Sudangrass Hay Research Articles

Effect of propylene glycol and undegradable protein source on rumen fermentation, blood metabolism and milk production in lactating dairy cows

Eight lactating Holstein cows were divided into two groups (n = 4) and used in a double reversal trial with three periods of 14 days each, to evaluate diets containing propylene glycol (PG) and ruminally undegradable protein (RUP) blend on milk yield and composition, ruminal fermentation and blood metabolism. The control diet contained 20% chopped Sudangrass hay, 20% cubed alfalfa hay, 12% corn silage, and 48% of the respective concentrate mixtures (dry matter basis). The experimental diet (PG + RUP) partially replaced the concentrate mixture from the control diet with 1.4% PG and 2.1% RUP. Both diets contained about 16% crude protein and 71% total digestible nutrients. Dry matter intake was similar between the two diets. Daily production of milk, milk lactose and milk solids-not-fat increased by 9.0%, 11.3% and 9.3%, respectively (P < 0.1), for cows fed diets with PG + RUP; milk composition was unchanged. Although the concentration of ruminal total volatile fatty acids was unchanged, the proportion of propionic acid increased, and the proportion of acetic acid decreased with PG + RUP. The concentration of ruminal ammonia nitrogen and number of ciliate protozoa was not significantly affected by PG + RUP. The concentration of glucose in blood plasma increased, the concentration of urea nitrogen was unaffected, and the concentration of some essential free amino acids decreased with PG + RUP. It is suggested that these changes might be caused predominantly by PG, and the addition of PG may exert a favorable effect on milk production through increased metabolism.

Effects of varying levels of undegradable intake protein on endocrine and metabolic function of young post-partum beef cows

Twelve Hereford×Angus heifers, 2.5 year, 492±17 kg (BCS=5±0.5), were randomly assigned to one of three supplements, stratified by calving date and calf sex. Treatments consisted of a daily equivalent of: (1) low undegradable intake protein (UIP) (L: 908 g per cow per day; 36% CP, 108 g UIP), (2) middle UIP (M: 908 g per cow per day; 36% CP, 165 g UIP), and (3) high UIP (H: 908 g M+243 g feather meal per cow per day; 46% CP, 335 g UIP). Cows were fed sudan grass hay (7.3% CP, as fed) daily at 2% BW (as fed). Supplement was individually fed twice weekly from Week 2 to Week 11 post-partum. Cow body weight (BW), backfat (BF) and rumpfat (RF) thicknesses decreased in all cows, ( P<0.05) yet did not differ among treatments ( P>0.10). There were no differences among treatments in calf BW ( P>0.10). Serum insulin, blood urea nitrogen (BUN), milk components and yield did not differ among treatments ( P>0.10). Area under the curve (AUC) for serum LH was greater ( P=0.07) in H versus L and M (809 versus 599 and 607±69 U, respectively). No differences were observed in FSH AUC or mean serum concentrations ( P>0.10). Uterine pH did not differ among treatments or between supplement versus non-supplement days ( P>0.10). Serum progesterone remained below 1 ng/ml for all cows indicating absence of return to estrus. Under the conditions of this study, BW, BF, RF, serum insulin, BUN, milk components, and yield, uterine pH and serum FSH were not affected by level of UIP. However, supplement containing high levels of UIP enhanced GnRH-induced LH release.

