Inherited abnormalities of skeletal development in sheep

Inherited diseases of the skeleton are reported less often in sheep than in most other domestic animal species but are likely to occur more frequently than the veterinary literature would suggest. Although most are lethal or semi-lethal, the gene frequency for some of these diseases has reached surprisingly high levels in defined populations, presumably due either to the founder effect or the presence of a selective advantage of heterozygous individuals. This article reviews the clinical characteristics, pathology, mode of inheritance and molecular basis of skeletal diseases known to have a genetic aetiology in sheep. Inherited skeletal diseases of sheep are potential models for studying the treatment of similar diseases in humans.     

Dietary bioactive substances influenced perinatal bone development in piglets

Bioactive substances including taurine, l-carnitine, polyunsaturated fatty acids, flavonoids and antioxidants were shown to influence the perinatal development of a majority of mammalian systems, nervous, gastrointestinal, immune, etc. A blend of bioactive substances and plants was composed to supplement sow feedstuff, and our study aimed to examine the bone parameters in their offspring. Control sows were fed with a standard diet alone (n = 6). The sows from the supplemented group (n = 6) received the supplementation from the gestation day 80 until the end of lactation. From each sow two piglets were sacrificed, one at 7 d and the second at 28 d of life. The femur and humerus were isolated, bone mineral density and mineral content were determined using dual energy X-ray absorptiometry. Bone maximum strength and elastic force were determined by a three-point bending test. No differences in the body weight were found. At day 7, the bones of piglets from the supplemented group were characterized by higher weight, physical parameters and bone mineral content as compared to control, no difference in length and bone mineral density was observed. At day 28, no differences in humerus parameters were found as well as in femur mineral density and mineral content. However, in relation to the body weight, the weight and physical parameters of femur were higher in the supplemented group as compared to control. In conclusion, the supplementation of sow diet with bioactive substances influenced the development of bones in their offspring.     

Changes in bone structure of Corriedale sheep with inherited rickets: A peripheral quantitative computed tomography assessment

An inherited skeletal disease with gross and microscopic features of rickets has been diagnosed in Corriedale sheep in New Zealand. The aim of this study was to quantify the changes present in tibia from sheep with inherited rickets using peripheral quantitative computed tomography. In affected sheep, scans in the proximal tibia, where metaphysis becomes diaphysis, showed significantly greater trabecular bone mineral content (BMC) and bone mineral density (BMD). The sheep with inherited rickets had significantly greater BMC and bone area in the mid-diaphysis of the proximal tibia compared to control sheep. However, BMD in the mid-diaphysis was significantly less in affected sheep than in controls, due to the greater cortical area and lower voxel density values in affected sheep. From this it was concluded that the increased strain on under-mineralised bone in sheep with inherited rickets led to increased bone mass in an attempt to improve bone strength.     

Dietary phosphorus restriction affects bone metabolism,vitamin D metabolism and rumen fermentation traits in sheep

Homeostasis of calcium (Ca) and phosphate (P_i) is maintained by a concerted interplay of absorption and reabsorption via the gastrointestinal tract and the kidney and by storage and mobilization from the bone regulated mainly by parathyroid hormone (PTH), 1,25-dihydroxycholecalciferol and calcitonin. The present study aimed at characterizing the effects of dietary P restriction on bone, vitamin D metabolism and rumen fermentation traits reflecting the endogenous P cycle maintaining the ruminal P supply for microbial metabolism. The experiments were done in eleven female, non-pregnant, non-lactating four- to nine-year-old Black Headed Mutton sheep allotted to two feeding groups: "P-restricted" (0.11% P/kg DM and 0.88% Ca/kg DM) and "Control" (0.38% P/kg DM and 0.88% Ca/kg DM). Dietary P restriction did not lead to hypophosphataemia, probably due to a compensation by bone mobilization, demonstrated by increased serum concentrations of a resorption marker and altered gene expression in bone tissue. In addition, the RNA expression of fibroblast growth factor 23, a bone-derived factor involved in the regulation of vitamin D metabolism, was significantly reduced with dietary P restriction. Furthermore, several genes related to vitamin D metabolism and plasma concentrations of 1,25-(OH)₂D were associated with serum concentrations of phosphate (P_i). In the parotid gland, the expression of the P_i transporter NaPi2b was negatively associated with serum P_i and positively with parathyroid PTH expression. Although P_i concentrations in saliva and the gastrointestinal tract were significantly reduced, we found no adverse effects of the P-restricted ration on the production of short chain fatty acids, but slight differences in the production of butyrate as well as its relationship to rumen P_i and ammonia concentrations that might indicate an impact on ruminal fermentation.     

