Dietary fibre level and enzyme inclusion affect nutrient digestibility and excreta characteristics in grower pigs

An experiment was conducted with 12 grower pigs to determine the effects of (1) manipulating dietary neutral detergent fibre (NDF) level and (2) dietary inclusion of fibre‐degrading enzymes on nutrient digestibility and excreta characteristics in pigs. Four diets were formulated to contain three levels of NDF: 1, 66 g kg^?1 NDF (low fibre); 2, 121 g kg^?1 NDF (moderate fibre); 3, 222 g kg^?1 NDF (high fibre); 4, diet 3 plus 2.0 g kg^?1 enzyme. Increasing levels of dietary NDF linearly decreased dry matter and energy digestibilities (r² = 0.99, P < 0.05). Lowering dietary NDF from 222 to 121 g kg^?1 improved nitrogen digestibility by 13% (P < 0.01). Faecal production was decreased by 9% for each 1% decrease in dietary NDF content (r² = 0.99, P < 0.05). Inclusion of fibre‐degrading enzymes in the high‐fibre diet improved dry matter and energy digestibilities by 2 and 3% respectively, and reduced faecal production by 10% (P < 0.01). Faecal and manure (faeces plus urine) pH values from pigs fed the high‐fibre diet and the high‐fibre plus enzyme diet were lower than those from pigs fed the other experimental diets (P < 0.05). In conclusion, lowering the dietary NDF level or inclusion of fibre‐degrading enzymes in high‐fibre diets may offer relatively practical and easy methods for reducing waste production in pigs. © 2002 Society of Chemical Industry     

Utilisation of lemon (Citrus limon) and loquat (Eribotrya japonica) tree leaves alone or with NH3-treated straw for goats

Data are presented on the chemical composition and nutritive value of the leaves of the lemon (Citrus limon) and loquat (Eribotrya japonica) trees. Twenty-four castrated male Murciano-Granadina goats were used in 10 digestibility trials. The digestibility of untreated straw and straw treated with ammonia was measured in two trials, and in eight trials (4 trials×2 periods) lemon or loquat leaves were fed at levels of 25, 50, 75 and 100% in a diet with NH₃-treated barley straw. Crude protein (CP) contents were slightly higher for lemon tree leaves (11·2%), since the treated straw had a lower protein concentration (6·9%). CF, NDF and ADF contents in the leaves were lower than in the treated straw. Digestibility of OM and CP in treated straw was lower than in the leaves of either tree. In contrast, CF, NDF, ADF and cellulose digestibilities of the leaves were lower than that of NH₃-treated straw. The level of leaf inclusion in the diet significantly affected (P<0·05) DM, OM, CP and fibre digestibility, and DM intake. Diets including lemon leaves showed higher DM, OM, CP and NDF digestibilities than those with loquat leaves, but the DM intake was not affected (P>0·05) by the type of leaves. Results from the present study suggest that tree leaves can be used as a roughage source instead of NH₃-treated barley straw, with no adverse effect on intake or digestibility for goats. © 1998 SCI.     

Fibrous coproducts of corn and citrus as forage and concentrate sources for dairy cows

This study evaluated the effect on dairy cows of the partial replacement of whole plant corn silage (WPCS) with corn ear fibrous coproduct (CEFC) in diets with concentrate coproducts from citrus and corn on dry matter intake (DMI), lactation performance, digestibility, and chewing behavior. Holstein dairy cows (n = 20) in 5, 4 × 4 Latin squares (21-d periods) were fed a combination of strategies for feeding fibrous coproducts in a 2 × 2 factorial arrangement of the following treatments: (1) forage feeds: the partial replacement of WPCS (CS) with CEFC (CO), and (2) concentrate feeds: the partial replacement of wet corn gluten feed (GF) with a blend of pelleted citrus and corn distillers dried grains (CD) to have isonitrogenous diets. The concentrations of physically effective neutral detergent fiber (NDF; _peNDF_>8) were (% of dry matter): 21.8% for CS, 19.2% for CO, 20.7% for GF, and 20.2% for CD. Cows fed diet CS-CD had the highest yield of energy-corrected milk (30.0 kg/d) relative to the other diets (28.4 kg/d). Milk fat concentration was reduced on CO relative to CS. Cows fed the CO diets had higher DMI (21.2 vs. 20.2 kg/d) and digestible organic matter intake and tended to have a lower ratio of energy-corrected milk to DMI than cows fed CS. Diets CO reduced the daily intake of _peNDF_>8 and the intake as percent of body weight of _peNDF_>8, forage NDF, and total NDF relative to CS. Cows fed CO had greater meal frequency and lower daily meal time, meal duration, meal size, and duration of the largest meal than cows fed CS. The CO diet reduced rumination and total chewing in minutes per day and minutes per kilogram of DMI. When expressed per unit of _peNDF_>8 intake, rumination and total chewing were not affected by forage source. The total-tract starch digestibility coefficient was lower for cows fed CO than CS, but the intake of digestible starch was higher on CO than CS. Cows fed GF had reduced milk yield (29.6 vs. 30.8 kg/d), tended to have reduced DMI (20.4 vs. 21.0 kg/d), and had reduced digestible organic matter intake than cows fed CD. Feed efficiency was not affected by source of concentrate. The type of concentrate did not affect the intake of forage NDF and _peNDF_>8, but cows fed GF had higher intake of total NDF as percent of body weight than cows fed CD. The GF increased meal frequency and reduced meal size and largest meal duration and size. Cows fed GF had higher rumination and total chewing than cows fed CD (min/d, min/kg of DMI, and min/kg _peNDF_>8). Starch digestibility was higher and the intake of digestible starch tended to be higher on cows fed GF than CD. Plasma urea-N was higher, milk urea-N tended to be higher, and N utilization efficiency tended to be lower on cows fed GF than CD. Ruminal microbial yield was not affected by any treatment. All strategies evaluated were nutritionally viable and CEFC was a feasible partial replacement for WPCS.     

