阴离子盐对围产期奶牛的作用机理及其应用

本论文从阴离子盐的作用机理出发,综述了阴离子盐对奶牛采食量、尿液pH值、产奶性能与乳成分、血液离子浓度和血液生化指标、奶牛健康等的影响.     

Effect of concentrate extrusion and castration on diet digestion and performance of intensively reared male calves

Fifty-six male Friesian calves, half of them castrated, were used to study the effects of concentrate extrusion and animal castration on diet digestibility and performance in two different growth phases (from 91 to 250 and from 250 to 400 kg live weight). Diets consisted of a compound meal, extruded or nonextruded, and barley straw, both of them fed ad libitum. Half of the animals were slaughtered at 250 kg and the remaining at 400 kg live weight. Extrusion increased the gelatinization grade, resulting in a higher (p<0.01) fermentation rate, and reduced nitrogen solubility and degradation after 12 h of rumen incubation (p<0.05). Calves receiving the extruded meal showed a lower rumen ammonia concentration just before the first meal (p<0.001), the differences disappearing afterwards. Neither the pH nor the total VFA concentrations were affected, although butyrate, isobutyrate and isovalerate proportions before the first meal decreased with the extruded diet. Concentrate extrusion did not affect the apparent OM digestibility of total diet but caused a reduction of NDF (p<0.01) and CF (p<0.05) digestibility. In the first growth phase, concentrate and total DM intake decreased with extrusion (p<0.001), without affecting the average daily gain (ADG). Consequently, the concentrate and total feed conversion ratios were significantly lower (p<0.001 and p<0.01, respectively) with the extruded meal. Bulls showed a higher ADG than steers (p<0.001), resulting in lower feed conversion ratios (p<0.01) given that intake was not affected by castration. In the second growth phase, extrusion did not affect any of the performance parameters, however bulls showed a higher DM intake and ADG (p<0.05), but no differences in the feed conversion ratio were found between entire and castrated animals.     

Skeletal lesions of canine hepatozoonosis caused by Hepatozoon americanum

Canine hepatozoonosis, caused by Hepatozoon americanum, is an emerging tick-borne disease of dogs in North America. In addition to the skeletal and cardiac myositis that are prominent features of the disease, there is disseminated periosteal bone proliferation in most dogs that manifest clinical disease. Each of six experimentally infected animals (four dogs and two coyotes) and seven of eight naturally infected dogs had gross or histopathologic osteoproliferative lesions. Experimental animals were 6-9 months of age when exposed. Naturally infected dogs were 8 months to 11 years old when subjected to necropsy. Lesions occurred primarily on the diaphysis of the more proximal long bones of the limbs; however, flat and irregular bones were frequently involved. Lesions involving metacarpals, metatarsals, and digits were infrequent. The earliest observed periosteal lesions were in an experimentally infected dog 32 days after exposure to sporulated oocysts of H. americanum. There were hypertrophy and hyperplasia of osteoprogenitor cells, and osteoblasts appeared in the cellular zone of the periosteum. Spicules of woven bone oriented perpendicularly to bone cortex followed. Later yet, periosteal new bone was remodeled and tended to become oriented parallel to the cortical bone. Horizontally oriented zones of remodeled, condensed bone sometimes occurred in multiple layers on the original cortex, forming "pseudocortices." The osseous lesions of American canine hepatozoonosis, with few variations, are remarkably similar to those of hypertrophic osteopathy in domestic dogs and other mammalian species, including humans.     

Skeletal muscle lesions in turkeys associated with the feeding of monensin

The feeding of monensin as a coccidiostat in three separate flocks of turkeys was associated with increased mortality, posterior paresis, and a skeletal muscle myopathy. Mortality attributed to the disease was 1.65%, 1.86%, and 4.80% in the three flocks. Samples of monensin-supplemented feed fed to the flocks when showing clinical signs contained 88, 85, and 106 g/ton of complete feed, respectively. Clinically, the turkeys showed posterior paresis, inability to rise, incoordination, reluctance to move, and leg trembling and weakness. Necropsy findings included consistent lesions of pallor within the type I muscles of the legs, wings, and backs. Microscopic lesions included myofiber degeneration and necrosis with massive cellular proliferation interpreted as sarcolemmal nuclei proliferation. Occasional axonal degeneration with loss of axons was present in peripheral nerves embedded in the damaged musculature. In the youngest flock, multifocal areas of acute coagulation necrosis of the myocardium were also present. These outbreaks occurred following intake of monensin in the complete feed at levels considered therapeutic; however, no associated predisposing clinical condition, drug/toxin interaction, or excessive monensin levels in the feed could be demonstrated.     

