Effects of pen bedding and feeding high crude protein diets on manure composition and greenhouse gas emissions from a feedlot pen surface

Greenhouse gas (GHG) emissions from concentrated animal feeding operations vary by stage of production and management practices. The objective of this research was to study the effect of two dietary crude protein levels (12 and 16%) fed to beef steers in pens with or without corn stover bedding. Manure characteristics and GHG emissions were measured from feedlot pen surfaces. Sixteen equal-sized feedlot pens (19 x 23 m) were used. Eight were bedded approximately twice a week with corn stover and the remaining eight feedlot pens were not bedded. Angus steers (n = 138) were blocked by live weights (lighter and heavier) with 7 to 10 animals per pen. The trial was a 2 x 2 factorial design with factors of two protein levels and two bedding types (bedding vs. non bedding), with four replicates. The study was conducted from June through September and consisted of four -28-day periods. Manure from each pen was scrapped once every 28 days and composite manure samples from each pen were collected. Air samples from pen surfaces were sampled in Tedlar bags using a Vac-U-Chamber coupled with a portable wind tunnel and analyzed with a greenhouse gas gas chromatograph within 24 hr of sampling. The manure samples were analyzed for crude protein (CP), total nitrogen (TN), ammonia (NH3), total volatile fatty acid (TVFA), total carbon (TC), total phosphorus (TP), and potassium (K). The air samples were analyzed for methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) concentrations. The concentration of TN was significantly higher (p < 0.05) in manure from pens with cattle fed the high protein diets. The volatile fatty acids (VFAs) such as acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids concentrations were similar across both treatments. There were no significant differences in pen surface GHG emissions across manure management and dietary crude protein levels.

Evaluation of feedlot cattle working chute behavior relative to temperament, tenderness, and postmortem proteolysis

The objective was to investigate if the association between working chute behavior and beef tenderness found in our previous study is related to protein degradation and calpain system activity. Crossbred steers (n=183) allotted to 16 pens were weighed every 28 d. Temperament was evaluated as exit velocity (EV), chute score (CS), and catch score (CAPS). Between 14 and 16 mo of age (606±52 kg), steers were harvested. Strip steaks were collected and aged for 14 d. Subsamples were collected at 36 h and 7d postmortem and analyzed for calpastatin activity, μ-calpain autolysis, and troponin-T degradation. Shear force (WBSF) was correlated (P<0.05) with calpastatin activity and measurements of troponin-T. Calpastatin activity, μ-calpain autolysis, and troponin-T measurements did not correlate with the measurements of EV, CS, and CAPS. Therefore, activation of the calpain system or differences in protein degradation did not appear to influence the differences in tenderness that are correlated with working chute behavior.

Predicting beef tenderness using color and multispectral image texture features

The objective of this study was to investigate the usefulness of raw meat surface characteristics (texture) in predicting cooked beef tenderness. Color and multispectral texture features, including 4 different wavelengths and 217 image texture features, were extracted from 2 laboratory-based multispectral camera imaging systems. Steaks were segregated into tough and tender classification groups based on Warner-Bratzler shear force. The texture features were submitted to STEPWISE multiple regression and support vector machine (SVM) analyses to establish prediction models for beef tenderness. A subsample (80%) of tender or tough classified steaks were used to train models which were then validated on the remaining (20%) test steaks. For color images, the SVM model correctly identified tender steaks with 100% accurately while the STEPWISE equation identified 94.9% of the tender steaks correctly. For multispectral images, the SVM model predicted 91% and STEPWISE predicted 87% average accuracy of beef tender.