Nutritional value of feed grade chickpeas for ruminants and pigs

The feeding value of feed grade chickpeas (Kabuli and Desi type) for ruminants and pigs was determined in two studies. Two ruminally fistulated cows were used in the first study to determine the effects of moist heat treatment (127 °C for 10 min) on the ruminal protein degradability of feed grade chickpeas. Heat treatment reduced (P < 0.05) soluble crude protein and increased (P < 0.05) the amount of crude protein associated with neutral detergent fibre for both types of chickpeas. Ruminal degradability of crude protein for Kabuli and Desi chickpeas was reduced by 39 and 33% (P < 0.05) respectively as a result of heating. In the second study, 64 crossbred pigs were each assigned to one of four dietary treatments in a factorial (4 treatments × 2 sexes) design experiment. The experimental barley/wheat‐based diets were supplemented with either soybean meal (control), Kabuli chickpeas (300 g kg⁻¹), Desi chickpeas (300 g kg⁻¹) or field peas (300 g kg⁻¹). Dry matter and gross energy digestibility coefficients, determined using the indicator method, were lower (P < 0.05) for the Desi‐ than for the Kabuli‐supplemented diet. However, no differences were observed in dry matter or gross energy digestibility between the Kabuli chickpea‐supplemented diet and the control or the field pea‐supplemented diet. Diets supplemented with chickpeas or field peas had a lower (P < 0.05) crude protein digestibility than the control diet. Pigs fed either of the chickpea‐supplemented diets during the growing phase gained less (P < 0.05) than pigs fed the control diet. However, during the finishing phase and over the entire experiment, dietary treatment had no effect on pig performance. There were no significant differences in carcass traits between pigs fed any of the four diets. It was concluded that moist heat treatment is an effective method to increase the rumen escape protein value of chickpeas and that the inclusion of feed grade Kabuli or Desi chickpeas in finishing diets up 300 g kg⁻¹ had no detrimental effects on pig performance. © 2000 Society of Chemical Industry     

Ruminal fermentation,kinetics, and total-tract digestibility of lactating dairy cows fed distillers dried grains with solubles in low- and high-forage diets

The objective of this study was to investigate the effects of concentrations of forages and corn distillers dried grains with solubles (DDGS) on ruminal fermentation, ruminal kinetics, and total-tract digestibility of nutrients in lactating dairy cows. Four lactating Holstein cows with ruminal cannulas were assigned to a 4 × 4 Latin square in a 2 × 2 factorial arrangement of treatments. Diets were formulated to contain low forage [LF; 17% forage neutral detergent fiber (NDF)] or high forage (HF; 24.5% forage NDF) and DDGS at 0 or 18% (0DG or 18DG) of diet dry matter (DM). Intake of DM was not affected by the diets. Daily mean ruminal pH was affected by forage NDF × DDGS interactions, as the lowest ruminal pH was observed among cows fed LF18DG (6.02). Apparent total-tract digestibility for DM, organic matter, crude protein, NDF, acid detergent fiber, and starch was not affected by diets. Cows fed LF diets had a greater total volatile fatty acid concentration compared with cows fed HF (122 vs. 116 mM). Molar proportions of acetate were greater for HF compared with that of LF diets (62.6 vs. 57.5 mmol/100 mmol) and greater for 0DG diet compared with that of 18DG diets (61.3 vs. 58.7 mmol/100 mmol) diets. The molar proportion of propionate was affected by forage × DDGS interaction as the greatest propionate molar proportion was observed with cows fed LF18DG diet (27.7 mmol/100 mmol). Also, molar proportion of butyrate was affected by forage × DDGS interaction, as the greatest butyrate molar proportion was observed in cows fed HF18DG diet (13.5 mmol/100 mmol). Average fractional dilution rate for all diets was 11.9%/h and was not affected by diets. Fractional passage rate of the solid phase was greater for HF than for LF (4.40 vs. 3.76%/h). The ruminal retention time of solid phase was greater for LF compared with HF diets (27.3 vs. 23.3 h). Fractional passage rate of DDGS was affected by forage × DG interaction, as the highest fractional passage rate of DDGS was observed with cows fed HF18DG diet (7.72%/h). Our results demonstrated that concentrations of forage, DDGS, and their interaction influence ruminal degradation and kinetics of diets fed. Diets formulated at 17% forage NDF at 17% (DM basis) can decrease milk fat concentration compared with diets formulated at 25% forage NDF. Additionally, feeding DDGS at 18% DM basis to lactating dairy cows did not affect milk fat concentration or yield.     