Experimental study on allografts of amniotic epithelial cells in calcaneal tendon lesions of sheep

An experimental protocol was designed to study the survival and behaviour of an allograft of amniotic epithelial cells (AECs) in an ovine model. The study was conducted on three healthy adult sheep. A core lesion was created in both calcaneal tendons under ultrasound (US) guidance by injecting 400 UI of Type 1A collagenase diluted in 0.6 ml saline. The AECs were obtained from a 60–80-day-old fetus and cultured under standard conditions. After 15 days of collagenase treatment, 2 × 10⁶ AECs stained with a vital membrane fluorescent probe (PHK26) were injected under US guidance in 500 μl saline solution into the lesion of one limb. The contralateral untreated limb was used as a control. Animals were euthanatized 7 (1) and 30 (2) days later. Histological analyses performed on explanted tendons clearly demonstrate that AECs survived for at least 1 month inside the lesion without any adverse reactions. The damaged tissue of the treated tendons showed a high number of reparative cells in active proliferation that were accumulating collagen within the extracellular matrix. In addition, after 1 month, the neo-collagen began to be organized into parallel arrays of fibers oriented along the longitudinal axis of the tendon.

     

The propagation of induced tendon lesions in the equine superficial digital flexor tendon: An ex vivo study

Reasons for performing study: Clinical tendon lesions usually enlarge during the first days to weeks after sustaining the injury due to enzymatic and biomechanical influences. Limiting this enlargement would positively influence prognosis related to lesion size. Objectives: To investigate the effect of cyclic loading on the propagation of enzymatically and physically induced tendon lesions and to assess the effect of immobilisation thereon in an ex vivo model. Methods: Equine cadaver limbs with either physically or collagenase‐induced SDFT lesions were placed in a pneumatic loading device. Groups consisted of unloaded limbs, cyclically loaded limbs and cyclically loaded limbs with fibreglass cast immobilisation. Lesion size was evaluated ultrasonographically and macroscopically and load at failure was determined for groups where lesions enlarged. Results: Physically induced lesions did not propagate after cyclical loading and were not further investigated. Collagenase‐induced lesions propagated significantly more after cyclical loading compared to unloaded limbs. This propagation could effectively be reduced by immobilisation through a lower limb cast. Immobilisation did not influence load at failure. Conclusions: The combination of enzymatic and mechanical stimulation caused the lesions to propagate most. Casting appeared effectively to reduce the enlargement of the original tendon lesions in this ex vivo model, while it did not affect ultimate tendon strength. Potential relevance: As prognosis of tendon injuries is related to lesion size, the outcome of this study warrants further investigations in vivo.     

Autologous conditioned plasma as therapy of tendon and ligament lesions in seven horses

This case report describes the intralesional application of autologous conditioned plasma (ACP) in seven horses as treatment of severe tendinitis of the superficial digital flexor tendon, deep digital flexor tendon, or desmitis of the inferior check ligament. Follow-up data of the horses revealed a positive outcome in 10 to 13 months post injury. All horses treated with ACP were either performing in their previous work-load or were back in full training. Further studies with long-term follow-up will have to be performed to support these clinical intermediate-term observations.     

Collagen content and architecture of the pectoralis muscle in male chicks and broilers reared under various nutritional conditions

