Dry Matter Intake Digestibility Research Articles

Effects of Alfalfa and Brown Mid-rib Corn Silage and Level of Forage Neutral Detergent Fiber on Animal Performance of Lactating Cows in Michigan

Alfalfa silage and corn silage are the major dairy feeds in most dairy operations in Michigan, USA. In recent years, the need to improve digestible fiber and dry matter intake of forages to meet the nutrient requirements of high yielding dairy cows and the willingness to plant corn specifically for silage has led plant breeders to focus on the brown mid-rib (BMR) trait. The objective of this study was to investigate the effect of different ratio of alfalfa to BMR corn silage and ration level of forage neutral detergent fiber (NDF) on animal performance of lactating cows in the Upper Peninsula of Michigan. This study was conducted at the Upper Peninsula Experiment Station of Michigan State University in Chatham, Michigan, USA. Two different ratios of forage type (high alfalfa silage/low BMR corn silage, AS, and high BMR corn silage/low alfalfa silage, BMRCS) and two different dietary NDF contents (27% NDF, 27 = low forage/high grain feeding, and 33% NDF, 33 = high forage/low grain feeding) were used. The experimental design was a 4x4 Latin Square with 20 milking cows (12 multiparous and 8 primiparous). This trial had four 21-day periods with 14 d adaptation and 7 d data collection. Milk yield and body condition score (BCS) on the AS-27, BMRCS-27 and BMRCS-33 treatments were significantly (p<0.05) higher than on the AS-33 treatment. Dry matter intake of the AS-27 and BMRCS-27 treatments was significantly (p<0.05) higher than for the AS-33 and BMRCS-33 treatments. Milk urea nitrogen (MUN) on the AS-33 treatment was significantly (p<0.05) higher than on the other diet treatments. A key finding of this study was that the BMRCS-33 (higher amounts of brown mid-rib corn silage than alfalfa silage, high forage and low grain feeding diet at 33% NDF) led to the equal highest milk production whilst having the equal lowest dry matter intake. This study demonstrated that the diet with higher ratio of highly digestible NDF forage such as brown mid-rib corn silage to alfalfa silage could lower grain feeding in the ration.

Afternoon harvest increases readily fermentable carbohydrate concentration and voluntary intake of gamagrass and switchgrass baleage by beef steers12

Our objective was to determine if harvest in the morning (AM, 0600) vs. the afternoon (PM, 1800) affects composition and voluntary DMI of gamagrass (GG) or switchgrass (SG) stored as baleage. Iuka GG (Tripsacum dactyloides L.) and Alamo SG (Panicum virgatum L.) were cut with a mower-conditioner, immediately round-baled, wrapped in plastic, and stored as baleage. Beef steers (255 +/- 7 kg of BW) were assigned (5 steers/treatment) to GG/AM, GG/PM, SG/AM, or SG/PM. Ad libitum intake was measured for 21 d (7-d adjustment and 14-d intake estimate) followed by 7-d adjustment and 5-d digestion and N balance study. Chewing behavior was recorded during the balance study. Compared with AM, PM had more (P < 0.01) starch (9.3 vs. 4.7 g/kg of DM), total nonstructural carbohydrate (30.4 vs. 19.0 g/kg of DM), and monosaccharides (17.1 vs. 11.2 g/kg of DM). Compared with AM, PM had less (P = 0.05) acetate (13.0 vs. 18.6 g/kg of DM) and propionate (0.29 vs. 0.82 g/kg of DM) and tended (P < 0.13) to have less lactate (2.9 vs. 3.5 g/kg of DM) and butyrate (3.9 vs. 5.1 g/kg of DM). Compared with SG, GG had more (P = 0.01) DM (324 vs. 242 g/kg of baleage), CP (114 vs. 97 g/kg of DM), lactate (4.8 vs. 1.6 g/kg of DM), starch (9.4 vs. 4.7 g/kg of DM), total nonstructural carbohydrate (34.2 vs. 15.2 g/kg of DM), and monosaccharides (20.8 vs. 7.4 g/kg of DM). However, GG had a lower (P = 0.01) pH (5.32 vs.5.79) and less (P < 0.01) ethanol (18.7 vs. 27.3 g/kg of DM), acetate (12.3 vs. 19.2 g/kg of DM), propionate (0.00 vs. 1.11 g/kg of DM), and butyrate (0.6 vs. 8.4 g/kg of DM). Daily DMI (2.16 vs. 1.83% of BW) and digestible DMI (1.15 vs. 0.95% of BW) were greater (P = 0.03) for PM than AM. Plasma urea N concentrations at the end of the ad libitum intake phase were greater (P = 0.01) for AM (3.91 mM) than for PM (2.31 mM) and greater (P = 0.07) for GG (3.51 mM) than for SG (2.71 mM). Steers fed PM spent more time eating (P = 0.04) and less time resting (P = 0.01) during meals than steers fed AM. Apparent digestibility of DM and fiber components was not affected (P < 0.18) by treatment. Apparent digestibility and retention of N decreased from PM to AM for SG, but increased for GG (P = 0.05). Retention of N as a percentage of N intake or N digested decreased more from PM to AM for SG than for GG (P < 0.05). We conclude that increased nonstructural carbohydrate content of the PM harvest of these grasses stored as baleage caused increased voluntary intake and improved use of dietary N by beef steers.

