Water balance of flooded rice paddies

Rice (Oryza sativa L., var. Labelle) was grown in 300 m² paddies of Beaumont clay soil (Typic pelludert) and subjected to two management schemes of flooded rice culture. These schemes were continuous irrigation and intermittent irrigation. Careful measurements of irrigation, precipitation, evapotranspiration, deep percolation and runoff were made, and the total water balance for the two water management schemes was calculated.The results show continuous irrigation to be very wasteful of water with slightly over 1 m of irrigation water applied to supply an evapotranspirational need of 0.5–0.6 m. The intermittent irrigation management is less wasteful but still could be improved upon. Suggestions are presented for techniques to help improve the water use efficiency and reduce runoff losses.     

Lymphoreticular alterations in neonatally thymectomized and antilymphocyte globulin treated Holstein-Friesian calves

Neonatal calves were thymectomized when 4 to 10 days old and treated briefly with antilymphocyte globulin. Non-thymectomized calves were treated with normal horse globulin or not treated with antilymphocyte globulin. The lymph nodes were examined at selected times by light microscopy and immunofluorescence and after necropsy.The prescapular lymph nodes at 5 weeks represented normal, normally reactive and abnormally reactive structure. Peripheral lymph nodes from 5-week-old calves not treated by thymectomy or antilymphocyte globulin had a low level of lymphopoietic activity. The thymus intact calves treated with normal horse globulin had reactive lymphoid hyperplasia primarily of the cortex. The thymectomized, antilymphocyte globulin treated calves at this age had increased primary follicle activity and depletion of paracortical areas in peripheral lymph nodes. The degree of lymphoid hyperplasia corresponded to the relative frequency of cells with surface immunoglobulin at 5 weeks of age.The lymph nodes and spleen collected at necropsy at 16 to 26 weeks did not segregate into three distinct categories, probably a reflection of the additional stimulation on the immune system by experimental and natural antigen exposure. The differences between treatments were not observed at the time of necropsy. These morphological observations strongly support the conclusion that the calves were affected by neonatal thymectomy, but had recovered from the effect of thymectomy by 16 to 26 weeks of age.     

Corynebacterium equi: An interhost review with emphasis on the foal

A review of the recent and/or significant literature concerning Corynebacterium equi, including its morphologic, biochemical, immunological, and pathological characteristics in the foal, humans and other animals is presented. The similarity in the tissue responses of mammalian hosts to C. equi and Mycobacterium spp. is discussed.

The antigenic structure and virulence factors associated with C. equi. other corynebacteria and mycobacteria are compared.

The immunological aspects of resistance to C. equi are considered. The evidence suggests that the major immune response elicited in the foal by C. equi is cell-mediated. However, the immunopathogenic mechanism needs clarification. Areas of future research are suggested.     

A Procedure for Permanent Tracheostomy and Its Effects on Tracheal Mucosa

Permanent tracheostomies were performed on six dogs which were evaluated clinically and histologically. One dog had abnormal tracheal cartilages and died following tracheal collapse three days postoperatively. Problems with coughing, swallowing, and infection were not noted in the remaining five dogs. The exposed tracheal epithelium temporarily underwent squamous metaplasia but returned to a relatively normal appearance within 16 weeks.     

AGENESIS OF THE DISTAL PHALANX IN A MULE

Agenesis of the distal phalanx of a mule foal is documented. The condition was identified when the foal was 14 days old and supported by follow-up radiographs obtained at four months of age.     

Disorders of potassium homeostasis

Hypokalemia and hyperkalemia are common problems that may be artifactual, iatrogenic, or due to altered body homeostatic mechanisms. ECG may help one to recognize hyperkalemia but not hypokalemia. Excessive K supplementation is a common iatrogenic cause of hyperkalemia whereas fluid therapy is a common cause of iatrogenic hypokalemia. The most common causes of spontaneous hyperkalemia are renal failure and hypoadrenocorticism whereas the most common causes of spontaneous hypokalemia are vomiting, diarrhea, and renal wasting. Symptomatic therapy is usually done until the underlying cause(s) is resolved.     

Arthroscopy of the Coxofemoral Joint of Foals

An arthroscopic procedure for examination of the coxofemoral joint was developed in nine foals (four cadavers, five anesthetized) to determine if access was sufficient for evaluation and surgical treatment of intra-articular lesions. The joint was distended and the arthroscope inserted through the notch (incisura trochanterica) between the cranial and caudal parts of the greater trochanter. This portal allowed examination of the cranial, lateral, and caudal aspects of the joint. Mechanical distraction of the joint through an instrument portal located 2 to 4 cm cranial and 1 to 2 cm ventral to the arthroscope portal allowed examination of the ligament of the head of the femur, the femoral head, and articular and nonarticular surfaces of the acetabulum. Adduction and rotation of the limb improved visualization of the craniomedial and caudomedial portions of the femoral head. Traction applied to the distal limb allowed visualization of the same structures that were observed when mechanical distraction was used. Traction also created space for placement of surgical instruments into the joint through the instrument portal. Access to most regions of the joint was adequate, but access to the caudal and medial aspects of the joint was limited. Three foals were killed while they were anesthetized, and their coxofemoral joints were dissected. Two foals were allowed to recover from anesthesia and were observed for 30 days after surgery. One foal was mildly lame for 2 days after surgery. The other foal was not lame after surgery. The incisions healed, and the coxofemoral joints were radiographically normal by postoperative day 30.     

Distraction Osteogenesis Using Modified External Fixation Devices in Five Dogs

Distraction osteogenesis was used to treat five dogs with limb deformities or limb shortening. The affected bones underwent osteotomy, and modified external fixators were attached. Complications included pin loosening, implant breakage, and soft-tissue contracture. Adequate limb length was attained in all cases, but clinical results varied from poor to excellent. Two dogs were not lame after the procedure, two dogs had improved function but were still lame, and one dog had complications necessitating amputation.