Effects of brown midrib 3 mutation in corn silage on productivity of dairy cows fed two concentrations of dietary neutral detergent fiber: 3. Digestibility and microbial efficiency

The effects of digestibility of corn silage neutral detergent fiber (NDF) and dietary NDF content on ruminal digestion kinetics, site of nutrient digestion, and microbial N production efficiency were evaluated with eight multiparous high producing dairy cows in a duplicated 4 x 4 Latin square design with 21-d periods. Experimental diets contained corn silage from a brown midrib (bm3) hybrid or its isogenic normal control at two concentrations of dietary NDF (29 and 38%). The NDF digestibility estimated by a 30-h in vitro fermentation was higher for bm3 corn silage by 9.4 units (55.9 vs. 46.5%). Neither ruminal nor total tract NDF digestibility was affected by corn silage treatment. The bm3 corn silage diet decreased starch digestibility in the rumen and in the total tract, but increased postruminal starch digestibility compared with control diet. The bm3 corn silage diets increased microbial N flow to the duodenum and tended to decrease ruminal ammonia concentration. Microbial efficiency was greater for cows fed bm3 corn silage in spite of lower ruminal pH. Higher efficiency of microbial nitrogen production might be attributed to faster passage rate of NDF for cows fed bm3 corn silage compared with those fed control corn silage. Higher in vitro NDF digestibility might predict enhanced NDF fragility and ease of NDF hydrolysis in vivo. Enhanced in vitro NDF digestibility does not necessarily result in increased NDF digestibility either in the rumen or in the total tract, but possibly increases rate of passage and DMI, improving efficiency of microbial N production.     

The effect of either raw or boiled liquid extract from potato (Solanum tuberosum) on the digestibility of a diet based on barley in pigs

The nitrogen (N) of raw potato is poorly digested by the pig and the hypothesis tested in the experiment was that this is due to an anti-nutritive substance present in the tuber and not simply due to the physical inaccessibility of much of the potato protein to enzyme attack or to the protein of the potato being refractory to gut enzymes. Four growing pigs, each fitted with an ileal cannula were fed on a basal diet of barley plus minerals and vitamins to which was added minced raw potato (RP) or a liquid extract of potatoes which was either freeze-dried (LE) or boiled and concentrated (BE). These materials each contributed 12 g N day^?1 for each pig. Each pig was given 2.1 kg organic matter (OM) day^?1. In diet RP 25.5% of this was from potato compared with 7.2 and 7.8% in diets LE and BE, respectively. The digestibility of N determined at the terminal ileum was reduced with RP by 9.5% (NS) and with LE by 23% (P<0.01) while BE increased it by 24.7% (P<0.01) compared with the coefficient of digestibility for the N of the barley diet. The digestibility of OM was significantly (P<0.001) reduced by 9.5% with RP but with LE and BE it was similar to the control value. Over the whole gut, coefficients for N changed by ?19.8% (P<0.001), ?4.7% (NS) and +9.0% (P<0.05) when RP, LE or BE, respectively were included in the basal diet. Corresponding changes in OM were +2.4% (NS), +1.9% (NS) and +3.6% (P<0.05). It is suggested that the anti-nutritive factor in potatoes should be denatured by appropriate treatment to improve the digestibility of dietary protein.     

Ileal digestibility of defatted soybean,lupin and chickpea seed meals in cannulated Iberian pigs: I. Proteins

Five castrated male Iberian pigs (100 ± 2 kg body weight) fitted with T‐shaped cannulas at the terminal ileum were used to determine ileal digestibility of legume seed meals. The diets were based on defatted soybean, lupin or chickpea seed meals and contained similar levels of digestible energy (14.2–15.1 kJ g^?1) and protein (107 g kg^?1). Protein‐free and a hydrolysed casein diets were used to study endogenous ileal amino acid flows. Chromium oxide (10 g kg^?1 diet) was added to the diets as an indigestible marker. Ileal flows in pigs fed the hydrolysed casein diet were different (p < 0.05) in amino acid contents and composition from those on the protein‐free diet. Ileal sialic acid flows in pigs fed lupin‐ or chickpea‐based diets were higher (p < 0.05) than those of animals fed soybean or casein diets. Among essential amino acids, only the apparent ileal digestibilities of phenylalanine and valine in lupin meal were lower (p < 0.05) than those in soybean. Apparent ileal digestibilities of lupin aspartate and proline, together with chickpea aspartate, were also lower (p < 0.05) than those of soybean. True ileal digestibility of nitrogen in pigs fed lupin or chickpea meals, calculated according to values from animals fed the protein‐free diet, was lower (p < 0.05) than that for soybean or casein. Among individual essential amino acids, only the true ileal digestibility of phenylalanine in lupin was lower (p < 0.05) than that in soybean. True ileal digestibility of nitrogen calculated according to values obtained with pigs fed a hydrolysed casein diet was not different among soybean, lupin or chickpea meals. Among essential amino acids, only the true ileal digestibilities of isoleucine and lysine in chickpea were lower (p < 0.05) than those of soybean. It is concluded that true ileal nitrogen and amino acid digestibilities of lupin and chickpea meals are comparable to those of defatted soybean in Iberian pigs. The results with protein‐free diets tended to underestimate endogenous protein secretion in pigs fed on diets containing protein. Copyright © 2005 Society of Chemical Industry     

Lactation performance of dairy cows fed rehydrated and ensiled corn grain differing in particle size and proportion in the diet