Nutritive value index of treated wheat straw with Pleurotus fungi

Wheat straw was inoculated with spawns of two species of Pleurotus fungi (coded: PF and PO) and incubated in a fermentation room at 22?5?C and 70?5, relative humidity. After 17 days of spawning, when the substrate was completely covered by fungal mycelia, half of the bags were removed from the fermentation room, sun dried and used for in vitro measurements and in vivo study as well, using of sheep. For the remainder of the bags, fermentation was allowed for seven weeks during which the fruiting mushroom was harvested two times, and then spent straw was collected and dried under the sun. In a feeding trial, in vivo digestibility and voluntary intake of treated straw was compared with initial straw in cattle, when the dietary treatments were: 1) Initial wheat straw (IWS); 2) Fungal (PF) treated wheat straw before mushroom formation (FTWS); 3) Fungal (PF) spent wheat straw (SPWS) after mushroom was harvested. Results showed that, the fungal treatments significantly (P&lt;0.05) affected the nutrient composition of wheat straw by increasing the CP and ash, but decreasing the OM, NDF, ADF, ADL, cellulose (CL) and hemi cellulose (HCL) contents. The in vitro digestibility of DM and OM were significantly (P&lt;0.05) the highest for PF treated straw but the lowest for the initial straw. The in vivo digestibility of most components were significantly (P&lt;0.05) increased, in sheep, however treatment PF showed the higher amounts of digestibility than that of the PO with exception for crude protein CP and HCL. Regarding the feeding trial by cow, results indicated that, the highest amount of DM and OM digestibility were found in FTWS followed by SPWS, but the initial straw had the lowest digestibility (P&lt;0.05). Average daily intake of DM, OM, as well as the digestible DM and OM intake were significantly (P&lt;0.05) affected by the treatments. In comparison to the IWS, PO inoculated straw increased the voluntary intake of digestible DM and OM, at the stage of mycellial running, however, the digestibility and intake of SPWS were significantly (P&lt;0.05) reduced to the level of initial straw. In conclusion, fermentation of wheat straw by Pleurotus florida and P. ostreatus, improved the nutritive value of straw although the effect of P.F. was more than that of the P.O. In addition, fungal treatment of straw before mushroom formation, improved the nutritive value index, but no enhancement was found in SPWS comparing with the initial straw.

Improving nutritive value of a North African range grass ( Stipa tenacissima): Effect of dung ash and urea treatment on digestion by goats

In arid zones of North Africa, hays formerly harvested from native range forages such as Alfa ( Stipa tenacissima), can provide alternative diets for livestock during periods of forage scarcity. However, they usually constitute low-quality forages. Soaking Alfa hay in alkaline solutions prepared from dung ash, with the addition of urea, was evaluated as a potential economic treatment for improving rumen digestibility. A digestion trial was conducted using 3-year-old male goats to compare digestibility of untreated Alfa hay with a treatment containing a 200 g/L solution of dung ash from dromedary, and 30 g/kg urea. A second experiment was conducted in order to evaluate the effectiveness of dung ash source (dromedary or goat), concentration of dung ash solution (0, 100, 200 or 300 g/L) and urea (0 or 30 g/kg) on in vitro digestibility of Alfa amongst goats. Results of digestion trials showed that treated Alfa hay had higher (P<0.01) digestion coefficients for dry matter (0.483 versus 0.420), organic matter (0.558 versus 0.487), neutral detergent fiber (0.664 versus 0.531) and acid detergent fiber (0.620 versus 0.545) than untreated hay. Crude protein apparent digestibility presented no significant different values (P>0.05) between untreated and treated hay (0.356 versus 0.402). Daily dry matter intake ranged from 40.8 to 46.2 g/kg BW 0.75 for untreated and treated hay, respectively (P<0.05). This resulted in an increase of the daily digestible dry matter intake of about 31% for treated hay as compared with the untreated hay. Results of the second experiment showed that in vitro organic matter digestibility coefficient (IVOMD) raised from 0.271 for untreated hay to 0.499 for Alfa hay treated with a 300 g/L solution of dung ash from goats and with 30 g/kg urea. Dung ash from goats appeared to have a higher effect than those from dromedary. Meanwhile, IVOMD of Alfa hay only treated with 30 g/L urea was intermediary (0.403). It is concluded that treating Alfa hay with a 200 g/L solution of dung ashes and 30 g/kg urea can provide an average quality forage which meets the nutritional maintenance requirements of livestock. The significance of these findings is discussed in relation to feeding management strategies for low-input livestock systems.

