VTechWorks Repository :: Browsing by Author "Polan, Carl E."

Browsing by Author "Polan, Carl E."

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Adding Urea to Corn Silage
Murley, W. Ray; Mast, C. C.; Fontenot, Joseph P.; Polan, Carl E. (Virginia Cooperative Extension Service, 1967-09)
Considerable interest in adding urea to corn silage at ensiling time has been shown in recent years because of the low protein content of corn silage. Also, when fed in proper amounts, urea is a low-cost source of protein. Research results at Virginia Tech and the Forage Research Station, Middleburg, as well as other state research stations, indicate that urea can be added to corn silage at ensiling time and good response obtained in beef and dairy animals. Adding urea to corn silage raises the level of protein in the silage, thus, a lower percent protein supplement can be fed, or in feeding dry cows or beef cows, no protein supplement is needed.
Alterations in Mammary Gland Synthesis and Secretion of Fatty Acids in Response to Trans Isomers of Octadecenoic Acid or Conjugated Linoleic Acid Isomers
Loor, Juan Jose (Virginia Tech, 2001-04-13)
Experiments were conducted to investigate: 1) production of trans-18:1 and cis/trans-18:2 isomers due to input of forage and corn grain in continuous culture fermenters, 2) concentrations of trans-18:1 and cis/trans-18:2 isomers in blood and milk fat of grazing cows fed a grain supplement containing solvent- or mechanically-extracted soybean meal, 3) plasma and milk fatty acid profiles of lactating cows in response to a conjugated linoleic acid (CLA) mixture infused into the rumen, and 4) effects of cis9,trans11-18:2 (9/11CLA) or trans10,cis12-18:2 (10/12CLA) on de novo synthesis and desaturation of milk fatty acids in lactating cows fed unsaturated oils. In the first study, rumen fermenters were fed (50 g DM/d) orchardgrass or red clover with 0, 8, or 16 g/d corn replacing equal portions of forage DM. Outflow of trans11,cis15-18:2 (11/15LA) in effluents was greater when DM input was clover or grass only. With each increment of corn, output of 9/11CLA increased until it was 205% greater compared with forage alone. Trans11-18:1 (TVA), an intermediate in 18:2n6 (LA) and 18:3n3 (LN) hydrogenation, output increased by 28% with corn addition. Outputs of trans10-18:1 and 10/12CLA nearly doubled as corn increment increased. In the second experiment, Holstein cows grazing mixed clover-grass pastures were fed a grain supplement (6.7 kg/d) containing 1.7 kg solvent-extracted soybean meal (SES, 15 mg LA/g of DM), 1.9 kg mechanically-extracted soybean meal (MES, 24 mg LA/g of DM), or 1.9 kg MES plus 30 g of liquid methionine hydroxy analog (MESM). Cows fed MES or MESM had greater concentrations of LA, TVA, 9/11CLA, and 11/15LA in blood compared with cows fed SES. Daily yields of 18:0 (SA), LA, LN, TVA, and 9/11CLA in milk fat also were greater for cows fed MES or MESM compared with SES. In experiment 3, four Holstein cows were used in a 4 x 4 Latin square to determine plasma and milk fatty acid profiles during infusion of a CLA mixture at 0, 45, 90, or 180 g/d for 48 h into the rumen. Relative to the control, infusion of 180 g CLA/d decreased milk fat percentage and yield. Lower milk fat yield resulted from depressed concentrations of saturated 6:0 to 16:0 medium-chain fatty acids (MCFA). Concentrations of TVA, trans10-18:1, and 10/12CLA in blood plasma, and yields in milk fat increased in response to each dose of CLA. Stearic acid yield also increased as dose of CLA increased. Yield of cis9-18:1 (OA) in milk fat, however, was lower at 180 g CLA/d. In experiment 4, four cows were fed high-oleic (HO) or high-linoleic (HL) (2.5% of DM) oil for 11 d prior to abomasal infusion (15 g/d) of 9/11CLA or 10/12CLA for 48 h (2 x 2 factorial). Milk fat percentage and yield decreased 25% due to infusion of 10/12CLA compared with 9/11CLA, regardless of diet. Lower fat yields resulted from lower MCFA concentrations and yields. Regardless of diet, concentration (but not yield) of SA increased 40% when 10/12CLA was infused compared with 9/11CLA. Concentrations and yields of OA, 9/11CLA, and 20:4n6 also were reduced by infusing 10/12CLA compared with 9/11CLA regardless of diet. Thus, in addition to inhibiting de novo fatty acid synthesis, 10/12CLA appeared to inhibit desaturation via delta-6 and delta-9 desaturases. Significant implications from the above studies include: 1) 11/15LA and TVA are the primary intermediates flowing out of the rumen during hydrogenation of pasture lipids, 2) replacing forage DM with starch, OA, and LA increases synthesis of trans10-18:1 and 10/12CLA in the rumen, 3) desaturation of TVA produced in the rumen provides an alternate source for 9/11CLA in milk fat, and 4) 10/12CLA decreases de novo synthesis and desaturation of milk fatty acids.