Regional cotton lint yield, ET c and water value in Arizona and California

Water value as agriculture production may be overlooked, though it is an important factor to rational water allocations within a region. An analysis of cotton (Upland and Pima) lint yield, lint yield-consumptive use ratio (LY:ET c), water-use efficiency (WUE) and lint price for Arizona (AZ) and California (CA) during 1988–1999 is considered as part of an attempt to determine lint water value, or benefit. It included determination of means and variability of cotton lint production, LY:ET c ratios and associated irrigation water values (IWVs) and compared these numbers with published estimates of WUE, forage hay water values and municipal water costs. Available rainfall, reference evapotranspiration (ET o), lint yields and price data for counties in both states were used. Consumptive use was estimated using a four-stage crop coefficient function verified by literature values or County Advisor experience. As with dry matter production, cotton lint yields in interior valley regions of CA were weakly correlated with ET c and averaged 1.33 Mg/ha (Upland) and 1.08 Mg/ha (Pima). Cotton lint yields in desert regions of AZ and CA were not correlated with ET c. The greatest LY:ET c ratios (1.9–2.1 kg/ha-mm) were in the San Joaquin valley of CA, were similar to that from WUE type studies and resulted in gross IWVs (∼3400–3800 US$/ha-m), with relatively moderate variability at a net irrigation water requirement (IWR) of approximately 720 mm. While this IWV is 2.5 times greater than water delivery prices below the California Delta, it is less than average municipal water costs of ∼4200 US$/ha-m for Los Angeles, San Francisco and Pheonix while the overall AZ/CA average cotton lint IWV is considerably less. However, cotton lint IWV is two to three times greater than that obtained for alfalfa and sudangrass hay crops in all regions.

Reduced-Runoff Irrigation of Sudan Grass Hay, Imperial Valley, California

Sudan grass is a moderately salt-tolerant annual that is capable of substantial osmotic adjustment under high soil salinity conditions, but little is documented about its actual water use and yield under saline conditions. We estimate water use and evaluate the effects of “reduced-runoff” irrigation on soil salinity associated with Sudan grass hay production during a three-year field study (1996–98) in the Imperial Valley, California. The reduced-runoff irrigation method relies on the application of a simplified volume-balance surface irrigation model, and can result in negligible surface runoff; however, its use may have adverse impacts on soil salinity. Despite an anticipated salinity-induced yield reduction of about 15% associated with an average soil salinity of 6 dS/m (0–0.6 m depth), use of the reduced-runoff method resulted in satisfactory crop yields, practically no tailwater runoff, and a slight decrease from the initial average profile soil salinity. The average applied water depth and estimated...

Sudangrass uses water at rates similar to alfalfa, depending on location

Although sudangrass hay is the second largest forage crop (next to alfalfa), grown south of Sacramento and its planted area has quadrupled in the past decade, little information is available about its water use or relative water value. We would expect the sudangrass yield-water use relationship to be similar to that of alfalfa. Limited data suggest that under moderate soil salinity conditions in the Imperial Valley, sudangrass water-use efficiency (WUE–-the ratio of hay yield to water used) approximates the low end of measured alfalfa WUE. However, when we account for an estimated salinity-induced yield loss of 15% in the Imperial Valley, sudangrass WUE approximates the high end of measured alfalfa WUE. In order to better characterize the relationship between water use and crop production, as well as develop information about the relative water value associated with sudangrass-hay production, we compared hay yields and prices with estimated crop water use from 1988 to 1999 in Merced and Stanislaus, Riverside and San Bernardino, and Imperial counties. Linear regression analysis between yield and crop water use from the five-county dataset resulted in different WUE values depending on whether or not the Imperial Valley data was included. Variability in the crop-yield-to-water-use ratio from year to year was greatest in Imperial County and least in Merced and Stanislaus counties, while irrigation-water values (not including production costs) for sudangrass hay were lowest with the greatest variability in the northern counties.

Effects of an Estradiol Implant on Locoweed Consumption, Toxicity, and Recovery in Growing Beef Steers11This research was supported by funds from the New Mexico Agricultural Experiment Station and Grant #ARS 58-5428-6-122 from the USDA.