Short Communication: Growth and attainment of puberty in calves from cows supplemented with linseed meal during late gestation and early lactation

Ilse, B. R., Anderson, V. L., Buchanan, D. S., Odde, K. G., Lardy, G. P. and Vonnahme, K. A. 2012. Short Communication: Growth and attainment of puberty in calves from cows supplemented with linseed meal during late gestation and early lactation. Can. J. Anim. Sci. 92: 443–447. To test the objective that a linseed meal (LSM) supplement in beef cows during late gestation and early lactation would impact offspring growth performance, steer carcass composition, and attainment of puberty in heifer calves, multiparous beef cows received either LSM or a control supplement for the last 60 d of gestation (exp. 1; n=72) or during the first 60 d of lactation (exp. 2; n=91). In both experiments, birth weight, weaning weight, and ADG of calves were not affected (P>0.31) by LSM supplementation. There was no effect (P>0.09) of supplementation on carcass characteristics of steer progeny fed to market weight. In exps. 1 and 2, attainment of puberty in heifer calves was not influenced (P>0.58) by supplement type. Linseed meal supplementation during late gestation or early lactation does not appear to affect calf growth, onset of puberty in heifer calves, or steer carcass quality.

Interplay between desolvation and secondary structure in mediating cosolvent and temperature induced alpha-synuclein aggregation

Both increased temperature and moderate concentrations of fluorinated alcohols enhance aggregation of the Parkinson's disease-associated protein α-synuclein (αS). Here, we investigate the secondary structural rearrangements induced by heating and trifluoroethanol [TFE]. At low TFE concentrations, CD spectra feature a negative peak characteristic of disordered polypeptides near 200 nm and a slight shoulder around 220 nm suggesting some polyproline-II content. Upon heating, these peaks weaken, while a weak negative signal develops at 222 nm. At high TFE concentrations, the spectra show distinct minima at 208 and 222 nm, indicative of considerable α-helical structure, which diminish upon heating. We observe a crossover between the low-TFE and high-TFE behavior near 15% TFE, where we previously showed that a partially helical intermediate is populated. We postulate that the protein is well solvated by water at low TFE concentrations and by TFE at high TFE concentrations, but may become desolvated at the crossover point. We discuss the potential roles and interplay of desolvation and helical secondary structure in driving αS aggregation.

Effects of increasing field pea (Pisum sativum) level in high-concentrate diets on growth performance and carcass traits in finishing steers and heifers

Three experiments were conducted to determine the effect of increasing field pea level in high-concentrate finishing cattle diets on ADG, DMI, G:F, and carcass traits, and to estimate the NE of field pea. In Exp. 1, 118 yearling heifers (417.9 +/- 2.4 kg initial BW) were blocked by initial BW and assigned randomly to 1 of 4 treatments (0, 10, 20, or 30% dry-rolled field pea, DM basis; 4 pens/treatment). In Exp. 2, 143 beef steers (433 +/- 19 kg initial BW) were blocked by BW and assigned randomly to 1 of 4 treatments (0, 10, 20, or 30% dry-rolled field pea, DM basis; 6 pens/treatment). In Exp. 3, 80 beef steers (372.4 +/- 0.4 kg initial BW) were assigned randomly to 1 of 4 treatments (0, 18, 27, or 36% cracked field pea, DM basis; 4 pens/treatment). Field pea replaced a portion of the grain (dry-rolled and high moisture corn, dry-rolled corn, and barley and barley sprouts; Exp. 1, 2, and 3, respectively) and protein supplement. In Exp. 1, field pea inclusion decreased DMI linearly (P = 0.03), whereas ADG and G:F were not affected by treatment (P > or = 0.17); however, dietary NE(g) increased quadratically with increasing field pea level (P = 0.04). Fat thickness responded quadratically (P = 0.008) where heifers fed 20% field pea had greatest fat thickness and 30% field pea inclusion the least. Marbling tended (P < or = 0.09) to respond quadratically as field pea increased. No differences (P > or = 0.17) were observed for HCW, LM area, or KPH. In Exp. 2, DMI, ADG, G:F, dietary NE(g), HCW, marbling, LM area, 12th-rib fat, and USDA yield grade (YG) were unaffected by dietary field pea inclusion (P > or = 0.12). In Exp. 3, marbling score increased linearly (P = 0.05), fat thickness increased quadratically (P = 0.01), and YG tended to increase (P = 0.07) quadratically as field pea increased. Field pea inclusion did not affect (P > or = 0.38) DMI, ADG, G:F, dietary NE(g), HCW, or LM area. These results indicate that field pea can be included successfully into rations at levels up to 36% of DM without negatively affecting growth performance and most carcass characteristics of finishing beef cattle; however, effects on marbling score were variable. These data also indicate the energy content of field peas is similar to cereal grains, such as corn and barley, when included in high-concentrate finishing diets.

