Effect of feeding increasing levels of whole cottonseed on milk and milk components, milk fatty acid profile, and total-tract digestibility in lactating dairy cows

Dietary fat is fed to increase energy intake and provide fatty acids (FA) to support milk fat production. Oilseeds contain unsaturated FA that increase the risk for biohydrogenation-induced milk fat depression, but FA in whole cottonseed (WCS) are expected to be slowly released in the rumen and thus have a lower risk for biohydrogenation-induced milk fat depression. Our hypothesis was that increasing dietary WCS would increase milk fat yield by providing additional dietary FA without induction of milk fat depression. Four primiparous and 8 multiparous lactating Holstein cows, 136 ± 35 and 127 ± 4 DIM, respectively, were arranged in a replicated 4 × 4 Latin square design with 21-d periods. Treatments were WCS provided at 0%, 3.4%, 6.8%, and 9.9% of dietary dry matter, and WCS was substituted for cottonseed hulls and soybean meal to maintain dietary fiber and protein. Treatment did not change milk yield. There was a treatment-by-parity interaction for milk fat percent and yield with a quadratic decreased in primiparous cows but no effect of WCS in multiparous cows. Cottonseed linearly increased milk fat trans-10 18:1 in primiparous cows but not in multiparous cows. Increasing WCS increased milk preformed (18C) FA yield and partially overcame the trans-10 18:1 inhibition of de novo FA synthesis in the primiparous cows. Apparent transfer of 18C FA from feed to milk decreased in all cows as WCS increased, but the magnitude of the change was greater in primiparous cows. Increasing WCS decreased total-tract apparent dry matter, organic matter, and neutral detergent fiber digestibility. There was no change in total FA digestibility. However, 18C FA digestibility tended to be decreased in both parities and 16C FA digestibility was quadratically increased in multiparous cows but not changed in primiparous cows. Total fecal flow of intact WCS increased as WCS level increased, but fecal flow of intact seeds as a percentage consumed was similar across treatments. Fecal flow of intact seeds was greater in multiparous cows (4.3% vs. 1.1% of consumed). Plasma concentrations of glucose, nonesterified FA, triglycerides, and insulin were not changed. However, plasma urea-N increased with increasing WCS. Plasma gossypol increased with WCS (0.08-1.15 µg/mL) but was well below expected toxic levels. In conclusion, WCS maintained milk and milk component yield when fed at up to 9.9% of the diet to multiparous cows without concerns of gossypol toxicity, but primiparous cows were more susceptible to biohydrogenation-induced milk fat depression in the current trial. This highlights the interactions of parity with diet composition when feeding rumen-available unsaturated fat to dairy cows.

218 Evaluation of a Direct-Fed Microbial Product (DIRECTä) on Fecal Shedding of Shiga Toxin-Producing Escherichia Coli in Finishing Cattle in a Commercial Feedlot

Shiga toxin-producing Escherichia coli (STEC), particularly seven serogroups O26, O45, O103, O111, O121, O145, and O157, are major food borne pathogens. Cattle are a major reservoir in which STEC colonize the hindgut and are shed in the feces. Most cattle shed the organisms at low concentrations and a small proportion, called super shedders, shed at high concentrations (≥ 104 per g). Our objective was to evaluate the effect of a commercial DFM product containing lactic acid and propionic acid bacteria (Microbios Direct LA = 1 x 107 CFU and Direct PRO = 5 x 107 CFU/animal/d). The study was conducted in a commercial feedlot and a total of 16 pens were randomly assigned to control or DFM-treated group. Twenty pen-floor fecal samples were collected from each pen on 3 occasions, at 2-week intervals, approximately 100 d after DFM supplementation. Fecal samples were subjected to culture and PCR methods to quantify E. coli O157 and determine prevalence of the 6 non-O157 serogroups and 4 major virulence genes, Shiga toxins 1 and 2, intimin (an adhesin) and enterohemolysin. Data were analyzed using PROC MIXED procedure with pen as the experimental unit. The treatment means comparison within sampling day were carried out for variables that showed significant treatment and sampling day interaction. The overall fecal shedding of E. coli O157 was higher in the control group than in the DFM group, and the difference was significant in the third sampling day. Among the top-6 STEC, O26 and O103 were the dominant serogroups. The prevalence of the 4 major STEC virulence genes and the non-O157 STEC serogroups were not affected by inclusion of the DFM in the diet. In conclusion, DFM supplementation appeared to reduce fecal shedding E. coli O157, but prevalence of the 6 non-O157 serogroups and virulence genes were not affected.

