东方铃蟾两性形态特征的研究

为了解长白山地区东方铃蟾(Bombina orientalis)两性的形态特征差别,试验动物采自长白山北麓,测量体长、头长、头宽、吻长、眼间距、鼻间距、眼径、前臂及手长、后肢长、胫长、体重11项形态学指标,采用SPSS 22.0统计软件分析两性形态特征的差别。结果表明:雌雄东方铃蟾体长差异不显著(P0.05),雌性的吻长极显著大于雄性(P0.01),胫长显著小于雄性(P0.05),雄性体重、头宽、胫长与体长均呈显著正相关(P0.05),但头宽和胫长随体长的增长速率差异不显著(P0.05)。东方铃蟾两性同形的形态特征与铃蟾属其他物种相似,可能具有种属的特征。     

实验室条件下东北林蛙配偶选择的形态特征

为了研究两栖类配偶选择机制与其两性形态特征之间的关系,在实验室条件下以东北林蛙(Rana dybowskii)为研究对象,采用统计学的方法对其体重、体长、头长、头宽、眼间距、前肢长、后肢长7项形态指标进行测量后分析。结果表明:参与繁殖(抱对)的雌性东北林蛙的身体形态显著大于未参与繁殖(未抱对)的雌性东北林蛙;影响抱对的第1主成分包括体重、体长、头长、头宽、后肢长,第2主成分包括眼间距、前肢长。     

塔里木河下游河段叶尔羌高原鳅形态生物学研究

为了更好地保护塔里木河水系渔业资源,维护塔里木河流域的生态平衡,采用经典生物学法对塔里木河下游3个河段叶尔羌高原鳅形态生物学进行测量分析。结果表明:阿尔干、台特玛湖、车尔臣河3个群体叶尔羌高原鳅体长范围是56.71～78.61 mm、65.7～76.58 mm、49.94～128.61 mm;其体长和体质量关系分别为W=0.001L~(5.612),(R~2=0.693)、W=0.005L~(3.432),(R~2=0.914)、W=0.024L~(2.647),(R~2=0.928)。阿尔干与台特玛湖群体中体长与体质量差异不显著(P0.05),阿尔干与车尔臣河差异显著(P0.05),台特玛湖与车尔臣河差异显著(P0.05);肥满度,阿尔干和台特玛湖与阿尔干和车尔臣河群体差异极显著(P0.01),台特玛湖与车尔臣河差异不显著(P0.05);3个群体间体高/体长、头长/体长、头宽/体长、尾柄长/体长、口宽/头长、吻长/头长差异极显著(P0.01)。说明塔里木河下游3个河段的叶尔羌高原鳅因长时间断流、种群之间不能交流、生境破碎化造成生存条件不同而导致其形态显示出差异性。     

黄颡鱼二倍体和三倍体的形态特征比较研究

为了解黄颡鱼二倍体和三倍体的形态特征区别,分别选取性成熟的黄颡鱼二、三倍体雌雄个体,测量鱼体形态各指标并进行比较研究。结果:雌性的体长/尾柄长、头长/尾柄长、头长/眼后头长之比均无显著差异(P0. 05),而体长/体高、体长/头长、体长/眼径、头长/眼径、体高/体厚有显著差异(P0.05);雄性的体长/体高、体长/头长、体长/尾柄长、体长/眼径、头长/眼径、头长/尾柄长、头长/眼后头长均无显著差异(P0.05),而体高/体厚的有显著差异(P0.05)。结果表明:可通过体高/体厚的比值快速鉴别雄性或雌性二、三倍体黄颡鱼,在体高相同的情况下三倍体比二倍体的体厚较薄。     

安徽东至发现罕见大树蛙

1998年9月25日晚在安徽省东至县尧渡镇尧南路路旁的小树上,一干警采到此只大树蛙(Rhacophorus dennysi),雄性,体长133mm,重300g.体形扁平而略长,头宽大于头长,吻端突出,鼻眼间的吻棱明显,鼓膜大而圆,背面青绿色,体两侧及头背面     

圈养扬子鳄繁殖能力的探查

为了探查扬子鳄人工种群的繁殖能力,对1996~2005年安徽省扬子鳄繁殖研究中心的亲本鳄和子一代鳄繁殖情况进行观察和研究。经过对其繁殖参数的统计分析,得出亲本鳄与子一代鳄在卵的短径和重量、窝卵数、卵受精率和孵化率、出壳一周内雏鳄的死亡率以及雏鳄生长量方面无显著性差异,即子一代鳄的繁殖能力与亲本鳄的相同。该结果表明目前圈养扬子鳄的繁殖能力尚未降低。     

