Diurnal Variation in the Composition of Ileal Digesta and the Ileal Digestibilities of Nutrients in Growing Pigs

Diurnal variation in the chemical composition of digesta and its effect on nutrient digestibilities of diets varying in dietary fibre content was examined in pigs fitted with a PVTC-cannula at the terminal ileum. The pigs were fed three times a day (08:00, 16:00 and 24:00 h). A barley control diet and four barley-based diets containing two levels (100 or 200 g kg^-1 diet) of alfalfa meal or white clover meal and Cr₂O₃ as an indigestible marker were fed according to a 5×5 Latin square design. In each experimental period, digesta were collected for 1 h every third hour on each of two separate sampling days, covering in total a 24 h period. The concentration of dry matter (DM), crude protein (CP), ash and chromium (Cr) in the ileal digesta varied in relation to time of feeding. However, the patterns were similar after all three meals (08:00, 16:00 and 24:00 h) and independent of diet. The maximum DM, CP and ash contents were reached 4–5 h post-feeding. The highest (P < 0·05) DM concentration was found in the ileal digesta of pigs fed the barley control diet. The DM concentration decreased (P < 0·05) as the inclusion level of alfalfa meal and white clover meal was increased. The lowest DM concentration was found for the highest inclusion level of alfalfa meal. The ileal digestibilities of both organic matter and CP were lower 1–2 h post-feeding compared with those recorded 3–5 h later, indicating that the less digestible components of a diet have shorter transit times. The pooled ileal digestibilities of organic matter and CP from the three 8 h periods (08:00–16:00 h, 16:00–24:00 h, 24:00–08:00 h) did not differ (P < 0·05) from each other. Therefore, the estimate of digestibility can be based on digesta samples collected from any interval between two consecutive meals. However, care must be taken to obtain representative samples of digesta between meals. © 1997 SCI.     

Exocrine Pancreatic Secretions in Young Pigs Fed Diets Containing Faba Beans (Vicia faba) and Peas (Pisum sativum): Nitrogen,Protein and Enzyme Secretions

Two experiments were carried out to investigate the effect of feeding diets containing faba beans and peas on pancreatic secretions in young pigs fitted with a pancreatic pouch re-entrant cannula. In Experiment 1, eight barrows, with an average initial weight of 8·5 kg, were fed one of two maize starch-based diets formulated to contain 200 g crude protein (CP) kg⁻¹ according to a completely randomised design. In one of the diets, soya bean meal was the sole protein source; in the other diet, soya bean meal and faba beans (cv Fibro; dark-flowering) each supplied 50% of the dietary CP. In Experiment 2, five barrows, with an average initial weight of 18·1 kg, were fed one of two diets according to a two-period change-over design. The diets were formulated to contain 150 g CP kg⁻¹ with peas (cv Ascona or cv Radley) as the sole protein source. In both experiments, the experimental periods consisted of 8 days: 6 days adaptation followed by a 2 day collection of pancreatic juice. The soya bean meal diet and the faba bean diet contained 0.04 and 0.21% tannins (catechin equivalents), respectively. The trypsin inhibitor activities of the Ascona and Radley pea diets were 0·76 and 3·24 mg of trypsin inhibited per gram, respectively. In both experiments, diet did not affect ( P> 0·05) the pancreatic secretions of nitrogen, protein, amylase, lipase and chymotrypsin. In Experiment 1, specific trypsin activity was higher ( P< 0·05) in pancreatic juice from pigs fed the diet containing soya bean meal and faba beans (53700 units litre⁻¹) than for those fed the soya bean meal diet (41200 units litre⁻¹). However, there was no effect ( P> 0·05) when trypsin activity was expressed as total activity (units 24 h⁻¹). It is concluded that the inclu-sion of faba beans and peas in diets for young pigs has only minor effects on exocrine pancreatic secretions.     