<h2>Abstract</h2> Two experiments were conducted to determine effects of an estradiol implant (Compudose®) on locoweed consumption and toxicity in growing steers. In Exp. 1, 16 crossbred steers (185.3 ± 6.1 kg) were randomly assigned to two replicated treatments and received either an estradiol implant or no implant. Steers were assigned to one of four pastures and were rotated through all pastures, which differed in locoweed distribution, to allow equal access. Bite counts were recorded twice daily at 0600 and 1700h during a period when steers were likely to consume locoweed. For bite counts, steers were observed for 5min each, starting at 0600 and at 1700 h, and the number of bites taken of cool- and warm-season grasses, forbs, and locoweed were recorded. Blood was collected on d 0, 7, 28, 35, 63, and 119, and individual BW was recorded on d 0, 35, 63, and 119. Proportion of bites of locoweed consumed by implanted vs nonimplanted steers did not differ (P>0.10). Likewise, ADG, serum alkaline phosphatase activity, and thyroxine concentrations did not differ (P>0.10) between implanted and nonimplanted steers. In Exp. 2, 20 crossbred steers (212.3 ± 6.1 kg) were divided into four groups and individually fed in a 2 × 2 factorial arrangement of treatments. Treatments included: 1) estradiol implant + locoweed, 2) implant, no locoweed, 3) no implant + locoweed, and 4) no implant, no locoweed. Steers were implanted at d 0 and fed either a ground forage diet containing 80% sudangrass hay and 20% locoweed, or a diet of 100% sudangrass hay. Implanted steers had improved ADG vs nonimplanted steers (P<0.10) through 63 d on trial, but no differences were observed in steers fed locoweed vs sudangrass hay diets (P>0.90; locoweed x implant, P>0.10). Alkaline phosphatase activity was greater (P<0.05) for steers fed locoweed vs those not receiving locoweed on d 7, 14, and 21, whereas, thyroxine concentration was lower (P<0.06) in steers fed locoweed than those not fed locoweed on d 14 and 21. Estradiol concentrations were greater in implanted steers vs those not implanted (P<0.05). These results suggest no effect of an estrogen implant on locoweed consumption or on severity of locoweed toxicity by beef steers.

Factors affecting water balance and fecal moisture content in suckling calves given dry feed.

Holstein bull calves were used to examine factors affecting water balance and fecal moisture content in suckling calves given dry feed for 2 wk from 1 wk of age. In Experiment 1 (n = 16), the shift of water balance (decreased urine volume, and increased water retention and fecal water excretion) and elevation of fecal moisture content were greatest when calf starter and Sudangrass hay were fed in addition to liquid milk replacer, compared with calves receiving only milk replacer. Intermediate changes occurred when calves were fed milk replacer and calf starter or milk replacer, calf starter, and rice straw. Water retention was correlated positively with digestible DMI and negatively with urine volume. Fecal water excretion was highly correlated with fecal DM excretion. In Experiment 2 (n = 18), water balance and fecal moisture content during wk 2 were affected by free access to calf starter and hay from wk 1. Urine volume of calves fed dry feed and milk replacer was lower than that of calves fed only milk replacer; however, when water was available in addition to dry feed, urine volume was similar to that of calves fed only milk replacer. Fecal water excretion was highly correlated with water retention rather than with fecal DM excretion, suggesting a close relationship to extracellular fluid volume. Ruminal fermentation would be an important factor affecting both water balance and fecal moisture content in suckling calves given dry feed.

Effect of Solid Feed on Water Balance in Suckling Calves Given Free Access to Water

Effects of solid feed on water balance of suckling calves were examined under three different conditions. Holstein bull calves (n=18) were divided into three groups of M, MS and MSW. The M received only 3.6l/d of liquid milk replacer containing 500-g dry milk replacer for 2wk from 1wk of age. The MS was given free access to solid feed (concentrate and Sudangrass hay) in addition to the milk replacer, and MSW was allowed to drink water in addition to solid feed and milk replacer during this period. As a result, water balance differed among the three groups. Urine volume tended to be larger in M and MSW than in MS. Apparent water retention, fecal water excretion, and fecal moisture content were higher in MS and MSW than in M, although significant differences were not detected between MS and MSW. Fecal water excretion was highly correlated with apparent water retention.

Influence of dietary sulfur level on growth performance and digestive function in feedlot cattle.

