Degradable Intake Protein Research Articles

Effects of various supplemental starch and protein levels on ruminal fermentation and liquid passage of beef steers fed tallgrass-prairie hay (1997)

The effect of supplements containing various proportions of degradable intake protein (DIP) and starch on ruminal digestion characteristics of forage-fed beef steers was evaluated. Fluid passage rates, ruminal ammonia (N H), 3 and total volatile fatty acid (VFA) concentrations increased as the amount of supplemental DIP increased. Starch infused at .3% of BW increased molar proportion s of propionate and butyrate and decreased acetate, compared to feeding DIP alone. However, proportions of branched-chain VFA increased with DIP at all levels of starch infusion. Total digestible organic matter intake (TDOMI) was increased with each addition of DIP; however, infusing starch within a DIP level decreased TDOMI. Providing supplemental DIP is more important for improving the use of low-quality, tallgrass-prairie hay than is ruminally available starch.

Effect of urea level in protein supplements on performance by beef cows consuming low-quality, tallgrass-prairie forage (1997)

One hundred thirty two Hereford x Angus cows grazing tallgrass-prairie range during winter were used to evaluate the effects of varying the amount of supplemental degradable intake protein (DIP) derived from urea on cow and calf performance. Treatment groups were: 0, 15, 30, and 45% of the supplemental DIP from urea. Supplements were formulated to contain 30% crude protein (CP), with approximately 70% of the CP being DIP. Palatability was not a significant problem within the range of urea inclusion tested. In general, prepartum weight and condition losses were greater with increasing levels of urea, although the magnitude of condition loss was greater when urea comprised more than 30% of the DIP. Calf performance was not affected by treatment.

Evaluation of the effects of carbohydrate source and level of degradable intake protein on the intake and digestion of tallgrass-prairie hay by beef steers (1997)

Thirteen ruminally fistulated steers were used to determine the effect of carbohydrate (CHO) source and degradable intake protein (DIP) on intake and digestion of tallgrass-prairie hay. In general, DIP supplementation had positive effects on intake and digestion, although response varied somewhat with CHO source. Increasing the amount of supplemental CHO generally decreased hay intake, but effects on digestion were dependent on CHO source.

Effect of increasing proportion of supplemental nitrogen from urea on intake and utilization of low-quality, tallgrass-prairie forage by beef steers.

Five Angus x Hereford steers with ruminal and duodenal fistulas were used in a 5 x 5 Latin square to determine effects of increasing the proportion of urea in supplemental degradable intake protein (DIP) on intake, fermentation, and digestion. Steers had ad libitum access to low-quality, tallgrass-prairie forage (2.4% CP, 76% NDF). Supplemental DIP (380 g/d) was from sodium caseinate and(or) urea and was balanced with cornstarch to provide a final supplement (approximately 939 g DM/d) that contained 40% CP. The percentages of supplemental DIP from urea were 0, 25, 50, 75, and 100%. Intake of forage OM was not affected (P > or = .30) by urea level. Ruminal and total tract digestibilities of OM and NDF generally responded in a quadratic manner (P < or = .09) to increasing urea, with the lowest values observed at the highest urea level. As a result, digestible OM intake (DOMI) declined (linear, P = .03) with increasing proportions of urea and tended (quadratic, P = .14) to exhibit the largest proportional decline at the highest urea level. The effects of increasing urea on duodenal N flow, microbial efficiency, ruminal contents, and fluid dilution rate were minimal. Ruminal ammonia N and molar percent acetate increased linearly (P < or = .02), whereas most other VFA (except propionate) decreased (P < or = .05) with increasing urea. In conclusion, although forage OM intake was not altered, OM digestion, NDF digestion, and DOMI were lowest when all supplemental DIP was supplied as urea. Changes in fermentation characteristics reflected the change in source of available nitrogen.