中国北方放牧绵羊硒的营养状况和季节变化

通过对我国４省区１５个牧场３００只放牧绵羊血浆和粪硒含量的采集和分析发现，在全年的部分时间，甘肃省的各个牧场和新疆的巩乃斯羊场均存在着硒的供给不足。此种现象在夏季和秋季表现最为明显，而此时动物和牧草生长最快。此时若不给予适量的硒，很容易使动物产生硒缺乏。对羔羊尤其需要引起注意，即使在夏季草场放牧时，也需给羔羊补硒     

Mild exercise early in life produces changes in bone size and strength but not density in proximal phalangeal, third metacarpal and third carpal bones of foals

Exercise or lack of it in early life affects chondro-osseous development. Two groups of horses were used to investigate the effects of age and exercise regimen on bone parameters of diaphyseal, metaphyseal, epiphyseal and cuboidal bones of the distal limb of Thoroughbreds. One group had exercised only spontaneously from an early age at pasture (PASTEX group), while the other group of horses were exposed to a 30% greater workload through additional defined exercise (CONDEX). Longitudinal data from peripheral quantitative computed tomography (pQCT) were obtained from eight scan sites of the left forelimb (proximal phalangeal (P_p; 1 site), third metacarpal (Mc3; six sites) and third carpal (C₃; one site) bones) of 32 Thoroughbred foals scanned five times from ∼3 weeks to 17 months of age. The primary outcome measures were bone mineral content (BMC), bone area (BA), and periosteal circumference (Peri C) in diaphyseal bone, with cortical thickness (CortTh), volumetric bone mineral density (BMD_v) and a bone strength index (SSI) also being analysed.At the P_p site within the model there was a significant effect (P = 0.00–0.025) of conditioning exercise increasing bone parameters, except endosteal circumference (Endo C) and BMD_v. The BMC, BA, and SSI of P_p were significantly greater in the CONDEX than PASTEX groups at 12 and 17 months (P = 0.015–0.042) and CortTh at 17 months (P = 0.033). At the M55 site of Mc3 BMC, BA and SSI (P = 0.02–0.04), and at the M33 site, SSI (P = 0.05) were higher in the CONDEX than PASTEX group. The adaptive responses, consistent with diaphyseal strengthening, were more marked in the diaphysis of P_p than Mc3. In the Mc3, metaphysis, trabecular BMD_v was less in the CONDEX than PASTEX group, associated with greater bone mineral accretion in the outer cortical-sub-cortical bone in the CONDEX group. There were no significant between-group differences in any epiphyseal or cuboidal bone parameter. Although the early imposed exercise regimen was not intensive, it had significant effects on diaphyseal bone strength, through change in size but not bone density.     

Geographical isolation of native sheep breeds in the UK—Evidence of endemism as a risk factor to genetic resources

This study addresses the potential risk to the genetic resources of UK sheep breeds from endemism. Twelve native breeds are analysed that exist in significant numbers and continue to be commercially farmed livestock. The breeds were selected to represent regions of the British Isles: North of England hill breeds (Herdwick, Rough Fell, Lonk, Dalesbred), South of England breeds (Southdown, Romney, Devon Closewool, Exmoor Horn), Scottish breed (South Country Cheviot) and Welsh/Welsh border breeds (Welsh Hill Speckled Face, South Wales Mountain (Nelson), Clun Forest).For each breed, numerical data were collected in collaboration with breed society members and analysed in terms of population size and structure together with the extent of their geographical range. The number of flocks per breed proved to be highly variable, questioning the assumption that has been made that the number of breeding units can be disregarded in the calculations of endangerment. The data also indicated that an average flock size for a breed cannot be estimated to gain an insight of the population structure, since this parameter was found to vary considerably within and between breeds. The endemism was best illustrated in the breed maps which clearly highlighted the degree to which each breed was associated with a distinct geographical area. From the maps, ten of the twelve breeds analysed were concentrated, but the flocks of two breeds were visually more dispersed. In numerical terms, the ten breeds were found to have up to 95% of their breed numbers concentrated within a radius of 65 km from the mean centre of each breed.The study provides a valuable foundation for future research into genetic diversity within and between the sheep breeds analysed, a baseline of information to enable population trends to be examined and a robust evidence-base for policy decisions on Farm Animal Genetic Resources (FAnGR).     

