Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate.

Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2 ) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes.

Qualitative fit test outcomes for N95 filtering facepiece respirators in health care workers.

BACKGROUND: We analyzed the qualitative fit test results of the filtering facepiece respirators (FFRs) used at our institution to determine their performance and utility. METHODS: We retrospectively analyzed 12,582 qualitative fit testing results for several FFR models among 8,809 health care workers (HCWs). RESULTS: The overall failure rate for HCWs was 15.2%. Nearly one-third (2933/8809, 33.3%) had multiple FFRs fit tested. HCW sex was a statistically significant indicator of fit testing failure (χ2 = 29.9, df = 1, P < .001), with women having a 44% higher likelihood (OR, 1.4; 95% CI: 1.27-1.65) than men. There were statistically significant differences in the failure rate across FFRs (Fig 4, F[5, 12475] = 8.4, P < .001). Fluidshield 46867S had a significantly higher failure rate (49%) than the 3M 1860 (P = .012), 3M 1860S (P < .001), 3M 8210 (P < .001), and Safelife (P < .001) FFRs. CONCLUSIONS: There was a large degree of variation in fit testing results for the FFRs tested. Although we were unable to find an FFR that fit more than 95% of the HCWs successfully, we identified poorly functioning FFRs that can help our institution with decision-making and budgeting for acquisition and stocking appropriate FFRs.

Binding specificity of serum amyloid P component for the pyruvate acetal of galactose.

Serum amyloid P component (SAP) is a normal plasma protein that is of interest because of its presence in amyloid deposits, its presence in normal human glomerular basement membrane, and its stable evolutionary conservation. It has calcium-dependent ligand-binding specificity for amyloid fibrils, fibronectin (Fn), C4-binding protein (C4bp), and agarose. Although the binding to agarose, a linear galactan hydrocolloid derived from some marine algae, is unlikely per se to be related to the physiological function of SAP, it does provide a model system in which to explore the precise ligand requirements of SAP. We report here that the amount of SAP from human, mouse, and plaice (Pleuronectes platessa L.) serum able to bind to agarose from different sources reflect precisely their pyruvate content. Methylation with diazomethane of the carboxyl groups in the pyruvate moiety of agarose completely abolishes SAP binding to agarose. The pyruvate in agarose exists as the 4,6-pyruvate acetal of beta-D-galactopyranose. We have therefore synthesized this galactoside, using a novel procedure, established its structure by analysis of its nuclear magnetic resonance spectra, and shown that it completely inhibits all known calcium-dependent binding reactions of SAP. The R isomer of the cyclic acetal, methyl 4,6-O-(1-carboxyethylidene)-beta-D-galactopyranoside (MO beta DG) was effective at millimolar concentration and was more potent than its noncyclic analogue, while pyruvate, D-galactose, and methyl beta-D-galactopyranoside were without effect. The autologous protein ligands of SAP presumably, therefore express a structural determinant(s) that stereochemically resembles MO beta DG. Availability of this specific, well-characterized, low molecular weight ligand for SAP should facilitate further investigation of the function of SAP and its role in physiological and pathophysiological processes.

Uncertainty in the response of terrestrial carbon sink to environmental drivers undermines carbon-climate feedback predictions.

Terrestrial ecosystems play a vital role in regulating the accumulation of carbon (C) in the atmosphere. Understanding the factors controlling land C uptake is critical for reducing uncertainties in projections of future climate. The relative importance of changing climate, rising atmospheric CO2, and other factors, however, remains unclear despite decades of research. Here, we use an ensemble of land models to show that models disagree on the primary driver of cumulative C uptake for 85% of vegetated land area. Disagreement is largest in model sensitivity to rising atmospheric CO2 which shows almost twice the variability in cumulative land uptake since 1901 (1 s.d. of 212.8 PgC vs. 138.5 PgC, respectively). We find that variability in CO2 and temperature sensitivity is attributable, in part, to their compensatory effects on C uptake, whereby comparable estimates of C uptake can arise by invoking different sensitivities to key environmental conditions. Conversely, divergent estimates of C uptake can occur despite being based on the same environmental sensitivities. Together, these findings imply an important limitation to the predictability of C cycling and climate under unprecedented environmental conditions. We suggest that the carbon modeling community prioritize a probabilistic multi-model approach to generate more robust C cycle projections.