Barley for Silage in Virginia
Starling, Thomas M.; Polan, Carl E.; Murley, W. Ray (Virginia Cooperative Extension Service, 1968-07)
Barley silage harvested at boot and soft dough stages for lactating cows
Acosta, Yamandu Martin (Virginia Tech, 1989-04-05)
Barley (Hordeum vulgare, L.) harvested at boot (5/7/88) and soft dough (6/6/88) stages of maturity was ensiled for nutritive comparisons. Boot stage was wilted and soft dough was direct cut at 15 (SD-Lo) and 25 cm (SD-Hi) above ground. Yields (kg DM/ha) were 3690, 8750 and 6287 for boot, SD-Lo and SD-Hi respectively. Digestibilities (%) of DM, CP and ADF were 74.7, 74.5 and 70.8 for boot; 61.9, 50.4 and 44.7 for SD-Lo; and 62.3, 47.2 and 49.7 for SD-Hi, respectively. Calculated TDN was 71.2, 62.0 and 62.8 for boot, SD-Lo and SD-Hi, respectively. Thirty-six lactating Holstein cows were fed boot silage at 75 and 60% of diet DM, SD-Lo fed at 75 and 60 and SD-Hi fed at 75 and 60, respectively. Milk yields (kg/d) were greatest for high concentrate diets and averaged 25.7, 28.3, 24.8, 26.3, 25.7 and 26.9, respectively. There were no differences among diets for DM intake or 4% FCM. Boot silage had a greater In Situ rumen degradability of DM, CP, ADF and NDF (68.6, 89.3, 44.2 and 45.1% respectively) than SD-Lo (57.8, 76.9, 20.9 and 24.2%) and SD-Hi (62.5, 80.0, 22.8 and 26.4%). Predictability of ruminal degradability of complete diets from weighted averages of single ingredients determined separately was low. In Situ incubation of single ingredients resulted in underestimation of DM and overestimation of CP degradability compared with complete diet incubation.
Bioavailability of phosphorus from various sources for young turkeys
Potchanakorn, Manop (Virginia Polytechnic Institute and State University, 1988)
Three series of experiments were conducted to determine the relative bioavailability of various phosphate products with an emphasis on the defluorinated phosphates. In Series I, phosphorus in commercial mono/dicalcium phosphates, commercial dicalcium phosphates, commercial defluorinated phosphates, and experimental defluorinated phosphates were found to be 93, 81, 70, and 76% as available as that in dicalcium phosphate dihydrate, respectively, using 3-week bodyweight and toe ash in a nonlinear regression analysis. In Series II, phosphorus in a commercial defluorinated phosphate was compared directly with that in a commercial dicalcium phosphate using poult from 1 to 4 weeks of age. No significant differences were found between the two products which may be attributed partly to the feeding of the starter diet during the pre-experimental period. The commercial defluorinated phosphate was numerically less available than the commercial dicalcium phosphate in all cases. In Series III, phosphorus in various defluorinated phosphates was compared with that in a dicalcium phosphate dihydrate. Ash of dry unextracted tibia, ash of dry toe, and 0 to 3-week body weight gain as responses to added phosphorus followed a sigmoidal regression model while 0 to 2-week body weight gain followed an asymptotic model in Experiment 1. The defluorinated phosphate was found to be 53% as available as the standard. In Experiment 2, an experimental defluorinated phosphate from Series I which was found to be 76% as available as the standard was found to be 62% as available as the standard used in Series III, indicating differences in bioavailability of the two standards. In Experiment 3, two commercial defluorinated phosphates were found to have equal relative biological values, 67.2 and 67.6% as compared with the standard using poults from 0 to 2 weeks of age, and three experimental defluorinated phosphates 51.7, 74.0, and 88.2% with the product with the fine particles having the highest relative biological value. In cases where the sigmoidal regression gave a significantly better fit to the data than the asymptotic model, the relative biological values and the associated confidence limits from the asymptotic model were equal to those from the sigmoidal model.
Comparison of lactational and metabolic responses of postpartum dairy heifers and cows fed diets supplemented with corn, calcium stearate and tallow
Bower, Laurie A. (Virginia Tech, 1986-03-05)
Twenty first-calf heifers and 24 cows in their second or greater lactation were randomly assigned to 4 dietary treatments from day 15 to day 61 postpartum. Mixed diets consisted of corn silage, alfalfa haylage, orchard grass hay, and a pelleted concentrate. Concentrates were control (C), C + additional corn (H), C + 4% calcium stearate (S), or C + 4% tallow (T). C, S, and T contained 50:50 forage and concentrate dry matter and H contained 40:60.