Effect of field peas, chickpeas, and lentils on rumen fermentation, digestion, microbial protein synthesis, and feedlot performance in receiving diets for beef cattle

Two experiments were conducted to evaluate the use of pulse grains in receiving diets for cattle. In Exp. 1, 8 Holstein (615 +/- 97 kg of initial BW) and 8 Angus-crossbred steers (403 +/- 73 kg of initial BW) fitted with ruminal and duodenal cannulas were blocked by breed and used in a randomized complete block design to assess the effects of pulse grain inclusion in receiving diets on intake, ruminal fermentation, and site of digestion. Experiment 2 was a 39-d feedlot receiving trial in which 176 mixed-breed steers (254 +/- 19 kg of initial BW) were used in a randomized complete block design to determine the effects of pulse grains on DMI, ADG, and G:F in newly received feedlot cattle. In both studies, pulse grains (field peas, lentils, or chickpea) replaced corn and canola meal as the grain component in diets fed as a total mixed ration. Treatments included 1) corn and canola meal (control); 2) field pea; 3) lentil; and 4) chickpea. Preplanned orthogonal contrasts were conducted between control vs. chickpea, control vs. field pea, and control vs. lentil. In Exp. 1, there were no differences among treatments for DMI (11.63 kg/d, 2.32% of BW daily, P = 0.63) or OM intake (P = 0.63). No treatment effects for apparent ruminal (P = 0.10) and total tract OM digestibilities (P = 0.40) were detected when pulse grains replaced corn and canola meal. Crude protein intake (P = 0.78), microbial CP flow (P = 0.46), total tract CP digestibility (P = 0.45), and microbial efficiency (P = 0.18) were also not influenced by treatment. Total-tract ADF (P = 0.004) and NDF (P = 0.04) digestibilities were greater with field pea vs. control. Total VFA concentrations were lower for field pea (P = 0.009) and lentil (P < 0.001) compared with control. Chickpea, field pea, and lentil had lower (P < or = 0.03) acetate molar proportion than control. Ruminal pH (P = 0.18) and NH3 (P = 0.14) were not different among treatments. In Exp. 2, calves fed chickpea, field pea, and lentil had greater overall DMI (7.59 vs. 6.98 kg/d; P < or = 0.07) and final BW (332 vs. 323 kg; P < or = 0.04), whereas chickpea and lentil had greater ADG (1.90 vs. 1.71 kg/d; P < or = 0.04) than control. Gain efficiency (P = 0.18) did not differ among treatments. Steers fed pulse grains had similar CP and OM digestibilities compared with a combination of corn and canola meal in receiving diets. Pulse grains are a viable alternative for replacement of protein supplements in receiving diets for beef cattle.

Effect of processing flax in beef feedlot diets on performance, carcass characteristics, and trained sensory panel ratings1

To assess the effects of flax addition and flax processing on feedlot performance and carcass characteristics, 128 yearling beef heifers (360 +/- 14 kg of initial BW) were blocked by weight and assigned randomly to feedlot diets that included no flax (control), whole flax (WHL), rolled flax (RLD; 1,300 microm), or ground flax (GRD; 700 microm). Heifers were fed a growth diet (31% corn, 30% corn silage, 18% barley malt pellets, 14% alfalfa, 4% linseed meal, and 3% supplement; DM basis) for 56 d, after which they were adapted to a finishing diet (79% corn, 7% corn silage, 7% alfalfa, 4.75% linseed meal, and 2.25% supplement; DM basis). In WHL, RLD, and GRD, flax replaced all linseed meal and partially replaced corn at 8% of diet DM. All diets provided 0.5 mg of melengestrol acetate, 2,000 IU of vitamin E, and 232 mg of monensin per heifer daily. Cattle were slaughtered by block after 96, 97, and 124 (2 blocks) d on feed. At 24 h postmortem, carcass data were collected, and a portion of the loin was removed, vacuum-packaged, and aged for 14 d. After aging, 2 steaks were removed from each loin for Warner-Bratzler shear force measurement, sensory panel evaluation, and fatty acid analysis (approximately 100 g of muscle was collected). Flax inclusion (WHL, RLD, and GRD vs. control) did not affect DMI (P = 0.79), fat thickness over the 12th rib (P = 0.32), or LM area (P = 0.23). Flax inclusion increased ADG (P = 0.006), G:F (P = 0.006), and USDA yield grade (P = 0.01). Flax processing (RLD and GRD vs. WHL) increased ADG (P = 0.05), G:F (P = 0.08), and apparent dietary NEm and NEg (P = 0.003). Muscle from heifers fed flax had greater phospholipid 18:3n-3 (P < 0.001), 20:5n-3 (P < 0.001), 22:5n-3 (P < 0.001), and 22:6n-3 (P = 0.02) fractions, and greater neutral lipid 18:3n-3 (P < 0.001). Feeding 8% flax to feedlot heifers increased gain and efficiency, and processing flax increased available energy and resulted in increased efficiency of gain. Feeding 8% flax also increased levels of n-3 fatty acids in fresh beef.