Rehydrated and ensiled mature ground corn has high ruminal starch digestibility, but particle size (PS) and dietary starch proportion (ST) can affect starch digestion and lactating cow performance. We evaluated the effect of rehydrated and ensiled corn (REC), PS, and ST on intake, lactation performance, nutrient digestibility, ruminal fermentation profile, and chewing behavior of dairy cows. Kernels from an 84% vitreousness hybrid were finely (FN) or coarsely (CS) ground, yielding geometric mean particle sizes of 1,591 and 2,185 µm, respectively. Ground kernels were rehydrated [60% dry matter (DM)] and ensiled in 200-L buckets for ≥205 d. The grinding rate (t/h) was 3.9 for FN and 11.7 for CS. The PS did not affect DM loss (11.3% of ensiled) or silage pH (3.8). Samples of each bucket (n = 15/PS) before and after silage fermentation were incubated in situ for 0, 3, 6, 18, and 48 h in 4 rumen-cannulated lactating cows. Ensiling increased the effective ruminal in situ DM degradation (63.7 vs. 34.1%), regardless of PS. Sixteen Holstein cows (152 ± 96 d in milk) in 4 × 4 Latin squares (21-d periods) were individually fed a 2 × 2 factorial combination of low (LO) or high (HI) starch diets with FN or CS. Cows were fed the same REC incubated in situ. Varied concentration of starch in the diet (29.2 vs. 23.5% of DM) was achieved by partial replacement of REC (22.0 vs. 14.2% of DM) with citrus pulp (0 vs. 8.2% of DM). Milk, protein, fat, and lactose yields did not differ. Milk fat percentage was reduced and protein percentage was increased by HI. Treatment FN increased feed efficiency (energy-corrected milk/digestible organic matter intake) when fed with HI. Total-tract starch digestibility tended to be reduced by CS (96.4 vs. 97.2% of starch intake). Serum β-hydroxybutyrate was increased by LO. High-starch diet reduced the molar proportions of acetate and butyrate in ruminal fluid and increased propionate and isoacids. Particle size did not affect ruminal fermentation profile. Coarse grinding reduced plasma d-lactate concentration with HI. Diet HI reduced the proportion of daily intake from 1900 to 0700 h and induced preferential intake of feed particles <8 mm and greater refusal of particles >19 mm in the morning. Fine REC reduced rumination time per day and increased eating time per DM intake. Milk and plasma urea-N did not differ. Ensiling of mature flint corn for >200 d largely eliminated the effect of the PS of REC on the studied outcomes. The proportion of REC in the diet affected ruminal fermentation profile and milk solids concentration, but did not affect short-term performance and digestibility. Coarse grinding of REC may allow increasing the grinding rate and thus save labor and energy during ensiling.     

Evaluation of barley and triticale as feed ingredients in growing Iberian pigs: amino acid and carbohydrate ileal digestibility

BACKGROUND: Iberian pig production is linked to the use of the Mediterranean woodland, where the use of local feed resources is of paramount importance for the sustainability of the system. The aim of the present work was to explore the potential of triticale cv. Camarma as compared to barley cv. Esgueva in Iberian pig feeding by studying their respective ileal digestibilities of amino acids and carbohydrates in animals cannulated at the end of the ileum. RESULTS: Leu, Met and Tyr had (P < 0.05) greater standardised ileal digestibilities (SID) in pigs fed triticale diet. There was a trend (P = 0.07) towards greater SID of Thr in pigs fed the barley diet. The least digestible indispensable amino acids were Ile (74.6% SID) for barley and Thr (78.9% SID) for triticale. Except for β‐glucans, apparent ileal digestibilities (AIDs) of individual non‐starch polysaccharide (NSP), sugars and starch were greater in pigs fed triticale (P < 0.05). Nevertheless, total amounts of NSP digested were greater in pigs fed the barley diet (P < 0.05). CONCLUSION: Overall, triticale cv. Camarma had greater amino acid and carbohydrate AID than barley cv. Esgueva and may represent a valuable grain for Iberian pig feeding. Copyright © 2008 Society of Chemical Industry     

Effects of probiotic,prebiotic and synbiotic follow‐up infant formulas on large intestine morphology and bone mineralisation in rats

The effects of powder functional follow‐up infant formulas on the morphology of the large intestine and the bone mineral content in rats were investigated. Infant formulas were supplemented with probiotics (Bifidobacterium bifidum and Bifidobacterium longum), prebiotics (galacto‐oligosaccharides (4′‐GOS) at 12, 50 and 100 g kg^?1) or synbiotics (bifidobacteria and 4′‐GOS) and administered to seven groups of weanling rats over 30 days. After sacrificing the animals, the caecum and colon were removed and the luminal content pH and the crypt depth and cell density within the epithelial layer were measured. Results showed that groups fed synbiotic diets had significantly (P < 0.05) lower caecal and colonic content pH values compared with the control group. However, no test diet significantly modified the crypt depth or cell density in the caecum. In contrast, all seven test diets significantly increased (P < 0.05) the crypt depth in both the proximal and distal portions of the colon. There was a high correlation (Pearson correlation coefficient 0.870) between caecal and colonic content pH values. On the other hand, colonic content pH was negatively correlated with crypt depth in both the proximal and distal colon and with cell density in the distal colon. The authors previously reported increases in calcium, magnesium and phosphorus absorption using the same infant formulas. In the present study it was concluded that the increase in calcium absorption took place in the distal colon whereas magnesium absorption increased in both the proximal and distal colon, and their contents (especially that of calcium) increased in both the femur and tibia. Copyright © 2007 Society of Chemical Industry     