The ability of peripheral quantitative ultrasound to identify patients with low bone mineral density in the hip or spine.

This study aims to assess the sensitivity and specificity of two commercially available quantitative ultrasound (QUS) scanners (CUBA Clinical, Sunlight Omnisense), to differentiate patients with osteoporosis (OP) or osteopenia at the spine and hip confirmed by dual-energy x-ray absorptiometry (DXA) and to investigate the optimum cut-off values to maximize the effectiveness of the screening technique. Participants (n = 268) received DXA scans on their lumbar spine (L1-L4) and hip, with paired QUS scans on their distal radius, proximal phalanx, midshaft tibia and calcaneus. Scanners were evaluated by using receiver-operating characteristics curves and their area under the curve (AUC) values. Measurement of the calcaneus by the CUBA Clinical showed a superior ability to predict DXA, with AUC values between 0.75 to 0.83 in comparison with AUC values of 0.60 to 0.70 for the Sunlight Omnisense. Cut-off values varied according to the technique used and the accuracy of the screening required. Assessment of the calcaneus was the best QUS technique for the prediction of low bone density at the axial skeleton as diagnosed by DXA.

Novel analogs of tricyclic psychopharmacological agents.

The synthesis of several novel analogs of amitriptyline and chlorprothixene, in a number of which the position of the side-chain nitrogen atom rigidly fixed with respect to the tricyclic nucleus, is described. The compounds were evaluated for antidepressant-like activity in the Dopa and serotonin interaction tests and for potential antipsychotic activity in the methamphetamine interaction test. 5-(3-Dimethylaminocyclohex-1-enyl)-5H-dibenzo[a,d]cycloheptene (12) was about equipotent with imipramine in the Dopa and methamphetamine tests, and 3-chloro-10,11-dihydro-5H-dibenzo[a,d]cycloheptene-5-spiro-6'-3'-methyl-3'-azabicyclo[3.1.0]hexane (23) also displayed marked activity in the same tests. Prototype compounds for other ring systems, 3-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene tropane (16) and 5-(3-dimethylaminocycloheptylidene)-10,11-dihydro-5H-dibenzo[a,d]cycloheptene (18), were less active.

Systematic comparison of ILWAS, MAGIC, and ETD watershed acidification models: 3. Mass balance budgets for acid neutralizing capacity.

Three watershed acidification models-ILWAS, MAGIC, and ETD-were quantitatively compared to determine model structural differences by using a combination of input mapping and ANC mass balance budgets. Input mapping is a set of rules and algorithms to ensure that consistent input values were simultaneously derived for all three models. ANC budget analysis under current SO4(2-) deposition and a 70% reduction in SO4(2-) deposition allows examination of the relative importance of biogeochemical processes in affecting predictions of ANC or predicted changes in ANC. Model inputs were based on two dissimilar watersheds having characteristics typical of watersheds in the northeastern US. After mapping inputs, the three models predicted values of outflow ANC fluxes that were similar among the models for each watershed and deposition scenario. Within each watershed, the changes in outflow ANC fluxes between the scenarios were similar for the three models. Terrestrial weathering was the major source of ANC for all three models for both watersheds and deposition scenarios. The contributions of other processes to the ANC of the two watersheds were, under certain conditions, model-specific. Cation exchange was responsible for changes in ANC when deposition decreased for the three models. Other processes responsible for changes in ANC between scenarios were SO4(2-) sorption (for MAGIC) and in-lake weathering (for ETD). The processes responsible for the change in ANC from a change in deposition (cation exchange, SO4(2-) sorption, and in-lake weathering) were different from the processes contributing to the absolute ANC for a given deposition scenario (terrestrial weathering). The budget analysis complements an earlier Monte Carlo analysis that showed that the three models are structurally different and that predictions viewed on a relative scale are more similar than absolute scale predictions.

Contribution of the scrotum, testes, and testicular artery to scrotal/testicular thermoregulation in bulls at two ambient temperatures.