Effects of increasing level of supplemental barley on forage intake, digestibility, and ruminal fermentation in steers fed medium-quality grass hay1

Objectives of this research were to evaluate effects of increasing level of barley supplementation on forage intake, digestibility, and ruminal fermentation in beef steers fed medium-quality forage. Four crossbred ruminally cannulated steers (average initial BW = 200 +/- 10 kg) were used in a 4 x 4 Latin square design. Chopped (5 cm) grass hay (10% CP) was offered ad libitum with one of four supplements. Supplements included 0, 0.8, 1.6, or 2.4 kg of barley (DM basis) and were fed in two equal portions at 0700 and 1600. Supplements were fed at levels to provide for equal intake of supplemental protein with the addition of soybean meal. Forage intake (kg and g/kg BW) decreased linearly (P < 0.01), and total intake increased linearly (P < 0.03) with increasing level of barley supplementation. Digestible OM intake (g/kg BW) increased linearly (P < 0.01) with increasing level of barley supplementation; however, the majority of this response was observed with 0.8 kg of barley supplementation. Treatments had only minor effects on ruminal pH, with decreases occurring at 15 h after feeding in steers receiving 2.4 kg of barley supplementation. Total-tract digestibility of DM, OM, NDF, and CP were increased (P < 0.04) with barley supplementation; however, ADF digestibility was decreased by 1.6 and 2.4 kg of barley supplementation compared with controls. Ruminal ammonia concentrations decreased linearly (P < 0.01) at 1 through 15 h after feeding. Total ruminal VFA concentrations were not altered by dietary treatments. Ruminal proportions of acetate and butyrate decreased (P < 0.10) in response to supplementation. Rate, lag, and extent (72 h) of in situ forage degradability were unaffected by treatment. Generally, these data are interpreted to indicate that increasing levels of barley supplementation decrease forage intake, increase DM, OM, and NDF digestibility, and indicate alteration of the ruminal environment and fermentation patterns.

Effect of energy source and ruminally degradable protein addition on performance of lactating beef cows and digestion characteristics of steers