Using ammonium sulfate, three levels of dietary S (.15, .20, and .25%, DM basis) were evaluated in a finishing trial with 108 yearling crossbred heifers (384 kg). The basal diet contained (DM basis) 4% alfalfa hay, 6% sudangrass hay, 74% steam-flaked corn, 4% yellow grease, 6% cane molasses, and 6% protein-mineral supplement. Increasing dietary S decreased ADG (quadratic effect, P < .10), DMI (linear effect, P < .10), feed efficiency (quadratic effect, P < .10), diet NE (quadratic effect, P < .10), and longissimus muscle area (linear effect, P < .05). Six Holstein steers (218 kg) with cannulas in the rumen and proximal duodenum were used to evaluate treatment effects on characteristics of digestion. Treatment effects on ruminal and total tract digestion of OM and N were small (P > .10). However, ruminal digestion of ADF and starch was slightly lower (quadratic effect, P < .10), and postruminal digestion of ADF and starch was correspondingly greater (quadratic effect, P < .05) with supplemental S. Dietary S level did not influence (P > .10) ruminal synthesis of microbial N. Increasing dietary S did not influence (P > .10) ruminal pH or lactic acid. Increasing S decreased molar proportions of acetate (quadratic effect, P < .10) and increased molar proportions of propionate (linear effect, P < .10). We conclude that S in excess of .20% of dietary DM may have detrimental effects on growth performance and dietary NE. Excessive dietary S may also compromise carcass merit by decreasing longissimus muscle area.

Roughage Source and Level in Beef Cattle Finishing Diets

Three experiments were conducted to evaluate the effects of roughage level and source in beef cattle finishing diets. In Exp. 1,228 crossbred beef heifers (initial BW=346kg) were fed diets containing 7.5 or 15% roughage (DM basis), with alfalfa hay, sudangrass hay, or cottonseed hulls as roughage sources. Daily gain was not affected (P>0.10) by roughage level, but DMI was increased (P<0.10) with 15 vs 7.5% roughage. Among roughage sources, daily gain was less (P<0.05) with alfalfa than with cottonseed hulls or sudangrass. Dry matter intake was greater (P<0.05) with sudangrass than with alfalfa and intermediate with cottonseed hulls. Feed:gain did not differ (P>0.10)among roughage sources, but heifers fed alfalfa were least efficient. In Exp. 2, 224 crossbred beef steers (initial BW=308kg) were fed 90% concentrate diets with either whole-shelled or steam-flaked com as grain sources and either alfalfa hay or sudangrass hay as roughage sources. Daily gain was not affected by grain source, but DMI and feed:gain were greater (P<0.01) with whole-shelled than with steam-flaked com. Similarly, gain did not differ (P>0.10) between sudangrass and alfalfa, but steers fed sudangrass had greater (P<0.02) DMI and were less efficient (P<0.03) than those fed alfalfa as the roughage source. In Exp. 3, 132 crossbred steers (initial BW=313kg)were used in a randomized block design with different roughage sources and levels, including: alfalfa hay at 10% of dietary DM or sudangrass hay at 5, 7.5, and 10% of dietary DM. Daily gain was greater (P<0.06) with diets containing sudangrass than with the alfalfa diet, but level of sudangrass did not affect (P>0.10) daily gain. Daily DMI was increased (P<0.03) for diets with sudangrass vs alfalfa, and responded quadratically (P<0.11) to sudangrass level, with maximum DMI at 7.5% sudangrass. Feed:gain did not differ between the roughage sources but increased linearly (P<0.11) with increasing level of sudangrass. These results indicate that roughage level and source alter DMI and performance by finishing beef cattle. Sudangrass hay consistently increased DMI relative to alfalfa hay in high-concentrate beef cattle finishing diets, but responses in daily gain and feed efficiency were not consistent between these two roughages. Further research is needed to characterize the relationship between chemical and physical characteristics of roughages and finishing beef cattle performance.