Cow performance, adrenal function, and milk quality under varying levels of competition
Friend, Theodore Henry (Virginia Tech, 1977-02-15)
Twelve dairy cows were used to determine behavior with varying numbers of free stalls and length of feed trough. A least squares procedure, which regressed for numbers of observations, was adapted for obtaining dominance values. Available free stalls were 1.0, .83, .67, .50, .33 per cow. With 1.0 free stalls, linear feed trough was .5, .4, .3, .2, .1 m per cow changed at 7-day intervals. Cow behavior and locations were quantified by time-lapse photography at I-minute intervals during the last 3-days of each treatment. Spatial recommendations for dairy cattle can be greatly reduced. Behavior was altered only when less than .67 free stalls or .2 m of linear trough was available per cow. Minimum stalls needed per cow without altering daily free stall usage = [14.2 hours (average use)]/[hours per day free stalls are available to the herd X .93 (maximum. efficiency before crowding)]. Linear feed trough of .2 m appears adequate to ensure desired amount of eating time when individuals have access to feed in trough 21 hours per day. Estimated individual dry matter intakes were the same at .5 m and .25 m of trough per cow. Intake was affected by time spent eating for .25 m. In 10-variable models for various levels of competition, time spent eating, or in free stalls, and individual dry matter intake were described predominantly by production variables, not dominance values. Adrenal responsiveness to 200 IU adrenocorticotrophic hormone (ACTH) was determined by quantifying plasma corticosteroids in two groups of lactating Holstein cows. One group of 18 cows received ACTH via jugular catheter 0, 2, or 9 days after introduction to an established group in restricted space (3.96 m2 lot space and .67 free stalls per cow). Differences in total plasma corticoids (area under curve) in response to ACTH were not statistically different although corticoid response 2 and 9 days of stress tended to be greater than day O. A second group of 16 cows received ACTH at 0, 1, 2, or 3 days after introduction to a new group and crowding (2.97 m2 lot space and .5 free stalls per cow). Mean corticoid response to ACTH (area under the curve, ng/ml ± SD) were 161.6 ± 12.6, 158.2 ± 28.2, 227.7 ± 32.2 and 229.9 ± 40.3 for cows inject~d days 0, 1, 2, and 3 respectively, days 2 and 3 differed from day 0 (P<.OS). Bacteriological status of quarter milk samples was not changed by stress. In non-infected quarters of 24 stressed cows, 8 quarters increased above 150,000 somatic cells/ml while 5 quarters decreased below 150,000 cells/m1 of milk after 4 days of stress when compared to 2 and 6 days prior to stress. Stress did not affect milk production relative to controls.
Defining effective fiber content of dairy rations
Maddox, Terry L. (Virginia Polytechnic Institute and State University, 1982)
Cottonseed hulls (CSH), chopped orchardgrass (OG) or alfalfa (ALF) hays were added to corn silage-based rations to determine effects on dry matter intake (DMI), nitrogen balance (NB), rumen volatile fatty acids (VFA), and rumen fluid (RFD) and solids (RSD) dilution rates. DMI was highest for added fiber rations and higher for CSH than hay rations. Digestibility of DM was depressed for added fiber rations with lowest for CSH. Most favorable NB was for CSH rations. Rumen VFA were not altered by fiber additions. Highest RFD was for 0% rations and lowest for 9% rations, however CSH had greatest positive influence on RFD. RSD trend was similar to that for RFD. In Experiment II, 4 corn silage-based rations containing 9% OG, ALF, or CSH plus a Control (9% OG) were compared for effect on DMI, rumen VFA, chewing time (CT), RSD, and RFD. Ration density decreased with OG and ALF whereas CSH had no effect compared to Control. DMI was higher for CSH compared to OG and ALF. Total CT (min/d) and Roughage Value Index (CT/kg DMI) were reduced for ALF compared to OG. Total VFA were lower for added fiber rations compared to Control. Acetate:propionate (APR) and non-glucogenic (NGR) ratio were not affected by fiber additions. RFD was reduced for ALF compared to OG whereas CSH was higher than OG and ALF. Reduced RFD was associated with reduced total CT for ALF. RSD was not affected by fiber additions. Chopped OG was supplemented at 0, 9, or 18% of ration DM in a finely chopped corn silage-based ration. Analysis of covariance was performed using 18 lactating Holsteins. Ration density decreased with each increment of OG. DMI was highest for 18% OG ration. Cows on 0% showed decreased DMI whereas cows on 9 and 18% rations increased DMI from covariate period. Rumen acetate, APR and NGR increased while propionate and total VFA decreased with increasing OG. RFD and RSD increased with increasing OG supplementation. Response to 9 and 18% supplementation of OG, ALF, or CSH to corn silage-based rations appears to follow similar pattern as when all-forage rations were compared to all-concentrate rations for lactating dairy cows. A more quantitative evaluation of physical form is needed for dairy rations and feedstuffs leading to an acceptable routine evaluation procedure.
