Pharmacokinetics of boldenone and stanozolol and the results of quantification of anabolic and androgenic steroids in race horses and nonrace horses

Anabolic steroids (ABS) boldenone (BL; 1.1 mg/kg) and stanozolol (ST; 0.55 mg/kg) were administered i.m. to horses and the plasma samples collected up to 64 days. Anabolic steroids and androgenic steroids (ANS) in plasma were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limit of detection of all analytes was 25 pg/mL. The median absorption (t1/2 partial differential) and elimination (t1/2e) half-lives for BL were 8.5 h and 123.0 h, respectively, and the area under the plasma concentration-time curve (AUCho) was 274.8 ng.h/mL. The median t1/2e for ST was 82.1 h and the was 700.1 ng.h/mL. Peak mean (X+/-SD) plasma concentrations (Cmax) for BL and ST were 1127.8 and 4118.2 pg/mL, respectively. Quantifiable concentrations of ABS and ANS were found in 61.7% of the 988 plasma samples tested from race tracks. In 17.3% of the plasma samples two or more ABS or ANS were quantifiable. Testosterone (TES) concentrations mean (X+/-SE) in racing and nonracing intact males were 241.3+/-61.3 and 490.4+/-35.1 pg/mL, respectively. TES was not quantified in nonracing geldings and female horses, but was in racing females and geldings. Plasma concentrations of endogenous 19-nortestosterone (nandrolone; NA) from racing and nonracing males were 50.2+/-5.5 and 71.8+/-4.6 pg/mL, respectively.     

金川牦牛肋数、年龄对血清、被毛矿物元素含量的影响及血清与被毛矿物元素含量的相关性

本试验旨在分析金川县牦牛血清和被毛的矿物元素含量,探讨肋数和年龄对矿物元素含量的影响,并对被毛矿物元素含量与血清中相应元素含量的相关性进行分析。采用二因素有重复试验设计,将32只公牦牛进行分组,按照肋数[14肋(n=17)和15肋(n=15)]和年龄[0(初生)~2岁(n=10)、3~4岁(n=11)、5~6岁(n=5)、7~8岁(n=6)]共分为8组。分别采集血清及被毛样品,进行矿物元素含量分析。结果表明:1)肋数、年龄对血清中的钙(Ca)、铜(Cu)、铁(Fe)、钾(K)、镁(Mg)、锰(Mn)、钠(Na)、锌(Zn)的含量均无显著影响(P0.05);年龄和肋数间无互作(P0.05)。2)肋数对被毛Ca、Cu、Fe、Mg、Mn、Na、Zn含量无显著影响(P0.05);年龄可影响被毛K含量,7~8岁被毛K含量显著高于其他年龄段(P0.05),但对被毛其他元素含量均无显著影响(P0.05),年龄和肋数间无互作(P0.05)。3)被毛Ca、Cu、Fe、Mg、Zn与血清中相应元素含量相关性极显著(P0.01),相关系数分别为0.623 0、0.539 8、0.569 2、0.468 4、0.505 3,而K、M n、Na含量的相关性则不显著(P0.05)。综合可知,金川14肋与15肋牦牛矿物元素含量无显著差异;7~8岁被毛中的K含量显著升高;牦牛被毛、血清Ca、Cu、Fe、M g、Zn含量具有显著的相关性,可由被毛代替血清测定相应的矿物元素含量。     

Effect of chromium picolinate and chromium propionate on glucose and insulin kinetics of growing barrows and on growth and carcass traits of growing-finishing barrows

Two experiments were conducted to determine the effects of dietary Cr tripicolinate (CrPic) or Cr propionate (CrProp) on growth, carcass traits, plasma metabolites, glucose tolerance, and insulin sensitivity in pigs. In Exp. 1, 36 barrows (12 per treatment; initial and final BW were 20 and 38 kg) were allotted to the following treatments: 1) corn-soybean meal basal diet (control), 2) as 1 + 200 ppb Cr as CrPic, or 3) as 1 + 200 ppb Cr as CrProp. Growth performance data were collected for 28 d, and then 23 pigs (seven, eight, and eight pigs for treatments 1, 2, and 3, respectively) were fitted with jugular catheters and a glucose tolerance test (500 mg glucose/kg BW) and an insulin challenge test (0.1 IU of porcine insulin/kg BW) were conducted. Both CrPic and CrProp decreased (P < 0.05) ADG and ADFI but did not affect gain:feed (P > 0.10). Fasting plasma glucose, total cholesterol, urea N, insulin, and high-density lipoprotein cholesterol:total cholesterol concentrations were not affected (P > 0.10) by either Cr source. Pigs fed CrPic had lower (P < 0.02) fasting plasma NEFA concentrations than control pigs, but plasma NEFA concentrations of pigs fed CrProp were not affected (P > 0.10). During the glucose tolerance test, glucose and insulin kinetics were not affected by treatment (P > 0.10). During the insulin challenge test, glucose clearance was increased (P < 0.01) in pigs fed CrProp but not affected (P > 0.10) in pigs fed CrPic. Glucose half-life was decreased (P < 0.03) in pigs fed CrPic or CrProp, but insulin kinetics were not affected (P > 0.10). In Exp. 2, 48 barrows (four replicates of four pigs per replicate; initial and final BW were 23 and 115 kg) were allotted to the same dietary treatments in a growing-finishing study. Average daily gain, ADFI, and gain:feed were not affected (P > 0.10) by treatments. Carcass length tended (P = 0.10) to be greater in pigs fed CrPic than in pigs fed CrProp, but other carcass measurements were not affected (P > 0.10). Glucose kinetics from the insulin challenge test indicate that both CrPic and CrProp increase insulin sensitivity and that both Cr sources are bioavailable.     