Influence of dietary forage level and forage coarseness of grind on growth performance and digestive function in feedlot steers.

We conducted two trials to examine the influence of dietary forage level (FL; 16 and 8% sudangrass hay) and forage coarseness of grind (COG; ground to pass through a 2.5- vs 7.6-cm diameter screen) on growth performance and digestive function in feedlot steers fed a steam-flaked corn-based finishing diet. Thirty-two Mexican crossbred steers (297 kg) were used to determine treatment effects on growth performance during an 80-d finishing period. There were no treatment interactions (P > .10). Reducing FL increased (17%, P < .05) ADG. decreased (23%, P < .01) feed/gain, and increased (17% and 22%, P < .01) dietary NEm and NEg. Coarseness of grind did not affect (P > .10) steer performance. Treatment effects on digestive function were evaluated using four Holstein steers with cannulas in the rumen and proximal duodenum. There were no treatment interactions (P > .10) on nutrient digestibility. Forage level did not affect (P > .10) ruminal digestion of OM, N, or microbial efficiency. However, decreasing FL increased (P < .05) total tract digestion of OM (5.0%), N (5.7%), and ME (8.7%). Increasing COG increased total tract digestibility of OM (2.3%, P < .01), ADF (24.4%, P < .01); N (3.8%, P < .01), and ME (3.7%, P < .05). Increasing FL increased (P < .10) ruminal pH and decreased (P < .10) ruminal molar proportions of butyrate. Increasing COG did not influence (P > .10) ruminal pH or ruminal VFA molar proportions. We conclude that increasing coarseness of ground sudangrass may not improve the performance of feedlot steers when the forage is fed at either 8 or 16% of diet DM, although measures of ruminal and total tract nutrient digestibility may be slightly increased.

Protein and energy value of dehydrated poultry excreta in diets for feedlot cattle.

Four Holstein steers (222 kg) with cannulas in the rumen and proximal duodenum were used in a crossover design experiment to evaluate the energy and protein value of dehydrated poultry excreta (DPE). Dietary treatments contained (DM basis) 4% alfalfa hay, 8% sudangrass hay, 49% flaked barley, 8% cane molasses, 3% yellow grease, .8% urea, 1.4% limestone, .3% mineral salt, and .4% chromic oxide, plus 25% of either tapioca pellets or DPE. The DPE contained 42% ash and 27% CP (6% true protein). Substituting DPE for tapioca decreased the DE value of the diet (P < .01). The estimated DE value of the DPE was 1.36 Mcal/kg (.34 Mcal NEm/ kg). There were no treatment effects (P > .10) on microbial N flow to the small intestine or ruminal microbial efficiency (grams of microbial N/kilogram of OM fermented). The addition of DPE increased (P < .05) the flow of non-ammonia and feed N to the small intestine. The estimated ruminal escape N value of DPE was 22%, although very little of this was true protein. Dehydrated poultry excreta did not increase (P > .10) flow of alpha-amino N to the small intestine. Ruminal degradability of uric acid was 96%. Total tract true digestibility of N in DPE was 84%. It is concluded that the NE value of DPE is markedly overestimated in current tables of feeding standards. Less than 10% of the N in DPE escapes the rumen as true protein N.

Prepartum nutrition and solar radiation in beef cattle: I. Relationships of body fluid compartments, packed cell volume, plasma urea nitrogen, and estrogens to prenatal development.