鲢鱼和鲤鱼主要生物学特征的比较

鲢鱼﹑鲤鱼均属鲤科鱼类,鲢鱼属于长纺锤形体型,鲤鱼为典型的纺锤形体形。这两种鱼都是我国的主要经济鱼类,分布地域广,市场所占比例较大。目前,鉴定鱼类的分类学主要依据形态方面的特征,为了更好的区分二者之间的主要生物学特征,本次试验分别测量鲢鱼和鲤鱼的体长﹑体高﹑头长﹑吻长,计算体长与体高,体长与头长及头长与吻长的比值,并作统计分析。试验结果表明鲢鱼与鲤鱼体长/体高差异极显著,体长/头长差异显著,头长/吻长差异极显著。此试验对于研究鱼类形态学的变化及选育优质鱼种具有一定的作用;而且也可以为选择同类鱼提供参照。     

扬子鳄的人工饲养及繁殖

扬子鳄(Alligatorsinensis)隶属爬行纲,鳄目,鳄科,鼍属。有古生物“活化石”之称。扬子鳄有很高的科研和生态价值,对研究恐龙类的起源与演化,了解地质变迁和物质的起源演化具有不可估量的作用。然而,由于人类活动的增加,自然栖息地遭到破坏,加上气候变迁、环境污染、遗传多样性的丧失等因素,导致扬子鳄种群数量逐年减少,成为世界上23种鳄类中最濒危的物种。人工饲养和繁殖是拯救扬子鳄的有效途径,我园自1985年开始饲养扬子鳄,2001年又从海南岛引进4条扬子鳄,按体形大小编为1～4#,其中1#、2#为雄性,3#、4#为雌性。从体长和背鳞上的年轮推断,…     

黑龙江省东部两种林蛙两性异形比较研究

为了解黑龙江林蛙(Rana amurensis)和东北林蛙(Rana dybowskii)的两性异形特征,试验动物为采自黑龙江省东部地区的黑龙江林蛙60只(公、母各半)和东北林蛙114只(公、母各半),测量头体长、头长、头宽、前臂及手长、后肢长和胫长,采用SPSS 17.0统计软件分析形态特征的两性异形特点。结果表明:两种林蛙的形态特征存在显著两性异形,黑龙江林蛙两性异形程度指数为0.082,东北林蛙两性异形程度指数为0.074。两种林蛙两性的所有局部形态特征均与其头体长呈显著正相关(除黑龙江林蛙雌性前臂及手长P0.05,其余均P0.001),两种林蛙雌雄头体长比值分别为1.089,1.080,雌性的头体长和头长均大于雄性,雄性前臂及手长均大于雌性。     

贵州白香猪不同杂交组合后代生长发育指标的测定

试验选用贵州白香猪作为母本,分别以大约克猪、杜洛克猪、长白猪作为父本进行杂交组合试验,测定了3个杂交组合F1代及对照组香猪的初生重、20日龄重及2～6月龄的生长发育指标。结果表明,初生重为杜×香大×香长×香香猪,长×香组与对照组香猪间差异不显著(P0.05);20日龄重为杜×香大×香长×香香猪。生长发育各指标间差异显著,并且随着月龄增加各试验组间生长发育显著性增大,除2月龄体长为杜×香大×香长×香香猪、3月龄体重,体长、胸围、腹围指标及5月龄体高、体长指标为大×香长×香杜×香香猪外,其余月龄生长发育各指标为大×香杜×香长×香香猪。     

Age- and sex-dependent regression models for predicting the live weight of West African Dwarf goat from body measurements

The relationships between live weight and eight body measurements of West African Dwarf (WAD) goats were studied using 211 animals under farm condition. The animals were categorized based on age and sex. Data obtained on height at withers (HW), heart girth (HG), body length (BL), head length (HL), and length of hindquarter (LHQ) were fitted into simple linear, allometric, and multiple-regression models to predict live weight from the body measurements according to age group and sex. Results showed that live weight, HG, BL, LHQ, HL, and HW increased with the age of the animals. In multiple-regression model, HG and HL best fit the model for goat kids; HG, HW, and HL for goat aged 13–24 months; while HG, LHQ, HW, and HL best fit the model for goats aged 25–36 months. Coefficients of determination (R ²) values for linear and allometric models for predicting the live weight of WAD goat increased with age in all the body measurements, with HG being the most satisfactory single measurement in predicting the live weight of WAD goat. Sex had significant influence on the model with R ² values consistently higher in females except the models for LHQ and HW.     