Development of equations to predict dry matter intake of dairy heifers
Quigley, J. D. (Virginia Polytechnic Institute and State University, 1985)
Equations to predict daily dry matter intake (DMI) of individual animals were developed with 118 Holstein heifers fed totally mixed rations (TMR). Animals grouped according to body weight (136, 227, 317 kg) were fed TMR (corn silage, ground hay, high moisture corn, soybean meal) once daily for 28 days. Rations were balanced to mean body weight according to National Research Council (NRC) recommendations for protein, vitamins and minerals, and to 85, 95, 105, and 115% of recommendation for energy. Independent variables were body weight (BWT, kg/day) daily body weight gain (GAIN, kg), environmental temperature (AMBT, °C), ration acid detergent fiber (ADF, percent of dry matter), neutral detergent fiber (NDF, percent of dry matter), net energy for maintenance and gain (NEM, NEG, megacalories), total digestible nutrients (TDN, percent of dry matter), and bulk density (BULK, g/ml as fed). Squared terms, appropriate interaction terms, and metabolic body weight (MBWT, kg^.75) were included in the model. Stepwise regression was utilized to generate two models, simplified and expanded. Simplified model was: DMI (kg/day) = -29.86 + (-.54E-05 * BWT²) + (.157 * MBWT) + (2.090 * GAIN) + (-.118 * GAIN²) + (.730 * TDN) + (-.005 * TDN²) + (-.001 * BWT * GAIN) + (-.019 * TDN * GAIN); n = 4797, r² = .59, s_y.x = 1.18. Expanded model was: DMI (kg/ day) = -1906.91 + (-0.04 * BWT) + (0.37 * MBWT) + (32.36 * ADF) + (2305.51 * NEM) + (-664.06 * NEG) + (-0.08 * AMBT) + (-0.13 * ADFSQ) + (-637.68 * NEMSQ) + (42.31 * NEGSQ) + (-5.35 * BULKSQ) + (0.001 * AMBTSQ) + (-1.56E-04 * BWT * ADF) + (8.873E-05 * BWT * AMBT) + (246.30 * NEM * NEG) + (-21.30 * NEM * ADF) + (7.83 * NEG * ADF) + (0.04 * NEG * AMBT) + (0.01 * GAIN * ADF) + (-0.01 * GAIN * AMBT); n = 4429, r² = .65, s_y.x = 1.09. Predicted intakes by simplified equation agree with those of NRC at TDN recommended by NRC and .7 kg/day. Computerized ration formulation systems were developed using simplified model. Expanded model requires further refinement prior to incorporation into a ration formulation system.
Digestion and utilization of nutrients in diets containing feather meal and (or) supplemental fat by lactating dairy cows
Ellingson, Terry Allen (Virginia Tech, 1993-01-05)
Two experiments with dairy cows during early lactation were conducted to determine the effects of feeding feather meal and fat. The objective of Experiment 1 was to determine milk production, milk composition, feed intake, and concentrations of AA and long chain fatty acids in blood plasma. Thirty two Holstein cows began a six week trial at the start of the fourth week of lactation. Diets included a control diet (51% forage, 49% concentrate, 16.8% CP, and 19.1% ADF) and diets containing 2.2% feather meal, 3.6% supplemental fat (hydrogenated tallow), or feather meal plus fat. Feather meal and supplemental fat were substituted for soybean meal and corn grain, respectively, in the control diet concentrate. For Experiment 2, four lactating Holstein cows (15, 20, 21, and 65 d postpartum) with ruminal and duodenal cannulae were used in a 4X4 Latin square design (21 d feeding periods) to determine digestibilities of the four diets. The markers used to estimate digesta flow were Co- EDTA and chromic oxide. When cows were fed feather meal, milk fat % was higher, milk protein % was lower, and plasma total essential AA were increased. Dry matter intake, milk production, and plasma long chain fatty acids increased when cows were fed diets containing fat. Differences between concentrations of AA in the tail artery and mammary vein indicated significant uptake by the mammary gland. The mammary gland extracted approximately 36% of the total essential AA in plasma. Intake, duodenal flow, and ruminal and total tract digestibilities of DM, ADF, N, and OM were similar for all diets. No changes were seen in rumen pH, rumen ammonia-N, VFA's, or rumen bacteria AA. Intake and fecal output of total, essential, and non-essential AA were greater when cows were fed diets containing feather meal. However, flow of AA to the duodenum, AA absorbed, and AA digestibilities did not differ. Results suggest that bypass proteins with a complimentary EAA profile must be fed with feather meal to compensate for the low amounts of Lys, Met, and His provided by feather meal.
