Evaluation of 12-month interval methods for estimating animal-times at risk in a traditional African livestock farming system

Demographic parameters are useful for assessing productivity and dynamics of tropical livestock populations. Common parameters are the annual instantaneous hazard rates, which can be estimated by m/T (where m represents the number of the considered demographic events occurred during the year and T the cumulated animal-time at risk). Different approaches are encountered in the literature for computing T from on-farm survey data. One crude approach (“the 12-month interval approach”) only uses estimations of herds’ sizes at beginning and end of the year and aggregated counts of demographic events over the year. I evaluated the potential biases in using four 12-month interval methods (M1–M4) to estimate T. Biases were evaluated by comparing the 12-month estimates to gold-standard values of T. Data came from long-term herd monitoring on cattle and small ruminants in extensive agro-pastoral systems. Animal-times at risks were correctly estimated in average by methods M1, M2 and M4 (average relative biases <=6% in absolute values), except for adult-male small ruminants. For young animals, M2 and M4 showed equivalent biases. M2 is simple to implement and has the advantage of being applicable for any age-group, although M4 is only applicable for young animals. M3 was highly biased and I do not recommend it. Although accurate in average, 12-month interval methods showed highly variable biases. This variability results from interactions between the dates delimiting the 12-month interval and the distributions of the demographic events over time. This phenomenon is particularly important for the adult-male small ruminants. Based on the bias variability observed in the study, the user of 12-month interval methods has to remember that they only provide approximate results and that they cannot completely replace the gold-standard approaches.     

The roles of calving migration and climate change in the formation of the weak genetic structure in the Tibetan antelope (Pantholops hodgsonii)

Geographical barriers and distance can reduce gene exchange among animals, resulting in genetic divergence of geographically isolated populations. The Tibetan antelope (Pantholops hodgsonii) has a geographical range of approximately 1600 km across the Qinghai–Tibet Plateau, which comprises a series of tall mountains and big rivers. However, previous studies indicate that there is little genetic differentiation among their geographically delineated populations. To better understand the genetic structure of P. hodgsonii populations, we collected 145 samples from the 3 major calving regions, taking into consideration their various calving grounds and migration routes. We used a combination of mitochondrial sequences (Cyt b, ATPase, D‐loop and COX I) to investigate the genetic structure and the evolutionary divergence of the populations. Significant, albeit weak, genetic differentiation was detected among the 3 geographical populations. Analysis of the genetic divergence process revealed that the animals gradually entered a period of rapid genetic differentiation approximately 60 000 years ago. The calving migration of P. hodgsonii cannot be the main cause of their weak genetic structure because this cannot fully homogenize the genetic pool. Instead, the geological and climatic events as well as the coupling vegetation succession process during this period have been suggested to greatly contribute to the genetic structure and the expansion of genetic diversity.     

Tissue distribution of dexamethasone in canine ocular compartments following topical application of dexamethasone-21-isonicotinate and oxytetracycline HCl

Objective  To study the dexamethasone (DXM) concentration at different time points in various compartments of the canine eye following topical application of DXM-21-isonicotinate and oxytetracycline hydrochloride
Animals studied  Thirty dogs to be euthanized for reasons not related to this study were selected and their ocular health status evaluated. Selected animals were treated with DXM-oxytetracycline ointment and euthanized after 6, 11 or 16 h.
Procedure  The concentration of DXM was determined in the following compartments of the eye: third eyelid, cornea, aqueous humor, iris, lens, vitreous body and choroid/retina. The DXM concentration in the eye was measured by radioimmunoassay. The applied amount of DXM was 0.04 mg in 0.2 mL ointment. Dogs were treated once with Corti Biciron^® eye ointment (DXM-21-isonicotinate and oxytetracycline hydrochloride, S & K Pharma, Perl, Germany) and were euthanized 6, 11 and 16 h after treatment.
Results  At 6 h following topical application the mean DXM concentration was highest in the anterior structures of the eye (third eyelid: 18 ng/g, cornea: 36 ng/g). The concentration in the posterior structures was below detection level. A decreased DXM concentration in the anterior structures was measured 11 and 16 h after treatment.
Conclusion  It could be demonstrated that therapeutically relevant concentrations of DXM after a single topical administration are only achieved in anterior structures of the eye. A dosing interval of 6–11 h is recommended to achieve therapeutic drug concentration in those structures. The posterior structures of the eye are not reached by topical administration.     

Diagnostic and prognostic utility of surface electrocardiography in cats with left ventricular hypertrophy

Objectives

To assess the ability of electrocardiography (ECG) to predict left ventricular hypertrophy (LVH) in the cat and to investigate the prognostic value of selected ECG variables in cats with LVH.