The influence of duration of photoperiod and hemicastration on growth and testicular and endocrine functions of boars

Yorkshire boars were used to evaluate the influence of duration of photoperiod and hemicastration on growth and testicular and endocrine functions. At 10 wk of age, 5 hemicastrate (HC) and 5 intact (I) boars were assigned to either 8 or 16 hr of light daily until 6 mo of age. Body weights were recorded biweekly throughout the experiment. Venous cannulae were placed in all boars at 6 mo of age, and serum was collected at 30 min intervals from 0800 to 2000 hr. Gonadotropin releasing hormone (GnRH) was infused at 2000 hr (50 micrograms) and at 2030 hr (250 micrograms), and samples of serum were collected until 2400 hr. The following day, all boars were castrated, and the weights and sperm content of the testes and epididymides were determined. At castration, all pigs were given implants containing testosterone. Two weeks later, pigs were again canulated, and serum was obtained at 15 min intervals for 2 hr. Growth of boars was not significantly affected by duration of photoperiod or number of testes. Duration of photoperiod did not affect weight or sperm content of testes or epididymides. Hemi-castrated boars had greater testicular (P less than .01) and capita-corpora (C-C) epididymal weights (P less than .05) and more testicular and C-C sperm (P less than .01) per testis. Neither average concentrations of luteinizing hormone (LH) nor number and amplitude of pulses of LH were affected by photoperiod treatment. However, HC boars had greater average concentrations of LH (P less than .05) than I boars (.71 +/- .05 vs .52 +/- .05 ng/ml). Hemicastrated boars in 16 hr light daily had greater concentrations of FSH in serum (P less than .05) than 8I, 8HC, and 16I boars. Intact and HC boars had similar concentrations of prolactin (PRL) and testosterone. Similarly, concentrations of PRL and testosterone were not affected by duration of photoperiod. Secretion of LH and testosterone after treatment with GnRH was not significantly affected by duration of photoperiod. In general, HC boars released more LH in response to GnRH treatment than I boars. Concentrations of LH were greater (P less than .05) in HC than I boars at .5, 1, 2, and 3 hr after GnRH and tended (P less than .10) to be elevated at 1.5, 2.5, 3.5 and 4 hr after GnRH. The FSH response to GnRH was greater (P less than .05) for 16HC than 8I, 8HC, or 16I boars.(ABSTRACT TRUNCATED AT 400 WORDS)     

T细胞的发育分化及胸腺激素的作用

胸腺既是免疫器官,又是内分泌器官。胸腺是T淋巴细胞发育、分化和成熟的场所。原胸腺细胞,经过前胸腺细胞、CD4-CD8-双阴性细胞、CD4 CD8 双阳性细胞以及CD4 CD8-或CD4- CD8 两个单阳性胸腺细胞亚群共5 个阶段,发育分化为成熟的T淋巴细胞。胸腺微环境是T淋巴细胞发育分化的重要条件。胸腺上皮细胞分泌产生的胸腺激素在T淋巴细胞发育分化过程中起重要作用。文章着重综述了T淋巴细胞发育分化过程及胸腺激素的生化性质和生物学功能。     

Effect of wheat and high-moisture sorghum grain fed singly and in combination on ruminal fermentation, solid and liquid flow, site and extent of digestion and feeding performance of cattle

Two experiments were conducted to determine how varying the proportion of wheat (W) and high-moisture sorghum grain (SG) in 80% grain dies would affect ruminal fermentation, liquid and solid flow, site and extent of digestion (Exp. 1) and feeding performance of cattle (Exp. 2). In Exp. 1, three ruminal, duodenal and ileal cannulated steers (average weight 295 kg), fed at 1.54% of body weight, were used in a six-period crossover design. Treatments were: W, 50W:50SG (W:SG) and SG. Increasing wheat level decreased ruminal pH, molar proportion of acetate, and acetate:propionate ratio (P less than .05) and increased (P less than .05) L-lactate concentration, molar proportions of propionate and valerate and total volatile fatty acid concentration. Ruminal liquid dilution and outflow rates were faster (P less than .05) and retention time was shorter (P less than .05) for the W diet. Duodenal and ileal liquid flow increased (P less than .05), and solid flow decreased (P less than .05), as dietary level of wheat increased. Apparent ruminal digestion (% of intake) of dry matter (DM) and organic matter (OM) was greater (P less than .01) with the wheat-containing diets. Intestinal DM and OM digestion (percent of intake) was higher (P less than .05) with the SG and W:SG diets. Ruminal, small intestine, large intestine and total tract starch digestion (percent of intake) was 93.5, 5.6, .7, 99.8, 71.5, 20.4, 5.7, 97.6; and 48.0, 32.5, 10.5, 91.0 with the W, W:SG and SG diets, respectively. In Exp. 2, group-fed (24 pens) steers (avg initial weight 341 kg) were fed ad libitum once daily for 121 d. Treatments were: W, 67W:33SG, 33W:67SG and SG. Rates of gain (kg/d) with the W (1.32), 67W:37SG (1.33) and 33W:67SG (1.30) diets were similar (P greater than .05), but faster (P less than .05) than those with the SG diet (1.16). Feed intake was lower (P less than .01) with the W and 67W:33SG diets, but the wheat-containing diets were utilized more efficiently (P less than .01). Increasing the proportion of wheat in sorghum grain feedlot diets improved cattle performance by optimizing ruminal and post-ruminal digestion.     