Digestibility and digestive organ development in indigenous and improved chickens and ducks fed diets with increasing inclusion levels of cassava leaf meal

Growing indigenous Cambodian chickens and ducks, and broiler chickens and White Pekin ducks were fed diets containing 0%, 7%, 14% and 20% of cassava leaf meal (CLM) to study the effects of CLM level on diet digestibility and gastrointestinal tract (GIT) and organ development. The coefficient of total tract apparent digestibility (CTTAD) of dry matter (DM) and intake of digestible DM decreased with increased dietary CLM. DM and digestible DM intake was higher for local breeds than for the corresponding exotic breeds, and higher for ducks than for chickens (p < 0.001), although there were no species or breed effects on CTTAD of DM (p > 0.05). Weight of small intestine, caeca, gizzard and pancreas, expressed as per kg body weight, increased with increased CLM in the diet (p < 0.001). There was no consistent diet effect on liver weight. Length of small intestine and caeca, expressed on a mass-specific basis, increased with dietary CLM content (p < 0.001). When expressed as per kg body weight small intestine, proventriculus, gizzard, pancreas and liver weights, and small intestine length, were higher in ducks than in chickens (p < 0.001), and were higher in the indigenous than in the improved breeds (p < 0.01), except for small intestine weights, which were similar. However chickens had higher weight of caeca (p < 0.001) and colon (p < 0.01) in absolute units and per kg body weight.

Variation in feed intake of grazing crossbred ewes and genetic correlations with production traits

Feed for maintenance of the ewe flock is a major cost in lamb production systems and a reduction in these feed requirements could have an effect on carrying capacity and both biological and economic efficiency in sheep flocks. Inclusion of feed intake in breeding programs requires knowledge of its genetic variation and genetic relationships with other production traits. This study reports on the variation in relative digestible dry matter intake (rDDMI) of 2528 mature, non-pregnant, crossbred ewes that are the progeny of 91 rams of various maternal breeds. Feed intake of pasture under grazing conditions was estimated using the faecal marker dilution technique with chromium sesquioxide controlled-release devices. There was significant variation in intake associated with liveweight, liveweight gain, prior reproductive status, fat depth, and muscle depth of the ewes. Sire breed was not significant for rDDMI, although there was a considerable range of &gt;30% across sire progeny groups within most sire breeds, and rDDMI had an estimated heritability of 0.41 ± 0.07 (s.e.). The genetic correlations with a range of production traits (growth, carcass, wool, and reproduction) were all close to zero. The potential for inclusion of genetic improvement of efficiency of feed utilisation in breeding programs for sheep is discussed.

Comparative seasonal acclimatization of food and energy consumption in adjacent populations of common spiny mice (Acomys cahirinus)

AbstractAnimals inhabiting environments with low productivity and food availability commonly have reduced energy demands and increased digestive efficiencies. The dry matter intake (DMI), apparent digestible dry matter (ADDM), digestible efficiency (DE) and digestible energy intake (DEI) of two populations of common spiny mouse Acomys cahirinus were compared during both winter and summer under conditions of simulated water stress. Mice were captured from the north‐ and south‐facing slopes (NFS and SFS) of the same canyon that represent mesic and xeric habitats, respectively. Measured variables were also compared between F1 mice that had been born to either NFS or SFS mice, and raised in the laboratory. SFS mice were able to assimilate energy more efficiently than NFS mice during the summer. By comparison, NFS mice were able to assimilate more energy during the winter. During winter, NFS mice assimilated more energy at low levels of water stress, whereas SFS mice assimilated more energy at higher levels. Differences were also apparent in F1 mice. It is therefore suggested that local climatic conditions can impose physiological adaptations that are retained in succeeding generations, creating unique meta‐populations.

Influence of sward height, daily timing of concentrate supplementation, and restricted time for grazing on forage utilization by lactating beef cows1,2