The objective of this study was to determine the contribution of the scrotum, testes, and the testicular artery to scrotal/testicular thermoregulation in bulls at two ambient temperatures. Crossbred beef bulls, 1.5 years of age, were placed in controlled environment chambers at ambient temperatures of 15 degrees C (n = 5) or 25 degrees C (n = 6). The distal lateral aspects and entire ventral part of the scrotum was incised under caudal epidural anaesthesia (xylazine, 0.07 mg kg-1. Both testes were withdrawn from the scrotum and then replaced and maintained by clamping the scrotal incisions with towel clamps. One testis was randomly chosen to be the exposed testis and was withdrawn prior to temperature measurements. Surface and internal temperature were measured with infrared thermography and needle thermocouples, respectively. Temperature gradients (degree C; difference in temperature from top to bottom at 15 and at 25 degrees C) were: scrotal surface (with testis), 1.5 and 1.3; scrotal surface (without testis), 2.1 and 1.6; surface of exposed testis, -0.6 and 0.0; sub-tunic of exposed testis, -2.2 and -0.6; intratesticular (covered testis), 0.0 and 0.4; and intratesticular (exposed testis), -1.3 and 0.4. The scrotum markedly affects testicular temperature but the testes have limited influence on scrotal surface temperature. The bovine scrotum and testes have opposing temperature gradients that complement one another, resulting in a relatively uniform intratesticular temperature. These temperature gradients are attributed in part to the testicular artery, which goes from the top of the testis to the bottom, divides into several branches and ramifies dorsally and laterally before entering the testicular parenchyma. Intra-arterial temperatures (measured with needle thermocouples) were lower (P < 0.05) where the artery entered the testis than at both the bottom and top of the testis for both the covered (31.7, 33.4 and 34.3 degrees C) and exposed testis (29.6, 32.0 and 32.5 degrees C) at an ambient temperature of 15 degrees C. Temperature differences were similar, but less pronounced, at 25 degrees C (covered testis, 34.8, 36.3 and 36.5 degrees C; exposed testis, 32.4, 33.5, 33.9 degrees C). Results supported the hypothesis that blood within the testicular artery has a similar temperature at the top of the testis (just ventral to the testicular vascular cone) compared with the bottom, but subsequently cools before entering the testicular parenchyma.

The testicular vascular cone, scrotal thermoregulation, and their relationship to sperm production and seminal quality in beef bulls.

The objectives of the present study were to determine changes with age and relationships among characteristics of the testicular artery, scrotal surface temperature, scrotal circumference, testicular consistency, seminal quality and sperm production. Beef bulls aged 6 mo (n=12), 1 yr (n=12), 2 yr (n=11), and 3 yr (n=12) were used in this study. The mean length of the testicular artery as well as the length, width, and surface area of a latex cast of the testicular artery all increased between 6 mo and 1 yr of age (P<0.01). Wall thickness of the testicular artery and testicular arterial-venous distance in the spermatic cord decreased with age and with proximity to the testicle (P<0.01). Distance from the testicular vascular cone to the inner surface of the skin at the top of the scrotal neck (primarily fat) increased between 1 and 3 yr of age (P<0.01), and was associated with an increased top scrotal surface temperature (P<0.09). Increased epididymal sperm reserves were associated with an increase in testicular consistency, scrotal circumference and scrotal surface temperature gradient, and with a decrease in testicular arterial wall thickness and testicular vascular cone to skin distance. A decrease in sperm defects was associated with an increase in testicular consistency and with a decrease in the average scrotal surface temperature. Increased sperm motility was associated with increased scrotal circumference and a decreased top testicular vascular cone to skin distance. These findings emphasize the importance of thermoregulation to sperm production and seminal quality.

Insulating the scrotal neck affects semen quality and scrotal/testicular temperatures in the bull.