Adaptations in body fluid pools during pregnancy were monitored in cows (n = 19) assigned to either low (LO, 70% NRC total feed intake) or high (HI, 110% NRC total feed intake) nutritional level (sudangrass hay) and to either shade (S) or no shade (NS) treatments in a 2 x 2 factorial experiment. Body water distribution (empty body water [EBW] by urea dilution; extracellular water [ECW] by thiosulfate dilution; intracellular water [ICW] by difference; plasma volume by Evans Blue dilution; interstitial water [ISW] by difference) was measured at 4-wk intervals beginning at 3 mo of pregnancy until birth and then immediately after birth. Both EBW and ICW in LO cows showed a steady decline (P < or = .05), whereas HI cows tended to maintain these body pools throughout gestation. Shading did not affect the pattern of change in EBW; however, it did produce a greater (P < or = .05) ICW in the S than in the NS cows throughout gestation. Generally, other body fluid pools (ECW, ISW, and plasma) were either not affected, or were just slightly affected, by shading or nutrition. Most of the body fluid pools (EBW, ECW, ICW, and ISW) inversely followed the seasonal changes in solar radiation. Calf birth weights were not affected by treatments but were moderately correlated to EBW (r = .49; P < or = .05) and ICW (r = .50; P < or = .05). Plasma urea nitrogen change, although not affected by nutrition, was affected (P < or = .05) by shading.(ABSTRACT TRUNCATED AT 250 WORDS)

Prepartum nutrition and solar radiation in beef cattle: II. Residual effects on postpartum milk yield, immunoglobulin, and calf growth.

Residual effects of nutrition and solar radiation during the last two-thirds of gestation on postpartum milk yield, immunoglobulin (Ig) G and M in both colostrum and calf serum, and calf growth were determined in beef cattle. Nineteen mature, multiparous crossbred cows (Bos taurus) at d 90 of pregnancy were assigned to either low (LO, 70% NRC total energy intake) or high (HI, 110% NRC total energy intake) nutritional level (sudangrass hay) and to either shade (S) or no shade (NS) treatments in a 2 x 2 factorial experiment. After parturition, all cows were moved into a large paddock and managed uniformly. Calf weights and calf serum were collected within 1 d postpartum, thereafter at 2-wk intervals for the next 12 wk, and then at 4-wk intervals until weaning. Colostrum samples were taken from the cow and milk yields were determined by the "weigh-suckle-weigh" technique. Neither prepartum nutrition nor environment influenced lactational performance of the dam. Concentrations of IgG were elevated in the colostrum of LO cows (15.3 vs 7.8 g/100 mL, LO vs HI, respectively; P < or = .05) but were not affected by shading. The patterns of IgG concentration in the calf serum were not altered by prepartum nutrition or environment; however, the pattern of IgM concentrations was greater (P < or = .01) in calves from S cows than in those from NS cows. This difference in IgM profile did not seem to be due to any residual effect from prepartum treatments. Postnatal growth of calves from birth until weaning were similar across all prepartum treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation of lysinoalanine following alkaline processing of soya bean meal in relation to the degradability of protein in the rumen

AbstractEffects of sodium hydroxide (NaOH) treatment on the formation of lysinoalanine (LAL) and on in‐situ and in‐vivo utilisation of soya bean meal (SBM) protein were investigated. Defatted SBM was sprayed with 0 (water), 25, 50 and 100 g NaOH (kg−1 dry matter), dried at 80°C for 2 h and then fed to four rumen cannulated goats in a 4 × 4 Latin square as a mixed diet (9: 1 w/w) of sudangrass hay and the SBM. LAL was not detected in non‐alkaline SBM, but the cross‐linked amino acid increased according to the level of NaOH addition. The maximum concentration of LAL was 1.26 g per 16 g nitrogen when the highest level of NaOH was applied. The NaOH treatment did not alter the digestibility or the retention of nitrogen of the mixed diet. Addition of NaOH at 25 and 50 g (kg−1 dry matter) lowered the solubility of protein, while the highest level of treatment had little effect. Lag time and rate of degradation of protein decreased due to the increasing level in NaOH treatment. A significant correlation (r = —0.860, P &lt; 0.01) between LAL content and rate of protein degradation suggested that the formation of cross‐linked amino acid would render protein more resistant to microbial degradation in the rumen.