Exocrine Pancreatic Secretions in Young Pigs Fed Diets Containing Faba Beans (Vicia faba) and Peas (Pisum sativum): Concentrations and Flows of Total,Protein-Bound and Free Amino Acids

Two experiments were carried out to investigate the effects of feeding diets containing faba beans and peas on the concentration, flow and composition of total, protein-bound and free amino acids (AA) in pancreatic juice collected from young pigs fitted with a pancreatic pouch re-entrant cannula. In Experiment 1, eight barrows, with an average initial weight of 8·5 kg, were fed one of two semi-purified diets formulated to contain 200 g kg⁻¹ crude protein (CP) according to a completely randomised design. In one of the diets, soya bean meal was the sole protein source; in the other diet, soya bean meal and faba beans (cv Fibro; dark-flowering) each supplied 50% of the dietary CP. In Experiment 2, five barrows, with an average initial weight of 18·1 kg, were fed one of two diets formulated to contain 150 g kg⁻¹ CP with peas (cv Ascona or cv Radley) as the sole protein source. There was no effect (P>0·05) of the diet, 8 h sampling period or experimental period on the concentration (mM), composition (% and g 16 g N⁻¹) and flow (mmol 24 h⁻¹) of total, protein-bound and free AA or on the percentage of protein-bound AA in pancreatic juice. The concentrations of total, protein-bound and free AA were higher in pancreatic juice collected from younger pigs in Experiment 1 than in pancreatic juice collected from older pigs in Experiment 2. However, the daily flows of total, protein-bound and free AA in pancreatic juice were similar in both experiments. The percentages of protein-bound AA in pancreatic juice were similar in both experiments. In conclusion, the concentrations, compositions and flows of total, protein-bound and free AA in pancreatic juice were not affected by diet, 8 h sampling period or experimental period.     

Response of pancreatic secretions to feeding diets with low and high levels of soybean trypsin inhibitors in growing pigs

Studies were carried out to determine the effect of soybean trypsin inhibitors (SBTI) on exocrine pancreatic secretions in growing pigs. Six barrows with an average initial body weight (BW) of 27·1±1·4 kg were fitted with permanent pancreatic re-entrant cannulas and fed two diets according to a crossover design. Two maize starch-based diets were formulated to contain 200 g kg⁻¹ crude protein from either Nutrisoy (food grade defatted soy flour) or autoclaved Nutrisoy. The concentrations of SBTI in Nutrisoy and autoclaved Nutrisoy diets were 13·4 and 3·0 g kg⁻¹, respectively. The experiment consisted of two periods of 9 days each. The average BW at the start of the first and second experimental periods was 33·5±2·7 and 37·2±3·7 kg, respectively. The average BW at the conclusion of the experiment was 41·8±3·9 kg. The volume of pancreatic secretion was higher (P<0·01) when the Nutrisoy, as opposed to the autoclaved Nutrisoy diet was fed (3804 vs 2634 ml (24 h)⁻¹). The concen-tration of nitrogen and protein and specific activities (units litre⁻¹) of amylase, chymotrypsin and trypsin were lower (P<0·05) in pancreatic juice of pigs fed the Nutrisoy diet. There were no differences (P>0·05) in the total secretions of nitrogen (g (24 h)⁻¹) and total activities (units (24 h)⁻¹) of amylase, lipase, chymotrypsin and trypsin in pancreatic juice of pigs fed the Nutrisoy and autoclaved Nutrisoy diets. However, the total secretion of protein was slightly higher (25·7 vs 22·8 g (24 h)⁻¹; P<0·05) in pancreatic juice of pigs fed the autoclaved Nutrisoy diet, which corresponded with the increase in the secretion of protein-bound amino acids. There was also an increase in the total secretion of free amino acids in pancreatic juice. These studies show no effect of SBTI on the total enzyme activities in pancreatic juice of growing pigs. © 1998 SCI.     