PSXII-9 The effects of DFM plus tannins on measures of immunity and growth performance of weaned beef calves

A two-year study was conducted to determine the effects of direct-fed microbials plus tannins (DFM + TN) on weaned calf performance and indicators of innate immune response. Angus calves (n = 142 year 1; 143 year 2) were weaned at 6 months of age, transferred to a feedlot, and fed one of two diets for 42 days: a ration with added DFM + TN (2×108 Propionibacterium acidipropionici; 5×107 CFU/hd/day Lactobacillus animalis; 5×107 CFU/hd/day Bifidobacterium animalis; and tannins 15 g/hd/day) or a ration with no added DFM +TN (CON). Body weights were taken on consecutive days and averaged at the beginning and ending of the study, while single day weights were taken on d 14, and 28. Upon completion of the feeding study (year 2), calves (n = 72) were transported to Laramie, WY (204 km), where blood samples were taken on d 0, 2, 4, 7, and 9 relative to transportation to measure plasma haptoglobin. Data were compared among groups using a categorical response mixed model. The model included the fixed effect of treatment group and the data were measured repeatedly. DFM + TN calves had lower overall (P = 0.001) F:G and tended to have greater ADG (P = 0.15) and lower F:G (P = 0.12) during the first 28 days and greater overall ADG (P = 0.06) and greater (P = 0.11) total gain overall. There was a tendency (P = 0.09) for a treatment x day effect for DFM + TN calves to have lower plasma haptoglobin concentration on day 0 and 4 than CON calves. Weaned calves fed DFM + Tannins tended to have greater growth performance during the first 42 days post weaning and tended to have a reduction in plasma haptoglobin concentrations, suggesting a reduction in stress and a positive impact on calf growth.

PSVI-12 Effects of polyphenols (mixed tannins) and saponin (Yucca schidigera), with or without a direct fed microbial (DFM) on in vitro rumen fermentation

Rumen fluid from fistulated steers receiving a high concentrate diet was utilized to examine the impact of polyphenols and saponin with or without a direct fed microbial (DFM) on in vitro fermentation characteristics. Treatments consisted of: Control (no polyphenols, saponin or DFM); 2) Polyphenols (Mixed Tannins = 15 g/hd/d); 3) Saponin (Y. schidigera = 2 g/hd/d); 4) Polyphenols + DFM (DFM = 1E+7 Lactobacillus animalis + 1E+8 Propionibacteria acidilactici cfu/hd/d); and 5) Saponin + DFM. Rumen fluid was collected and combined in equal amounts from 3 rumen fistulated steers and mixed at a 1:1 ratio of artificial saliva to rumen fluid. Fermentation substrate consisted of 0.5 g of the high concentrate diet. Fermentation bottles were capped with an air-tight rubber stopper and incubated in a water bath for 12 and 18h (7 replicates/treatment/time point). After incubation, the total volume of gas produced was measured and a subsample analyzed for N, CH4 and CO2 concentrations. After gas sampling, pH, VFA concentrations, and DMD were determined. In vitro fermentation parameters were analyzed using a mixed effects model repeated measures analysis for a completely randomized block design. Acetic acid was decreased while valeric acid was increased (P < 0.05) by the Saponin + DFM treatment vs. Control. At 12h DMD was greater in Saponin, Saponin + DFM and Polyphenols + DFM (P < 0.001) treatments compared to Control or Polyphenols alone. Polyphenols produced greater amounts of CH4 /DMD than all other treatments (P < 0.01). Microbial protein production and efficiency were greater (P < 0.001), Saponin + DFM compared to other treatments. Other fermentation parameters measured were not impacted by treatments. Under the conditions of this experiment these data suggest combining DFM with Saponin or Polyphenols produces different ruminal effects from when they are fed alone.