Body measurements of west African dwarf sheep as parameters for estimation of live weight

The relationships between live weight and eight body measurements of West African Dwarf (WAD) sheep were studied using 210 animals under on farm condition. Data obtained on height at withers (HW), heart girth (HG), body length (BL), head length (HL), head width (HDW), loin girth (LG), length of hindquarter (LHQ) and width of hindquarter (WHQ) were fitted into linear, allometric and multiple regression models to predict live weight from the body measurements. Results revealed that body measurements of WAD sheep were generally higher in the rams than in the ewes. Coefficient of determination (R(2)) values computed for the body measurements were generally higher (0.87-0.99) using allometric regression model than linear regression model (0.44-0.94). Heart girth (HG) and WHQ depicted the highest relationship to live weight in linear and allometric models compared to other body measurements. Based on stepwise elimination procedure, HG, HL and WHQ were better in predicting live weight in multiple linear regression models. The magnitude of correlation coefficient (r) indicate that WHQ shows the highest correlation with live weight (r = 0.96) compared to HG (r = 0.94).     

Analysis of size and conformation of native Creole goat breeds and crossbreds used in smallholder agrosilvopastoral systems in Puebla,Mexico

Liveweight (LW) of does and bucks of the native Creole goat breed and crosses of Creole does and Nubian bucks, aged 1.5–5 years, were recorded and body traits including: head length (HL), head width (HW), body length (BL), trunk length (TL), chest girth (CG), abdominal perimeter (AP), rump length (RL), and height at withers (HW) were measured to develop equations for predicting LW from the body measurements. Weight, sex, breed and kidding date of 354 kids were recorded at birth, and LW of the kids was measured monthly for one year to determine the effect of kidding season on growth rate. Bucks had higher (p < 0.05) body measurements than the does (HL 15.1 ± 0.1 vs 16.6 ± 0.2 cm; BL 97.6 ± 0.4 vs 104.6 ± 1.2 cm; CG 78.8 ± 0.4 vs 79.9 ± 1.0 cm; AP 82.4 ± 0.5 vs 87.2 ± 1.1 cm; HW 62.7 ± 0.4 vs 70.1 ± 0.8 cm). With the exception of TL, F₂ does had higher (p < 0.05) body measurements and LW (28.8 ± 1.5 vs 27.7 ± 0.5 kg) than Creole does. The body traits of the F₁ does were similar (p > 0.05) to those of Creole does with the exception of HL, BL and HR. The F₂ kids were heavier (p < 0.05) at birth (3.31 ± 0.1 vs 2.60 ± 0.1 kg) and grew faster than the Creole kids. Male kids were heavier (p < 0.05) at birth (3.21 ± 0.10 vs 2.73 ± 0.13 kg), and grew faster than female kids. Season had a significant effect on birth weight. The results showed that LW of Creole goats and Creole × Nubian does could be estimated in the field using body traits. Birth weight and growth rate of kids could be improved by management practices that affect season of kidding.     

Relationship between latency of brainstem auditory-evoked potentials and head size in dogs.

Cranium and brainstem dimensions were measured in 32 postmortem dog heads. Positive correlations were found between cranium length (CL) and brainstem length (BL) (r = 0.87), between cranium width (CW) and brainstem width (BW) (r = 0.83), and between cranium distance (CD = CL+CW/2) and brainstem distance (BD = BL+BW/2) (r = 0.91). Positive correlation coefficients were also found between CL and CW (r = 0.90), and between BL and BW (r = 0.85). It was concluded that head size accurately reflected brainstem size. A least squares estimation of the brainstem distance (BD) from CL and CW values was BD = 10.9 + 0.16 (CL+CW/2) (BD, CL and CW in mm). Brainstem auditory evoked potentials (BAEPs) and cranium dimensions were measured in 43 dogs (86 ears) with different head size, body size, sex and age. Wave form, absolute and interpeak latencies and correlation coefficients, relating latencies to cranium dimensions and body weight, were analysed. CL, CW, and CD were positively correlated with body weight (r = 0.93, 0.70 and 0.93, respectively), and CL, CW, and CD were correlated with age (r = 0.33, 0.52, and 0.40, respectively). BAEPs consisted of five distinct positive peaks (I to V). Secondary positive peaks following peaks I and II were seen in 60% (I') and 90% (II') of the recordings. Late waves were recorded in 90% (VI), 50% (VII), and 25% (VIII) of the recordings. Latencies increased with decreasing stimulus intensity level (from 90 dB to 10 dB hearing level, HL), especially for peaks I, II, V, and the I-V interpeak interval.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of head position on intraocular pressure in horses