Two trials were conducted to determine the effect of energy source (ENG) and ruminally degradable protein (RDP) on lactating cow performance and intake and digestion in beef steers. In Trial 1, 78 cow-calf pairs were used in a 2 x 2 factorial design to determine the effect of ENG (corn or soyhulls; SH) and RDP (with our without sunflower meal) to a forage diet for lactating beef cows. The basal diet consisted of 75% grass hay (11.5% CP) and 25% wheat straw (7.4% CP). Supplement treatments and predicted RDP balances were corn (-415 g of RDP/d); SH (-260 g of RDP/d); corn plus RDP (0 g of RDP/d); or SH plus RDP (0 g of RDP/d). Data were analyzed as a split-plot in time, with pen as the experimental unit (two pens per treatment). No interaction between ENG and RDP was present (P > 0.08) for any response variable. No differences (P > 0.39) due to ENG or RDP were noted for BW, BCS, or milk yield; however, final calf weight tended to increase with ENG (P = 0.06). In Trial 2, a 5 x 5 Latin square was used to determine effects of ENG and RDP on intake and digestion in steers (686 +/- 51 kg BW). Treatments were arranged as a 2 x 2 plus one factorial and comprised a control (CON; grass hay, 7% CP), grass hay plus 0.4% BW SH, grass hay plus 0.4% BW SH and 0.15% BW sunflower meal, grass hay plus 0.4% BW corn, and grass hay plus 0.4% BW corn and 0.2% BW sunflower meal. Preplanned contrasts included main effects of ENG and RDP, ENG x RDP interaction, and CON vs. supplemented (SUP) treatments. Supplementation increased total DMI compared with CON (P = 0.001), but forage DMI was greater (P = 0.001) for CON than for SUP. An ENG x RDP interaction occurred for forage DMI (P = 0.02); addition of RDP to corn decreased forage intake, whereas addition of RDP to SH had no effect. There was an ENG x RDP interaction (P = 0.001) for ruminal pH; pH tended to increase with RDP addition to SH (P = 0.07), but decreased with RDP addition to corn (P = 0.001). Supplementation increased ruminal ammonia compared with CON (P = 0.001). Likewise, RDP increased ruminal ammonia (P = 0.001). An interaction occurred for OM disappearance (OMD; P = 0.01). The RDP addition to SH numerically decreased OMD (P = 0.23), whereas RDP addition to corn numerically increased OMD (P = 0.14). Intake and digestion seem to respond differently to RDP addition depending on supplemental energy source. Both corn or SH seem to be suitable supplements for the quality of forage used in this trial. Addition of supplemental protein did not improve cow or calf performance.

Chlorinated dibenzo-p-dioxin and dibenzofuran concentrations in beef animals from a feeding study

Four calves were fed polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans for 120 days at levels somewhat higher than what may be found in forage near some waste incinerators and manufacturing plants. Four calves were fed identical diets but without the chemicals. Using bioelectrical impedance measurements of total body fat, 30-50% of the dosed 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, and 2,3,4,7,8-PeCDF was estimated to be retained by the animals. Although these same congeners were bioconcentrated in adipose tissue (BCF approximately 10), consumer products such as ribeye showed concentrations less than what were found in the animal feed (BCF approximately 0.1). Distribution of the dioxins and furans into various lipid compartments appeared to be rather uniform in back fat, perirenal fat, and ribeye for tetra to hexa congeners. Ribeye, serum, and liver lipids had higher concentrations of the higher chlorinated congeners, due in part to not reaching a steady state. An unexpected source of dioxin and furan contamination was discovered during the experiment, resulting in the control animals having concentrations of some congeners that were equal to or in some cases greater than those of the dosed animals. Pentachlorophenol-treated wood components in the pole barn where the feeding experiment was conducted were found to have contributed to the animals' exposure.

Effect of crambe meal on performance, reproduction, and thyroid hormone levels in gestating and lactating beef cows

Crambe meal was compared to a combination of sunflower and soybean meal as a protein supplement for mature beef cows in two experiments. In Exp. 1, cows (n = 80, average BW 651+/-14.4 kg) were fed crambe meal at 9.86% of dry matter intake (DMI) during the last trimester of gestation. No differences (P < .05) were detected due to treatment for cow weight, condition score, thyroid hormones, calf birth weight, or calving interval. In Exp. 2, cows (n = 100, average BW 566+/-6.82 kg) were fed crambe meal at 7.44% of DMI during the last trimester of gestation and at 8.33% of DMI during early lactation (53+/-6 d of lactation). Gains were greater during gestation (P = .09) and throughout the supplementation period (P = .06), and days to first estrus were reduced (P < .01) for cows fed crambe meal. During lactation, serum triiodothyronine (T3) concentrations did not decline as much (P = .03) in cows fed crambe meal as in cows fed sunflower-soybean meal-based supplements. No differences (P > .10) were apparent for condition score, birth weight, calf growth rate, weaning weight, thyroid hormones during gestation, or calving interval. These data indicate that crambe meal fed at the levels used in this experiment can be used as a protein supplement for beef cows without negatively affecting cows' performance.