Effect of body condition and ration protein source on performance of high producing cows during early lactation
Seymour, William Matthew (Virginia Tech, 1985-04-05)
Forty-two high producing Holstein cows were paired by body condition and mature equivalent milk production and fed either a high or low energy complete ration ad libitum during the last 16-20 weeks of lactation. Cows fed the high energy ration ate more feed, produced more milk and gained more body condition than cows fed the low energy ration. Cows were fed to maintain condition during the dry period. During weeks 3-15 of the next lactation, half the cows in each condition group (fat or thin) were fed a mixed ration with soybean meal (SBM) as the major protein source. The remaining cows were fed a ration with dried brewers grains (DBG) as the main protein source.
The effect of different sources of dietary fiber on the plasma total and lipoprotein cholesterol, liver cholesterol, fecal neutral steroid excretion and histology of major organ tissues in hamsters
Jonnalagadda, Satya Srivathsa (Virginia Tech, 1992-05-05)
The effect of diets with various dietary fiber sources on the plasma lipids, liver cholesterol, the histology of the gastrointestinal tract, heart, liver and kidney and the fecal neutral steroid excretion was investigated in hamsters. 155, 9-11 wk old, male Golden-syrian hamsters were fed a purified basal hypercholesterolemic diet (0.1% cholesterol, 10% fat, 4% dietary fiber) for 5 wk to elevate plasma lipid levels. Based on wk 4 plasma total cholesterol (TC) levels hamsters with elevated levels were randomly assigned, 16 animals/group, into six groups for another 4 wk: control, oat bran, guar gum, cellulose, xylan and sacrifice. After 4 wk of the fiber diets (10% dietary fiber), the plasma TC levels were significantly lowered in the oat bran, guar gum and xylan groups (16%, 12% and 15%, respectively) (p<.05). They were also significantly lower than the control and cellulose groups. Plasma HDL-C concentrations tended to be lower in all the treatment groups, but was significantly decreased only in the guar gum group (12%) (p<.05). The combined plasma VLDL-C + LDL-C was significantly lowered by the oat bran, cellulose and xylan diets (38%, 40% and 34%, respectively) (p<.05). The liver cholesterol concentration increased significantly from 1 mg cholesterol/g liver to 4.1 mg cholesterol/g liver (p<.05) after 4 wk of the control diet; this was further increased significantly only in the cellulose group (5.6 mg cholesterol/g liver), while the other treatment groups showed no significant changes or differences compared to the control diet group (wk 4). The total fecal neutral steroid excretion was significantly (p<.05) higher in the oat bran group compared to the other treatment groups. No major differences were observed in the tissue histology of the animals in the different treatment groups. In the present study, it appeared that oat bran, guar gum and xylan were effective hypocholesterolemic agents; however, their mechanism of action is still not clear.
The effect of early nutrition and activity levels on the development of obesity in rats
Bazzarre, Terry Lee (Virginia Tech, 1973-11-06)
This investigation was undertaken to study the effects of feeding two levels of caloric density factorially with two levels of activity on the growth rate and body composition of male weanling pups from 25 to 67 days of age. The effects of ad libitum feeding the dams of these pups the same two diets during gestation and lactation on the growth rates and activity levels of these pups were also examined. Following weaning, the pups in both Studies A and B, were placed by weight in outcome groups of four each. The pups in each outcome group were then randomly assigned to one of the following four treatments: I - high-fat diet, spontaneous exercise; II - high-fat diet, restricted exercise; III - chow diet, spontaneous exercise; IV - chow diet, restricted exercise. The pups whose dams were given the 60% fat ration during gestation and lactation (B) attained a higher weaning weight (73 g) than the pups of the dams fed a 4.5% fat ration (Purina Chow) during gestation and lactation - A (55 g). The final body dimensions (length and width) did not appear to be different (Tables IV and V). Pups in Study B tended to run considerably more meters per day than the pups in Study A although the differences were uncertain because of the wide variation. The final body weights attained were greater for the pups in Study B than the pups in Study A except for treatment I. Except for treatment I, the Except for treatment I, the order of the weight gains within treatments among experiments was comparable. It appeared that the differences in final body weight attained could be attributed to the initial differences present at weaning which reflected the dietary treatments of the dams during gestation and lactation. The difference of treatment I in Study B from the trends exhibited by the other three treatments, was manifest by the lower final body weight attained (246.25 ± 9 g) and the lower total weight gain (170.77 ± 8 g) of Study A. The animals in Study B all consumed a greater number of kcal per day than the animals in the corresponding treatments in Study A. The differences in feed consumption between the two experiments appeared to be significant only for those animals receiving the 60%-fat diet.