波德代、无角陶赛特与甘南藏羊F1生长发育研究

试验结果表明:在相同的自然条件下,波杂(波德代羊×甘南山谷型藏羊)F1羔羊和陶杂(无角陶塞特羊×甘南山谷型藏羊)F1羔羊在初生重、0~180日龄平均日增重,公羔分别为4.65 kg、124.67 g/d和4.57 kg1、21.39 g/d;母羔分别为4.36 kg1、12.11 g/d和4.19 kg1、16.67 g/d,均显著高于甘南山谷型藏羊的相应指标,差异极显著。1、3、6月龄体重、体高、体长、胸围均高于甘南山谷型藏羊,差异极显著;管围、尻宽差异不显著体型指数优于甘南山谷型藏羊,接近肉用羊体型。     

Influence of intensity and changes of physical activity on bone mineral density of immature equine subchondral bone

Reasons for performing study: Subchondral bone provides structural support to overlying articular cartilage and plays an important biomechanical role in osteochondral diseases. Mechanical features of bone correlate strongly with bone mineral density, which is directed by the loading conditions to which the tissue is subjected. Objective: To investigate the influence of physical activity levels on subchondral bone mineral density (sBMD) in foals during early development. Methods: Three groups of foals were subjected to different physical activity levels from birth until age 5 months. A proportion of these foals were subjected to euthanasia at 5 months while remaining foals were subjected to similar physical activity levels for 6 months until euthanasia at 11 months. Osteochondral specimens were collected for measurement of sBMD with peripheral quantitative computed tomography at 2 differently loaded anatomical sites of the proximal phalangeal bone at 1, 2, 3, 4 and 5 mm depth from the osteochondral junction. Results: Growth significantly increased sBMD but by a different amount depending on anatomical location and physical activity level. Significantly higher sBMD was found at the habitually loaded central area in comparison to the intermittently peak loaded marginal site. Exercise increased sBMD throughout the whole depth of analysed tissue, but changes were generally more obvious at a depth of 2 mm. Interestingly, foals subjected to additional sprint training preserved the exercise‐induced sBMD increase at the habitually loaded central area during the 6 months of the second phase of the study. Conclusions: Habitual low‐intensity loading elicits a greater response in sBMD in quantitative terms than high‐intensity low‐frequency loading at the sites investigated in this study. Future sBMD may be influenced by means of well‐tailored exercise regimens at young age. Potential relevance: Specific physical activity levels during early development may potentially reduce the prevalence of osteochondral injury later in life.     

PER2基因组织表达及多态性与绵羊季节性繁殖的相关性研究

为探究PER2基因在绵羊繁殖相关组织中的表达水平及其多态性与绵羊繁殖性状的关系,本实验通过实时荧光定量PCR(qPCR)检测PER2基因在季节性发情的苏尼特羊和常年发情的小尾寒羊松果体、下丘脑、垂体、卵巢、输卵管以及子宫组织中的表达情况,同时利用Sequenom MassARRAY~?SNP技术检测季节性发情绵羊品种(草原型藏羊、苏尼特羊、滩羊共204只)和常年发情绵羊品种(小尾寒羊、湖羊、策勒黑羊共564只)PER2基因g.2852655T>C位点的多态性。结果表明:PER2基因在绵羊的松果体、下丘脑、垂体、卵巢、输卵管以及子宫组织中均有表达,且在季节性繁殖的苏尼特羊卵巢和子宫组织中的表达均显著高于常年发情小尾寒羊(P<0.05),而在输卵管组织中则相反(P<0.05);分型结果表明,PER2基因的g.2852655T>C位点存在3种基因型,该位点的基因型频率和等位基因频率在发情性状不同的绵羊品种之间具有显著差异。综上,PER2基因在季节性发情苏尼特羊卵巢组织中的表达量显著高于常年发情小尾寒羊,初步推测卵巢中较高水平PER2基因的表达通过抑制LHR受体的表达及孕酮的分泌,进而影响绵羊的季节性发情,且较高水平PER2基因表达可能在卵子受精和胚胎发育过程中也起到重要调控作用。     

荒漠草地放牧系统常量矿物质元素季节变化及盈缺分析

采取现场调查、实地采样和实验室分析相结合的方法,对内蒙古地区四子王旗地区短花针茅荒漠草地土壤-牧草-家畜生态系统中常量元素的水平进行检测.结果显示:土壤中硫元素处于临界缺乏状态,其他元素处于正常水平;牧草中钙元素全年处于过量状态,磷和钠元素全年为缺乏状态,钾和硫元素处于季节性缺乏状态;结合该地区放牧绵羊唾液、血浆和体组织中矿物质的含量,以及对各种矿物质的摄入量和消化率进行综合分析表明,该地区处于高钙、低磷、低钠、低钾的生态环境,同时硫元素处于季节性缺乏状态.     