Varying chicken growth rates were induced with different nutritional regimes, and the collagen content and architecture of M. pectoralis (PT) were compared among 21‐day‐old chicks and broilers at 80 or 95 days of age. The percentage of muscle weight to live weight was higher in rapid growing chicks (8.4%) than slow growing chicks (6.3%). The 80‐day‐old broilers engaged in compensatory growth after the early slow growth period producing PT muscle at 11% of live weight. The 80‐ and 95‐day‐old chicks with restricted late growth after an early rapid growth period showed PT weight at 8% and 9% of live weight, respectively. Collagen content of the PT muscle markedly decreased from the chicks to the broilers. The collagen concentration was higher in the late‐growth restricted broilers (1.67–1.88 mg/g) than the compensatory growth broilers (1.01–1.10 mg/g). Collagen concentration did not differ between the rapid and slow growing chicks (2.72 and 2.94 mg/g). Scanning electron micrographs showed thick and thin perimysia, and honeycomb endomysia. In the perimysia, a stack layer of collagen platelets and a reticular layer of collagen fiber cords were distinguished and collagen baskets of adipocytes were observed. The perimysial collagen fibers became thicker during growth of the chicks to broilers. However, in the late‐growth restricted broilers, the perimysial collagen fibers seemed to have retarded development compared with the compensatory growth birds. The PT muscle of chickens develops optimally when body growth is enhanced. The PT muscle of the compensatory growth broilers had improved collagen architecture regardless of the marked decrease in collagen content.     

Genital lesions and histopathology of male guinea-pigs infected with trypanosomes.

Sixty adult male guinea-pigs were used to study the effect of Trypanosoma brucei brucei and Trypanosoma congolense infections on genitalia, testicles and reproductive capacity. Both infections showed acute to chronic courses. T. b. brucei appeared more virulent than T. congolense. In both cases the infection periods significantly (P < 0.01) influenced resultant decrease in body and gonadal weight, testicular mass index and extent of lesion formation. Histopathological lesions included mononuclear infiltration, distortion of seminiferous tubules and degeneration of germ cells. Both trypanosomes impaired reproductive capacity through impaired hormone biosynthesis, sperm production and reserves. Use of guinea-pigs as a laboratory model for the study of trypanosomosis in domestic animals is discussed.     

Ultrasonographic evaluation of induced testicular lesions in male goats

To study testicular ultrasonographic features, unilateral testicular artery ligation was performed in 12 bucks to induce predictable ischemic necrosis of the testis. Both scrotal testes then were scanned subsequently on days 1, 3, 5, 7, 15, and 30. On each of the designated days, 2 bucks each were castrated and the excised testes were rescanned outside the scrotum before gross and histologic examinations. In each goat, the testis without the ligated artery served as a control. Gross and histopathologic findings in the testis were compared with ultrasonographic observations. As the study progressed from day 0 to day 15, visually and microscopically, the testis involved in the testicular artery ligation had edema that changed to areas of peripheral necrosis with thickening of the testicular capsule. On day 30, the affected testis had granulation tissue in the areas that previously had been necrotic. Ultrasonographically, the testicular changes were consistent with the gross and histopathologic findings. There were areas of decreased echogenicity that corresponded to the necrotic areas and foci of high echogenicity that corresponded to areas of tubular mineralization. On day 30, the granulation tissue was difficult to differentiate ultrasonographically from normal testicular parenchyma. Between days 3 and 15, hydrocele was seen ultrasonographically in several goats. The excellent association between ultrasonographic findings and gross and histologic changes suggested that testicular ultrasonography might be a valuable diagnostic tool for assessing testicular disease in domestic animals.     

The effect of breed and feed-type on the sensory profile of breast meat in male broilers reared in an organic free-range system

1. Studies on the sensory profiling of male broiler breast meat were carried out to evaluate the effect of two very different broiler breeds (JA757 and New Hampshire), two different feed types (broiler and grower feed) and age at slaughter (82 and 110 d). 2. The sensory profiling consisted of a pilot study, 4 training sessions, and finally the assessment. During the training session a panel of 9 assessors defined 17 attributes, which were used to describe the smell, texture and flavour of the breast fillets. Each attribute was evaluated on a 15-cm unstructured line scale. 3. The breast meat became significantly less hard, and more juicy and tender in the New Hampshire at 110 d of age, whereas the opposite was found in JA757, which also acquired a more "sourish" flavour with age. The smell of "sweet/maize" and "bouillon" became weaker with age in JA757, but not in New Hampshire. 4. Several significant differences in relation to the main factors of breed and age were found. The traditional broiler hybrid JA757 did best for most smell and flavour attributes, whereas New Hampshire did best for the texture attributes. Age had a negative effect on the flavours and smell attributes "fresh chicken", "neck of pork" and "sweet maize", but a positive effect on the texture attribute "crumbly". In addition meat was more "stringy" at 110 d of age. 5. The flavours "neck of pork" and "umami" were significantly improved when JA757 was fed on the broiler feed and when New Hampshire was given the grower feed. The meat smelt more "sourish" at 82 d of age and less "sourish" at 110 d of age when the grower feed was consumed. Meat was significantly harder and stringier when JA757 was fed on the grower feed. This was not the case for New Hampshire. In general, the meat was significantly less crumbly and stringier with the grower feed. 6. Overall a very distinct difference in sensory profile was found between the two breeds. In addition different slaughter ages and feeding strategies should be taken into consideration in a niche production based on alternative genotypes.     