Effect of energy and undegraded intake protein on growth and feed efficiency of growing Holstein heifers
Bethard, Greg L. (Virginia Tech, 1994-09-30)
Two trials using 32 heifers each evaluated response to undegraded intake protein (UIP) (30 or SO% CP), energy (supporting .S9 or .91 kg ADG), and source of UIP (blood meal or combination protein supplement). Trial one was a 2x2 factorial, with two levels of energy and UIP. High UIP was achieved with blood meal supplementation. From 6-13 mo of age (phase I), high energy increased ADG and DMI, and high UIP decreased DMI. DM efficiencies (kg DMIlkg BW gain) improved with high energy and high UIP, and roN efficiencies (kg IDN/kg BW gain) improved with high UIP. From 13 mo until calving (phase n), heifers were housed together and fed a common diet. Low energy, high UIP treatment had the highest ADG (1.01 kg/day) for phase I, but the lowest for phase n (.33 kg/day), and low energy, low UIP treatment had the lowest ADG (.62 kg/day) for phase I, but the highest for phase n (.S3 kg/day). Overall ADG from 6 mo until calving averaged .S9 kg/day, and was not affected by energy or UIP. In trial 2, two levels of energy and two sources ofUIP were compared, resulting in four treatments: low energy, high UIP with combination protein supplement; low energy, high UIP with blood meal; low energy, low VIP with soybean meal; and high energy, low UIP with soybean meal. Combination protein supplement contained blood meal, com gluten meal, and fish meal. Trial was 300 days long, and began at 6.5 mo. of age. Dry matter intake and ADO were increased with high energy, but not affected by VIP. Overall DM efficiency was not affected by VIP or energy level. Results of both trials indicate VIP may improve feed efficiency of growing Holstein heifers.
The effect of oral contraceptive agents on copper and zinc balance in young women
Crews, Michael Glen (Virginia Tech, 1978-08-15)
An 18-day balance study was designed to test the hypothesis that the use of oral contraceptive agents would change the metabolic balance of copper and zinc in young women. The subjects were divided into two treatment groups based on the use or non-use of oral contraceptive agents, The mean age was 21 years and 6 months for the non-oral contraceptive group and 21 years and 2 months for the oral contraceptive group. The mean weight was 57.2 kg for the non-oral contraceptive group and 59.7 kg for the group on oral contraceptive therapy. The study was composed of three 6-day periods. The subjects of both groups consumed identical diets for the three experimental periods. The diet contained approximately 2 mg of copper, 9 mg of zinc, 50 g of protein, 181 mg of cholesterol, and 2000 kcal per day. The first experimental period served as an adjustment period with the latter two periods serving as the balance periods. Subjects were given a multi-vitamin supplement daily. All urine and feces were collected and assayed for copper, zinc, and nitrogen. Food samples were measured for content of copper, zinc, and nitrogen. Blood samples were taken and the plasma fraction analyzed for copper, zinc, and cholesterol content. Urinary copper was measured as an organic chelate by atomic absorption spectrophotometry. Copper and zinc content of the other samples were assayed in wet ashed samples by atomic absorption spectrophotometry. Food and fecal nitrogen was assayed by Kjeldahl analysis. Urine nitrogen and creatinine was measured by standard automated techniques. No significant differences were found in the metabolic balances of copper, zinc, and nitrogen. Oral contraceptive users were found to have significantly (p<0.01) higher plasma cholesterol and copper levels, but plasma zinc concentrations were not significantly different. No difference was found in hemoglobin or hematocrit for the two groups. The urinary excretion of zinc was similar for the two groups. The excretion of copper and creatinine was significantly (p<0.01) higher for the oral contraceptive group. The urinary and fecal excretion of copper and zinc was not significantly different for the two groups. While the balance data was not different for the two groups, it is of interest that both groups maintained negative balance states on intakes similar to projected intakes for the general population. This indicated that both groups needed more copper and zinc than they received, It therefore appears that consideration should be given to a possible suboptimal nutritional state existing for copper and zinc nutrition for at least this sex-age group.
The effects of a dairy cow body condition scoring system on selected production and metabolic parameters
Wildman, Edward E. (Virginia Polytechnic Institute and State University, 1979)
A dairy cow body condition scoring system was devised by the author as a practical means of determining the body condition, or fitness pertaining to the degree of body fat of dairy cows at any point during the lactation cycle. The factors considered were the thoracic and lumbar regions of the vertebral column (chine, loin and rump), spinous processes (loin), anterior coccygeal vertebrae (tailhead), tuber sacrale (hooks), and tuber ishii (pin bones). All factors in the body condition scoring system must be considered while appraising each cow. Each cow was scored on a 1 to 5 scale with 1 indicating severe undercondition and 5 indicating severe overcondition. During an 18-month period, 28 cows in each of 29 Virginia dairy herds were used for obtaining body condition scores, body weight, frame size measurements and blood samples. Herds were chosen according to rolling herd milk production average and cows were chosen at random from within five Estimated Relative Producing Ability groupings to insure a representative sample of herds across and levels of production in Virginia and of cows within each herd. Herds were sampled at 3-month intervals and complete Dairy Herd Improvement Association records were obtained for each cow in each herd. The relationships of dairy cow body weight, frame size measurements, milk production and related parameters, and blood profiles to the body condition scoring system were determined. Body condition using this method was found to be independent of frame size and only moderately correlated with body weight, the number of intercostal spaces and the ratio of body weight to wither height. Body condition was found to be relatively low during early lactation and to increase through late lactation and remain constant during the dry period. Dairy cows of greatest milk production efficiency did not increase significantly in body condition throughout lactation, had fewer days open, but had less persistency of lactation. Dairy cows that increase significantly in body condition throughout lactation were less efficient milk producers, had a greater number of days open, had relatively high body condition scores in late lactation, but had greater persistency of lactation. Blood parameters, although statistically significant in many cases, were found to be of little or no practical value when compared between body condition, stage of lactation, and dairy merit groupings. The dairy cow body condition scoring system is a practical means of quantitating body condition of dairy cows.