To establish the effect of sward height, concentrate feeding time, and restricted time for grazing on forage utilization by grazing cattle, 32 crossbred beef (24 Angus and eight Hereford) cows (632 kg BW) and calves (104 kg BW) were grouped by weight and calving date. They were assigned randomly to two sward height treatments (4 to 8 or 8 to 12 cm), replicated four times. The herbage comprised mainly Kentucky bluegrass, orchardgrass, some forbs, and white clover. The cows were restricted to 12 h/d grazing (0700 to 1900) or unrestricted to 24 h/d grazing and fed a concentrate supplement (4.1 kg DM.cow(-1).d(-1), approximately 0.65% of BW or 33% of total DMI) either at 0700 or 1800. The experiment was repeated over three 15-d periods in May, June/July, and August 2000. The herbage on high sward height pasture was higher (P = 0.06) in NDF and ADF and lower (P < 0.01) in CP than low sward height herbage. For cows restricted to 12 h/d grazing, supplementing at 0700 as opposed 1800 resulted in greater (P = 0.04) forage DMI (8.6 vs. 8.1 kg/d), whereas cows that were unrestricted showed little change (8.2 kg/d at 0700 vs. 8.4 kg/d at 1800). Supplementing at 1800 as opposed to 0700 resulted in greater (P = 0.03) herbage DM digestibility (67.7 vs. 64.5%) for cows on high sward height, whereas cows on low sward height exhibited minimal differences (65.4% at 1800 vs. 66.3% at 0700). Cows restricted to 12 h/d grazing and supplemented at 0700 as opposed to 1800 resulted in greater (P = 0.06) digestible DMI (5.0 vs. 4.7 kg/d), whereas unrestricted cows exhibited the opposite response (4.6 kg/d digestible DMI at 0700 vs. 4.9 kg/d at 1800). Supplementing at 1800 as opposed to 0700 increased the time spent grazing to a greater (P = 0.09) extent for restricted than for unrestricted cows. When forage availability or grazing time was limiting (due to a low forage allowance and restricted access to forage, respectively) supplementing concentrates at 0700 resulted in greater forage utilization and intake rate because of increased forage DMI, DM digestibility, and digestible DMI. However, when forage or grazing time was not limiting, supplementing concentrates at 1800 resulted in greater forage utilization because of increased forage DM digestibility.

Inoculação microbiana da alfafa para silagem sobre a digestibilidade total e ruminal em bovinos

Doze vacas (640 kg de PV) não-gestantes e não-lactantes foram distribuídas em um delineamento em blocos, em que os tratamentos corresponderam à silagem pré-secada de alfafa (60,0% de MS e 19,5% de PB) controle ou inoculada com o produto Silobac® (Lactobacillus plantarum e Pediococcus pentosaceus), com o objetivo de avaliar os efeitos da inoculação microbiana da silagem de alfafa sobre a digestibilidade total e ruminal em bovinos. A dieta experimental continha 50% de silagem de alfafa e 50% de concentrados, com base na matéria seca. O experimento teve duração total de 21 dias, sendo os dez últimos destinados à administração do marcador óxido crômio e os cinco últimos destinados à coleta de fezes e incubação dos sacos de náilon. A inoculação da silagem de alfafa não alterou a digestibilidade total da MS (inoculada = 70,0% vs. controle = 71,2%), PB (72,3% vs. 73,0%), EE (77,0% vs. 76,8%), FDN (61,2% vs. 55,9%), FDA (66,8% vs. 61,8%), EB (72,5% vs. 73,7%) ou NDT (70,6% vs. 71,8%) da dieta. Também não alterou o consumo de MS digestível (12,2 vs. 11,4 kg/animal/dia ou 1,7% vs. 1,8% do PV) ou o consumo de NDT (12,4 vs. 11,4 kg/animal/dia ou 1,8% vs. 1,8% do PV). Entretanto, a inoculação diminuiu a degradabilidade efetiva da MS da silagem de alfafa para taxas de passagem de 2%/h (61,2% vs. 65,1%), 5%/h (54,1% vs. 58,6%) e 8%/h (50,0% vs. 54,4%), bem como reduziu a degradabilidade efetiva da PB da Alfafa para taxas de passagem de 2%/h (84,8% vs. 86,8%) e 5%/h (79,9% vs. 82,5%).

Influence of Berseem and Lucerne Silages on Feed Intake, Nutrient Digestibility and Milk Yield in Lactating Nili Buffaloes

This study was conducted to evaluate feeding value of berseem and lucerne silage as a replacement for conventional fodder (berseem fodder) in lactating Nili buffaloes. Fifteen early lactating multi-parous Nili buffaloes, five buffaloes in each group were allotted three experimental diets. Berseem and lucerne fodders were ensiled at 30% DM (wheat straw was used to adjust the DM of fodders) with molasses (at the rate of 2% of fodder DM) in two bunker silos for 30 days. The diets contained 75% DM from berseem fodder (BF), 75% DM from berseem silage (BS) and 75% DM from lucerne silage (LS). Each diet contained 25% concentrate DM. Diets were mixed daily and fed twice a day at ad libitum intakes. Dry matter intake (DMI) was significantly higher (13.8 kg/d) in buffaloes fed BF diet than those fed LS (12.5 kg/d) and BS (11.9 kg/day) diets. The differences in digestible DMI and DMI as percent body weight were significant between fodder and silage based diets but non-significant when BS and LS were compared. Lower DMI with silage-based diets was probably because of low silage pH. Intake of NDF (NDFI) was higher (5.68 kg/d) in buffaloes fed BF diet followed by those fed LS (5.50 kg/d) and BS (5.00 kg/d) diets. The difference was significant (p<0.05) across fodder and silage based diets but NDFI was non-significant across both silage-based diets. The apparent DM digestibility was significantly different (p<0.05) between fodder and silage-based diets but was non-significant between LS and BS diets. Four percent fat corrected milk yield was significantly different (p<0.05) between fodder and silage-based diets but was non-significant between LS and BS diets. Higher milk yield with fodder based diet was because of more digestible nutrient intake (Table 3) compared with silage based diets. Milk CP, TP and NPN and SNF did not show any treatment effects. The present results indicated that the berseem and lucerne fodder ensiled at 30 %D M level with 2% molasses could safely replace (75% DM) the conventional leguminous fodder in the diets of lactating Nili buffaloes. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 4 : 475-478)