Effect of hypothalamic electrolytic lesions in White Leghorn and broiler male cockerels

1. This study compared the effect of bilateral electrolytic lesions of the basomedial hypothalamus (HL) in broiler and White Leghorn (WL) males. 2. Hypothalamic lesions were placed in WL at 10 weeks of age (body weight 1.1 kg) and in broilers, either at 6 weeks (body weight 1.5kg) or at 10 weeks of age (body weight 3.4kg). They were fed ad libitum until autopsy at 16 and 17 weeks of age for broilers and WL, respectively. 3. Hypothalamic lesions caused obesity (high percentage weight of abdominal adipose tissue) in both strains. Obese fowls with unimpaired reproductive systems were classified as OB and those with functional castration as FC (functionally castrated) or FCLC (functionally castrated with large comb). 4. All post-HL syndromes-OB, FC and FCLC-were present in WL, whereas all obese broilers (which are immature at this age) were classified as OB. 5. The percentage weight of abdominal adipose tissue in OB broilers was lower than in OB WL (3% vs 5%, respectively). 6. Daily food intake of OB broilers was higher than control at 12 to 15 weeks of age, regardless of time of placement of HL, whereas daily food intake of OB WL was significantly higher than that of control WL only during the first 2 weeks following HL. 7. Body weight of OB broilers at autopsy was 20% higher than control broilers, whereas body weight of OB WL was not significantly affected. 8. An additional group of broilers was reared to sexual maturity under food restriction until 28 weeks of age. HL were placed at 10 weeks of age (body weight 1.7 kg). Autopsy was performed after a 4-week period of ad libitum feeding. 9. There were OB as well as FC and FCLC among the HL, food-restricted broilers. Percentage weight of testes and spleen were reduced in OB fowls of both strains, but more so in OB WL. 10. Hyperphagia and weight gain were not observed during the ad libitum feeding period of those obese broilers after HL, indicating that hyperphagia and weight gain are secondary to obesity.     

生态立体笼养与网上平养肉仔鸡对比试验

本文旨在比较分析蔬菜大棚立体笼养与网上平养对肉仔鸡生产性能、成活率、燃料消耗及经济效益等方面的影响.在北方进行夏、冬两次试验,每次试验选用14日龄同一批次27 000只肉仔鸡,供试验、对照肉仔鸡54 000只.进行对半分组,测定增重、成活率、料肉比、燃料消耗、消毒药品用量.结果显示,蔬菜大棚立体笼养在保护环境、节约资源、降低成本、提高品质等方面具有积极的作用,单位面积养殖量提高,增重效果明显,从而为当前肉鸡养殖过程中的成本高、收益低,污染环境,预防、消毒预防用药量大等难题提供解决思路,以在生产实践中种养结合实现双赢,为绿色产品摸索出一条新路.     

Identification of surgically-induced longitudinal lesions of the equine deep digital flexor tendon in the digital flexor tendon sheath using contrast-enhanced ultrasonography: an ex-vivo pilot study