The diurnal pattern of ileal dry matter and endogenous ileal nitrogen flows in the growing pig

The aim was to examine the diurnal pattern of endogenous nitrogen flow at the terminal ileum of the pig. Seven entire male pigs with a mean body weight of 58 kg had post‐valve T‐caecum (PVTC) cannulae surgically implanted for the collection of ileal digesta. The pigs were fed equal‐sized meals (10% of metabolic body weight, W^0.75, per day) twice daily at 08:00 and 17:00. The semi‐synthetic diet included enzyme‐hydrolysed casein (<5000 Da, 100 g kg^?1 diet) as the sole source of nitrogen (N). The diet also contained chromic oxide (6 g kg^?1) as an indigestible marker. The pigs received the diet for an 8 day period, and digesta were continuously collected for 24 h periods (commencing at 08:00) on the fifth and eighth days. Digesta were analysed for dry matter (DM) and chromium (Cr), and endogenous N was determined in the precipitate + retentate fraction of the digesta following centrifugation and ultrafiltration (10 000 Da molecular weight cut‐off). The concentration of Cr expressed on a digesta DM basis and the ratio of endogenous N to Cr in the digesta were relatively constant over the 24 h digesta collection periods, with no statistically significant (P > 0.05) differences found for the latter measure in the digesta collected between 12:00 and 08:00. The endogenous N flow through the terminal ileum is the net effect of the secretion and reabsorption of endogenous N that occurs throughout the digestive tract. The net result of the latter two processes in the small intestine of the pig leads to a relatively constant endogenous N flow over time post‐feeding. © 2002 Society of Chemical Industry     

Amino acid and energy digestibility in peas (pisum sativum) from white-flowered spring cultivars for growing pigs

Six barrows, average initial weight 35 kg, fitted with a simple T-cannula at the distal ileum, were used to determine the apparent ileal digestibilities of amino acids (AA) and the digestibility of energy in six diets according to a 6 x 6 Latin square design. The pigs were fed six corn starch-based diets formulated to contain 165 g CP per kg from six different white-flowered spring pea cultivars. Chromic oxide was used as the digestibility marker. The pigs were fed twice daily, at 08:00 and 20:00 h. Each experimental period lasted 9 days. Faeces were collected from 08:00 on day 6 to 08:00 h on day 8; ileal digesta from 08:00 on day 7 to 08:00 h on day 9. Of the indispensable (+semi-) AA, there were differences (P≤0.05) in the AA digestibilities of arginine, methionine, phenylalanine and tyrosine between the cultivars. In the same order for these AA, the digestibilities ranged from 81.3 to 89.0%, 67.8 to 75.1%, 68.0 to 74.6% and 66.1 to 74.8%, respectively. Within each cultivar, the digestibilities of cysteine and threonine were relatively low, ranging from 58.5 to 65.9% and from 59.6 to 67.4%, respectively. The digestibility of lysine was relatively high, ranging from 80.3 to 84.0%. The energy digestibilities in the pea cultivars ranged from 87.4 to 90.2% (P≤0.05); the digestible energy content from 14.0 to 14.4 MJ kg^-1 DM. There was considerable disappearance of energy in the large intestine, ranging from 4.4 to 6.2 MJ kg^-1 DM intake from peas. In conclusion, when measured with the ileal analysis method, there were differences (P≤0.05) in the digestibilities of some of the indispensable AA between the pea samples. Furthermore, the relatively low digestibilities of methionine and cysteine further accentuate the limitation of the sulphur-containing AA in protein from peas.     

Influence of formaldehyde-treated soybean meal on milk production

Forty-eight Holstein cows were fed one of four diets containing 12.5% crude protein (negative control); 15.5% crude protein with untreated soybean meal; 15.5% crude protein with formaldehyde (.3%)-treated soybean meal; or 18% crude protein (positive control). Diets were 60% concentrate, 22% corn silage, 14% alfalfa hay, and 4% beet pulp (dry matter). Data were collected during the first 200 d of lactation. Dry matter intake, milk, and milk component yields did not differ among cows fed the untreated soybean meal, treated soybean meal, and positive control diets. Cows fed negative control diet consumed less dry matter and produced less milk than cows fed the other diets. Milk protein yield was lower for cows fed the negative control diet compared with the other diets. Nonprotein nitrogen content of milk increased as dietary protein increased.     