A meta-analysis of energy and protein requirements for maintenance and growth of Nellore cattle

A meta-analysis was conducted to determine NE and net protein requirements of growing bulls, steers, and heifers of Nellore purebred and Nellore x Bos taurus crossbreds. A database of 16 comparative slaughter studies (n = 389 animals) was gathered to provide enough information to develop equations to predict the requirements of NE(m), NE(g), and net protein for maintenance (NP(m)) and growth (NP(g)). The data were analyzed using a random coefficients model, considering studies as random effects, and sex and castrate status (bulls, steers, and heifers; n = 262, 103, and 24, respectively) and breeds as fixed effects. There were no differences in NE(m) requirements among sex and castrate status (P = 0.73) and breeds (P = 0.82). The combined data indicated a NE(m) requirement of 75 kcal/ kg(0.75) of empty BW (EBW) with a partial efficiency of use of ME for NE(m) of 0.67. The NE(g) requirement was different (P = 0.009) among sex and castrate status and tended (P = 0.06) to be different among breeds. The equation for NE(g) requirement for bulls was 0.0514 x EBW(0.75) x EWG(1.070); for steers, it was 0.0700 x EBW(0.75) x EWG(1.070); and for heifers, it was 0.0771 x EBW(0.75) x EWG(1.070), where EWG = EBW gain (kg/d). The partial efficiency of use of ME for NE(g) was not different among sex and castrate status (P = 0.33) and breeds (P = 0.20) and averaged 0.44. There were no differences in NP(m) requirement among sex and castrate status (P = 0.59) and breeds (P = 0.92); the overall NP(m) requirement was 1.74 g of NP.kg(-0.75) of EBW.d(-1). The overall MP requirement for maintenance was 2.59 g of MP.kg(-0.75) EBW.d(-1). The NP(g) requirement (g/d) was not different among sex and castrate status (P = 0.59) and breeds (P = 0.14); the overall equation was EWG x [217 - (12.8 x RE/EWG)], where RE = retained energy (Mcal/d). The percentage of RE deposited as protein (%RE(p)) decreased exponentially as the content of RE in the gain (REc, Mcal/kg of EWG) increased. Because no study effect was observed, we pooled the data across studies and the overall equation to predict %RE(p) was 10.1 + 167e((-0.66 x REc)). Our results do not support the hypothesis that bulls have greater NE(m) requirements than steers and heifers. Likewise, no significant differences in the NP(m) requirements among bulls, steers, and heifers were detected. Nonetheless, the NE(g) requirement of steers was greater than bulls and less than heifers. Even though the %RE(p) was negatively correlated with the concentration of energy in the EWG, our findings indicated no differences in NP(g) requirement among bulls, steers, and heifers.     

Impact of energy intake and pregnancy status on rate and efficiency of gain and backfat changes of sows postweaning

A collaborative study was conducted to evaluate factors related to determining optimal feeding and management programs for increasing net returns from marketing cull sows. A total of 269 multiparous sows averaging 192 kg of body weight were weaned, moved to individual gestation crates, and assigned to one of eight treatment combinations in a 2 x 2 x 2 factorial arrangement for a 42-d postweaning feeding experiment. Factors included limited (L) (1.8 kg/sow/d) or ad libitum (AL) access to feed during wk 1 postweaning, a corn-soybean meal (corn) or barley-sunflower meal (barley) diet, and pregnant or nonpregnant status. All sows were provided ad libitum access to feed from wk 2 to 6 postweaning. Gain and feed intake (FI) data were collected weekly for each sow and used to calculate gain:feed (G/F). Ultrasonic backfat (BF) data were collected on d 0, 21, and 42 postweaning. Sows on the AL treatment had greater FI (P < 0.05) but similar gain (P = 0.80) for the 42-d postweaning period compared to sows on the L treatment. Most of this response was due to lower sow body weight loss during wk 1 postweaning (P < 0.01) when sows were provided AL (-7.2 kg) vs L (-13.2 kg) access to feed. Sows fed the corn diet had higher gain (P < 0.01), improved G/F (P < 0.01), and increased BF (P < 0.01) over the 42-d feeding period than sows fed barley. The corn diet resulted in less sow BW loss (P < 0.01) during wk 1 (-8.8 kg) than the barley diet (-11.6 kg). Pregnant sows had higher gain, FI, G/ F, and BF (P < 0.01) than nonpregnant sows over the 42-d feeding period. Most of this advantage occurred during wk 4 postweaning when FI and gain of nonpregnant sows was lower (P < 0.01) than for pregnant sows. An economic analysis indicated that, when cull sow prices are relatively high and feed prices are moderate to low, maintaining and managing cull sows for an additional 6 wk postweaning may be economically advantageous compared to 0 or 3 wk. Pregnant sows fed the corn diet produced the greatest economic return. These results suggest that mating sows as they return to estrus postweaning and providing ad libitum access to a corn-soybean meal diet improves growth performance and feed efficiency, and may thereby provide increased returns when marketing cull sows.     