Re-evaluation of Evans blue dye dilution method of plasma volume measurement

To simplify the method of plasma volume measurement by Evans blue dye dilution we used, for the first time, the same venous site for injection of dye and collection of samples. In a series of 49 studies the dye decay between 10 and 35 min after injection was highly linear (r = 0.991 +/- 0.01), indicating that contamination of samples is very unlikely. We repeated the measurements after eight weeks in nine patients; the mean difference was 16.4 +/- 19.6 ml, indicating a high degree of reproducibility. We found that extrapolation of the dye decay curve to time zero is required for accurate estimates of plasma volume. There was good agreement between the estimates of plasma volume obtained by extrapolation from only three samples taken at 10, 20 and 30 min after dye injection with the results obtained using all six samples. We also found good agreement between the estimates of plasma volume obtained by using standard curves constructed from four standard dilutions of 1.25, 2.5, 5 and 10 mg/l and those obtained by the use of standard curves constructed from the blank and only one standard dilution of 10 mg/l. We therefore conclude that the Evans blue technique can be simplified with minimal loss of accuracy, by using only one venous site for injection and withdrawal, withdrawing only three samples between 10 and 30 min after injection and using a two point calibration line.

Measurement of plasma volume in neonates

There is no reliable and safe method for measuring plasma volume in ill newborn infants. We describe an adaptation of the dye dilution technique using indocyanine green as the plasma label, which can be used in the sickest and smallest of infants with the minimum of disturbance. To avoid the need to take large volumes of blood from the infant, samples were diluted 1:1 with distilled water and pooled adult sera was used to construct the dye dilution standard curves. Eighteen preterm and fullterm infants were studied on 30 occasions. The measured plasma volume ranged between 21.4 and 106 ml/kg. Paired measurements were performed within 30-90 minutes of each other in seven infants. In five infants estimations of plasma volume were made shortly before and 30 minutes after the infusion of a known quantity of plasma. In eight out of 12 infants who had two measurements made there was close agreement between the second measured volume and the first measured volume, taking into account how much plasma had been given to or taken from the infant between the two measurements. The error ranged from 0.2 to 5.2 ml and the plasma recovery error ranged from -2.9% to +4.7%. In the remaining four infants the errors ranged from 2.1 to 9.5 ml and -14.2% to +8.8%. Errors in the measurement of plasma volume may arise as the result of sampling too early before full mixing of the dye has occurred, and there is a potential error in the measurement due to the distribution of albumin in the extracellular space in sick infants resulting in an overestimation of the plasma volume. Proposals for reducing sources of errors are discussed.

Influence of sarsaponin on growth, feed and nitrogen utilization in growing male rats fed diets with added urea or protein

Two experiments were conducted with growing male rats to determine the effects of 120 ppm of dietary sarsaponin (S) on nitrogen (N) metabolism when urea or protein are added to the diet. Growth, feed efficiency, N digestibility and balance, urinary N and ammonia-N (NH3-N), and cecal urease and NH3-N were measured. Growth and feed utilization were unaffected by dietary S. Adding urea or protein to the diet increased apparent N digestibility and increased urinary-N excretion. Urea did not affect N balance, whereas growth, feed utilization and N balance were maximized with 22% compared with either 16 or 28% dietary protein. Urinary NH3-N excretion was decreased by S when urea was added to the diet but was not affected when fed with increasing dietary protein. Cecal urease was decreased by S when urea was added or when the protein level was increased in the diet; effects on cecal NH3-N varied between the two experiments. Plasma urea-N was decreased by S. It is concluded that S has minor effects on N metabolism in rats and that NH3-N formation or excretion is only marginally affected by dietary S. If S decreases NH3-N level in confinement facilities, it is concluded that the effect is after the waste material is excreted by the animal, perhaps through reduced urease activity.