Effects of supplemental degradable intake protein on intake and digestibility of forage sorghum hay (1997)

Effects of supplemental degradable intake protein on intake and digestibility of forage sorghum hay (1997)

Effect of Type of Supplemental Nutrient on Grass Silage Utilization by Sheep

ABSTRACT In order to determine whether energy, ruminally degradable intake protein, ruminally undegradable intake protein, or quality of undegradable intake protein limit utilization of nutrients in young ruminants consuming grass silage (12% crude protein, CP; 56% neutral detergent fiber), two nitrogen balance experiments were conducted as replicated 4 × 4 Latin squares with 16 ewe lambs (average body weight 37 ± 2 kg). In Experiment 1, lambs were supplemented with either: control, minerals only (C); 264 g of dry matter (DM) as barley (B); 70 g of DM as soybean meal (S); or 70 g of DM as heated soybean meal (H). In Experiment 2, lambs were supplemented with either C; H; 67 g of DM as H with 15% Menhaden fish meal (H15); or 64 g of DM as H with 30% Menhaden fish meal (H30). All supplements (except C) were offered in isonitrogenous amounts. In Experiment 1, daily intakes of total DM and digestible DM were greatest for B (1,859 and 1,289 g) and lowest for C (1,612 and 1,091 g). In both experiments, percentage of CP digested and retained were lowest for C (55 and 24%, respectively). Retention of CP was greatest for B (30%) in Experiment 1 and greatest for H30 in Experiment 2 (32%). In Experiment 2, retention of CP increased linearly, whereas urinary loss of CP decreased linearly with addition of fish meal to H (among H, H15, H30). Results of Experiment I indicate supplementation of B can most efficiently improve energy intake plus be effective at improving utilization of CP. Results from Experiment 2 suggest that as the quality of undegraded intake protein increases, the efficiency of its use increases.

Strategies of feeding supplemental soybean meal to primiparous dairy cows

Primiparous dairy cows were utilized in two experiments to evaluate the productive benefits of modifying the strategy of within-day feeding of soybean meal (SBM) as a supplement to a basal mixed ration fed twice daily. The design of the two experiments was the same, although one was completed with early-lactation cows and the other with late-lactation cows. The evaluation of protein status of all treatments, after the experiments were complete, indicated that cows were limited by supplies of digestible undegraded intake protein (DUIP) on all treatments of both experiments. However, benefits of feeding 800 g d−1 of supplemental SBM versus none were primarily restricted to enhanced production of milk protein, and it is suggested that this was primarily the result of the contribution of DUIP from SBM to intestinal protein supply. Feeding SBM in two versus four daily meals either 1 or 1 and 5 h, respectively, after offer of the mixed ration had no influence on animal performance at either stage of lactation. However, feeding SBM in two daily meals 1 h prior to the mixed ration versus in two daily meals 1 h after offer of the mixed ration enhanced milk, milk energy, and milk lactose output in late lactation, but not in early lactation. These apparently inconsistent production responses between stages of lactation are consistent with a hypothesis that microbial growth is progressively restricted as supplies of degraded intake protein (DIP), relative to requirements, decline. Under these conditions, which applied to the late-lactation cows, feeding DIP at times of the day when rumen-soluble N levels would be lowest (i.e., pre-feeding) would be beneficial for stimulating microbial growth prior to ingestion of the mixed ration. Key words: Management, strategy, sequence, dairy cattle

The influence of various levels of supplemental starch and degradable intake protein on prairie hay intake and digestion by beef steers (1996)

A study was conducted to determine the effect of varying the amount of supplemental degradable intake protein (DIP) and starch on prairie hay intake and digestibility. In general, DIP increased forage intake, whereas starch decreased intake. Diet digestibility also improved with increasing DIP; however, the effect of starch on digestion depended on the level of feeding. Digestible dry matter intake (which estimates total energy input) r esponded dramatically to DIP but not to starch. These results illustrate the positive effect of DIP on forage intake and digestibility; however, supplying additional starch within a DIP level appeared to have minimal effect on altering total energy supply.

Effect of increasing degradable intake protein on intake and digestion of low-quality, tallgrass-prairie forage by beef cows.