Effects of graded levels of bentonite on serum clinical profiles, metabolic hormones, and serum swainsonine concentrations in lambs fed locoweed (Oxytropis sericea)1

To determine which clay minerals have the potential to bind swainsonine, an in vitro screening procedure was conducted. Twenty compounds were screened in one replicated in vitro trial. A commercially available bentonite bound approximately 10% swainsonine and was chosen for use in a subsequent lamb feeding trial. Twenty fine-wool lambs (30.5 +/- .7 kg) were assigned to one of five treatments (four lambs/treatment). Treatments included 1) positive control, 100% sorghum sudangrass hay, 2) 85% sorghum sudangrass:15% locoweed (Oxytropis sericea, 430 ppm [DM basis] of swainsonine) +0 g of bentonite, 3) Treatment 2 + 14 g of bentonite, 4) Treatment 2 + 28 g of bentonite, and 5) Treatment 2 + 42 g of bentonite. Lambs were fed the experimental diets for 35 d and were then fed the positive control diet for an additional 21 d. Lambs were weighted and blood was collected via jugular venipuncture weekly from d 0 through 56. On d 35, additional blood samples were collected 1, 2, 4, and 8 h after feeding. Weekly blood samples were analyzed for serum clinical chemistry profiles, and additional blood samples collected on d 35 were analyzed for serum metabolic hormones and serum swainsonine concentrations. Within 1 wk, serum alkaline phosphatase and glutamic oxaloacetic transaminase activities increased markedly (P < .05) in lambs fed locoweed. Serum insulin, growth hormone, and prolactin concentrations were not affected by feeding locoweed, but serum triiodothyronine and thyroxine concentrations were decreased by approximately 50% (P < .05) in lambs fed locoweed.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of flake thickness on the feeding value of steam-rolled wheat for feedlot cattle

Seventy-two medium-framed, crossbred steers (348 kg) were used in a randomized complete block design performance trial. Experimental diets contained (DM basis) 6% alfalfa hay, 6% sudangrass hay, 79% wheat, 2% yellow grease, 4% cane molasses, and 3% supplement. Treatments were 1) dry-rolled wheat (DRW, density = .52 kg/L); 2) steam-rolled wheat, coarse flake (SRW-C, density = .39 kg/L); and 3) steam-rolled wheat, thin flake (SRW-T density = .30 kg/L). Steam processing increased amyloglucosidase reactivity of wheat starch by 238 and 287% for SRW-C and SRW-T, respectively. Cattle performance was similar (P > .10) for SRW-C and SRW-T. Steam processing wheat increased ADG (13.5%, P < .10) and decreased DM intake/gain (8.8%, P < .05). Diet NE was precisely as expected for DRW, confirming the applicability of tabular NE values. Diet NEm was 3.7% lower (P < .05) for DRW than for SRW. The NEm and NEg of SRW were 2.28 and 1.59 Mcal/kg, respectively. Twelve Holstein steers (266 kg) were "T" cannulas in the rumen and proximal duodenum were used in a completely random design experiment to evaluate treatment effects on characteristics of ruminal and total tract digestion. Ruminal digestibilities of OM and starch were similar (P > .10) for DRW and SRW. Postruminal and total tract digestibility of OM (P < .10) and starch (P < .01) were increased with SRW. Dietary DE and ME values were greater (6.1 and 6.6%, respectively; P < .10) for SRW than for DRW.(ABSTRACT TRUNCATED AT 250 WORDS)