Effect of linseed oil supplementation on ruminal digestion in dairy cows fed diets with different forage:concentrate ratios

The effect of linseed oil (LSO) supplementation on total-tract and ruminal nutrient digestibility, N metabolism, and ruminal fluid characteristics was investigated in dairy cows fed diets containing different forage to concentrate ratios (F:C). The experimental design was a 4 x 4 Latin square with 2 x 2 factorial arrangement of treatments. Four lactating Holstein cows were fed a forage-rich diet without LSO (F; F:C = 65:35, dry matter basis), a forage-rich diet with LSO (FO; F:C = 65:32, 3% LSO), a concentrate-rich diet without LSO (C; F:C = 35:65), or a concentrate-rich diet with LSO (CO; F:C = 35:62, 3% LSO). Total-tract digestibility of DM and OM was greater with supplemental LSO. A tendency for greater total-tract digestibility of NDF and ADF also was observed in cows fed LSO. Ruminal digestibility of NDF or ADF decreased when CO was fed compared with C. In contrast, feeding FO increased NDF or ADF digestibility compared with F. Although ruminal starch digestion was nearly complete with all diets, digestibility was greater when cows were fed C or CO compared with F or FO. Bacterial N flow to the duodenum decreased when FO was fed compared with F. In contrast, feeding CO increased bacterial-N flow compared with C. Neither F:C nor LSO supplementation affected ruminal pH or total VFA concentration in ruminal fluid. However, molar proportion of propionate was greater with C or CO compared with F or FO and increased with LSO supplementation regardless of F:C. Molar proportion of n-butyrate decreased with LSO supplementation. Total protozoal numbers in ruminal fluid decreased markedly only when CO was fed. Overall, data show that feeding LSO had no negative effects on total-tract digestion in dairy cows but may decrease ruminal fiber digestibility when fed with high-concentrate diets. The widely spread idea that LSO decreases digestibility, arising from studies with sheep, did not seem to apply to lactating cows fed 3% LSO.     

Milk production, nitrogen balance, and fiber digestibility prediction of corn, whole plant grain sorghum, and forage sorghum silages in the dairy cow

Total mixed rations containing corn (CS), whole plant grain sorghum (WPGS), or forage sorghum (FS) silages were fed to 6 primiparous Italian Friesian cows to determine the effects on lactation performance, nutrient digestibility, and N balance. Furthermore, the relationship between in vivo total-tract neutral detergent fiber (NDF) digestibility (ttNDFD) and the ttNDFD derived by the Cornell Net Carbohydrate and Protein System (CNCPS) model was assessed. Cows were assigned to 1 of 3 diets in a replicated 3 × 3 Latin square with 28-d periods. The experimental treatment was silage type and 3 different silages were included in the diets. The diets were formulated to be iso-NDF. Accordingly, each diet was formulated to contain 41.5% CS silage, 36.7% WPGS silage, or 28.0% FS silage, on a DM basis. Starch content was balanced by adding the appropriate amount of corn meal. Separate collection of total urine and feces was performed. Dietary forages were analyzed for in vitro NDF digestibility (6 and 24h of incubation) to predict fiber digestion rate with 2 NDF pools (digestible and indigestible). Rumen digestibility of the potentially digestible NDF pool was predicted using CNCPS version 6.1, using the in vitro forage fiber digestion rate. The ttNDFD was predicted assuming that intestinal digestibility of the NDF amount escaping rumen digestion was 20%, according to the CNCPS model. Dry matter intake was decreased by approximately 1.8 kg/d in cows fed the FS diet compared with the other diets, probably for the greater particle size of FS diet. Hence, milk yield (kg/d) was lowest for FS (23.6), intermediate for WPGS (24.6), and highest for the CS diet (25.4). Milk urea N (mg/dL) was highest for FS (12.9), intermediate for WPGS (11.9), and lowest for CS (10.7) diet. In vivo ttNDFD (%) was 51.4 (CS), 48.6 (WPGS), and 54.1 (FS); this was probably due to a higher retention time of FS diet in the rumen rather than to a better quality of the FS silage, as confirmed by in situ and in vitro results. Urinary N excretion (% N intake) was highest for FS (31.8), intermediate for WPGS (29.3), and lowest for the CS (27.5) diet. The predicted ttNDFD (37.7, 36.3, and 39.5% for CS, WPGS, and FS, respectively) were lower than the in vivo results. Providing an adequate starch supplementation, whole plant grain sorghum silage can replace corn silage in dairy cows TMR. Forage sorghum silage had rumen NDF digestibility comparable to the other silages; however, it had a negative effect on dry matter intake and milk production, probably due to an inadequate effect of processing.     