Markers of bone metabolism in dog breeds of different size

Serum and urinary markers of bone turnover may be of value in animals as noninvasive tools for determining the response of the skeleton to disease and injury. Although normal values for bone markers have been reported for the Beagle, concerns remain that breed to breed differences will complicate the interpretation of bone marker data in dogs. To explore this, we examined serum bone markers in two breeds of vastly different size, Pomeranians and Irish Wolfhounds. Our hypothesis was that serum concentrations of bone markers are similar in toy and giant dog breeds and fall within the same range as those reported for Beagles. Bone alkaline phosphatase (BALP) and carboxy-terminal telopeptide of type I collagen (ICTP), respectively markers of bone formation and bone resorption, were measured in age matched Pomeranians (n=14) and Irish Wolfhounds (n=14). No statistically significant differences between the mean BALP and mean ICTP serum concentrations from Pomeranians and Irish Wolfhounds were found. All BALP and ICTP concentrations were within the reference range reported for Beagles. The results of this study suggest that serum BALP and ICTP concentrations in giant and toy breeds are the same as in Beagles and that these assays may be used for dogs of all sizes.     

Subclinical mastitis changes the patterns of maternal-offspring behaviour in dairy sheep

Subclinical mastitis was induced by inoculating one mammary gland in dairy ewes (n=8) with a Staphylococcus simulans isolate; control ewes (n=4) were included. The milk yield of inoculated glands decreased (P<0.001), the California Mastitis Test (CMT) score increased and the organism could be recovered from the inoculated glands. With time, there was significantly increased frequency of "hindering sucking" (P=0.016) and "head up posture" (P<0.001) in the control ewes. Infected ewes had a significantly increased frequency of "vocalisation" (P=0.013) compared to controls. There was a significant difference in the frequency of "sucking attempt" and "successful suck" (P<0.05) behaviours between lambs of the two groups. Lambs of the challenged ewes also showed significantly increased frequency and duration of these behaviours towards the uninoculated glands of their dams, rather than to the challenged glands (P<0.05); no such difference was evident for the lambs of control ewes. It was concluded that subclinical mastitis alters the sucking behaviour of both ewes and lambs.     

Interaction between nutrition and gastrointestinal parasitism in sheep

Effects of gastrointestinal nematode infection on metabolism and nutrient utilisation in sheep are reviewed. Infection induces protein deficiency by increasing the demand for amino acids in the alimentary tract while reducing supply through depression of appetite. Mechanisms through which improved protein nutrition could improve the performance of the host are then discussed. Opportunities for capitalising on such effects are limited by our rudimentary understanding of the cell-mediated immune response in gastrointestinal epithelial tissue. Both resistance of the animal to larval establishment and performance in the face of larval challenge can be enhanced by improved protein nutrition. However, enhanced immune responses may not necessarily be synonymous with improved productivity except at luxurious levels of protein intake, because of apparently competing demands for protein. Such levels of protein nutrition are difficult to achieve in pasture-based systems, because of the protein limiting role of the rumen. Work with protein-protecting tannins to overcome this limitation is discussed. The much more limited evidence for effect of mineral nutrition, particularly copper (Cu), molybdenum (Mo), cobalt (Co) and phosphorus (P), on outcome of larval challenge is also reviewed.     

In growing pigs, chlortetracycline induces a reversible green bone discoloration and a persistent increase of bone mineral density dependent of dosing regimen

We studied in growing pigs the effects of exposure to dietary chlortetracycline on bone mineral density (BMD) and bone color. Pigs were randomly allocated to a drug-free diet (n = 48) or a diet fortified with 800 ppm of chlortetracycline, starting either at 28- or 84-d of age, and for either a 28- or 56-d duration (n = 16 pigs/group). The lumbar vertebral discoloration and BMD of randomly chosen pigs were evaluated at 28-d intervals up to 168-d of age. The odds of bone discoloration increased with dosing duration and age at treatment onset, and decreased with the withdrawal time and age at treatment onset interaction (p ? 0.001). The measured trabecular BMD linearly increased with age and squared treatment duration (p ? 0.005). Therefore, TC-induced bone discoloration is reversible, and may be prevented with proper dosing regimen design. Moreover, TC induces a persistent increase on BMD that could be detected with quantitative computed tomography.     