OBJECTIVE: To evaluate the effect of head position on intraocular pressure (IOP) in horses. ANIMALS: 30 horses. PROCEDURES: Horses were sedated with detomidine HCl (0.01 mg/kg, IV). Auriculopalpebral nerve blocks were applied bilaterally with 2% lidocaine HCl. The corneas of both eyes were anesthetized with ophthalmic 0.5% proparacaine solution. Intraocular pressures were measured with an applanation tonometer with the head positioned below and above heart level. The mean of 3 readings was taken for each eye at each position for data analysis. The effect of head position on IOP was assessed and generalized estimating equations were used to adjust for the correlation from repeated measures of the same eye and intereye correlation from the same horse. RESULTS: Of the 60 eyes, 52 (87%) had increased IOP when measured below the heart level. A significant difference (mean +/- SE, 8.20 +/- 1.01 mm Hg) was seen in the mean IOP when the head was above (17.5 +/- 0.8 mm Hg) or below (25.7 +/- 1.2 mm Hg) heart level. No significant effect of sex, age, or neck length on IOP change was found. CONCLUSIONS AND CLINICAL RELEVANCE: Head position has a significant effect on the IOP of horses. Failure to maintain a consistent head position between IOP measurements could potentially prevent the meaningful interpretation of perceived aberrations or changes in IOP.     

Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): II. age at slaughter

Crocodile morphometric (head, snout‐vent and total length) measurements were recorded at three stages during the production chain: hatching, inventory [average age (±SE) is 265.1 ± 0.4 days] and slaughter (average age is 1037.8 ± 0.4 days). Crocodile skins are used for the manufacture of exclusive leather products, with the most common‐sized skin sold having 35–45 cm in belly width. One of the breeding objectives for inclusion into a multitrait genetic improvement programme for saltwater crocodiles is the time taken for a juvenile to reach this size or age at slaughter. A multivariate restricted maximum likelihood analysis provided (co)variance components for estimating the first published genetic parameter estimates for these traits. Heritability (±SE) estimates for the traits hatchling snout‐vent length, inventory head length and age at slaughter were 0.60 (0.15), 0.59 (0.12) and 0.40 (0.10) respectively. There were strong negative genetic (?0.81 ± 0.08) and phenotypic (?0.82 ± 0.02) correlations between age at slaughter and inventory head length.     

Relationship between latency of brainstem auditory‐evoked potentials and head size in dogs

Summary

Cranium and brainstem dimensions were measured in 32 postmortem dog heads. Positive correlations were found between cranium length (CL) and brainstem length (BL) (r=0.87), between cranium width (CW) and brainstem width (BW) (r=0.83), and between cranium distance (CD = CL CW/2) and brainstem distance (BD = BL+BW/2) (r=0.91). Positive correlation coefficients were also found between CL and CW (r=0.90), and between BL and BW (r=0.85). It was concluded that head size accurately reflected brainstem size. A least squares estimation of the brainstem distance (BD) from CL and CW values was BD = 10.9 + 0.16 (CL CW/2) (BD, CL and CW in mm).

Brainstem auditory evoked potentials (BAEPs) and cranium dimensions were measured in 43 dogs (86 ears) with different head size, body size, sex and age. Wave form, absolute and interpeak latencies and correlation coefficients, relating latencies to cranium dimensions and body weight, were analysed CL, CW, and CD were positively correlated with body weight (r=0.93, 0.70 and 0.93, respectively), and CL, CW, and CD were correlated with age (r=0.33, 0.52 and 0.40, respectively). BAEPs consisted of five distinct positive peaks (I to V). Secondary positive peaks following peaks I and II were seen in 60% (I') and 90% (II') of the recordings. Late waves were recorded in 90% (VI), 50% (VII), and 25% (VIII) of the recordings. Latencies increased with decreasing stimulus intensity level (from 90 dB to 10 dB hearing level, HL),especially for peaks I, II, V, and the I‐V interpeak interval Absolute and interpeak latencies were positively correlated with cranium distance and body weight. Correlation coefficients increased as wave latencies increased At 90 dB HL, the highest correlation coefficients, relating cranium distance to peak V and the I‐V interpeak latency, were 0.55 and 0.53 (P < 0.00001), respectively. Regression analysis showed that each 1 cm increase in cranium distance was accompanied by an increase of 0.006 ms in the latency of wave I, 0.03 ms for wave III, 0.05 ms for wave V, and 0.05 ms for the I‐V interpeak interval Regression analysis showed that an increase of 1 kg in body weight was accompanied by an increase of 0.001 ms in the latency of wave I, 0.005 ms for wave III, 0.011 ms for wave V, and 0.01 ms for the I‐V interpeak interval. It is concluded that head size, which accurately reflects brain size, is a relevant source (25%) of intersubject variance of BAEP latencies in the dog.     