Sorghum forage in precision-fed dairy heifer diets

Sorghum forage is an alternative crop that is more adapted to drier conditions and more resistant than corn to drought conditions. Thus, sorghum forage maximizes water utilization. The objective of this study was to evaluate sorghum silage (SS), including digestibility and fermentation parameters, in precision-fed dairy heifers. Eight Holstein heifers (13.7 ± 0.6 mo of age and 364.8 ± 17.64 kg of body weight) fitted with rumen cannulas were used in a replicated 4 × 4 Latin Square design; treatments were 4 levels of forage to concentrate ratios (85:15, 75:25, 65:35, and 55:45). Rumen contents were sampled at various times to determine pH and volatile fatty acid concentrations. Dry matter (DM) and neutral detergent fiber (NDF) in situ degradation kinetics were compared between SS and corn silage (CS) diets. Fecal total collection was used to estimate apparent total-tract digestibility. Fecal grab samples at 0, 6, 12, and 18 h after feeding were used to estimate total-tract starch digestibility. Amount of concentrate in the diet affected the time that heifers spent eating as well as rumen pH. When the concentrate proportion of the diet increased, eating time and rumen pH decreased linearly. Total volatile fatty acid concentrations were not affected by treatment, but butyrate increased as the proportion of concentrate increased in the diet. Digestibility of DM and starch were higher in diets with lower forage to concentrate ratio, but NDF, acid detergent fiber, and hemicellulose digestibility were not affected. Corn silage had greater DM and NDF digestibility than SS. Also, fractional rate of digestion was faster for CS than SS (2.78 vs. 2.42% per hour, respectively). We conclude that fecal grab samples are suitable for predicting starch digestibility in heifers given the starch levels studied. In addition, SS was an adequate alternative forage in precision-fed dairy heifers with outcomes very similar to CS-based rations.     

Physical effectiveness of corn silage fractions stratified with the Penn State Particle Separator for lactating dairy cows

This study evaluated the physical effectiveness of whole-plant corn silage (CS) particles stratified with the Penn State Particle Separator, composed of 19- and 8-mm-diameter sieves and a pan, for lactating dairy cows. Eight Holstein cows (27.6 ± 2.8 kg/d of milk, 611 ± 74 kg body weight; 152 ± 83 d in milk) were assigned to two 4 × 4 Latin squares (22-d periods, 16-d adaptation), where one square was formed with rumen-cannulated cows. Three CS particle fractions were manually isolated using the 8- and 19-mm diameter sieves and re-ensiled in 200-L drums. The 4 experimental diets were (% dry matter): (1) CON (control): 17% forage neutral detergent fiber (NDF) from CS (basal roughage), 31.5% starch, and 31.9% NDF; (2) PSPan: 17% forage NDF from CS + 9% NDF from CS particles <8 mm, 25.9% starch, and 37.9% NDF; (3) PS8: 17% forage NDF from CS + 9% NDF from CS particles 8 to 19 mm, 25.5% starch, and 38.3% NDF; and (4) PS19: 17% forage NDF from CS + 9% NDF from CS particles >19 mm, 24.9% starch, and 38.8% NDF. Cows fed PS8 had greater dry matter intake and energy-corrected milk yield (22.4 and 26.9 kg/d, respectively) than cows fed CON (20.8 and 24.7 kg/d) and PS19 (21.2 and 24.8 kg/d), but no difference was detected between PSPan (21.6 and 25.8 kg/d) and other treatments. Milk fat concentration was greater for PS8 than CON, with intermediate values for PSPan and PS19. Milk fat yield was greater for cows fed PS8 than CON and PS19, and cows fed PSPan secreted more fat than CON cows but were not different from cows fed the other 2 diets. Cows fed CON had a lower meal frequency than cows fed PSPan, shorter meal and rumination times than PS8, and greater meal size and lower rates of rumination and chewing than the other 3 diets. Total chewing per unit of NDF was higher for PS8 than PSPan, although neither treatment differed from CON or PS19. Cows fed PS19 had higher refusal of feed particles >19 mm than cows fed CON and PSPan. The refusal of dietary NDF and undigested NDF in favor of starch were all greater for PS19 than on the other treatments. Cows fed PS19 had a greater proportion of the swallowed bolus and rumen digesta with particles >19 mm than the other 3 diets. Cows fed CON had the lowest ruminal pH and greatest lactate concentration relative to the other 3 diets. Plasma lipopolysaccharide was higher for cows fed CON and PSPan than for cows fed PS8 and PS19, and serum d-lactate tended to be lower on PSPan than for CON and PS8. In summary, the inclusion of CS fractions in a low-forage fiber diet (CON) reduced signs of ruminal acidosis. Compared with CS NDF <8 and >19 mm, CS NDF with 8- to 19-mm length promoted better rumen health and performance of dairy cows. These results highlight the importance of adjusting CS harvest and formulating dairy diets based on the proportion of particles retained between the 8- and 19-mm sieves.     