Nine Simmental X Angus bulls (2-yr of age) were used in 2 experiments. In Experiment 1, the scrotal neck was insulated (from Day 1 to Day 8) in 5 bulls, and semen was collected from all 9 bulls by electroejaculation approximately every 3 d until Day 35. Bulls with insulated scrotal necks had lower percentages of normal spermatozoa (P < 0.08) and higher percentages of spermatozoa with head defects (P < 0.06) or droplets (P < 0.08) than the untreated bulls. There was a time-by-treatment interaction (P < 0.04) for midpiece defects; the incidence was higher (P < 0.05) in the insulated than noninsulated bulls from Day 5 to Day 32. Spermatozoa within the epididymis or at the acrosome phase during insulation appeared to be the most affected. Compared with the noninsulated bulls, the insulated bulls had twice as many (P < 0.02) spermatozoa with midpiece defects and 4 times as many (not significant) with droplets on Day 5, fewer (P < 0.04) normal spermatozoa and 3 times as many with midpiece defects (P < 0.05) and with droplets (not significant) on Day 8, fewer (P < 0.02) normal spermatozoa on Days 15 and 18, and more sperm cells (P < 0.05) with head defects on Days 18 and 21. In Experiment 2, scrotal subcutaneous temperature (SQT; degrees C, mean +/- SE) prior to and after the scrotal neck had been insulated for 48 h in all 9 bulls was 30.4 +/- 0.7 and 32.4 +/- 0.6 (P < 0.01) at the top, 30.3 +/- 0.7 and 31.8 +/- 0.6 (P < 0.03) at the middle, and 30.2 +/- 0.8 and 30.7 +/- 0.6 (P < 0.05) at the bottom of the scrotum. Concurrently, there was an increase (0.9 degrees C) in intratesticular temperature (ITT) at the top (P < 0.07), middle (P < 0.04), and bottom (P < 0.04) of the testes. Scrotal surface temperature (SST) prior to and after the scrotal neck had been insulated for 24 h was 29.2 +/- 0.7 and 28.2 +/- 0.4 (P < 0.05) at the top of the scrotum and 24.7 +/- 0.6 and 25.3 +/- 0.7 (not significant) at the bottom, resulting in SST gradients of 4.6 +/- 0.6 and 2.9 +/- 0.5, respectively (P < 0.05). However, after the scrotal neck had been insulated for 48 h, none of the SST end points were significantly different from those prior to insulation. It appears that compensatory thermoregulatory mechanisms restored SST but were not able to restore SQT and ITT. Insulation of the scrotal neck affected SST, SQT, ITT and semen quality, emphasizing the importance of the scrotal neck in scrotal/testicular thermoregulation.

Ejaculation increases scrotal surface temperature in bulls with intact epididymides.

The objective of the study was to determine the effects of ejaculation on scrotal surface temperature (SST) measured with infrared thermography in bulls. In 18 Holstein bulls (18 mo old), sexual stimulation and spontaneous ejaculation (into an artificial vagina) increased SST at the bottom of the scrotum (0.9 degrees C; P < 0.0001). In 11 Angus bulls (1 yr old) electroejaculation increased both bottom and average SST (1.7 degrees C; P < 0.005 and 0.9 degrees C, P < 0.05), while in 12 Simmental cross bulls (2 yr old) electroejaculation significantly increased top, bottom and average SST (1.0, 1.2 and 1.1 degrees C, respectively). However, there was no significant increase in SST following electroejaculation in 15 Simmental cross bulls (2 yr old) with caudal epididectomies. The increase in SST was attributed to a localized increase in SST over the cauda epididymides, perhaps due to heat produced by contraction of the cauda epididymides during ejaculation. The results support the hypothesis that spontaneous ejaculation or electroejaculation increases SST and that this response is mediated by the cauda epididymides. Infrared thermography of the scrotum for evaluation of scrotal/testicular thermorégulation for clinical or research purposes should be performed before semen collection since thermography conducted soon after ejaculation may be misleading.

Effects of immunization against GnRH, melengestrol acetate, and a trenbolene acetate/estradiol implant on growth and carcass characteristics of beef heifers.