Determination of RNA and ATP in the rumen liquid of cows fed with diets differing in forage to concentrate ratio

The effect of dietary composition on the RNA and ATP concentrations in rumen bacteria was determined. Four dry Simmental cows received two diets (H, hay only; C, hay and concentrate) and samples of rumen fluid were taken at three different times during the day. Rumen fluid was analysed for DM, N, pH, VFA, RNA, ATP and total bacterial count. There were no significant differences in RNA concentration whether it was determined in fresh or frozen samples or after having been precipitated overnight. The effect of time of sampling was almost always significant: for pH, ammonia nitrogen, propionic acid, n-butyric acid and total VFA this was particularly evident at 12:00 h in comparison with 08:00 and 16:00 h (P < 0·05). Bacterial DM, total count and ATP content decreased linearly with increasing time from the morning meal (P < 0·01), while the highest RNA content was observed at 12:00 h and the lowest at 16:00 h (P < 0·01). The bacterial content (DM basis) of RNA and the RNA:N, RNA:total count and ATP:N ratios were significantly higher with diet C, while differences for ATP (μg mg^?1 DM), nitrogen (mg per 100 mg DM) and ATP:RNA ratio were not significant. The effect of sampling time was similar for the two diets: the RNA content of bacterial cells increased from 08:00 h to 12:00 h (P < 0·05), while the RNA:N, RNA:total count and ATP:RNA ratios increased from 08:00 to 12:00 h and decreased from 12:00 to 16:00 h. The ATP content had a similar trend to that of RNA, but differences with time were not significant. Although the use of RNA and ATP as bacterial markers has to be considered with some caution, their determination together with rumen parameters, such as pH, VFA and ammonia, could contribute to useful investigations of the anaerobic fermentative process.     

Palm kernel meal as the major protein concentrate in the diets of pigs in the tropics

Three trials were carried out to determine the suitability of locally produced palm kernel meal (PKM) as the major protein concentrate in the diets of weaners, growers and fattening pigs in the tropics. Large White and Large White×Land-race cross barrows and gilts were used. These were individually fed at semi-restricted levels the various diets formulated to contain approximately 15, 12 and 16.5% crude protein for trials 1, 2 and 3 respectively, the PKM or other protein sources contributing at least 50% of the total dietary protein in all the diets. In trial 1, pigs on the PKM diet grew at a lower rate, had poorer feed: gain ratio and protein efficiency ratio and lower feed consumption than the pigs on other diets. Pigs on a fish meal diet (FM) had the best performance throughout. In trial 2, the same trends as for trial 1 were observed, except that pigs on the dried skimmed milk (DSM) diet performed better than those on all other diets. In trial 3, the pigs on the PKM diet supplemented with 10% groundnut cake or 15% DSM had slower growth rate and lower feed:gain ratio than the pigs on other diets containing lower quantities of PKM supplemented with fish meal (FM) or blood meal (BM).     

Acceptability and nitrogen utilisation of Tower and Erglu rapeseed meals by the growing pig.

Acceptability and nitrogen utilisation studies were made with diets containing barley and either extracted soy bean meal (SBM) or one of the two low glucosinolate extracted rapeseed meals Tower (TRSM) and Erglu (ERSM). In acceptability studies SBM, TRSM and ERSM were substituted isometrically at 20% in diets which were offered ad libitum for 8 weeks to pigs of 23 kg initial liveweight. There were four groups of four castrate male pigs, and four groups of four gilt pigs, per group, per diet. For the first 2 weeks intake per unit metabolic weight (W^0.75) was greatest, but thereafter was least, for the SBM diet. In metabolism studies three diets were computed and fed so that 54.5 % of the daily intake of 170 g of crude protein was derived from SBM, TRSM or ERSM. Twelve caged castrate male pigs of 25 kg liveweight were fed on each diet. Apparent digestibility of crude protein was higher for the SBM diet compared with the TRSM (P<0.05) and ERSM (P>0.05) diets. Nitrogen retention decreased significantly from the SBM to the ERSM to the TRSM diets. In an individual feeding growth experiment, using 12 castrate male and 12 gilt pigs per diet, isonitrogenous diets based on SBM, TRSM and ERSM were fed, on a liveweight related basis, between 23 and 67 kg liveweight. The SBM fed pigs grew significantly faster and required significantly less crude protein per unit of gain than those fed TRSM and ERSM, between which there were no significant differences.     