不同精料补饲水平对藏绵羊生产性能和消化代谢影响的研究

选择1~2岁藏羊30只,以青干草为基础日粮,每只按每天150,300,450 g 3种精料水平补饲。研究不同精料补饲量对藏羊生产性能和日粮营养物质的消化代谢的影响。结果表明:随精料补饲水平提高,日粮干物质、有机物、氮和钙、磷的表观消化率随之提高。藏羊能量摄入量、表观消化率和代谢率也随之升高,在300 g与450 g精料水平下,能量表观消化率和代谢率差异不显著(P>0.05);300 g粪能损失最低。ADF表观消化率随补饲水平提高而下降。在本试验条件下,从生产性能和藏羊营养代谢方面考虑,藏羊每天补饲精料300 g效果最佳。     

修剪高度对季节性温度变化下早熟禾生理生态特性的影响

修剪高度的差异会影响冷季型草坪草的生长,探究合理的修剪高度可为草坪草可持续利用提供理论基础。本研究通过测定两年生长季（2012年和2013年）草地早熟禾（8年生）草坪的外观质量（TQ）、地上部分生物量（AB）、光合作用（Pn）、总呼吸作用（R_total）和碳水化合物（TNC）等指标,探讨了修剪高度对冷季型草坪草生理生态特性的影响。试验结果表明,当大气温度高于23~24℃时,不同修剪高度7.6 cm （高修剪高度,HM）和3.8 cm （低修剪高度,LM）下的早熟禾TQ、AB和Pn均降低,与HM相比,在LM下下降更显著。在7—9月的高温条件下,早熟禾地上部分、根系和土壤R高于Pn;但在美国新泽西州较冷的季节（5—6月） Pn高于R。研究表明,较低的修剪高度尤其是在高温条件下降低了草坪草Pn,季节性温度变化下可以通过改变修剪高度影响成熟草坪草的生长,从而缓解高温对草坪生长带来的不利影响。     

高寒草地放牧系统铜的季节动态与盈缺分析

通过对青海省三角城种羊场夏（6月中旬）,秋（9月中旬）和冬（12月中旬）季的水、土壤、牧草、绵羊被毛、血液、组织器官中铜含量的分析测定,得出结果：青海环湖地区夏,秋和冬季土壤中铜含量均处于临界缺乏状态;牧草中的铜夏季〉秋季〉冬季,冬季缺铜。3季中绵羊血铜正常,肝铜明显缺乏,被毛中铜含量低于正常范围的下限。     

柱花草和苜蓿抗氧化系统及光合作用的季节性变化

为探讨热带和温带牧草对温度胁迫抗性差异的生理机制,本文比较研究了柱花草(Stylosanthes guianensis)和苜蓿(Medicago sativa)叶片抗氧化系统、可溶性糖和叶绿素荧光参数的季节性变化。结果表明:柱花草在冬季丙二醛(MDA)含量升高,苜蓿MDA含量在夏季升高;柱花草超氧化物歧化酶(SOD)活性在越冬前和越夏前升高,苜蓿SOD活性在秋冬季较高,春夏季较低;柱花草和苜蓿的过氧化氢酶(CAT)活性在越冬前均升高,但柱花草春夏季维持稳定,苜蓿CAT活性夏季升高;柱花草抗坏血酸-过氧化物酶(APX)活性全年较稳定,苜蓿的APX活性在春夏季不断升高;柱花草抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量在越冬前、后均升高,而苜蓿只在越冬前升高,越冬后维持稳定水平;柱花草和苜蓿的可溶性糖含量在越冬前均积累,柱花草积累高峰出现得较晚,且在越冬后再次大量积累,苜蓿在越冬前就大量积累,更有利于提高抗寒性;柱花草光系统Ⅱ(PSⅡ)最大光化学效率(F_v/F_m)和非光化学荧光猝灭(NPQ)在冬季有一定程度降低,PSⅡ光化学量子效率(Ф_PSⅡ)和光化学荧光猝灭(q_p)等叶绿素荧光参数明显降低,苜蓿F_v/F_m、Ф_PSⅡ和q_p等参数较稳定,但NPQ在春夏季不断降低。这说明,柱花草和苜蓿抗寒和抗热性的不同与其抗氧化系统、可溶性糖和PSⅡ季节性变化的差异有关。