth performance and carcass characteristics. Lambs were fed a dry-rolled corn-based finishing diet (3.04 Mcal/kg of ME) supplemented with 0, 0.15, 0.20, or 0.25 mg/kg of live weight d⁻¹ zilpaterol (as zilpaterol chlorhydrate, Zilmax^®, Intervet México, México City). DM intake averaged 1.099 ± 0.042 kg/d and was not affected (P = 0.40) by treatments. Compared with control lambs, zilpaterol supplementation increased gain efficiency (15.8%, P < 0.03), apparent energy retention per unit DMI (10.9%, P = 0.03), and tended to increased daily gain (16%, P < 0.07) and total gain (17.7%, P < 0.08). Zilpaterol supplementation did not affect (P = 0.20) carcass weight, longissimus muscle area (LM), or fat thickness, but increased (2.3%, P = 0.04) carcass dressing percentage and reduced (36%, P < 0.01) kidney-pelvic fat. Increasing level of zilpaterol supplementation increased total weight gain (linear component, P < 0.05), gain:feed (linear component, P < 0.01), and dressing percentage (linear component, P < 0.02), and decreased (linear component, P < 0.01) kidney-pelvic fat. We conclude that zilpaterol supplementation enhances growth performance and dressing percentage in lambs in a manner comparable to that of cattle (greater muscle accretion, reduced body fat). Responses to zilpaterol was optimal when supplemented at 0.20 mg of zilpaterol/kg of live weight d⁻¹.     

Effects of dietary zinc on performance, nutrient digestibility and plasma zinc status in Cashmere goats

Thirty-six 1.0-year-old Liao Ning Cashmere goat wethers (BW = 22.01 ± 0.59 kg) were used to determine the effects of dietary zinc (Zn) level on the performance, nutrient digestibility and plasma Zn status during the cashmere fiber growing period. The goats were randomly divided into four groups that were fed a basal diet containing 22.3 mg Zn/kg dry matter (DM) with 0, 15, 30 or 45 mg Zn/kg DM as reagent grade ZnSO₄·7H₂O. The experiment lasted 60 days including a 7-day metabolism trial. Both average daily gain (ADG) and feed efficiency were improved (P < 0.05) by Zn supplementation and were higher (P < 0.05) for the treatment groups supplemented with 30 and 45 mg Zn/kg DM compared with 15 mg Zn/kg DM. Zn supplementation had no influence on the length and diameter of cashmere fiber (P > 0.05). Digestibility of DM, crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) did not differ among treatments (P > 0.05). Plasma Zn concentrations were increased (P < 0.01) by Zn supplementation and were higher (P < 0.05) for the treatment groups supplemented with 30 and 45 mg Zn/kg DM compared with 15 mg Zn/kg DM. Zn apparent absorption rate and apparent retention rate were decreased (P < 0.05) by Zn supplementation, but did not differ among Zn supplemented treatments (P > 0.05). In conclusion, a control diet containing 22.3 mg Zn/kg DM was inadequate for achieving optimal growth performance in Cashmere goats, and the recommended level of dietary Zn for such goats is 52.3 mg/kg DM during the cashmere fiber growing period.     

Methane emission by goats consuming different sources of condensed tannins

Twenty-four yearling Boer × Spanish wethers (7/8 Boer; initial body weight (BW) of 37.5 ± 0.91 kg) were used to assess effects of different condensed tannin (CT) sources on methane (CH₄) emission. Diets were Kobe lespedeza (Lespedeza striata; K), K plus quebracho providing CT at 50 g/kg dry matter (DM) intake (KQ), Sericea lespedeza (Lespedeza cuneata; S), and a 1:1 mixture of K and S (KS). Forages harvested daily were fed at 1.3 times the maintenance metabolizable energy requirement. The experiment was 51 days divided into two phases. In phase A forage diets were fed alone, and in phase B, 25 g/day of polyethylene glycol (PEG) was given mixed with 50 g/day of ground maize grain. Adaptation periods were 28 and 7 days in phases A and B, respectively. After adaptation there were 8 days for feces and urine collections, with gas exchange measured on the last 2 days. Ruminal fluid was collected at the end of the experiment via stomach tube for microbiology assays. The N concentration was 22.8 and 23.6 g/kg DM, in vitro true DM digestibility was 0.698 and 0.648, and the level of CT was 140 and 151 g/kg DM for S and K, respectively. DM intake was similar among treatments in both phases (phase A: 720, 611, 745, and 719 g/day (S.E. = 59.0); phase B: 832, 822, 867, and 880 g/day (S.E. = 55.3) for K, KQ, S, and KS, respectively). N digestibility was affected by treatment in phase A (P<0.05) but not in phase B (phase A: 0.514, 0.492, 0.280, and 0.413 (S.E. = 0.0376); phase B: 0.683, 0.650, 0.638, and 0.662 (S.E. = 0.0203) for K, KQ, S, and KS, respectively). Gross energy digestibility was similar among treatments in phase A (0.475, 0.407, 0.393, and 0.411 (S.E. = 0.0353)) but differed among treatments in phase B (0.449, 0.373, 0.353, and 0.409 for K, KQ, S, and KS, respectively (S.E. = 0.0221)) CH₄ emission was 9.6, 6.8, 10.6, and 8.9 l/day (S.E. = 1.44) in phase A and 19.0, 16.6, 21.8, and 19.2 l/day (S.E. = 1.51) in phase B for K, KQ, S, and KS, respectively (S.E. = 1.25). When data of both phases were pooled, supplementation with PEG in phase B markedly increased (P<0.05) CH₄ emission (9.0 l/day versus 19.1 l/day). In accordance, there was a substantial difference (P<0.05) between phases in in vitro CH₄ emission by ruminal fluid incubated for 3 weeks in a methanogenic medium and with other conditions promoting activity by methanogens (11.5 and 22.9 ml in phases A and B, respectively). Counts of total bacteria and protozoa were similar among treatments in both phases, but values were greater (P<0.05) in phase B versus phase A. In summary, CT from different sources had a disparate influence on N digestion, but similar effects on ruminal microbial CH₄ emission by goats, possibly by altering activity of ruminal methanogenic bacteria though change in actions of other bacteria and/or protozoa may also be involved.     