A 2 x 3 factorial experiment was conducted to determine the effects of an implant (trenbolene acetate/estradiol or no implant) and method of estrus suppression (immunization against GnRH, melengestrol acetate, or no suppression) on growth performance and carcass characteristics of heifers fed for slaughter. At the start of a 21-d feed adaption phase, crossbred beef heifers (n = 144, 390+/-2.8 kg) were given their first dose of an anti-GnRH vaccine or started on melengestrol acetate (MGA). Thereafter, heifers were fed a high-concentrate diet (78% barley grain) for 84 d (Days 0 to 83), received implants on Day 0, a second vaccination on Day 21, and were slaughtered on Days 84 or 85. Implanting increased average daily gain (1.72 vs 1.50 kg/d, P < 0.01), feed efficiency (6.02 vs 6.75 kg dry matter intake/kg gain, P < 0.01), preslaughter weight (532 vs 513 kg, P < 0.01), carcass weight (301 vs 289 kg, P < 0.01), and ribeye area (88.6 vs 85.9 cm2, P < 0.05), but had no affect (P > 0.05) on dry matter intake, grade fat thickness, marbling score, or lean yield. Compared to heifers fed MGA, those immunized against GnRH had a greater ribeye area (90.0 vs 84.6 cm2) and lean yield (63 vs 61%), and had thinner grade fat (7.5 vs 8.6 mm; P < 0.05 for each). Furthermore, immunized heifers had lower (P < 0.001) plasma progesterone concentrations than control heifers on Days 42, 63 and 83. Heifers fed MGA had less estrus mounting activity (P < 0.05) and lower plasma progesterone concentrations (P < 0.001) than the remaining heifers. Method of estrus suppression did not affect (P > 0.05) preslaughter weight, average daily gain, dry matter intake, feed efficiency, carcass weight, or marbling score. In conclusion, implanting significantly increased growth performance and preslaughter and carcass weights. Compared to heifers fed MGA, immunization against GnRH significantly increased ribeye area and lean yield, and reduced grade fat thickness

Endocrine and thermal responses to GnRH treatment and prediction of sperm output and viability in holstein-Friesian breeding bulls.

A study was conducted to determine changes in serum LH and testosterone concentrations and in scrotal surface temperature (SST; measured with infrared thermography) following GnRH treatment and to predict the number of spermatozoa collected and the proportion that were viable. Holstein-Friesian breeding bulls (n = 22, average age, 24.3 m.o.; range, 15 to 41 m.o.) were examined twice 30 d apart. Concurrently, semen was collected twice weekly with an artificial vagina. Treatment with GnRH (100 micrograms, i.m.) increased (P < 0.0001) serum LH and testosterone concentrations and increased (P < 0.0001) SST (range 0.6 to 1.1 degrees C; P < 0.05) at the top and bottom of the scrotum. In regression models to predict the total number of spermatozoa, significant independent variables included ultrasonic echotexture of the testes (negative slope), scrotal width (positive slope) and SST at the bottom of the scrotum 45 min after GnRH treatment (positive slope). In regression models to predict the percentage of live spermatozoa, ultrasonic echotexture was a significant independent variable (negative slope). Measurement of testicular ultrasonic echotexture and SST after GnRH treatment augmented measurement of testicular size for predicting the number and percentage of live spermatozoa.

Effects of dietary energy on scrotal surface temperature, seminal quality, and sperm production in young beef bulls.

The objective of this study was to determine the effect of dietary energy, breed (British vs Continental x British crosses), and their interactions on scrotal surface temperature (SST), seminal quality, and sperm production in bulls. This experiment, replicated over 2 yr, included 72 Angus, Angus x Simmental, or Hereford x Simmental bulls fed either a moderate- (100% forage) or high-energy (80% grain, 20% forage) diet for 168 d after weaning. At the end of the feeding period, SST was determined by infrared thermography, seminal samples (two ejaculates) were collected by electroejaculation, and reproductive tracts were collected at slaughter. Bulls fed the high-energy diet were heavier (P < .0001; diet x time interaction), had thicker backfat (P < .05; diet x line x time interaction), and had a larger scrotal circumference (P < .05). Testicular tone decreased over time (P < .0001) with a diet x time interaction (P < .05). There was no significant effect of diet on top, bottom, or average SST. However, bulls fed the moderate-energy diet had a larger (P < .02) SST gradient (3.9 vs. 3.4 degrees C). Bulls fed the moderate-energy diet had more (P < .01) morphologically normal spermatozoa (68.8 +/- 2.1 vs 62.5 +/- 2.5%) and a higher proportion (P < .006) of progressively motile spermatozoa (53.4 +/- 2.1 vs 44.5 +/- 2.4%). No effects (P > .05) of dietary energy on epididymal sperm reserves or daily sperm production were detected. Increased dietary energy may affect scrotal or testicular thermoregulation by reducing the amount of heat that can be radiated from the scrotal neck, thereby increasing the temperature of the testes and scrotum.