Protein sources evaluated for ruminating Holstein calves

Fifty calves were fed a basal diet of 11.6% crude protein or one of four diets (15.5% crude protein) containing added soybean meal, corn gluten meal, cottonseed meal, or fish meal. Diets were calculated 75% total digestible nutrients. Body weight gain increased an average of 17% with added protein. Fish meal and soybean meal generated highest rates of gain. Ruminal ammonia-nitrogen was higher for soybean meal and cottonseed meal than other diets, indicating greater rates of degradability. Molar proportions of rumen volatile fatty acids were not different among diets, but concentration was lower for fish meal. Serum urea nitrogen was lowest for the basal and fish meal diets. Microbial nitrogen in the abomasum was 33.6% of total nitrogen for corn gluten meal and 42.8% for soybean meal. Apparent dry matter and nitrogen digestibilities were greater for corn gluten meal and fish meal diets than for soybean meal or cottonseed meal diets. Rumen degradability of feedstuffs, as determined by dacron bag technique, ranged from 38.1% for corn gluten meal to 71.3% for soybean meal. Degradability of mixed diets reflected those of the protein supplement present in each diet except for diet containing cottonseed meal. Fish meal and soybean meal were better protein sources for growth of ruminating calves than were corn gluten meal or cottonseed meal.     

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     

Influence of Dietary Protein Concentration and Degradability on Milk Production,Composition, and Ruminal Protein Metabolism

Four groups of cows in early lactation, each group containing one mature cow and three cows in first lactation, were in a 4 × 4 Latin-square arrangement of treatments for us to study influences of altering quantity of undegraded dietary crude protein and quantity of crude protein on milk production and composition. Diets supplemented with protein sources were 1) soybean meal positive control (22.7% crude protein), 2) whole cottonseed-corn gluten meal (14.7% crude protein), 3) extruded whole soybean (14.5% crude protein), or 4) soybean meal supplemented (15.7% crude protein). Concentrate and sorghum silage were fed in a ratio of 62:38 dry matter. Dry matter intake was not influenced by dietary crude protein concentration or source. Cows consuming diet 2 produced less milk, milk protein, total solids, and solids-not-fat than cows receiving diets 1 and 4. Efficiency of conversion of dietary crude protein to milk protein was highest for cows receiving diet 3 and lowest for diet 1.Trial 2, a 4 × 4 Latin-square trial for collection of abomasal digesta, had four ruminal and abomasal cannulated steers and the four diets from the lactation trial; the trial was to determine the influence of source and concentrations of protein on quantity of protein reaching the abomasum daily. Crude protein intake by steers fed diet 1 was greater than for the other three diets. Percentages recovery of dietary crude protein were 122 and 130 for treatments 2 and 3, intermediate for treatment 4 (107%), and lowest for diet 1 (88.0%); crude protein digestibility in the total tract was highest for steers receiving diet 1.     

Replacement of starch from corn with nonforage fiber from distillers grains and soyhulls in diets of lactating dairy cows

Forty Holstein cows were used in a completely randomized design with a 2-wk covariate period followed by a 6-wk experimental period to evaluate incremental substitution of nonforage fiber provided by dried distillers grains with solubles (DDGS) and soyhulls (SH) for starch provided by corn in the diet. Diets provided decreasing concentrations of starch: 29% starch with 0% DDGS; 26% starch with 7% DDGS; 23% starch with 14% DDGS; and 20% starch with 21% DDGS. Diets contained 27% corn silage, 22% alfalfa hay, and 51% concentrate mix and were formulated to be 17% crude protein, 4.7% fat, and 23% neutral detergent fiber from forage. Total neutral detergent fiber increased as DDGS and SH were included in the diet. Soyhulls were included in a linear fashion along with DDGS to replace soybean meal and expeller soybean meal, thereby maintaining a similar crude protein content across diets. Dry matter intake decreased linearly; consequently, feed efficiency tended to increase linearly as starch was replaced by nonforage fiber. There was no effect of diet on milk production or milk fat and protein percentage or yield. Milk fatty acid profiles were similar across diets. Other response variables, including 4% fat-corrected milk, total solids, and milk urea nitrogen, were unaffected by dietary treatments. Ruminal volatile fatty acid concentration did not differ between diets. Concentrations of blood glucose and β-hydroxybutyrate were similar across diets. Results from this research suggest that nonforage fiber from DDGS can partially substitute for starch from corn in dairy cow diets without affecting milk production and milk composition. Economic analysis of the diets showed that feeding DDGS and SH in substitution of corn was cost-effective. Results from this experiment indicate that DDGS and SH can replace corn as an energy source to decrease feed costs.     