Localization and Coexistence of Calcium-Binding Proteins and Neuropeptides in the Vagal Ganglia of the Goat

This study was performed to investigate the neurochemical characteristics of the vagal ganglia of the goat by immunohistochemical methods using calbindin D-28k (CB), calretinin (CR). parvalbumin (PA), substance P (SP). calcitonin generelated peptide (CGRP) and galanin (GAL) antibodies. In the proximal vagal ganglia (jugular ganglia), CGRP- (57.1%), SP- (48.2%), GAL- (8.6%), PA- (8.7%), CB- (8.5%) and CR-like (5.3%) immunoreactive cells were observed. In the distal vagal ganglia (nodose ganglia), CGRP- (40.5%), SP- (30.20%), CB- (22.0%) and CR-like (18.10%) immunoreactive cells were present. The double immunohistochemical study showed, that in the proximal vagal ganglia, CGRP immunoreactivity was co-localized in SP- (84.8%), GAL-(100%), CB- (5.6%) and CR- (5.7%) immunoreactive cells: SP immunoreactivity was co-localized in the CGRP- (80.0%), GAL- (100%). CB- (5.3%) and CR- (5.6%) immunoreactive cells; GAL immunoreactivity coexisted in the CGRP- (4.4%) and SP- (19.8%) immunoreactive cells, but not in calcium-binding proteins (CBP)-immunoreactive cells; PA immunoreactivity was absent in the CGRP- and SP-immunoreactive cells; CB and CR immunoreactivities were seen in the CGRP-(0.8%) and SP-immunoreactive (0.9%) cells. On the other hand, in the distal vagal ganglia, CGRP immunoreactivity appeared in SP- (66.6%), CB- (1.0%) and CR- (1.2%) immunoreactive cells; SP immunoreactivities were observed in the CGRP- (44.1%), CB- (1.0%) and CR- (1.2%) immunoreactive cells; CB immunoreactivities were present in the CGRP- (0.5%) and SP- (0.8%) immunoreactive cells; CR immunoreactivities were contained in the CGRP- (0.5%) and SP- (0.8%) immunoreactive cells. These findings indicate that the goat is distinct from other mammalian species in the distribution and localization of neurochemical substances in the vagal ganglia. and suggest that these differences may be related to physiological characteristics, particular those of the ruminant digestive system.     

肉鸡腹水症对组织钙磷分布及钙磷利用率的影响

本试验研究了肉鸡腹水症(PHS)对组织钙磷分布及饲料钙磷利用率的影响。120只1日龄艾维茵(AA)肉鸡随机分成2组,即对照组和试验组,每组6个重复,每个重复10只鸡。试验组采用低温(LAT)和饲粮添加三碘甲腺原氨酸(T3,1.5mg/kg)诱导产生腹水症。试验期为21d。试验结果表明:1)14日龄时,试验组肉鸡的心脏、肝脏、十二指肠中钙含量与对照组相比,有增加趋势,胫骨、血清钙有下降趋势,但差异均不显著(P>0.05)。试验组肉鸡的心脏磷含量极显著低于对照组(P<0.01),十二指肠磷含量显著高于对照组(P<0.05)。饲料中钙磷利用率,试验组极显著低于对照组(P<0.01)。2)21日龄时,试验组肉鸡的心脏、肝脏中的钙含量显著高于对照组(P<0.05)。十二指肠、胫骨、血清中的钙含量两组间无显著差异(P>0.05)。十二指肠、血清磷含量试验组显著高于对照组(P<0.05),其余组织磷含量两组间无显著差异(P>0.05)。饲料中钙磷利用率,试验组极显著低于对照组(P<0.01)。3)血清碱性磷酸酶含量14、21日龄试验组和对照组差异均不显著(P>0.05)。     

Characterization and comparison of the responses of equine digital arteries and veins to endothelin-1