Five ruminally and duodenally fistulated Angus x Hereford cows were used in a 5 x 5 Latin square to monitor intake, ruminal fermentation responses, and site and extent of digestion associated with providing increasing amounts of supplemental degradable intake protein (DIP). Cows had ad libitum access to low-quality, tallgrass-prairie forage (1.9% CP, 77% NDF) that was fed twice daily. The supplemental DIP (sodium caseinate; 90% CP) was infused intraruminally at 0630 and 1830 immediately before feeding forage. Levels of DIP were 0, 180, 360, 540, and 720 g/d. Each period consisted of 14 d of adaptation and 6 d of sampling. Forage OM intake increased quadratically (P < .01) with increasing supplemental DIP reaching a peak at the 540 g/d level. True ruminal OM and NDF digestion increased with the addition of 180 g/d supplemental DIP, but exhibited only moderate and somewhat variable responses when greater amounts of supplemental DIP were infused (cubic, P < or = .03). Microbial N flow and efficiency increased linearly (P < .01) with increasing supplemental DIP. However, a quadratic effect (P < .01) was observed for total duodenal N flow, which was maximized at 540 g/d supplemental DIP. A linear (P = .02) treatment effect was observed for ruminal fluid dilution rate. Total ruminal VFA and ammonia concentrations increased (P < .01) in response to DIP supplementation. In conclusion, increasing supplemental DIP generally improved forage utilization; intake of digestible OM was maximized when it contained approximately 11% DIP.

Assessing nutrient composition and digestibility of tallgrass-prairie hay (1996)

Thirteen steers were used in a 4 13 incomplete Latin square to determine chemical composition and digestibility for 13 samples of tallgrass prairie hay. Hays were collected from a variety of locations in east-central Kansas and represented a wide array of harvest dates and storage conditions. Steers were fed prairie hay and soybean meal at 1.5% and .2% of body weight, respectively, to equalize intakes relative to body weight and prevent degradable intake protein (DIP) from limiting extent of digestion. Prairie hay samples were analyze d for N, ADIN, ADF, NDF, ADIA, monosaccharides (sugars), and alkali-labile phenolic acids (lignin components). The relationships of various forage chemical components to diet organic matter digestibility (OMD) were examined using simple, linear regression. There was a close relationship between OMD and ADF (r 2 = .62; OMD = .822 [ADF] + 96.47). In addition, the ratio of xylose:glucose (r2 = .62; OMD = 41.93[X:G] + 94.14) explained significant amounts of the variation in OMD. Defining the chemical composition of bluestem hay may be of value in predicting organic matter digestibility and, ultimately, energetic value.

Comparison of microbial fermentation in the rumen of dairy cows and dual flow continuous culture

Four ruminal and duodenal cannulated lactating dairy cows and four dual flow continuous culture fermenters were used in a replicated 4 × 4 Latin square to compare fermentation and microbial ecology of in vivo and in vitro systems. Diets contained 32% maize silage, 19.8% alfalfa-grass hay, and 48.2% concentrate, and were arranged in a 2 × 2 factorial with two levels of non-fibrous carbohydrate (40%, 25%) and two levels of ruminally degradable intake protein (12%, 9%). Concentrations of viable bacteria were greater ( P = 0.01) in vitro compared with in vivo, averaging 5.04 × 10 9 and 2.75 × 10 9 cells per ml, respectively. Cellulolytic bacterial concentrations (cells per ml) were lower ( P = 0.04) in vitro (4.09 × 10 7) compared with in vivo (6.15 × 10 7), but concentrations of proteolytic and amylolytic bacteria were similar ( P > 0.1). Protozoal concentrations (cells per ml) were greater ( P = 0.0001) in vivo (3.72 × 10 5) compared with in vitro (2.8). Digestion of neutral detergent fiber (NDF) and total non-structural carbohydrate (TNC) exhibited square × NFC interactions ( P < 0.002), and comparison of these interaction means revealed that the difference in NDF and TNC digestion between ruminal and in vitro fermentations occurred only for the 40% NFC diets. Mean TNC digestion was 87.6, 61.7, 60.9, and 60.4% whereas NDF digestion was 33.8, 55.9, 57.6, and 58.4% for the in vitro-40% NFC, in vitro-25% NFC, in vivo-25% NFC, and in vivo-40% NFC treatments, respectively. These data suggest that the continuous culture system had difficulty simulating digestion of high TNC diets. Other differences between fermentation in continuous culture and in vivo can be attributed mainly to lack of absorption from the fermenters, defaunation of the in vitro system, and endogenous protein contamination in vivo.