The effects of administered indigenous micro-organisms on uptake of ¹²⁵I-gamma globulin in in vitro intestinal segments of neonatal calves
James, Robert E. (Virginia Tech, 1978-07-04)
Two experiments were conducted using newborn colostrum-deprived calves to establish the distribution of uptake of ¹²⁵I- globulin in smail intestine and to investigate effects of added microorganisms on ¹²⁵I-gamma globulin uptake. Ten calves less than 12.5 h of age (X̅ = 7 h) were anesthetized and intestines exteriorized through an abdominal incision. Intestine was ligated into 10 cm segments at 70 cm intervals beginning at the ileocecal junction, injected with ¹²⁵I-gamma globulin in an electrolyte solution and incubated for 1.5 h. One additional segment was formed adjacent to segments 1, 5 and 10 to assess effects of .5 h exposure to ¹²⁵I-gamma globulin on uptake by epithelium. After prescribed gamma globulin exposure, segments were excised, volume of lumen contents, segment weight and tissue activity were determined. Age, birth weight and intestine length were recorded. Location of each segment (PSEG) was expressed as percentage of distance from cecum to abomasum. Uptake was expressed as milligrams gamma globulin internalized per gram of segment tissue. Distribution of gamma globulin uptake after 1.5 h exposure was a cubic function of PSEG. Uptake was greatest In a region 15% of cecumabomasum distance, declining progressively towards the abomasum. After .5 4 exposure, regression of uptake on PSEG was a quadratic function with greatest uptake at 30% of cecum-abomasum distance. Uptake after 1.5 h exposure was greater than after .5 h. In experiment II, 10 calves less than 14 h of age (X̅ = 8.6 h) were anesthetized and intestines surgically exteriorized. Intestine was ligated into segments 10 cm in length at three cm intervals beginning 1.8 m above the ileocecal junction. Seven treatments were assigned in random order to segments in three successive sections of small intestine. Three treatments compared uptake in segments receiving one ml of either live intestine origin bacteria culture, sterile microbiological broth or autoclaved bacteria culture with four h incubation followed by 1.5 h exposure to ¹²⁵I-gamma globulin. Two treatments measured anaerobic microbial growth after four h incubation with one ml of either sterile broth or live bacteria culture. Residual ¹²⁵I-gamma giobulin was measured in segments receiving one ml of sterile broth or live bacteria culture with 5.5 h incubation followed by 15 second exposure to ¹²⁵I-gamma globulin. Measurements were as described for the first 10 calves. Serum corticosteroids, total protein and protein components were measured at O h and 5.5 h later. Uptake was lowest in segments receiving live bacteria as compared to segments receiving sterile inocula. Number of bacteria per gram of segment tissue was negatively correlated with uptake. Low serum corticosteroids were associated with low gamma globulin uptake. Body weight and age were not related to uptake in either experiment.in a decisive manner.
Effects of dietary soybean meal and fish meal on protein digesta flow in Holstein cows during early and midlactation
Zerbini, Ercole (Virginia Polytechnic Institute and State University, 1986)
Six lactating Holstein cows fitted with rumen cannulae and T-type cannulae in the proximal duodenum were used to measure digesta and nitrogen compounds flow to the small intestine during early and midlactation. Fish meal and soybean meal provided 54 and 56% of the protein in the diets composed of corn grain, corn silage and orchardgrass hay, and which contained 15.4 and 15.5% crude protein and 20.9 and 20.5 acid detergent fiber. Spot samples of digesta were collected from the rumen, duodenum and rectum over a period of 72 hours. Co-EDTA and ytterbium were used as liquid and particulate digesta markers to estimate flow and digestibility of nutrients. Cytosine was used as microbial marker. True organic matter digestibility in the stomachs was 48.4, 49.8, 44.9, and 53.2% for fish meal and soybean meal diets and early and midlactation respectively. Protein degradability in the stomachs were 47.2, 65.8, 56.7, and 56.2% for fish meal and soybean meal diets and early and midlactation respectively. Amino acids intake was greater for soybean meal diet but total amino acids reaching the the duodenum were similar for both diets. Valine, methionine, lysine and histidine were less degraded for fish meal but were extensively degraded in soybean meal diet. Least degraded for both diets were glycine, valine, serine, proline and histidine. The advantage of greater quantity of protein escaping ruminal degradation with fish meal supplementation was counterbalanced by less microbial synthesis in the rumen partly explaining the similar response obtained with diets especially in early lactation.