OBJECTIVE: To compare the responses of equine digital arteries (EDAs) and equine digital veins (EDVs) to endothelin-1 (ET-1) and determine the role of the endothelium and type of receptors involved in the modulation and mediation of those responses, respectively. SAMPLE POPULATION: 5 to 9 palmar digital vessels/experiment from 28 healthy horses. PROCEDURE: Rings of dissected vessels were mounted under tension between force transducer wires in organ baths containing Krebs-Henseleit solution at 30 degrees C. Responses of EDAs and EDVs (with intact [+e] or denuded [-e] endothelium) to cumulative concentrations of ET-1 (10(-10) to 3 X 10(-7) M) were compared. For (+e)EDAs and (+e)EDVs precontracted with a thromboxane-mimetic (U44069; 10(-8) M) and (-e)EDAs and (-e)EDVs, responses to an ETB receptor agonist (S6c; 10(-10) to 3 X 10(-7) M) were evaluated. Responses to ET-1 (10(-7) M) in (-e)EDAs and (-e)EDVs were evaluated after incubation with an ETA receptor antagonist (BQ-123; 3 X 10(-7) M), an ETB receptor antagonist (BQ-788; 3 X 10(-7) M), or vehicle solution. RESULTS: Endothelin-1 induced a concentration-dependent contraction of endothelium-intact and -denuded EDAs and EDVs; EDVs were more sensitive. Neither vessel type relaxed in response to S6c, although 2 of the (-e)EDAs contracted mildly. Whereas BQ-123 inhibited the (-e)EDA and (-e)EDV responses to ET-1, BQ-788 had no effect. CONCLUSIONS AND CLINICAL RELEVANCE: Endothelin-1 induced digital vasoconstriction (marked constriction in veins). This action was unaffected by endothelium and mediated predominantly by ETA receptors. These findings suggest ET-1 can induce selective digital venoconstriction.     

Effect of source and amount of energy and rate of growth in the growing phase on performance and carcass characteristics of early- and normal-weaned steers

One hundred eighty-four Angus x Simmental steers (initial BW 161.7 +/- 3.4 kg) were used to determine whether different sources and amounts of energy in the growing phase could extend the growth curve and maintain high amounts of intramuscular fat deposition in early-weaned steers. Steers were allotted by source, age, and BW to one of four growing-phase (119 to 259 d of age) regimens. For three regimens, steers were weaned at 119 d of age and either 1) fed (DM basis) a 50% grain diet ad libitum (ALC); 2) limit-fed a 70% grain diet to achieve a gain of 0.8 kg/d from 119 to 192 d of age, and 1.2 kg/d from 193 to 259 d of age (LFC); or 3) fed a 60% haylage diet ad libitum from 119 to 192 d of age, and a 25% haylage diet ad libitum from 193 to 259 d of age (ALF). For the fourth regimen, steers were normal-weaned at 204 d of age and fed a silage diet from 205 to 259 d of age (NW). From 260 d of age to slaughter, all steers consumed a 70% grain (DM basis) diet. Limit-fed and ALF steers spent the most, and NW the least amount of time (P < 0.01) in the feedlot to achieve a target fat depth of 1.27 cm. Ad libitum-fed steers were the youngest (331 d), and NW the oldest (383 d) at slaughter (P < 0.01). Overall ADG was greatest for ALC and least for NW steers (P < 0.01). Overall, ALF steers consumed the most DM (P < 0.01). While in the feedlot, LFC and ALC steers were more efficient in converting feed to BW gain (P < 0.01) than ALF and NW steers. Normal-weaned had the least and ALC the greatest (P < 0.01) fat depth at 260 d of age. Consequently, NW steers produced the heaviest, and ALC the lightest (P < 0.01) carcasses at slaughter. Normal-weaned steers had the largest, and ALC and LFC steers had the smallest longissimus muscle area (P < 0.06). Growing phase dietary treatments did not affect (P > 0.20) yield grade. Marbling score did not differ (P > 0.35), but laboratory analysis revealed that ALC steers had the lowest percentage of fat (P < 0.02) in the longissimus muscle. Shear force was greatest (P < 0.08) for steaks from ALC and LFC steers, and least for steaks from ALF and NW steers. Feeding steers the ALC diet from 119 to 260 d of age hastened physiological maturity, decreased marbling scores, and decreased muscle tenderness compared with forage feeding (ALF, NW). Limit-feeding a high-grain diet also hastened physiological maturity and decreased muscle tenderness but did not decrease marbling scores. Source and amount of energy affected partitioning of fat deposition.     

Effect of season and location on semen quality and serum concentrations of luteinizing hormone and testosterone in Brahman and Hereford bulls