Dry matter intake and digestion of alfalfa harvested at sunset and sunrise1

The preference exhibited by animals in selecting one feed over another is important only if the preferred diet is consumed daily in larger quantities, digested to a greater extent, or both. Six alfalfa (Medicago sativa L.) hays were harvested in pairs at sunset (PM) and sunrise (AM) on consecutive days at three harvest dates. A previous study of these hays demonstrated differences in ruminant preference favoring PM harvests. This study evaluated the effects of time of cutting and harvest date on voluntary DMI and nutrient digestibility. The hays were field-cured, baled, and chopped before evaluation for intake and digestibility. Studies were conducted for sheep (Ovis aries), goats (Capra hircus), and cattle (Bos taurus). Goats, but not steers or sheep, demonstrated differences in nutrient digestibility between PM- and AM-cut hays. Goats consumed more PM than AM hay (2.97 vs. 2.83 kg/100 kg of BW; P = 0.07) and digested it to a greater extent (0.710 vs. 0.696; P = 0.03), resulting in greater digestible DMI (2.11 vs. 1.97 kg/100 kg of BW; P = 0.03). Sheep consumed (mean = 2.52 kg/100 kg of BW; P = 0.59) and digested (mean = 0.681; P = 0.25) PM- and AM-cut hays similarly. Steers consumed larger quantities of PM-than AM-cut hay (2.90 vs. 2.62 kg/100 kg of BW; P = 0.11), but digestion did not differ with cutting time (mean = 0.660; P = 0.75). Difference values (composition of fed hay minus composition of orts) indicated that sheep and goats selected from the feed offered similarly, whereas steers selected differently. Difference values for CP averaged 94 and 101 g/kg for goats and sheep and 32 g/kg for steers (P < 0.01), and difference values for NDF averaged 185 and 196 g/kg for goats and sheep and 73 g/kg for steers (P <or= 0.01). Steer DMI and digestible DMI were associated with preference (r = +0.83, P <or= 0.05; and r = +0.89, P <or= 0.05) and with coordinates for preference criteria (dimension 1; r = +0.90, P <or= 0.05; and r = +0.89, P <or= 0.05) from a previous preference trial. Intake and digestion responses for goats and sheep showed no relationship with the previous preference trial measurements. For cattle and goats, the management strategy of mowing in the afternoon seems to take advantage of small, but influential diurnal changes in the soluble carbohydrate fraction and offers the potential to improve forage quality.

The effect of a condensed tannin-containing forage on methane emission by goats1

The objective of this study was to compare methane emission by goats consuming the condensed tannin-containing forage sericea lespedeza (Les-pedeza cuneata) or a mixture of crabgrass (Digitaria ischaemum) and Kentucky 31 tall fescue (Festuca arundinacea). Two groups of 12 Angora does (initial average BW = 41.5 +/- 2.7 kg) that previously grazed a pasture of sericea lespedeza or crabgrass/tall fescue for approximately 4 mo were used. After 1 wk of adaptation to metabolism cages, gas exchange was measured for 24 h in an open-circuit respiration calorimetry system with four head boxes. Forage harvested daily from the previously grazed pastures was consumed ad libitum. Crude protein concentration was 10.3 and 13.0%, IVDMD was 64.5 and 75.3%, and the level of condensed tannins was 17.7 and 0.5% for sericea lespedeza and crabgrass/tall fescue, respectively. Dry matter intake (1.11 vs. 0.67 kg/d) and digestible DMI (estimated from IVDMD; 0.71 vs. 0.51 kg/d) were greater (P < 0.01) for sericea lespedeza than for crabgrass/tall fescue. Ruminal ammonia N (3.7 and 9.9 mg/dL; P < 0.001) and plasma urea-N concentrations (16.7 and 20.9 mg/dL; P = 0.07) were lower for sericea lespedeza than for crabgrass/tall fescue. Concentrations of individual and total VFA and the acetate-to-propionate ratio in ruminal fluid did not differ between treatments (P > 0.19). Despite higher DMI by goats fed sericea lespedeza, daily energy expenditure (409 vs. 431 kJ/kg BW(0.75)), heart rate (70 vs. 73 beats/min), and the ratio of energy expenditure to heart rate (5.82 vs. 5.94) did not differ between sericea lespedeza and crabgrass/tall fescue, respectively (P > 0.13). Methane emission expressed as both quantity per day or relative to DMI was lower (P <0.001) for sericea lespedeza than for crabgrass/tall fescue (7.4 vs. 10.6 g/d and 6.9 vs. 16.2 g/kg DMI). Substantial differences between the forages in condensed tannins concentration and methane emission by Angora goats suggest that condensed tannins decreased methane emission.