Comparison of microbial fermentation in the rumen of dairy cows and dual flow continuous culture

Four ruminal and duodenal cannulated lactating dairy cows and four dual flow continuous culture fermenters were used in a replicated 4 × 4 Latin square to compare fermentation and microbial ecology of in vivo and in vitro systems. Diets contained 32% maize silage, 19.8% alfalfa-grass hay, and 48.2% concentrate, and were arranged in a 2 × 2 factorial with two levels of non-fibrous carbohydrate (40%, 25%) and two levels of ruminally degradable intake protein (12%, 9%). Concentrations of viable bacteria were greater ( P = 0.01) in vitro compared with in vivo, averaging 5.04 × 10 9 and 2.75 × 10 9 cells per ml, respectively. Cellulolytic bacterial concentrations (cells per ml) were lower ( P = 0.04) in vitro (4.09 × 10 7 ) compared with in vivo (6.15 × 10 7 ), but concentrations of proteolytic and amylolytic bacteria were similar ( P > 0.1). Protozoal concentrations (cells per ml) were greater ( P = 0.0001) in vivo (3.72 × 10 5 ) compared with in vitro (2.8). Digestion of neutral detergent fiber (NDF) and total non-structural carbohydrate (TNC) exhibited square × NFC interactions ( P < 0.002), and comparison of these interaction means revealed that the difference in NDF and TNC digestion between ruminal and in vitro fermentations occurred only for the 40% NFC diets. Mean TNC digestion was 87.6, 61.7, 60.9, and 60.4% whereas NDF digestion was 33.8, 55.9, 57.6, and 58.4% for the in vitro-40% NFC, in vitro-25% NFC, in vivo-25% NFC, and in vivo-40% NFC treatments, respectively. These data suggest that the continuous culture system had difficulty simulating digestion of high TNC diets. Other differences between fermentation in continuous culture and in vivo can be attributed mainly to lack of absorption from the fermenters, defaunation of the in vitro system, and endogenous protein contamination in vivo.

Influence of degradable intake protein on site and extent of digestion in beef cows consuming low-quality, tallgrass-prairie forage (1995)

Five Angus x Hereford cow s with ruminal and duodenal fistulas were used to evaluate the effect of providing increasing degradable intake protein (DIP) o n the site and extent of digestion of dormant, tallgrass-prairie forage. The DIP was provided from sodium caseinate, divided in two equal portions and infused intraruminally twice daily. Levels of DIP were: 0, 180, 360, 540, and 720 g/day. Supplemental DIP generally improved utilization of low quality forage, with maximum effects on duodenal N flow and forage organic matter intake at 540 g DIP/day.

Influence of increasing proportion of supplemental nitrogen from urea on intake and fermentation characteristics in beef steers consuming low-quality, tallgrass-prairie forage (1995)

Five ruminally and duodenally fistulated Angus x Hereford steers were used to determine intake and fermentation responses associated with increasing the proportion of supplemental degradable intake protein (DIP) provided by urea. Steers had free access to a dormant, tallgrass-prairie forage. The supplemental DIP was provided by sodium caseinate and (or) urea , at a level that was determined previously to optimize use of a similar forage. Supplemental DIP was balanced with corn starch to provide a final supplement of 40% crude protein. Percentages of DIP from urea were: 0, 25, 50, 75, and 100%. Supplements were given intraruminally. Increasing the percentage of urea as supplemental DIP from urea did not significantly affect forage DM intake; however, fermentation characteristics changed.

Response of pregnant beef cows to undegradable intake protein fed in excess of the degradable intake protein requirement (1995)

Two concurrent experiments were conducted to evaluate the effect on performance and forage intake of increasing the supply of undegradable intake protein (UIP) to pregnant beef cows already receiving sufficient degradable intake protein (DIP) to maximize forage intake. Three supplements were fed at .34% BW/day, providing .092% B W/day of DIP (level determined in previous study to maximize forage intake) and .042, .059, and .077% BW/day of UIP (low , moderate, and high UIP, respectively) . In study 1, ad libitum tallgrassprairie forage intake was measured daily from 12/1/93 to 2/10/9 4 using 18 pregnant Angus x Hereford cows. Forage intake steadily increased throughout the study, but did not vary between supplements for the first 6 weeks. However , forage intake was less during the last 4 weeks for cows offered the moderate and high UIP supplements. In study 2, 117 pregnant Angus x Hereford cows grazing dormant bluestem range were used to determine the impact of the supplements on body weight and body condition changes. Level of UIP in the supplement exerted only minimal effects on cumulative or 28-day interval changes in body weight or condition.