Replacing corn silage with different forage millet silage cultivars: Effects on milk yield,nutrient digestion,and ruminal fermentation of lactating dairy cows

This study investigated the effects of dietary replacement of corn silage (CS) with 2 cultivars of forage millet silages [i.e., regular millet (RM) and sweet millet (SM)] on milk production, apparent total-tract digestibility, and ruminal fermentation characteristics of dairy cows. Fifteen lactating Holstein cows were used in a replicated 3 × 3 Latin square experiment and fed (ad libitum) a high-forage total mixed ration (68:32 forage:concentrate ratio). Dietary treatments included CS (control), RM, and SM diets. Experimental silages constituted 37% of each diet DM. Three ruminally fistulated cows were used to determine the effect of dietary treatments on ruminal fermentation and total-tract nutrient utilization. Relative to CS, RM and SM silages contained 36% more crude protein, 66% more neutral detergent fiber (NDF), and 88% more acid detergent fiber. Cows fed CS consumed more dry matter (DM; 24.4 vs. 22.7 kg/d) and starch (5.7 vs. 3.7 kg/d), but less NDF (7.9 vs. 8.7 kg/d) than cows fed RM or SM. However, DM, starch and NDF intakes were not different between forage millet silage types. Feeding RM relative to CS reduced milk yield (32.7 vs. 35.2 kg/d), energy-corrected milk (35.8 vs. 38.0 kg/d) and SCM (32.7 vs. 35.3 kg/d). However, cows fed SM had similar milk, energy-corrected milk, and solids-corrected milk yields than cows fed CS or RM. Milk efficiency was not affected by dietary treatments. Milk protein concentration was greatest for cows fed CS, intermediate for cows fed SM, and lowest for cows fed RM. Milk concentration of solids-not-fat was lesser, whereas milk urea nitrogen was greater for cows fed RM than for those fed CS. However, millet silage type had no effect on milk solids-not-fat and milk urea nitrogen levels. Concentrations of milk fat, lactose and total solids were not affected by silage type. Ruminal pH and ruminal NH₃-N were greater for cows fed RM and SM than for cows fed CS. Total-tract digestibility of DM (average = 67.9%), NDF (average = 53.9%), crude protein (average = 63.3%), and gross energy (average = 67.9%) were not influenced by dietary treatments. It was concluded that cows fed CS performed better than those fed RM or SM likely due to the higher starch and lower NDF intakes. However, no major differences were noted between the 2 forage millet silage cultivars.     

Partial replacement of forage with nonforage fiber sources in lactating cow diets. II. Digestion and rumen function

Replacement of forage with cereal byproducts may be a viable alternative for feeding dairy cows. The objective of this experiment was to evaluate total tract digestion and rumen fermentation profile when diets were formulated to contain low-forage neutral detergent fiber (NDF) (12.6% forage NDF, 18.8% total NDF), adequate NDF from forages (20% forage NDF, 24.4% total NDF) or low-forage NDF with high levels of NDF from cereal byproducts (12.7% forage NDF, 35.1% total NDF). Sodium bicarbonate (0.8% of dry matter) was factorialized over these diets. Total tract apparent digestibilities of organic matter (OM) and carbohydrates were determined in 73 Holsteins. Eight rumen-cannulated cows were used concurrently to evaluate rumen fermentation profile and in situ degradation of forages. Bicarbonate did not increase NDF or OM digestibility, but increased intake of digestible OM. Rumen fermentation parameters were determined by dietary alfalfa NDF content. Adding alfalfa NDF to the low-forage, high-starch diet increased in situ degradation of forage NDF more than adding byproduct NDF. However, increased ruminal forage NDF degradability was not reflected in greater total tract NDF digestibility. Replacement of dietary starch with NDF from byproducts decreased OM digestibility, but energy intake was similar across diets due to increased intake.     

Effects of forage particle size and grain fermentability in midlactation cows. I. Milk production and diet digestibility

Our study investigated the effects of, and interactions between, level of dietary ruminally fermentable carbohydrate (RFC) and forage particle size on milk production, nutrient digestibility, and microbial protein yield for dairy cows fed one level of dietary NDF. Eight cows (61 days in milk) were assigned to four treatments in a double 4 x 4 Latin square. Treatments were arranged in a 2 x 2 factorial design; finely chopped alfalfa silage (FS) and coarse alfalfa silage (CS) were combined with concentrates based on either dry cracked shelled corn (DC; low RFC) or ground high-moisture corn (HMC; high RFC). Diets were fed ad libitum as a total mixed rations with a concentrate to forage ratio of 61:39. Diets based on DC had a predicted NEL content of 1.73 Mcallkg dry matter (DM), while HMC diets contained 1.80 Mcal/kg DM. Diets averaged 18.7% CP, 24.0% NDF, 18.3% ADF, and 27.4% starch on a DM basis. Mean particle size of the four diets was 6.3, 2.8, 6.0, and 3.0 mm for DCCS, DCFS, HMCCS, and HMCFS, respectively. Increasing level of RFC decreased dry matter intake (DMI) from 25.0 to 23.8 kg/ d and organic matter intake from 22.3 to 21.1 kg/d, but intake was not affected by particle size. Milk production averaged 44.0 and 26.8 kg/d solids corrected milk (SCM) and was not affected by diet, but increasing level of RFC tended to increase milk yield. Efficiency of milk production, expressed as SCM/DMI, increased from 1.06 to 1.14 when level of RFC was increased. Milk composition or yield of milk components was not affected by diet, and averaged 3.53% fat, 3.11% protein, 1.55 kg/d fat, and 1.36 kg/d protein. Total tract digestibility of DM and OM increased from 71.4 to 73.0% and 72.4 to 76.1% for DM and OM, respectively, when level of RFC was increased. Total tract digestibility of fiber was unaffected by diet, but total tract starch digestibility increased from 93.1 to 97.4% when HMC replaced DC. Total urinary excretion of the purine derivatives uric acid and allantoin increased from 415 to 472 mmol/d when level of RFC was increased, and calculated microbial N supply increased from 315 to 365 g/d. When expressed as per kilogram of digestible OMI, increasing level of RFC tended to increase microbial N supply (20.4 vs. 22.2 g/kg). Cow productivity was not affected by forage particle size and ruminally fermentable carbohydrates in this study.     