Hereford bulls from Montana (MH; n = 15) and Nebraska (NH; n = 15) and Brahman bulls from Texas (BB; n = 18) were relocated to one of three locations (LOC): Montana (MT), Nebraska (NE) or Texas (TX). All bulls were pubertal at the time of relocation in late May 1984. Semen was collected by electroejaculation within 1 wk after relocation and at 90-d intervals beginning in November 1984 through early February 1986. Bulls were given a GnRH challenge (200 micrograms i.m.) during the same week of semen collections. Bulls also were bled for 8 h at 20-min intervals in the fall of 1984 and the spring and fall of 1985 to determine endogenous concentrations of LH and testosterone. Season affected sperm concentration in all breeds (P less than .05) with decreases during the winter in BB and during the summer in NH and MH bulls. Brahman bulls had lower percentage of live cells (LIVE) than NH and MH bulls did (P less than .0001). Brahman bulls decreased in LIVE during the winter (P less than .001). Area under the LH curve after GnRH was lower (P less than .005) in BB than in MH and NH. Brahman bulls in MT had greater (P less than .02) area under the LH curve and lower (P less than .06) area under the testosterone curve than did BB in TX or NE during the winter. There was no seasonal fluctuation in LH or testosterone response to GnRH in NH or MH bulls at any LOC. Area under the endogenous LH curve was lowest (P less than .04) in BB. Basal endogenous testosterone concentration was greater (P less than .03) in NH than in MH or BB. Area under the endogenous testosterone curve was lower (P less than .03) in MH than in NH or BB. These results indicate that BB exhibit seasonal fluctuations in semen quality. This was not so apparent in semen quality traits of Hereford bulls. There also was a seasonal influence in BB on both endogenous testosterone and GnRH-stimulated LH and testosterone concentrations. Compared with Hereford bulls, Brahman bulls had lower endogenous and GnRH-stimulated concentrations of LH.     

Effect of nonwaxy and waxy sorghum on growth, carcass traits, and glucose and insulin kinetics of growing-finishing barrows and gilts

Two experiments were conducted to determine the effect of nonwaxy (amylose and amylopectin starch) or waxy (amylopectin starch) sorghum on growth, carcass traits, and glucose and insulin kinetics of pigs. In Exp. 1 (95-d), 60 crossbred barrows or gilts (initial and final BW of 24 and 104 kg) were allotted to three treatments with five replications of four pigs per replicate pen in a randomized complete block design. The dietary treatments for Exp. 1 were 1) corn-soybean meal (C-SBM) diet, 2) sorghum-SBM (red pericarp, non-waxy), and 3) sorghum-SBM (red pericarp, waxy). In Exp. 2, 28 crossbred barrows (initial and final BW of 24 and 64 kg) were allotted to two treatments with three replications of four or five pigs per replicate pen in a randomized complete block design. Growth data were collected for 49 d, and then 20 barrows were fitted with jugular catheters, and then a glucose tolerance test (500 mg glucose/kg BW), an insulin challenge test (0.1 IU of porcine insulin/kg BW), and a feeding challenge were conducted. The dietary treatments for Exp. 2 were 1) sorghum-SBM (white pericarp, nonwaxy) and 2) sorghum-SBM (white pericarp, waxy). In Exp. 1, ADG (P = 0.10) and ADFI (as-fed basis; P = 0.02) were increased (P = 0.10) and gain:feed was decreased (P = 0.04) in pigs fed the sorghum-SBM diets relative to those fed the C-SBM diet. These responses may have resulted from the lower energy content of sorghum relative to corn. Plasma NEFA concentration (collected after a 16-h fast on d 77) was decreased (P = 0.08) in pigs fed the waxy sorghum-SBM diet relative to those fed the nonwaxy sorghum-SBM diet. Kilograms of carcass fat was decreased (P = 0.07) in pigs fed the waxy sorghum-SBM diet relative to those fed the nonwaxy sorghum-SBM diet. In Exp. 2, there was no effect (P = 0.57 to 0.93) of sorghum starch type on growth performance by pigs. During the glucose tolerance and insulin challenge tests, there were no effects (P = 0.16 to 0.98) of diet on glucose or insulin kinetics. During the feeding challenge, glucose (P = 0.02) and plasma urea N (P = 0.06) area under the response curves from 0 to 90 min were decreased in pigs fed the waxy sorghum-SBM diet. Feeding waxy sorghum had minimal effects on growth and carcass traits relative to pigs fed corn or nonwaxy sorghum. Waxy sorghum vs. nonwaxy sorghum had no effect on glucose or insulin kinetics in pigs.     

Isoproterenol- and salbutamol-induced relaxation of acetylcholine- and histamine-induced contraction of equine trachealis muscle in vitro

Strips of trachealis muscle were dissected from the midcervical portion of the trachea of horses that were free of respiratory tract disease, and the overlying epithelium and mucosa were removed. Muscle strips were suspended in tissue baths that were filled with Krebs-bicarbonate solution, aerated with 5% CO2 in oxygen and maintained at 37 C. Isometric tension was continuously recorded. The increase in active isometric tension was concentration dependent when acetylcholine (10(-9) to 10(-4) M) or histamine (10(-9) to 10(-4) M) was added to the tissue baths in 0.5-logarithmic increments. When the tissues were contracted with acetylcholine (3.1 x 10(-6) M) or histamine (10(-4) M), the decrease in active isometric tension was concentration dependent when isoproterenol (10(-9) to 10(-4) M) or salbutamol (10(-9) to 10(-4) M) was added to the tissue baths in 0.5-logarithmic increments. There was no difference between the response to isoproterenol and salbutamol when tissues from the same horses were compared whether the tissues were contracted in response to acetylcholine (3.1 x 10(-6) M) or histamine (10(-4) M). Relaxation was antagonized by 10(-6) M propranolol. The degree of relaxation obtained in these muscle strips was considerably less than that reported from other species' tracheal muscle strips that had the epithelium and mucosa intact. We concluded that equine tracheal smooth muscle contains beta-adrenoceptors that can be stimulated by either a mixed beta-1, beta-2 agonist or a selective beta-2 agonist.     