Nitrogen Fertilization on Rye Pasture: Effect on Forage Chemical Composition, Voluntary Intake, Digestibility and Rumen Degradation

AbstractThe effects of nitrogen (N) fertilization of a rye pasture (Secale cereale L.) on the chemical composition of forage and its utilization in vivo and in situ were investigated in winter (W) and early spring (S). Half of the paddock to be assayed was spread with 93 kg urea–N ha−1 (treatment F), and the other half was not fertilized (treatment NF). Each experiment lasted for 17 days; apparent dry matter digestibility in vivo, voluntary dry matter intake (DMI) and digestible DMI were measured on nine rams per treatment. Two rumen cannulated animals per treatment were under the same feeding regime, and used to collect samples of rumen contents. The concentrations of ammonia (NH3) and short‐chain fatty acids and pH were measured in these samples. The offered forage was also incubated in the rumen of three Holstein–Friesian steers to estimate its degradation parameters in situ. Fertilization with N increased total N and decreased dry matter (DM) and non‐structural carbohydrate concentrations in both periods. DMI was reduced by fertilization. The rumen concentrations of NH3 were higher in F than in NF in both periods. In both periods, the effective DM degradability of forage was higher in F than in NF. N fertilization affects chemical composition, voluntary intake and rumen digestion of forage from rye pasture.

Measurements of energy balance of grazing beef cows on Mediterranean pasture, the effects of stocking rate and season: 1. Digesta kinetics, faecal output and digestible dry matter intake

Intake and digesta kinetics of free-ranging beef cows in two stocking rates were estimated during the course of the grazing seasons, February through June 1998 and 1999. Area allocations were 0.9 and 1.8 ha/cow in the high (HSR) and low stocking rates (LSR), respectively. Cows with their calves were introduced to the plots from January to July and the calves were weaned in May each year. Intake measurements were carried out in eight cows in each plot three times in 1998 and twice in 1999. The herbage in the plots was sampled and analysed for chemical composition and in vitro digestibility at each time of measurements, and the standing biomass in the plot was determined at the same times. Intake and digesta kinetics were estimated from faecal concentrations of chromium and cobalt, following a single dose of Cr-mordanted NDF and Co-EDTA to the rumen. Dry matter and digestible matter intakes were calculated from the faecal output (FO) and in vitro DM digestibility. The effects of herbage composition and standing biomass on intake and digesta kinetics are presented and discussed. Dry and digestible matter intakes decreased, and digesta retention time increased as the season progressed from winter lush to summer dry herbage. The effect of stocking rate on intake was small and insignificant, but retention time of particles was numerically shorter in the high than in the low stocking rate in all the measurements, and those of solutes were shorter in the high than in the low stocking rate only in the winter. Intake was larger, and mean retention time of digesta was shorter in lactating then in non-lactating cows.

Balance and serum concentration of biotin in sheep fed alfalfa meal-based diets with increasing level of concentrate.

The objective of this study was to test the hypothesis that serum biotin concentration and biotin balance (consumed - [urinary output + fecal output]) measured as total avidin-binding substances (biotin + biotin metabolites) are responsive to changes in the proportions of dietary alfalfa meal and concentrate fed to sheep. Eight sheep (initial BW = 40 kg) consumed a pelleted alfalfa meal-based diet that had 95:5, 48:52, 23:77, or 9:91% alfalfa meal:concentrate ratios (DM basis) in a replicated 4 x 4 Latin square design with 20-d periods (10 d of acclimation, 7 d of adaptation, and a 3-d collection period with jugular blood drawn on the last day). Replacing alfalfa meal with concentrate in the pelleted diets decreased dietary concentrations of biotin proportionally. As the percentage of alfalfa meal in the diet decreased, there was a linear decrease in daily DM intake (1,128 to 901 g of DMI/d; P < 0.01), with a linear (P < 0.01) and quadratic (P < 0.01) increase in the apparent total-tract DM digestibility of diets (51.0 to 80.0%). The biotin consumed decreased with alfalfa meal proportion in the diet (linear, P < 0.01). Both fecal biotin concentration (linear, P < 0.01) and fecal biotin output (quadratic, P < 0.05) increased, reaching peaks at 23% alfalfa meal. Fecal biotin output was not correlated with biotin intake, DMI, or intake of digestible DM. Mean urinary output, urinary biotin concentration, urinary biotin output, and serum biotin concentration were not affected by treatments. Means of biotin balance were negative and revealed the same trends among treatments as did fecal output. Biotin balance was a quadratic (P < 0.05) function of decreasing alfalfa meal in the diet, with more negative values at the alfalfa meal:concentrate ratio of 23:77. Results suggest that the greatest synthesis of biotin in the total digestive tract occurs with diets of either 52 or 77% concentrate for sheep; however, research addressing the significance of biotin metabolites on biotin balance and plasma biotin pool is needed.