The effects of active immunization against gnRH on testicular development, feedlot performance, and carcass characteristics of beef bulls.

The objective was to determine the effects of a recombinant fusion protein anti-GnRH vaccine on testicular development, feedlot performance, and carcass quality of beef bulls. Crossbred beef bulls (n = 58, average weight 306 kg, 9 mo of age), were randomly allocated to two groups and received either an anti-GnRH vaccine (GnRH) or placebo (Control) by intramuscular injection on d 0, 56, and 112. There were group effects (P < 0.01; as a percentage of Control) on testicular weight (53%), daily sperm production (40%), and epididymal sperm reserves (16%). There were group x time interactions (P < 0.0001) for scrotal circumference and serum testosterone concentrations; at slaughter, bulls in the GnRH group had a smaller (P < 0.05) scrotal circumference (28.3 vs 33.9 cm) and lower (P < 0.05) serum testosterone concentrations (2.2 vs 8.6 ng/mL) than those in the Control group. Average daily gain, feed intake, and feed efficiency were not different between treatments during the backgrounding phase (d 0 to 84). During the finishing phase (d 98 to 182), ADG was greater (P < 0.05) for bulls in the Control group (1.69 vs 1.42 kg/d), as was carcass weight (6.9%; P < 0.01). However, GnRH bulls had numerically better feed efficiency (6.12 vs 7.08 kg DMI/kg gain; P < 0.23) and shear force values for ribeye that were 16% lower (P < 0.14) than Control bulls, warranting further investigation. Vaccinating bulls against GnRH suppressed testicular function, with growth and carcass characteristics similar to that expected with steers.

Effects of ambient temperature and scrotal fleece cover on scrotal and testicular temperatures in rams.

The objective was to determine scrotal and testicular temperatures in rams and how they are affected by ambient temperature (10 degrees C vs 25 degrees C) and scrotal fleece (densely fleeced vs shaved). Scrotal surface temperatures (SST) of the caudal aspect of the shaved hemi-scrotum at 10 degrees C vs 25 degrees C were (mean, degrees C) 28.9 and 30.5 (P < 0.03), 28.2 and 29.6 (P < 0.04), and 26.1 and 27.6 (P < 0.06) at the top, middle and bottom of the testis, respectively. Scrotal subcutaneous temperatures (SQT) on the fleeced vs shaved side were 33.5 and 32.0 (P < 0.02), 32.2 and 31.1 (P < 0.06), and 31.7 and 30.8 (P < 0.09) at the top, middle, and bottom at 10 degrees C; they were 33.9 and 32.1 (P < 0.02), 33.1 and 31.9 (P < 0.05), and 32.5 and 32.0 (P < 0.15) at 25 degrees C. Intratesticular temperatures (ITT; measured only at 25 degrees C) on the fleeced vs shaved side were 35.3 and 35.0 (P < 0.5), 35.5 and 35.2 (P < 0.4), and 35.4 and 35.0 (P < 0.3) at the top, middle, and bottom. Temperature gradients (difference from top to bottom) were greatest for SST (2.8 degrees C), moderate for SQT (1.8 to 0.1 degrees C), and not significant for ITT (-0.1 and 0.1 degrees C). The SST was approximately 1.5 degrees C warmer at all 3 locations at 25 degrees C vs 10 degrees C. Increased ambient temperature affected SQT more at the bottom than at the top. Conversely, the difference in SQT between the fleeced and shaved sides was greatest at the top. The difference in ITT (0.3 degrees C warmer on the fleeced vs the shaved side at all locations) was not significant. Therefore, the magnitude of temperature increase associated with ambient temperature or scrotal fleece was affected by both depth and vertical location.

Relationships among scrotal and testicular characteristics, sperm production, and seminal quality in 129 beef bulls.