Influence of non-fibrous carbohydrate and degradable intake protein on fermentation by ruminal microorganisms in continuous culture.

Four continuous culture fermenters were used in a 4 x 4 Latin square design to evaluate the effects of dietary non-fibrous carbohydrate (NFC) and ruminally degradable intake protein (DIP) on fermentation by ruminal microorganisms. Four diets, arranged in a 2 x 2 factorial, were formulated to contain either 25 or 40% NFC and 50 or 70% of dietary CP as DIP. Dietary DM contained 32% corn silage, 20% alfalfa-grass hay, and 48% concentrate. Solvent-extracted or lignosulfonate-treated soybean meal were used to alter DIP and contributed 40% of dietary CP. Corn or soybean hulls were included at 28% of dietary DM to alter NFC levels. Percentage of true OM digestion was similar (P > .05) among diets but NDF and total nonstructural carbohydrate digestion were inversely related depending on NFC content of the diet. Amylolytic bacterial concentrations (cells/milliliter) were lower (P = .03) in fermenters supplied with 25% NFC diets, resulting in less (P = .0001) total nonstructural carbohydrate digestion. Cellulolytic concentrations were similar (P > .05) among diets despite an increase (P = .002) in NDF digestion with 25% NFC diets. Total viable bacterial concentrations tended to decrease (P = .11) with 50% DIP diets, inducing a decline (P = .03) in total VFA production (millimoles/day). Reduced degradation of CP in 50% DIP diets (P = .008) increased outflow of total amino acid (P = .07) and individual outflows (P < .05) of glutamic acid, aspartic acid, arginine, histidine, and lysine. Few interactions occurred for the parameters measured despite the controlled nature of the fermentation in the current experiment. The preponderance of significant main effects illustrates that ruminal fermentation may not be improved by synchronization of energy and N release but may more likely be limited by either energy or N alone.

Lack of Response to Addition of Degradable Protein to a Low Protein Diet Fed to Midlactation Dairy Cows

Midlactation Holstein cows (n = 24, 12 primiparous) were subjected to four dietary treatments arranged in six Latin squares. Cows were assigned to squares according to parity and previous production within parity. Diets contained 53 to 55% DM from corn silage, and the remaining DM was from concentrates. The basal diet contained 13.9% CP with 9.5% rumen-degraded and 4.4% undegraded intake protein. Three other treatments were formulated to give one diet with more degradable true protein than the basal (11.9% degraded intake protein, 4.3% undegraded intake protein); another with urea added to the basal (12.2% degraded intake protein, 4.5% undegraded intake protein); and a third with additional undegraded protein added to the basal (8.3% degraded intake protein, 7.2% undegraded intake protein). Milk fat and protein concentration were unaffected by diet in all squares. Only the highest producing cows responded significantly to increased undegraded intake protein; milk production was 30.8, 30.9, 31.6, and 33.2 kg/d for basal, added degradable true protein, added urea, and added undegraded protein, respectively. Corresponding protein productions were 913, 929, 927, and 1004 g/d for these cows. Neither degradable true protein nor degradable N increased milk production in the highest producing cows, suggesting that microbial protein production was not limited by the amount of degradable protein in the basal diet. For midlactation, multiparous, and primiparous cows producing <30 and 25kg of milk/d, respectively, the protein content of the basal ration appeared to be adequate.