Relação entre variáveis na regulação do consumo de vacas Holandês × Zebu em lactação sob pastejo em capim-elefante

A análise fatorial de componentes principais (CP) foi usada no exame do relacionamento entre variáveis de um banco de dados da Embrapa Gado de Leite. As variáveis disponíveis foram relacionadas às vacas (dias em lactação, teores lácteos de gordura e extrato seco total, produção de leite, ordem de lactação, peso vivo e grau de sangue), ao manejo (dia de pastejo, disponibilidade e períodos de descanso da pastagem), ao ambiente (estação do ano, precipitação pluviométrica) e ao alimento (consumo de nutrientes do concentrado e da cana × uréia, consumo de MS de pastagem de capim-elefante, composição química e digestibilidade in vitro da pastagem e concentração fecal de PB, FDN e FDA). O primeiro CP (33,7% da inércia dos dados) representou o uso da suplementação volumosa (cana × uréia) da pastagem em resposta à redução sazonal da disponibilidade e do consumo de capim-elefante. O segundo CP (15,3% da inércia) foi relacionado ao consumo de nutrientes do concentrado. O terceiro CP (8,5% da inércia) representou efeitos do manejo sobre a composição química da pastagem. A interpretação gráfica dos resultados favoreceu a percepção mais dinâmica da intensidade da associação e do antagonismo entre as variáveis contextualizadas no estudo.

Influence of Ruminally Protected Fat and Urea Treated Corncobs Ensiled with or without Corn Steep Liquor on Nutrient Intake, Digestibility, Milk Yield and Its Composition in Nili-Ravi Buffaloes

Sixteen early lactating Nili-Ravi buffaloes, four animals in each group, were used in a Completely Randomized Design to evaluate the effect of varying levels of both ruminally protected fat and urea treated corncobs ensiled with or without corn steep liquor (CSL) on feed intake, digestibility and milk production and its composition. Four experimental diets were formulated. The control (C) diet was balanced to contain 0% fat and 35% urea treated corncobs ensiled with 0% CSL. The low fat (LF), medium fat (MF) and high fat (HF) diets had 45, 55 and 65% urea treated corncobs ensiled with 9% CSL and 2, 4 and 6% ruminally protected fat, respectively. Dry matter, crude protein (CP) and neutral detergent fiber (NDF) intakes by buffaloes remained similar across all treatments. However, DM and NDF as a percent of body weight and digestible DM intakes were higher in HF diet when compared to C, LF and MF diets. Digestible NDF intakes were also significantly higher in HF diet as compared to all other diets. The intakes of ADF and digestible ADF were higher in MF and HF than C and LF diets. The significant variation in digestible DM, ADF and NDF intakes may be attributed to the ammoniation of corncobs along with CSL that caused significant changes in the degradability and digestibility of the diets. Ether extract and digestible EE intakes differed significantly (p<0.05) among all treatments. Intakes of EE were the highest in animals fed HF diet, which was because of added fat. Apparent DM digestibility was the highest in animals C diet and was the lowest in those fed LF diet. Neutral detergent fiber and ADF digestibilities were higher in animals fed diets containing urea treated corncobs ensiled with 9% CSL when compared to those fed diets containing urea treated corncobs ensiled without CSL. Apparent digestibility of CP was noted highest (71.47%) in animals fed HF diet when compared to those fed MF (67.75%), LF (67.04%) and C (65.39%) diets. Milk yield (4% FCM) was the higher in buffaloes fed HF, MF and LF diets than those fed C diet. These results indicated that increasing levels both of fat and urea treated corncobs ensiled with CSL elevated the negative effects of poor quality fibrous feed on milk production by buffaloes. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 1 : 86-93)

A Study on the Seasonal Comparison of Dry Matter Intake, Digestibility, Nitrogen Balance and Feeding Behavior in Spotted Deer (Cervus nippon) Fed Forest By-products Silage and Corn Silage