Fine mapping of a calving QTL on Bos taurus autosome 18 in Holstein cattle

Decreased calving performance not only directly impacts the economic efficiency of dairy cattle farming but also influences public concern for animal welfare. Previous studies have revealed a QTL on Bos taurus autosome (BTA) 18 that has a large effect on calving traits in Holstein cattle. In this study, fine mapping of this QTL was performed using imputed high‐density SNP chip (HD) genotypes followed by imputed next‐generation sequencing (NGS) variants. BTA18 was scanned for seven direct calving traits in 6113 bulls with imputed HD genotypes. SNP rs136283363 (BTA18: 57 548 213) was consistently the most significantly associated SNP across all seven traits [e.g. p‐value = 2.04 × 10^?59 for birth index (BI)]. To finely map the QTL region and to explore pleiotropic effects, we studied NGS variants within the targeted region (BTA18: 57 321 450–57 625 355) for associations with direct calving traits and with three conformation traits. Significant variants were prioritized, and their biological relevance to the traits was interpreted. Considering their functional relationships with direct calving traits, SIGLEC12, CD33 and CEACAM18 were proposed as candidate genes. In addition, pleiotropic effects of this QTL region on direct calving traits and conformation traits were observed. However, the extent of linkage disequilibrium combined with the lack of complete annotation and potential errors in the Bos taurus genome assembly hampered our efforts to pinpoint the causal mutation.     

Serum biochemistry and hematology values and hemoglobin electrophoresis in Persian squirrels (Sciurus anomalus)

BACKGROUND: Serum biochemical and hematologic parameters are important in the management of game species in Iran, such as Persian squirrels. OBJECTIVE: The purpose of this study was to establish baseline serum chemistry and hematology values in Persian squirrels (Sciurus anomalus) and describe blood cell morphology and the electrophoretic pattern of hemoglobin. METHODS: Blood samples were collected from 30 Persian squirrels (Sciurus anomalus) maintained in captivity in the Tehran Zoo. Blood was placed into EDTA and serum clot tubes and analyzed using standard manual hematology and biochemical techniques. Hemoglobin electrophoresis was done on cellulose acetate paper strips. RESULTS: Minimum, maximum, and median values were obtained for 11 hematologic and 12 serum chemistry parameters. Hypersegmented neutrophils were observed frequently. We did not find basophils or band neutrophils. Hemoglobin electophoresis resulted in a band slightly anodal to that of human hemoglobin A. CONCLUSION: Biochemical and hematologic values in Persian squirrels were comparable to those of related species, and may be used as a standard profile for healthy Persian squirrels kept in captivity.     

流域泥沙模型中雨量资料的时空尺度分析

以经改进的格林－安普特下渗模型为基础,选择降雨资料有足够短的时段记载的流域和有足够密度雨量站的流域,分别变化时段长和站网密度计算产品,根据模型模拟精度与时段长及站网密度关系线的转折点,确定适当的时段长和合理的站网密度,通过曹坪流域的站网分析和６个小流域试验站的时段分析,发现对社些流域而言,时段长小于１５ｍｉｎ,站网密度大于２个／１００ｋｍ＾２,其降雨时空均化给模型计算带来的误差可以忽略。     

矮小型褐壳蛋鸡产蛋时间和间隔的统计分析

本文对８８０只纯系矮小型褐壳蛋鸡的产蛋时间进行了连续５天的观察,分析结果表明,矮小型褐壳蛋鸡的产蛋时间集中在上午１２时以前,并以９：００～１０：００期间产蛋最为密集,占全天产蛋的１９．５％。连产内第一枚蛋产出时间集中在上午（８９：３３％）,以７：００～９：００间产蛋最多（４９．７１％）;而最后一枚蛋产出时间集中在下午（７１．２０％）,以２：００～４：００间产蛋最多（３６．５８％）。矮小型褐壳蛋鸡连产内产蛋间隔范围为２２．３５～３１．１５小时,每枚蛋平均间隔高峰在２４小时（３６．０％）,群体平均产蛋间隔为２５．０８小时。相邻连产间间隔时间的变异范围很大,最短为３８．０小时,最长达１００．４５小时。     

兽医临床上常见黄牛异常发情的防治措施

随着农业机械化不断地推广,二牛抬杠式的原始农业耕作方式逐渐退出了农业生产。取而代之的农业机械化耕作,以前用来耕地的黄牛用途逐渐变成了产犊为主,农田里不见了黄牛耕作的身影,山坡不见了放牛人。取而代之的是舍饲圈养,肉牛以集约化育肥为主的养殖方式。通过对兽医临床遇到的病例统计发现,母牛的异常发情病例逐渐增多,高达30%~40%。作者根据实际兽医临床工作发现一个规律,一到冬季产犊季,母牛难产增多;母牛产犊后农户就会天天用玉米糊糊饲喂,瘤胃积食也会增多,冬季青贮饲草料价格高,资源匮乏,担心母牛产犊后掉膘,乳汁分泌不足,在这个过程中,很多母牛就会出现虚胖,犊牛腹泻,母牛伤食泻瘤胃酸中毒,最主要的是产犊后的母牛长期大量精料饲喂导致母牛体质偏胖,在中兽医诊断上就属于一种寒湿瘀滞的体质,卵泡不发育或者是发育不良。再加上畜主长期不正确的使用各种兽药,造成滥用药,致使动物机体损伤养殖业是一个需要倾注大量心血的行业,天道酬勤,养殖场户的辛勤付出才能换来牛羊的牧草丰富,茁壮生长,动物防疫工作者的辛勤付出才能换来动物群体的健康稳定,畜牧兽医工作者与农户一起服务于动物从配种到出栏。     

谈抚育间伐间隔期内林分的动态分析

本文论述了抚育间伐间隔期的确定,并对林分在抚育间伐间隔期林木径阶、平均直径、平均高以及活地被物的动态变化进行了分析。