Influence of crambe meal as a protein source on intake, site of digestion, ruminal fermentation, and microbial efficiency in beef steers fed grass hay

Four ruminally and duodenally cannulated beef steers (558 +/- 37 kg) were arranged in a 4 x 4 Latin square to evaluate the influence of crambe meal as a protein source on intake, digestion, and microbial efficiency. Steers were offered chopped (10.2 cm) brome hay (6.2% CP) for ad libitum consumption and one of four supplements. Protein sources used were soybean and crambe meals (CM). Protein sources were blended to provide four levels of supplemental CM protein (0, 33, 67, and 100%). Protein supplements were fed to provide similar amounts of protein and energy. Amounts of supplements fed were 831, 885, 950, and 996 g of DM/steer daily for 0, 33, 67, and 100% CM treatments, respectively. Crambe meal represented 0, 2.00, 3.83, and 5.88% of the DM intake for respective treatments. Steers were allowed a 21-d adaptation to diets before each collection period. Supplements were offered at 0800 and forage at 0830. Crambe meal had no influence (P > .10) on forage and total DM intake (grams/kilogram of BW). Apparent total tract, ruminal, and postruminal digestion of OM, NDF, ADF, and N were unaffected (P > .10) by CM supplementation.(ABSTRACT TRUNCATED AT 250 WORDS)

Crambe meal is equivalent to soybean meal for backgrounding and finishing beef steers

Growth, feed efficiency, and carcass characteristics of 70 crossbred steers fed one of four diets were compared. The four diets differed in source of protein supplementation: 100% soybean meal (SB), 67% SB and 33% crambe meal (CM), 33% SB and 67% CM, and 100% CM. All supplements were fed in isonitrogenous amounts. Steers were fed backgrounding diets (12.9% CP) for 84 d and finishing diets (11.2% CP) for 96 d. Average initial weight was 303.4 kg. Backgrounding gains ranged from 1.38 to 1.41 kg/d (P = .92). Finishing gains ranged from 1.43 to 1.47 kg/d (P = .86). Range in entire-experiment gains was 1.41 to 1.46 kg/d (P = .85). Feed efficiencies were equal; entire-experiment efficiencies averaged .144 (P = .96). Growth and efficiency patterns were the same for all four treatments. No overall treatment differences were detected for the seven carcass variables (P = .26 to .96). Average fat depth, longissimus muscle area, yield grade, and dressing percentage were .95 cm, 84.0 cm2, 2.45, and 61%, respectively. At the protein percentage levels of these diets, CM substituted equally for SB for growth rate, feed efficiency, and carcass characteristics.

A statistical approach for the development of an oral controlled-release matrix tablet

Tablet matrix compositions for optimized prolonged release were selected by surface response methodology. The extreme vertices experimental design was used to develop a surface response model which mathematically defined the release of active component from the tablet matrix as controlled by the percentage of the excipient components. The model, a statistical quadratic equation with a standard error of 3.3, was validated for accurate prediction of drug release profiles and used to identify optimum formulations. This study demonstrated a new application of the extreme vertices experimental design, an efficient method for evaluating a complex mixture system for controlled release, where specific constraints are placed on one or more of the components.

Dose-dependent pharmacokinetics of gentamicin in sheep

Dose-related changes in the pharmacokinetics of gentamicin sulfate were investigated in 9 sheep given 3, 10, or 20 mg/kg of body weight IV in a crossover design with a 24-day washout period. The pharmacokinetics of the 3 mg/kg single dose were compared with that of the terminal phase pharmacokinetics of 3 mg of gentamicin/kg IV every 8 hours for 7 days in 8 additional sheep. Serum concentrations were monitored for 21 to 24 days after the dose. Polyexponential equations were fit to each data set. The number of exponential terms was determined by optimizing the fit for each data set. The pharmacokinetics of the 3 mg/kg single dose were mainly described by triexponential equations. The 10 mg/kg and the 20 mg/kg single doses and the 3 mg/kg multiple-dose data were described by a tetraexponential equation. The elimination rate constant was significantly smaller (P less than 0.05) after the larger single doses, and the serum gentamicin clearance increased as the dose increased (P less than 0.05). The crossover design sequence had a significant effect on serum gentamicin clearance and the area under the curve normalized to unit dose (P less than 0.01). The final exponential phase was not detectable with the present assay sensitivity under the 3 mg/kg single dose. The triexponential equation underpredicted the terminal serum concentrations determined after the 3 mg/kg multiple dose, whereas the 4 phase equation overpredicted the same terminal serum concentrations, perhaps reflecting saturation of the tissue pools that were mirrored by the serum gentamicin concentrations after 24 hours. The present study emphasized the complexity of the terminal phase gentamicin. pharmacokinetics and acknowledged the need for a long-term washout period when using the crossover design for gentamicin pharmacokinetic studies.