Effects of age and indomethacin on response and sensitivity of pulmonary artery to phenylephrine and to histamine in pigs

The vasoconstrictor effects of phenylephrine and histamine were investigated in isolated strips of pulmonary arteries in pigs during ageing. Interactions between phenylephrine-induced responses and arachidonic acid derivatives were also studied by incubating the blood-vessels with indomethacin. Potency (pD2 values) and maximal effects (E_maxx) recorded in 5-week-old piglets (group I, n = 5) with phenylephrine [5.71 ± 0.17 and 0.76 ± 0.22 g/mg of dry tissue respectively (mean ± SEM)] were similar to values found in 12-week-old animals (group 2, n = 5) (5.49 ± 0.30 and 1.06 ± 0.27 g/mg of dry tissue respectively). The sensitivity and responsiveness of tissues to this agonist were significantly reduced in 26-week-old mature pigs (group 3, n = 6) as indicated by the decrease in pD2 (3.91 ± 0.23; P < 0.01) and E_max (0.27 ± 0.13 g/mg of dry tissue; P < 0.05) values observed in this group. Histamine (10^_3M)-induced maximal responses (E_max) were significantly higher in group 2 (2.23 ± 0.49 g/mg) than in group 1 (0.85 ± 0.11 g/mg; P < 0.05) and in group 3 (0.48 ± 0.10 g/mg; P < 0.01). In 5-week-old animals, indomethacin (3.10˜⁵M) significantly ( P < 0.05) shifted the concentration-response curve to phenylephrine to the right (0.28 log. units) and depressed contractions to this drug as shown by the significant decrease of 39.5% ( P < 0.05) in E_max. This cyclo-oxygenase inhibitor had no effect in other groups. These data indicate that phenylephrine is a potent and effective vasoconstrictor agent for the main pulmonary arteries in 5-week-old piglets and that alpha-1-adrenergic-induced contractions are enhanced by cyclo-oxygenase products. These findings can be related with the high reactivity of pulmonary vascular smooth muscles in these animals.     

Effect of water and feed withdrawal and health status on blood and serum components, body weight loss, and meat and carcass characteristics of Holstein slaughter cows

During marketing, cattle may be exposed to periods of water deprivation. The impact of water and feed access and health status on the physiological well-being and carcass characteristics of Holstein slaughter cows during preslaughter marketing was studied through analysis of serum components, BW loss percentage, and fresh meat composition. Ninety-one multiparous Holstein cows (609 ± 89 kg mean BW, 2.9 ± 0.5 mean BCS, varying stage of lactation) were purchased over 3 wk in 3 groups (n = 31, 29, and 31) at a terminal market in central Wisconsin. Each cow was screened to determine health status (sick or not sick) and randomly assigned to 1 of 3 water and feed withdrawal treatment pens (AL, ad libitum access to water for 36 h; 18H, 18 h of ad libitum access to water followed by 18 h of water withdrawal; 36H, 36 h of water withdrawal; all 3 treatments included 36 h of feed withdrawal) in a randomized complete block arrangement with repeated measures for serum components. Blood samples were collected by tail venipuncture at 0, 9, 18, 27, and 36 h of each treatment. Ambient temperatures were 1.9 ± 6.2°C during the trial period, which occurred over a 3-wk period in March and April 2007 near Arlington, WI. No difference (P > 0.05) was observed in mean serum cortisol in AL (18.41 ± 2.17 ng/mL) or 36H (22.98 ± 2.17 ng/mL). Mean serum glucose was greater (P < 0.05) in 36H pens (78.15 ± 0.77 mg/dL) than AL (75.91 ± 0.77 mg/dL). Mean serum creatinine was greater (P < 0.05) in 36H pens (0.71 ± 0.03 mg/dL) than AL (0.60 ± 0.03 mg/dL). The 36H pens also displayed increased (P < 0.05) serum albumin, anion gap, Ca, Cl, Na, cholesterol, and aspartate aminotransferase over AL. Greater (P < 0.05) mean percentage BW loss was observed in 36H pens (5.2 ± 0.6%) than AL (3.1 ± 0.6%). Mean muscle protein (%) was greater (P < 0.05) in 36H (22.2 ± 0.4%) than 18H (21.3 ± 0.4%). Mean muscle moisture (%) was greater (P < 0.05) in AL and 18H (75.3 ± 0.4% and 75.2 ± 0.4%) than 36H. Mean 24-h pH values were 5.92 (AL), 5.92 (18H), and 5.81 (36H; SE = 0.04) and were not different (P < 0.05). Observed pH and color values indicated a borderline dark-cutter state across all cattle in the study, regardless of water and feed access treatment. Based on these results, water and feed withdrawal in lairage should not exceed 18 h during the marketing of Holstein slaughter cows acclimated to springtime conditions to maintain BW, serum component concentrations, and fresh meat composition.     