The influence of fibre level and fat supplementation in expander‐processed diets on grower–finisher pig performance

Seventy‐two entire male pigs (40.4 ± 1.0 kg) were used to study the effects of increasing crude fibre (CF) level in the diet and maintaining the digestible energy (DE) content of the diet by increasing dietary fat inclusion on pig performance and nutrient digestibility in a 3 × 2 factorial experiment. Productive performance and nutrient digestibility were determined in individually fed pigs offered expander‐processed pelleted diets ad libitum containing three levels of CF (50, 60 and 70 g kg^?1) and two levels of fat supplementation (25 and 50 g kg^?1) until slaughter at 100 kg. All diets were expander processed at 105 °C for 5 s at 35 bar pressure having been previously conditioned at 85 °C for 5 s. All diets were formulated to have similar concentrations of digestible energy (13.5 MJ kg^?1) and lysine (10 g kg^?1) and the fat source was a 60:40 blend of tallow and palm oil. The increase in dietary CF level decreased (P < 0.05) the apparent digestibility of crude protein, organic matter (OM) and energy, while the inclusion of 50 g kg^?1 fat decreased (P < 0.01) OM and energy digestibility. The inclusion of 50 g kg^?1 fat in the diet increased (P < 0.01) ether extract digestibility at the 50 and 60 g kg^?1 CF levels; however, fat inclusion had no effect at the 70 g kg^?1 CF level. There was no CF × fat interaction in any growth criteria. The inclusion of 50 g kg^?1 fat in the diet significantly reduced (P < 0.05) feed intake (2.28 versus 2.43 kg day^?1, SEM 0.039), average daily gain (ADG; 0.877 versus 0.927 kg day^?1, SEM 0.017) and DE conversion ratio (36.1 versus 35.0 MJ kg^?1, SEM 0.40). The increase in dietary CF level decreased (linear, P < 0.05) feed intake (2.45 versus 2.32 versus 2.29 kg day^?1, SEM 0.040), ADG (0.940 versus 0.896 versus 0.872 kg day^?1, SEM 0.021) and kill‐out proportion (740 versus 741 versus 730 g kg^?1, SEM 3.6). In conclusion, increasing both the CF level and supplementary fat inclusion rate had a negative effect on pig growth performance and nutrient digestibility. © 2002 Society of Chemical Industry     

Lactation performance and digestibility of forages and diets in dairy cows fed a hemicellulose extract

Inclusion of hemicellulose extract (HE) in cattle diets have shown potential for improving fiber digestibility and production efficiency. The objective of this research was to evaluate production and digestibility effects of a HE on midlactation cows. Twelve multiparous Holstein cows (142 ± 44 d in milk, 685 ± 19 kg of body weight) including 4 with ruminal fistula were used in a 2 × 2 Latin square design with 21-d periods. Cows were fed a control (CON) diet containing 55% forage [dry matter (DM) basis, 2/3 corn silage and 1/3 alfalfa hay] or a similar diet where 1.0% of the diet DM was replaced with HE (TRT). Dry matter intake averaged 27.1 and 26.9 kg/d, for CON and TRT respectively, and was not affected by addition of extract. The percentage of milk protein (3.40 vs. 3.29%) was greater, whereas the percentage of milk fat (3.91 vs. 3.80%) tended to be greater, for cows fed the CON compared with the TRT diet. Because of numerically greater milk production (38.8 vs. 39.2 kg/d) for cows fed the TRT diet, no differences were observed in component yields other than lactose (1.86 vs. 1.94 kg/d), which tended to be greater for cows fed the TRT ration. Treatment improved neutral detergent fiber (NDF) digestibility (38.6 vs. 48.1%) for the TRT diet compared with the CON diet but did not affect apparent total-tract DM (67.8 vs. 68.5%), crude protein (67.2 vs. 67.9%), acid detergent fiber (ADF; 37.1 vs. 43.3%), or starch (92.8 vs. 92.2%) digestibility. For in situ determinations, Dacron bags containing corn silage, alfalfa hay, and either the CON or TRT ration were incubated in triplicate in the rumens of the cannulated cows at 0, 3, 6, 9, 12, 24, and 48 h on d 18 of each period. Each total mixed ration was incubated only in cows assigned to the corresponding diet. For corn silage, the rate of disappearance of NDF (1.70 vs. 4.27%) and ADF (1.79 vs. 4.66%) increased for cows fed the TRT diet. For alfalfa hay, the disappearance of fraction A of DM, NDF, and ADF decreased and fraction B of DM and NDF increased with treatment. The rate of disappearance for DM (8.03 vs. 11.04%), NDF (6.30 vs. 10.28%), and ADF (5.52 vs. 9.19%) increased for the alfalfa hay in rumens of treated cows. For the total mixed ration, the disappearance of the A fraction of NDF and ADF increased for cows fed the TRT diet. Supplementing diets of lactating dairy cows with an HE has beneficial effects on fiber degradation characteristics and provides opportunities for improving animal performance.