Effect of low level monensin supplementation on the production of dairy cows fed alfalfa silage

Effectiveness of low level monensin supplementation on N utilization in lactating dairy cows fed alfalfa silage was assessed using 48 multiparous Holsteins. Cows were fed a covariate diet [% of dry matter (DM): 56% alfalfa silage, 39% ground high moisture corn, 3% soybean meal, 1% ground corn, 1% vitamin-mineral supplements] for 2 wk, then grouped by days in milk into blocks of 4. Cows were randomly assigned within blocks to 1 of 4 diets that were fed for 10 wk: 1) control (covariate diet), 2) control plus 3% fish meal (replacing DM from high moisture corn), 3) monensin (10 mg/kg DM), and 4) monensin plus 3% fish meal. Diets 1 and 3 averaged 16.7% crude protein (25% from free AA in alfalfa silage); diets 2 and 4 averaged 18.5% crude protein. Monensin intake averaged 16 mg/d on diets 1 and 2 (due to contamination) and 248 mg/d on diets 3 and 4. There was no effect of fish meal or monensin on DM intake. However, weight gain and yield of milk, protein, and SNF increased with fish meal feeding, indicating metabolizable protein limited production. Feeding monensin increased blood glucose but reduced yield of 3.5% fat-corrected milk, milk fat content and yield, and milk protein content and yield. Apparent N efficiency was greatest on monensin (diet 3) but lowest on monensin plus fish meal (diet 4). Fish meal reduced blood glucose concentration and apparent N efficiency, and increased concentrations of milk and blood urea. Monensin increased ruminal propionate concentration and decreased concentration of acetate and butyrate and acetate:propionate in ruminally cannulated cows fed the experimental diets. However, these changes were small, suggesting that too little monensin was fed. Fish meal reduced ruminal total amino acid (AA) but monensin did not alter ruminal NH(3) or total AA. Both fish meal and monensin increased NH(3) formation from casein AA using ruminal inoculum from the cannulated cows. There was no evidence from this trial that feeding 250 mg of monensin per day to lactating cows improved N utilization by reducing ruminal catabolism of the large amounts of free AA in alfalfa silage.     

Performance of growing–fattening lambs fed diets containing different proportions of cotton seed meal

A lamb feedlot study was conducted to evaluate the nutritional value of cotton seed meal (CSM) as compared with that of sunflower meal as protein supplements for growing lambs. Forty-five Karagouniko male lambs immediately after weaning, having an average liveweight of approximately 14.7 kg, were assigned randomly to one of three growing lamb rations. CSM substituted for sunflower meal in a growing–finishing feedlot diet at levels of 0, 10 and 20% to provide 0, 50 and 100% of supplemental protein requirement, respectively. Diets were fed ad libitum and water was offered freely. All diets were approximately isonitrogenous and isocaloric. After being fed for 61 days and having reached a liveweight of approximately 27.6 kg, five lambs from each treatment were slaughtered and carcass data were collected. No significant differences (P > 0.05) in feed intake or the weight increase of lambs were found among groups given the 0, 10 and 20% treatments, indicating that lambs utilized CSM as effectively as sunflower meal when fed on an equal crude protein and crude fibre basis. The dressing percentage of the cold carcass, but not the warm carcass, and intestinal content weight were significantly influenced (P < 0.05) by the diet. Cooler shrink and intestinal fat, and perirenal fat and the combined weight of intestinal and perirenal fat were significantly (P < 0.05) correlated. Feeding margin was highest for the control diet, intermediate for the 10% CSM diet and lowest for the 20% CSM diet. It was concluded that CSM is accepted readily by growing sheep and can be incorporated into diets as a source of supplemental protein for growing–fattening lambs. No evidence of gossypol toxicity was noted. © 1999 Society of Chemical Industry     