The potential of Commelina benghalensis as a forage for ruminants

To evaluate the potential of Commelina benghalensis as a forage for ruminants, effects of plant maturity on chemical composition, rumen degradability as well as its increased dietary inclusion level on intake, digestibility and N balance in sheep fed Sorghum almum were investigated with forage obtained from the wild, re-established and harvested at 6, 10 and 14 weeks of growth. Composite herbage samples were analyzed for dry matter (DM), chemical components, total extractable phenolics (TEP) and amino acid content. In sacco rumen degradability measurements used six individually confined wethers (8 ± 0.5 months of age; 21 ± 2.6 kg live-weight (LW)) fitted with rumen cannulae and fed a ration of 3:1 fresh S. almum and Medicago sativa hay (about 1:2 on a DM basis). In sacco bags containing 5 g each of dry herbage were inserted into the rumen and withdrawn sequentially after 0, 12, 24, 36 and 48 h. Metabolizable energy (ME) was estimated from 24 h in vitro gas production. In the digestibility study, 12 wethers fitted with rumen canula were housed in metabolic crates and allotted to four treatment diets (i. e., D0, D10, D20 and D30) constituted from fresh S. almum and pre-wilted C. benghalensis in a randomized complete block design. The control diet (D0) was 3 kg fresh S. almum (≈535.5 g DM/wether/d about 30 g/kg LW), whereas D10, D20 and D30 were D0 +300, 600 or 900 g of wilted C. benghalensis (≈34, 68 or about 102 g DM/wether/d), respectively. The study lasted for 21 d. Dry matter, fibre and TEP content increased (P<0.001) with maturity of the forage, whereas those of CP and EE decreased (P<0.0001) over the same period. Amino acids (AA) also declined with maturity (P<0.05). Rumen degradability of DM and OM were unaffected, but DM intake increased linearly (P<0.0001) at a decreasing rate (Q: P<0.05) and DM digestibility (DMD) and N intake increased linearly (P<0.01 and P<0.0001, respectively) as level of C. benghalensis in the diet increased. Results indicate that advancing maturity affected chemical composition, but not rumen degradability, of C. benghalensis and also demonstrated that inclusion of C. benghalensis in S. almum diet improved intake, digestibility and N intake, suggesting its potential use as a feed supplement.     

Assessment of a brown midrib (BMR) mutant gene on the nutritive value of sudangrass using in vitro and in vivo techniques

The brown midrib (BMR) gene has been reported to reduce the lignin concentration in plants, which contributed to increased fiber digestion in ruminants. Three studies were completed to compare the digestibility of a BMR mutant of sudangrass (sorghum bicolor subsp. Drummondii) versus a non-BMR (‘Piper’) variety when included in diets fed to sheep (Study 1), to complete a rumen in vitro assessment of sheep and lactating cow diets (Study 2), and to compare digestibility when included in the diet fed to lactating dairy cows (Study 3). Four wether sheep were used in a 2 × 2 Latin square experiment (Study 1) with total fecal collection to determine total tract apparent digestibility of pelleted Piper (P) and BMR (P-BMR) sudangrass hays. Forage pellets consisted of either P-BMR or P hay with added urea to meet the maintenance crude protein (CP) requirement of the sheep. Digestibility of organic matter (OM; P<0.01), dry matter (DM; P<0.01), acid detergent fiber (ADF; P<0.05), and neutral detergent fiber (aNDFom; P<0.07) was higher for P-BMR than P sudangrass. In vitro rumen digestibility of aNDFom using cattle rumen fluid was higher at 24 (P<0.01), 48 (P<0.01) and 72 h (P<0.01) of fermentation for P-BMR versus P (Study 2). Four lactating Holstein dairy cows (251 ± 30 days in milk) and fitted with ruminal and duodenal cannulae were used in a 4 × 4 Latin square experiment. Total mixed rations (TMR) contained 180 g/kg DM shredded sudangrass hay and 180 g/kg sliced alfalfa hay, but the proportion of P to P-BMR sudangrass varied as 100:0, 66:34, 34:66, or 0:100. Yields of milk and milk protein were highest at the 66:34 level (Quadratic: P=0.06 and 0.07, respectively), but composition of milk fat, protein and lactose, as well as DM intake, did not differ (Study 3), probably because forestomach and total tract apparent digestion of aNDFom and OM did not differ due to sudangrass source.