Logistic growth curve of chickens: a comparison of techniques to estimate parameters

Parameters of a mathematical function of growth, fit to the body weight curve of two randombred control populations of each sex of chickens from hatching through 45 weeks of age, were estimated. The logistic function was chosen from among growth formulae that express rate of gain as a function of weight at a given time and gain to be made. Two logistic parameters, growth-rate constant and age at the point of inflection, were estimated by the methods of sample quantiles and nonlinear regression from weekly mean body weights of 225 males and 281 females of the Rhode Island Red (RIR) line, and 164 males and 239 females of the White Leghorn (WL) line. Males had a larger growth-rate constant than females of the same line. The RIR line had a larger rate constant than the WL line, for each sex. Age at the point of inflection was similar for males and females in the RIR line, but smaller for males than females in the WL line. Sample quantiles yielded larger, less precise estimates of the growth-rate constant than nonlinear regression. Estimates of age at the point of inflection were usually smaller using sample quantiles.

Irradiation-hyperthermia in canine hemangiopericytomas: large-animal model for therapeutic response

Results of irradiation-hyperthermia treatment in 11 dogs with naturally occurring hemangiopericytoma were reported. Similarities of canine and human hemangiopericytomas were described. Orthovoltage X-irradiation followed by microwave-induced hyperthermia resulted in a 91% objective response rate. A statistical procedure was given to evaluate quantitatively the clinical behavior of locally invasive, nonmetastatic tumors in dogs that were undergoing therapy for control of local disease. The procedure used a small sample size and demonstrated distribution of the data on a scaled response as well as transformation of the data through classical parametric and nonparametric statistical methods. These statistical methods set confidence limits on the population mean and placed tolerance limits on a population percentage. Application of the statistical methods to human and animal clinical trials was apparent.

The importance of cauterization to maintain a healthy cervix. Long-term study from a private gynecologic practice

A total of 13,897 patients from a private gynecologic practice were retrospectively analyzed with special regard to the benefits obtained from hot linear cautery. This has been performed as an office procedure since 1937, providing unique long-term follow-up. The exposed cervical transitional zone and mild, atypical, or dysplastic cervical cytology were so treated in 6,364 patients. A significantly higher percentage of carcinoma in situ and invasive disease was found in the noncauterized cervices. With the trend of cervical intraepithelial neoplasia (CIN) toward development at an earlier age in today's population, the importance of office cauterization in preventing cervical cancer becomes apparent.

The water-to-air transfer of 35SO4= by bursting bubbles

The transfer of 35SO4= from water to air by bursting bubbles was studied as a function of three levels each of three variables in a bubbling solution. The variables were pH, surfactant concentration, and Na2 35SO4 concentration. One combination of the above variables was also studied at three different temperatures. Sterile water solutions containing different combinations of the above factors and a fixed amount of 22NaCl were bubbled in an enclosure for 1 hour. After bubbling, samples of the aerosol produced, the larger drops that fell out of the air, and the bulk solution were collected and assayed for their 35S and 22Na content using liquid scintillation counting. The 35S/22Na enrichment for each droplet sample as compared to the ratio for the bulk solution was determined, and it was found to be dependent upon the combination of the factor levels being bubbled. Both positive and negative enrichments were found, with large positive enrichments being found consistently only for the highest value of surfactant concentration. The temperature study showed no significant enrichment differences for any of the three temperatures studied.