Standard breeding soundness examinations plus measurement of scrotal surface temperature (SST), internal/scrotal testicular temperatures, testicular ultrasonographic echotexture, daily sperm production, and epididymal sperm reserves were conducted on 129, 16-month-old crossbred beef bulls. There were significant positive linear correlations between SST and internal scrotal/testicular temperatures, a positive linear regression (P < 0.06) of bottom SST with the incidence of secondary sperm defects, but a negative linear regression (P < 0.01) with the incidence of primary sperm defects. Testicular echotexture had a positive linear regression with daily sperm production (P < 0.002) and testicular tone had a negative linear regression (P < 0.008) with epididymal sperm reserves. Scrotal circumference had a positive linear regression (P < 0.04) with the percentage of progressively motile sperm, a negative linear regression (P < 0.1) with the incidence of primary sperm defects, and a positive linear regression (P < 0.0001) with epididymal sperm reserves. In addition to seminal quality and scrotal circumference, testicular ultrasonographic echotexture has considerable promise for augmenting breeding soundness examinations of bulls.

Effects of GnRH treatment on scrotal surface temperatures in bulls.

Two experiments were conducted to characterize scrotal surface temperature (SST) in bulls treated with gonadotropin releasing hormone (GnRH). In Experiment 1, Angus bulls (n = 10, 18 mo, 597 kg) were given GnRH (400 ng/kg) or saline, IV. Bottom SST increased approximately 1.7 degrees C (P < 0.005) over time (0 to 90 min) at an ambient temperature of 5 degrees C. However, there was no significant effect of GnRH treatment and temperature increases were attributed to stress. When the experiment was repeated at an ambient temperature of 25 degrees C, SST was elevated prior to treatment, with no subsequent significant increase. Experiment 2 was conducted with Charolais bulls (n = 6, 12-14 mo, 517 kg) with an emphasis on minimizing stress. Bottom SST increased approximately 2 degrees C (P < 0.05) between 0 and 45 min after GnRH treatment, supporting the hypothesis that GnRH treatment increases SST in bulls. In conclusion, it was apparent that stress, high ambient temperatures, and GnRH treatment can all increase SST in bulls.

Scrotal/testicular thermoregulation and the effects of increased testicular temperature in the bull.

Scrotal/testicular thermoregulation is a complex process controlled by numerous local mechanisms that attempt to maintain the testes at conditions ideal for spermatogenesis. This article provides a background of the anatomy and physiology of the bovine scrotum and its contents with emphasis on thermoregulation. Experiments are cited that demonstrate scrotal/testicular thermoregulation mechanisms and the effect that changes in ambient temperature have on internal testicular temperature and subsequent seminal quality.

Synchronization of estrus in beef cattle with norgestomet and estradiol valerate.

Fifty-six cows received a norgestomet implant and an injection of norgestomet and estradiol valerate; half (n = 28) received 500 IU equine chorionic gonadotrophin (eCG) at implant removal, 9 d later. A third group (n = 25) received 2 doses of cloprostenol (500 micrograms) 11 d apart. Estrous rate was higher (P < 0.05) for cows given norgestomet and estradiol plus 500 IU eCG (75.0%) than for those receiving cloprostenol (44.0%); for those receiving norgestomet and estradiol alone, it was intermediate (67.8%). Pregnancy rates to artificial insemination (after estrus or timed) were higher (P < 0.05) for cows given norgestomet and estradiol than for those given cloprostenol (23 of 28, 82.1% vs 13 of 25, 52.0%), and intermediate (67.8%) for those given norgestomet and estradiol plus eCG. In a second experiment, for heifers treated with norgestomet and estradiol plus eCG (n = 15) or with 2 doses of cloprostenol (n = 16), estrous rates were 66.7% vs 56.2% (P > 0.5), ovulation rates were 100.0% vs 81.2% (P = 0.08), intervals from implant removal or cloprostenol treatment to estrus were 48.0 +/- 4.4 hours vs 61.3 +/- 7.0 hours (P = 0.12) and to ovulation were 70.4 +/- 4.4 hours vs 93.2 +/- 7.5 hours (P < 0.01), respectively; pregnancy rates were 41.7 and 35.7%, respectively (P > 0.5). Norgestomet and estradiol were as good as (heifers) or superior to (cows) a 2-dose cloprostenol regimen. In cows given norgestomet and estradiol, injecting eCG at implant removal did not significantly improve estrous or pregnancy rates.