Background

Longitudinal tears in the lateral aspect of the deep digital flexor tendon are the most common causes of pain localised to the equine digital flexor tendon sheath. However conventional ultrasonographic techniques provide limited information about acute lesions. Ultrasonographic contrast agents are newly developed materials that have contributed to advancement in human diagnostic imaging. They are currently approved for intravenous use in human and animal models. In this study we described intrathecal use in the horse. This study was undertaken to evaluate the reliability of standard and angle contrast-enhanced ultrasonography to detect and characterize surgically-induced longitudinal lesions in the deep digital flexor tendons.In this pilot study surgically-induced lesions were created in the lateral aspect of the deep digital flexor tendon within the digital flexor tendon sheath in 10 isolated equine limbs to generate a replicable model for naturally occurring lesions. Another 10 specimens were sham operated. All the limbs were examined ultrasonographically before and shortly after the intrasynovial injection of an ultrasound contrast agent containing stabilised microbubbles. The images were blindly evaluated to detect the ability to identify surgically-created lesions. The deep digital flexor tendons were dissected and a series of slices were obtained. The depth of longitudinal defects identified with contrast-enhanced ultrasound scans was compared to the real extent of the lesions measured in the corresponding gross tendon sections.

Results

Contrast-enhanced ultrasonography with both angle and standard approach provided a significant higher proportion of correct diagnoses compared to standard and angle contrast ultrasonography (p < 0.01). Contrast-enhanced ultrasonography reliably estimated the depth of surgically-induced longitudinal lesions in the deep digital flexor tendons.

Conclusion

Contrast-enhanced ultrasound of the digital flexor tendon sheath could be an effective tool to detect intrasynovial longitudinal tears of the deep digital flexor tendon, although an in vivo study is required to confirm these results for naturally occurring lesions.     

Proliferative lesions of serous membranes in ovariectomised female and entire male dogs after stilboestrol administration

This paper reports the effects of prolonged stilbestrol administration in ovariectomized female dogs and some observations on the effects of this hormone on a group of male dogs. It was shown previously that ovarian tumors, which frequently metastasise to serous surfaces, can be produced in dogs by prolonged administration of stilbestrol. Total amounts of stilbestrol given to individual dogs in this study ranged from 180 to 570 mg, mainly over a period of 48 weeks. The ability of non-ovarian serous surfaces to proliferate in response to stilbestrol, independently of ovarian metastases, was studied in 5 females and 4 males. Papillary proliferations occurred on the uterine serosae in 3 females and on the testicular and epididymal serosae in 2 males. In no case was there papillary proliferation on serous membranes of non-genital organs. One of 2 entire females given stilbestrol had proliferations regarded as metastases of ovarian origin on non-genital serous membrane. In addition to ovarian changes, stilbestrol can cause primary proliferative lesions in the serous membranes of certain genital organs in both sexes. There is no evidence that serous membranes of non-genital organs be capable of a primary proliferative response to stilbestrol.     

Endoscopic assessment and treatment of lesions of the deep digital flexor tendon in the navicular bursae of 20 lame horses

REASONS FOR PERFORMING STUDY: Clinical lesions of the deep digital flexor tendon and navicular bone are being reported with increasing frequency. However, the role of direct visualisation by navicular bursoscopy in the diagnosis and management of such injuries has not been explored. HYPOTHESIS: Navicular bursoscopy: 1) corroborates information obtained from other, noninvasive imaging modalities; 2) allows direct visualisation of lesions unidentified by other diagnostic modalities; 3) provides further information on morphology of lesions; and 4) permits minimally invasive surgical access to lesions. METHODS: The case records of all horses that underwent diagnostic navicular bursoscopy for the investigation of lameness admitted to 2 referral clinics (the Royal Veterinary College and Reynolds House Referrals) were evaluated retrospectively. Follow-up information was obtained by telephone questionnaire. RESULTS: Twenty-three bursae were examined endoscopically in 20 horses. Tears of the deep digital flexor tendon were seen in all horses (22 bursae). In 8 bursae, cartilage lesions were also present and in one bursa this was the only abnormal finding. Computed tomography and low field magnetic resonance imaging predicted tendon lesions in most cases, but failed to identify cartilage damage. Greater than 6 month follow-up information was available for 15 animals of which 11 were sound and 9 had returned to preoperative levels of performance. CONCLUSION: Lameness localised to the foot may result from tears of the deep digital flexor tendon and/or navicular fibrocartilage loss. Navicular bursoscopy allows comprehensive evaluation of these changes and also permits appropriate lesion management. POTENTIAL RELEVANCE: The diagnostic information obtained from and therapeutic options offered by bursoscopy justify its use in horses with clinical findings localising lameness to the navicular bursa.