Genetic and phenotypic parameters for Aleutian disease tests and their correlations with pelt quality,reproductive performance,packed-cell volume,and harvest length in mink

Aleutian disease (AD), caused by the Aleutian mink disease virus (AMDV), is a major health concern that results in global economic losses to the mink industry. The unsatisfactory outcome of the culling strategy, immunoprophylaxis, and medical treatment in controlling AD have urged mink farmers to select AD resilient mink based on several detection tests, including enzyme-linked immunosorbent assay (ELISA), counterimmunoelectrophoresis (CIEP), and iodine agglutination test (IAT). However, the genetic analysis of these AD tests and their correlations with pelt quality, reproductive performance, packed-cell volume (PCV), and harvest length (HL) have not been investigated. In this study, data on 5,824 mink were used to estimate the genetic and phenotypic parameters of four AD tests, including two systems of ELISA, CIEP, and IAT, and their genetic and phenotypic correlations with two pelt quality, five female reproductive performance, PCV, and HL traits. Significances (P < 0.05) of fixed effects (sex, year, dam age, and color type), covariates (age at harvest and blood sampling), and random effects (additive genetic, permanent environmental, and maternal effects) were determined under univariate models using ASReml 4.1 software. The genetic and phenotypic parameters for all traits were estimated under bivariate models using ASReml 4.1 software. Estimated heritabilities (±SE) were 0.39 ± 0.06, 0.61 ± 0.07, 0.11 ± 0.07, and 0.26 ± 0.05 for AMDV antigen-based ELISA (ELISA-G), AMDV capsid protein-based ELISA, CIEP, and IAT, respectively. The ELISA-G also showed a moderate repeatability (0.58 ± 0.04) and had significant negative genetic correlations (±SE) with reproductive performance traits (from −0.41 ± 0.16 to −0.49 ± 0.12), PCV (−0.53 ± 0.09), and HL (−0.45 ± 0.16). These results indicated that ELISA-G had the potential to be applied as an indicator trait for genetic selection of AD resilient mink in AD endemic ranches and therefore help mink farmers to reduce the adverse effects caused by AD.     

Chemical composition of whole body and carcass of Bos indicus and tropically adapted Bos taurus breeds

Relationships between the chemical composition of the 9th- to 11th-rib section and the chemical composition of the carcass and empty body were evaluated for Bos indicus (108 Nellore and 36 Guzerah; GuS) and tropically adapted Bos taurus (56 Caracu; CaS) bulls, averaging 20 to 24 mo of age at slaughter. Nellore cattle were represented by 56 animals from the selected herd (NeS) and 52 animals from the control herd (NeC). The CaS and GuS bulls were from selected herds. Selected herds were based on 20 yr of selection for postweaning BW. Carcass composition was obtained after grinding, homogenizing, sampling, and analyzing soft tissue and bones. Similarly, empty body composition was obtained after grinding, homogenizing, sampling, analyzing, and combining blood, hide, head + feet, viscera, and carcass. Bulls were separated into 2 groups. Group 1 was composed of 36 NeS, 36 NeC, 36 CaS, and 36 GuS bulls and had water, ether extract (EE), protein, and ash chemically determined in the 9th- to 11th-rib section and in the carcass. Group 2 was composed of 20 NeS, 16 NeC, and 20 CaS bulls and water, EE, protein, and ash were determined in the 9th- to 11th-rib section, carcass, and empty body. Linear regressions were developed between the carcass and the 9th- to 11th-rib section compositions for group 1 and between carcass and empty body compositions for group 2. The 9th- to 11th-rib section percentages of water (RWt) and EE (RF) predicted the percentages of carcass water (CWt) and carcass fat (CF) with high precision: CWt, % = 29.0806 + 0.4873 × RWt, % (r(2) = 0.813, SE = 1.06) and CF, % = 10.4037 + 0.5179 × RF, % (r(2) = 0.863, SE = 1.26), respectively. Linear regressions between percentage of CWt and CF and empty body water (EBWt) and empty body fat (EBF) were also predicted with high precision: EBWt, % = -9.6821 + 1.1626 × CWt, % (r(2) = 0.878, SE = 1.43) and EBF, % = 0.3739 + 1.0386 × CF, % (r(2) = 0.982, SE = 0.65), respectively. Chemical composition of the 9th- to 11th-rib section precisely estimated carcass percentages of water and EE. These regressions can accurately predict carcass and empty body compositions for Nellore, Guzerah, and Caracu breeds.