Effect of sorghum grain variety and reconstitution on site and extent of starch and protein digestion in steers

Hetero-yellow (HY), red (RED) and brown (BR, high tannin) sorghums were fed dry-rolled or reconstituted (RED and BR only) to evaluate the effect of variety and reconstitution on the site and extent of starch and protein digestion in steers fitted with ruminal, duodenal and ileal cannulae. Processed grains were incorporated into 88% sorghum (DM basis) diets fed at 2% of body weight in a 5 X 5 Latin square. Ruminal fermentation of organic matter, starch and protein tended to be lower for the dry-rolled RED than for either the dry-rolled HY or BR sorghum. Digestion of organic matter (OM) and starch in the small intestine was very low for dry-rolled sorghums. Total tract starch digestibility was lower for the dry-rolled RED sorghum (86.9%) than the BR (90.8%) and HY (91.4%). Nitrogen (N) digestibility ranged from 53.1% for the dry-rolled BR to 64.5% for the HY. Tannins were extensively (95.2%) degraded in the rumen, which may have enhanced fermentation of the BR sorghum. Reconstitution increased (P less than .05) total-tract starch digestion of the RED and tended to increase starch digestion of the BR as well. Total N flow to the duodenum tended to increase with reconstitution, with most of the increase being due to greater (P less than .05) microbial-N. Reconstitution also increased (P less than .05) total-tract N digestibility of the RED. The response to reconstitution for the RED sorghum appeared to be due primarily to an increase (P less than .10) in the extent of fermentation of organic matter and starch in the rumen. Reconstitution of BR, however, enhanced disappearance of starch from the small intestine. In both cases, most (97.3%) of the digestible starch of the reconstituted sorghums had disappeared before the terminal ileum. In contrast, 14.5% (621 g) of the digestible starch of dry-rolled RED disappeared in the large intestine. Sorghum grain variety and reconstitution appear to alter site and extent of starch and protein digestion, which may result in variable performance of cattle fed sorghum grain diets.     

果寡糖对肉鸡生长、肠道菌群和肠形态的影响

研究了饲粮中分别添加0、2000、4000、6000mg/kg果寡糖对艾维菌商品代肉鸡生长性能、肠道菌群和肠形态的影响。结果表明：目粮中添加4000mg/kg果寡糖使肉鸡日增重提高了9．53％（P＜0．01），2000、4000mg/kg果寡糖使料重比分别降低了5．09％（P＜0．05）和7．87％（P＜0．05）；4000mg/kg果寡糖使盲肠中双歧杆菌和总厌氧菌数分别增加了257．65％（P＜0．05）和100．00％（P＜0．05），使梭菌数下降了79．36％（P＜0．05）；2000、4000mg/kg果寡糖使盲肠中乳酸杆菌数分别增加了45．73％（P＜0．05）和67．97％（P＜0．01），使大肠杆菌数分别下降了75．71％（P＜0．05）和71．35％（P＜0．05）；4000和6000mg/kg果寡糖使盲肠中乙酸、丁酸和总短链脂肪酸含量分别提高了23．25％（P＜0．05）和26．08％（P＜0．05）、144．36％（P＜0．05）和202．97％（P＜0．01）、47．08％（P＜0．01）和58．31％（P＜0．01）；2000、4000和6000mg/kg果寡糖使盲肠中丙酸含量分别提高了45．27％（P＜0．05）、73．22％（P＜0．01）和89．37（P＜0．01）；4000、6000mg/kg果寡糖使盲肠上皮黏膜腺窝深度和细胞密度分别提高了22．62％（P＜0．05）和25．72％（P＜0．01）、19．28％（P＜0．05）和23．07％（P＜0．05）。     

Comparison of amylase and lipase activities in serum and plasma of dogs

BACKGROUND: Amylase and lipase activities are most often determined in serum, although heparinized plasma is more convenient to obtain and is used for many routine biochemical analyses. OBJECTIVE: The purpose of this study was to compare amylase and lipase activities in serum and plasma of dogs and to determine whether either specimen type is acceptable for analysis. METHODS: Serum and heparinized plasma were obtained from 101 randomly selected dogs and analyzed in parallel for alpha-amylase and lipase. Results were compared using Passing-Bablock regression, Bland-Altman difference plots, and correlation analysis. RESULTS: There was a high correlation between the results obtained from serum and those from plasma. Regressions (with 95% confidence intervals in parentheses) were as follows: lipase(plasma) = 0.984 (0.976/0.995) Chi lipase(serum) - 0.9 (2.9/0.7) (r =.999); a-amylase(plasma) = 1.003 (0.977/1.032) Chi alpha-amylase(serum) - 1.9 ( 20.7/23.3) (r =.991). Mean differences (serum - plasma) were 8 U/L and 4 U/L for lipase and alpha-amylase, respectively. Classification of results as normal or abnormal did not differ according to specimen type. CONCLUSION: In dogs, lipase and alpha-amylase activities can be determined with the same level of accuracy in serum and in heparinized plasma.