Tolerance of growing pigs to trypsin and chymotrypsin inhibitors in chickpeas (Cicer arietinum) and pigeonpeas (Cajanus cajan)

The threshold level of growing pigs to trypsin and chymotrypsin inhibitors was investigated by adding graded levels of meals rich in these inhibitors to diets and recording responses. Diets were formulated to contain either 250, 500 or 750 g kg^?1 of Opal chickpea, dehulled Tyson chickpea or dehulled pigeonpea meals and pig response compared to that of pigs given a wheat and soya-bean meal control. Trypsin inhibitor levels (mg g^?1) of the diets were, respectively, control, 0.2; chickpea meal 1, 1.2.32; chickpea meal 2, 1.7–4.7; pigeonpea meal, 1.4–3.6. Chymotrypsin inhibitor levels (mg g^?1) of the diets were, respectively, control, 0.2; chickpea meal 1. 0.9–2.2; chickpea meal 2, 1.6–4.5; pigeonpea meal. 0.8–2.1. The diets were offered ad libitum over the 20–50 kg growth phase. Growth responses of the pigs fed the two chickpea meals were similar to those of the pigs fed the control soya-bean meal diet (P>0.05). In contrast, the addition of pigeonpea meal linearly depressed growth rate (P<0.001), feed intake (P<0.05) and increased the feed conversion ratio (P<0.05), inclusion levels of the chickpea meals had no effect on organ weights, whereas the inclusion of pigeonpea meal significantly affected the weights of the liver and pancreas (P<0.05), indicating the presence of other anti-nutritional factors. The results indicate that the growing pig can tolerate dietary levels of at least 4.7 and 4.5 mg g^?1 of trypsin and chymotrypsin inhibitors, respectively. These threshold levels are unlikely to be exceeded in conventional diets containing the majority of grain legumes. The results also indicate that dehulled pigeonpea meal contains an anti-nutritional factor(s) for growing pigs.     

Effect of rumen-protected lysine supplementation of diets based on corn protein fed to lactating dairy cows

This trial tested whether rumen-protected Lys (RPL) supplementation would improve the nutritive value of rumen-undegradable protein (RUP) from corn protein. Thirty-two lactating Holstein cows were blocked by days in milk and parity into 8 squares of 4 cows each in replicated 4 × 4 Latin squares. Treatments provided all supplemental crude protein from: (1) soy protein (67% expeller soybean meal plus 33% solvent soybean meal); (2) a blend of soy and corn protein (33% expeller soybean meal, 17% solvent soybean meal, 25% corn gluten meal plus 25% distillers dried grains with solubles); (3) corn protein (50% corn gluten meal plus 50% distillers dried grains with solubles); or (4) corn protein plus RPL [diet 3 top-dressed with RPL (125 g/d of AjiPro-L Generation 1, supplying an estimated 20 g of absorbable Lys/d)]. Diets contained (dry matter basis) 22% alfalfa silage, 43% corn silage, 18% ground high-moisture and dry corn, 2.4% mineral-vitamin premix, 1.5 to 3.9% soy hulls, 15% crude protein, 30 to 32% neutral detergent fiber and predicted to contain equal rumen-degradable protein, RUP, and metabolizable protein. Cows within squares were randomly assigned to treatment sequences and fed diets for 4-wk periods before switching; production data and blood samples were collected during last 2 wk of each period. Data were analyzed using the mixed procedures of SAS. Intake was highest on diet 1, intermediate on diets 2 and 3, and lowest on diet 4; body weight gain was highest on diet 3, intermediate on diets 1 and 2 and lowest on diet 4. Intakes and body weight changes were reflected by differences in milk/dry matter intake, which was highest on diets 2 and 4 and lowest on diet 3. Milk yield was lower on diet 3 (44.3 kg/d) than on diets 1, 2, and 4 (average 45.8 kg/d) and protein yield was highest on diets 1 and 2 (average 1.35 kg/d), intermediate on diet 4 (1.30 kg/d), and lowest on diet 3 (1.25 kg/d). No effects of diet were detected on ruminal metabolites. Free nonessential amino acids and total protein AA were elevated in blood plasma on diet 3, reflecting reduced utilization for milk protein synthesis. These results indicated that 50% dilution of soybean meal RUP with that from corn protein did not reduce yield and that supplementing RPL to the corn protein-based diet increased yield 1.1 kg of milk/d and 50 g of true protein/d.     