Effects of Prepartum Energy and Protein Density on Productivity and Influence of Dietary Iron on Copper Status of Holstein and Jersey Cattle
French, Patrick Douglas (Virginia Tech, 1999-08-16)
In experiment 1, 24 multiparous Holsteins and 24 multiparous Jerseys were assigned at random to one of four diets containing either 1.25, 1.38, 1.50, or 1.63 Mcal NEL/kg DM to determine the effects of prepartum energy density on productivity. Cows were assigned to diets 28 d before expected calving and received a similar diet 0 to 60 d postpartum. Prepartum DMI increased linearly as dietary energy density increased. Non-esterified fatty acids did not differ for energy density and were greater for Holsteins. Milk and 4% FCM increased linearly as dietary energy density increased, although postpartum DMI was quadratic for energy density. Fat yield increased linearly with energy density and protein yield did not differ. Increasing prepartum diet energy density increased yield of milk and 4% FCM. In experiment 2, 26 multiparous and 18 primiparous Jerseys were assigned to one of two CP and rumen undegradable protein (RUP) concentrations 30 d before expected calving to determine the effects of CP and RUP on productivity. Cows received a similar diet 0 to 60 d postpartum. Prepartum CP concentrations were 12 and 15% and prepartum RUP (% of CP) concentrations were 30 and 45%. Dry matter intake was not affected by CP or RUP. Milk yield and 4% FCM yield did not differ for CP or RUP. In addition, milk protein concentration and yield were similar for CP and RUP. Positive calculated metabolizable protein balance for 12% CP and 30% RUP concentrations may have precluded responses to increasing prepartum CP and RUP. In experiment 3, 12 Holstein and 12 Jersey multiparous cows were assigned at random to diets containing 0 or 500 mg FeCO3/kg DM to investigate the effects of dietary Fe on milk production and Cu status. Hepatic Cu did not differ for breeds or Fe supplementation. For Jerseys, hepatic Fe was greater for cows receiving supplemental Fe. Hepatic Zn was similar for breed and Fe supplementation. Plasma Cu was greater for Jerseys compared to Holsteins and did not differ for Fe supplementation. Plasma Fe and Zn did not differ for breeds or Fe supplementation. Iron supplementation did not affect yield of milk or 4% FCM. Dietary Fe did not affect Cu status of Holstein and Jersey cows in this experiment.
Evaluating fish meal as a protein source for lactating dairy cows
Spain, James Nobles (Virginia Polytechnic Institute and State University, 1989)
A series of experiments were conducted to measure the mode of action by which fishmeal exerts its effect on milk composition of dairy cows. Production Study One measured the effect of increased fishmeal intake on milk production and milk composition in dairy cattle. Milk fat percentage and yield were decreased by increased fishmeal intake. This decrease was not associated with changes in ruminal fermentation patterns. Plasma long-chain n-3 polyunsaturated fatty acids were increased with increased fishmeal intake. Mammary slices from lactating bovine mammary gland were incubated with eicosapentaenoic acid. Changes in ¹⁴C-acetate metabolism were measured. Acetate oxidation and incorporation into milk lipid were not changed by eicosapentaenoic acid. However, tissue from mammary gland of cows milked 6 to 8 h prior to slaughter had 2 fold higher activity than tissue milked 1 h before slaughter. Disappearance of dry matter, crude protein, and lipid in fish meal from undegradable bags in the rumen was measured. Dry matter and crude protein degradation of fish meal were similar to published values. Lipid escaped rapidly with greater than 70% removed by 8 h. A subsequent fish oil infusion study revealed that intraruminal fish oil treatment did not significantly alter ruminal fermentation, or change fatty acid profiles in duodenal digesta, plasma, or milk. Duodenal infusion increased plasma concentrations of n-3 fatty acids but did not affect milk lipid fatty acid composition. A second production study compared the effects of fish meal versus fish oil on milk production and composition, and changes in fatty acids in plasma and milk. Fish meal significantly increased plasma n-3 fatty acids compared to the fish oil treatment. Residual fatty acids contained in fish meal seemed to be protected from rumen degradation and probably remained intact for digestion and absorption since plasma n-3 fatty acid concentrations increased. No changes in milk yield or composition were due to the experimental treatments. Fat in fish meal and fish oil source differed significantly in their ability to alter milk composition and plasma fatty acid profiles.

Browsing by Author "Polan, Carl E."

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