The purpose of this experiment was to assess seasonal variation of feed utilization by feed sources and to obtain information on the use of feed resources by comparing seasonal changes of dry matter intake, digestibility, nitrogen balance and feeding behavior in spotted deer (Cervus nippon) fed forest by-product silage (FBS) and corn silage (CS). Dry matter intake (DMI) of FBS was higher than that of CS in both winter and summer. While DMI of both diets was higher in summer, this was not significant at the 5% level. In contrast to DMI, digestible dry matter intake (DDMI) was higher for CS than for FBS in both seasons, but the difference was not significant. Digestibility of dry matter and crude protein was significantly higher (p 0.05) was found between the two seasons and diets for nitrogen intake (NI), 18.7 g/d in summer and 19.4 g/d in winter for FBS, 17.7 g/d in summer and 17.7 g/d in winter for CS. Fecal nitrogen was higher (p<0.01) for FBS than for CS and varied little seasonally. There was significant difference (p<0.01) between two seasons in urinary nitrogen, which was little difference between two diets. Retained nitrogen (RN) was different significantly (p<0.01) between two diets in both seasons, but there was little difference between seasons. Deer usually spent longer time on eating FBS than eating CS. Eating FBS took 221 min in summer and 187 min in winter, whereas eating CS took 113 min in summer and 109 min in winter. Deer spent less time on eating food in winter than in summer. Time spent on rumination was longer for FBS than for CS: for FBS, 504 min in summer and 456 min in winter, for CS, 423 min in summer and 279 min in winter. Time varied seasonally with both diets. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 1 : 80-85)

Influence of ad libitum feeding of urea-treated wheat straw with or without corn steep liquor on intake, in situ digestion kinetics, nitrogen metabolism, and nutrient digestion in Nili-Ravi buffalo bulls

Influence of different levels of corn steep liquor (CSL) on chemical composition of urea-treated wheat straw (UTWS), feed intake, ruminal characteristics, digestion kinetics, nitrogen (N) metabolism, and nutrient digestibility by ruminally cannulated buffalo bulls was studied using 4 × 4 Latin square design. Wheat straw was treated with 5% urea and ensiled with 0, 3, 6, and 9% CSL on a dry matter (DM) basis and was ensiled in laboratory silos for 5, 10, and 15 days. Neutral detergent fibre (NDF) contents of UTWS ensiled with 0, 3, 6, and 9% CSL were 74.01, 76.16, 77.34, and 78.93%, respectively. Acid detergent fibre (ADF), cellulose, and lignin were similar across treatments. The increase in NDF content was due to increased neutral detergent insoluble nitrogen (NDIN), as when NDF was calculated on crude protein (CP)-free basis (NDF – NDIN × 6.25), its concentration was same for UTWS ensiled with or without CSL. Four diets were formulated to contain 20% concentrate and 80% UTWS ensiled with or without CSL. Dry matter, digestible DM, organic matter (OM), CP, ADF, and NDF intakes were higher in bulls fed UTWS ensiled with CSL. Significant increases in both DM disappearance and rate of disappearance and a reduction in lag time of UTWS ensiled with CSL was noticed. There were significant differences in ruminal ammonia concentrations between diets containing UTWS ensiled with or without CSL at 3, 6, and 12 h postprandial. Higher digestibilities for DM, OM, CP, ADF, and NDF were noted with UTWS ensiled with CSL. Nitrogen balance was positive for all animals; however, the animals fed UTWS ensiled with CSL retained higher amount of N. These results indicated that CSL was very effective in enhancing the utilisation of ammoniated straw for buffaloes by minimising the nutrient loss at ruminal and cellular levels.

Nutritive Value of Urea Treated Wheat Straw Ensiled with or without Corn Steep Liquor for Lactating Nili-ravi Buffaloes

Influence of different levels of corn steep liquor (CSL) on chemical composition of urea treated wheat straw (UTWS) and its dietary effect on nutrient intake, digestibility, milk yield and its composition were studied. The 5% UTWS was ensiled with 0, 3, 6 and 9% CSL on dry matter (DM) basis. Total nitrogen and neutral detergent fiber (NDF) contents of UTWS ensiled with 0, 3, 6 and 9% CSL increased linearly with the increasing level of CSL. Increase in NDF content was due to increased neutral detergent insoluble nitrogen contents. Four experimental diets were formulated to contain 35% UTWS ensiled without CSL (control), 45 (WS45), 55 (WS55) and 65% (WS65) UTWS ensiled with 9% CSL, respectively. Dry matter, NDF and acid detergent fiber (ADF) intakes by lactating buffaloes fed diets containing varying levels of UTWS ensiled with or without CSL remained similar across all treatments. However, DM, NDF and ADF intakes as a percent of body weight and digestible DM, NDF and ADF intakes were higher in animals fed WS65 diet compared to those fed other diets. Apparent DM, crude protein (CP), NDF and ADF digestibilities were higher in diets containing UTWS ensiled with CSL compared to control. These differences may be attributed to higher rates of degradability of UTWS ensiled with 9% CSL than that ensiled without CSL. The 4% fat corrected milk and CP were statistically higher with WS65 diet compared to other diets. Percent milk fat, solid not fat and total solid remained unchanged across all treatments.