Evaluation of ruminally protected methionine and lysine or blood meal and fish meal as protein sources for lactating Holsteins.

Forty lactating Holstein cows averaging 55 days in milk were used in a randomized block designed experiment to evaluate the effectiveness of ruminally protected Met and Lys compared with that of ruminally undegradable protein for supporting lactation. Cows were fed total mixed diets for 15 wk. Diets were formulated to be isonitrogenous with the same base ingredients resulting in base crude protein percentage of 15.5. Supplemental crude protein supplied by urea, soybean meal, or a 50:50 (wt/wt) mixture of fish and blood meal increased total dietary nitrogen to 18.0% of diet DM. Two additional diets consisted of the basal diets soybean meal and urea, which were supplemented with ruminally protected DL-Met and Lys-HCL at 10 and 25 g/d, respectively (soybean meal + amino acids (AA), urea + AA). Mean measures of dry matter intake, milk yield, milk protein percentage, and milk fat percentage were not affected by protein supplement. Milk protein yield, milk fat yield, casein yield, and casein percentage also were not affected by source of supplemental protein. Results indicate that at the level of crude protein intake relative to milk production in this experiment, the source of protein did not affect lactational performance.     

Effects of feeding dairy cows protein supplements of varying ruminal degradability

Twenty-five (10 ruminally cannulated) Holstein cows averaging 82 +/- 34 d in milk were assigned to 5 x 5 Latin squares (21-d periods) and fed diets supplemented with one of four different proteins to assess effects on production, ruminal metabolism, omasal flow of N fractions, and degradation rates of protein supplements. Total mixed diets contained (dry matter basis) 44% corn silage, 22% alfalfa silage, 2% urea, and 31% concentrate. Five concentrate mixes were fed: 31% high-moisture shelled corn (HMSC; basal); 9% solvent soybean meal (SSBM), 22% HMSC; 10% expeller soybean meal (ESBM), 21% HMSC; 5.5% blood meal (BM), 25.5% HMSC; and 7% corn gluten meal (CGM), 24% HMSC. Diets averaged, respectively, 15.8, 19.1, 19.7, 20.3, and 19.3% crude protein. Feeding the basal diet reduced intake and yield of milk, fat-corrected milk (FCM), and all milk components compared to the protein-supplemented diets. Milk yield was higher for cows fed ESBM and CGM, fat yield was higher for cows fed SSBM and CGM, but FCM and protein yields were not different among cows fed supplemental protein. Based on omasal sampling, mean in vivo estimates of ruminal degradation rate for the crude protein in SSBM, ESBM, BM, and CGM was, respectively, 0.417, 0.179, 0.098, and 0.051/h (computed using passage rates observed for the small particle phase; mean = 0.14/h), and 0.179, 0.077, 0.042, and 0.026/h (computed using a passage rate of 0.06/h). The in vivo degradation rate computed for SSBM at a passage rate = 0.06/h was similar to that estimated using the inhibitor in vitro method. However, in vivo degradation rates computed at passage rate = 0.06/h for ESBM, BM, and CGM were about two, four, and three times more rapid than those estimated by inhibitor in vitro. Experimental proteins fed in this trial will be used as standards for developing in vitro methods for predicting rates of ruminal protein degradation.