Ruminal escape protein for lightweight feedlot calves

Effects of supplemental ruminal escape protein (REP) were evaluated in an 84-d growth study involving 140 feedlot steers (198 kg) and in a site of digestion study involving four steers (149 kg). Dietary treatments were as follows: 1) basal diet; 2) basal diet plus 2% of a REP blend (1/3 blood meal, 1/3 meat and bone meal, and 1/3 feather meal); 3) basal diet plus 4% REP; and 4) basal diet plus 6% REP. The basal diet contained 18% alfalfa hay, 10% sudangrass hay, 61% steam-flaked corn, 2.5% yellow grease, 6% molasses, and 2.5% supplement. The basal diet contained 12.2% CP, and urea was the sole source of supplemental N. There was a quadratic effect (P < .05) of REP supplementation on rate and efficiency of gain. The greatest response was with 2% REP, which increased rate and efficiency of gain by 13.4 and 8.4%, respectively, over that of the basal diet. Protein supplementation had a quadratic effect (P < .05) on the NE value of the diet. The addition of 2% supplemental REP increased the NE of the diet by 6.6%. In the site of digestion trial, supplemental REP linearly increased (P < .01) passage of nonammonia and amino acid N to the small intestine. Compared with estimated amino acid requirements and with muscle composition, postruminal supplies of arginine, histidine, lysine, methionine, and phenylalanine were the limiting amino acids in the basal diet. Excess bypass protein, by placing an additional demand on arginine for detoxification of ammonia, may limit growth and performance.

Comparison of A Qualitative Field Test Versus Laboratory Analysis for Nitrate Concentration in Hybrid Sudangrass Hays

A qualitative field test using .5% diphenylamine in concentrated sulfuric acid was compared to routine laboratory quantification of the nitrate (NO3) concentration in 1,064 hybrid sudangrass hay samples. A visual scoring system was used to define the color changes of a single drop of the diphenylamine solution on the inner tissues of stems of the forage. Scores were 1=clear, 2=yellow, 3=brown, 4=light-blue streaks, 5=solid blue, and 6=black. Diphenylamine has been reported to turn blue when it contacts nitrate in plant tissues. Color scores were assigned at 10 and 20s after the solution contacted the plant tissue. Two stems from each sample were tested with diphenylamine. After laboratory analysis, forage samples were grouped by assayed nitrate content into five classes: 0 to 2,500ppm, 2,500 to 6,000ppm, 6,000 to 10,000ppm, 10,000 to 15,000ppm, and greater than 15,000ppm. The percentages turning blue of either stem sampled were 46, 67, 86, 95, and 100% for each of the classes, respectively. Correlation between the 2Q-s reading and the laboratory quantification was similar to the correlation of the 10-s reading and the laboratory quantification. The diphenylamine test is only a crude field test for the presence of dangerous concentrations of nitrate. A higher percentage of false positives (60.6%) and a low percentage of false negatives (10.7%) indicates that the test is quite conservative.

Early aspects of locoweed toxicosis and evaluation of a mineral supplement or clinoptilolite as dietary treatments.

Sixteen crossbred beef heifers were used to determine the efficacy of serum clinical profiles as diagnostic tools for detection of early stages of locoweed toxicity and to test the ability of two mineral supplements for prevention or therapy of toxicosis. Dietary treatments were (DM basis) 1) 100% sorghum sudangrass hay, 2) 80% sorghum sudangrass hay:20% locoweed, 3) 80% sorghum sudangrass hay:20% locoweed plus 100 g of Silent Herder Mineral Mix (a mineral supplement reported to alleviate locoweed toxicity), and 4) 80% sorghum sudangrass hay:20% locoweed plus 100 g of clinoptilolite (a natural zeolite clay). Diets were fed at 1.5% of BW for 28 d, after which heifers had ad libitum access to sorghum sudangrass hay for 14 d. Jugular blood was sampled before feeding every 7 d, and at 2, 4, 6, and 8 h after feeding on d 28. Compared with controls, heifers fed locoweed had elevated (P less than .01) serum alkaline phosphatase activities from d 7 through 35. On d 42, alkaline phosphatase activities in heifers previously fed locoweed were lower (P less than .05) than in control heifers. Serum glutamic oxaloacetic transaminase activities were elevated (P less than .01) in heifers fed locoweed from d 7 through 42 compared with control heifers. In heifers fed locoweed, serum Fe concentrations were less (P less than .01) on d 7 through 28, but no treatment effects were noted (P greater than .10) on d 35 or 42.(ABSTRACT TRUNCATED AT 250 WORDS)