Protein-Fat Bypass Supplement for Lactating Dairy Cows

Holstein cows (n = 46) were fed free choice a silage mixture balanced weekly throughout lactation using 13 and 36% CP grains to individualize CP for each cow; grains contained 15 and 20% of distillers grains with solubles, respectively. Cows were blocked by parity (1 vs. >1) and assigned at calving to receive a commercial bypass protein-fat supplement at 0 (control) or 6% of weekly projected 4% FCM yield throughout lactation. In peak lactation, supplementation raised dietary fat from 4.3 to 6.0% of DM, NEL from 1.64 to 1.70 Mcal/kg of DM, and undegradable protein from 42 to 47% of CP and contributed about 25 and 20% of total CP in early and late lactation. Supplement reduced forage and total DMI significantly, which negated the potential nutritional value of the supplement. Reduction in protein content of milk from supplemented cows was small but significant; BW and yields of milk, SCM, and 4% FCM were not significantly affected by treatment. Supplementation increased fat test in parity 1 cows and lowered it in older cows. In wk 5 to 8, 21 to 24, and 37 to 40 postpartum, cows consumed 100 to 116% of the NRC recommendations of undegradable protein but only 65 to 94% of degradable CP needs; NEL intake generally was adequate except for primiparous cows in early lactation. Supplementation lowered Lys intake in early lactation. Addition of rumen-protected fat and undegradable, high quality protein mixture to the diet of lactating cows cannot be effective if its use reduces DMI or if degradable protein intake is inadequate.

Alterations of pH in response to increased dietary protein in cattle are unique to the uterus.

This study was undertaken with two objectives: 1) to determine whether the effect of excess dietary protein on intrauterine pH in cattle is specific to the uterus or manifested in other bodily fluids and 2) to determine whether the effect of excess ruminally degradable protein on uterine pH can be ameliorated by substitution with a less-degradable protein source. Thirty-six Holstein cows in early lactation were fed isoenergetic total mixed rations that either 1) met undegradable intake protein (UIP) and degradable intake protein (DIP) requirements (Balanced), 2) met DIP requirements and exceeded UIP requirements by 25% (High UIP), or 3) met UIP requirements and exceeded DIP requirements by 25% (High DIP). After diets had been fed > or = 2 wk, uterine, blood, salivary, and urinary pH and plasma urea nitrogen were determined at estrus (d 0) and d 7. Plasma urea nitrogen (mg/dL) was not different between estrus and d 7 but was significantly affected by diet (Balanced, 16.1 +/- 2.3; High UIP, 19.2 +/- 1.6; High DIP, 22.3 +/- 2.6; P < .05). There was no effect of treatment on the pH of any fluid measured at estrus: intrauterine, blood, salivary, and urinary pH averaged 6.84 +/- .05, 7.39 +/- .01, 8.30 +/- .05, and 8.15 +/- .05, respectively. In contrast, on d 7, uterine pH was significantly lower in both high-protein groups, regardless of protein degradability (Balanced, 7.13 +/- .05; UIP, 6.95 +/- .04; DIP, 6.85 +/- .05; P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Corn or alfalfa as the forage source in predominantly silage diets for late-lactation dairy cows

Twelve multiparous and three primiparous cows were used in a 10-wk lactation study with two repeated measures to evaluate diets containing 90% timothy–alfalfa silage (TA), 84% corn silage (CS) or an equal mixture of each (TA–CS). Each diet was supplemented with minerals to meet requirements; barley was used as a carrier. Diets CS and TA–CS were also supplemented with urea, casein and soybean meal, making them similar to TA for undegraded intake protein (UIP) and degraded intake protein (DIP) levels. Two of the cows on each treatment were fitted with a ruminal cannula. There were no treatment effects on intake (27 g DM kg−1 BW), body-weight change or body-condition score. Milk yield averaged 15.3 kg d−1 and was not treatment influenced (P &gt; 0.05); however, yield of fat and protein and percentage of lactose in milk showed a linear response to increased corn silage in the diet (P &lt; 0.05). Rumen pH was least and rumen ammonia concentration greatest in the mixed silage diet (P &lt; 0.05). Rumen pool sizes of organic matter and neutral detergent fiber were not treatment influenced (P &gt; 0.05). All treatments supported modest levels of production for cows in late lactation, with increasing dietary energy density from corn silage increasing energy output in milk. Key words: Dairy cow, silage diets, forage species, milk production