Phototropic Leaflet Reorientation in Alfalfa Germplasm Selected for Leaf Color and Size

Solar tracking has been described in several agronomic and wild species, yet variation within a given species has not been reported. To address that issue, photoperiod leaflet reorientation in response to vectorial light was measured in three alfalfa ( Medicago sativa L.) germplasm pools selected from the cultivar Ladak 65. Dark-leaf germplasm responded to all photosynthetic photon flux densities (PPFD) (100 to 700 μmol/m²/s) with no detectable lag period. Following a 24-h dark treatment only high PPFD (600 to 700μmol/m²/s) elicited reorientation. Pale-leaf germplasm responded to intermediate (300 to 400 μmol/m²/s) and high PPFD in a similar manner; however, the low (100-125μmol/m²/s) PPFD treatment had little effect on reorientation. The 24-h dark treatment decreased reorientation at all PPFD. Small-leaf germplasm responded equally to all PPFD and was not affected by the 24-h dark treatment. The results suggest that available energy levels may influence the reorientation response. Carbonyl cyanide m -chlorophenylhydrazone, an inhibitor of photophosphorylation, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea, an inhibitor of non-cyclic photosynthetic electron transport, reduced reorientation only in the pale-leaf type. These results suggest that stored energy reserves were adequate to maintain leaflet reorientation in the absence of photosynthesis in all but the pale-leaf germplasm. In that germplasm photosynthetically generated energy may be required to support reorientation.     

Frequency and severity of osteochondrosis in horses with cervical stenotic myelopathy

We compared the frequency and severity of osteochondrosis lesions in young Thoroughbred horses with cervical stenotic myelopathy (CSM) vs that in clinically normal Thoroughbreds of the same age. All lesions of the cervical vertebrae and appendicular skeleton were classified histologically as osteochondrosis or nonosteochondrosis and were measured for severity. Minimal sagittal diameter was significantly smaller in horses with CSM from C2 through C6; no difference was detected at C7. Severity of cervical vertebral osteochondrosis was greater in the horses with CSM, however frequency was not different. Frequency and severity of nonosteochondrosis lesions were not different in cervical vertebrae or appendicular skeleton. Frequency and severity of appendicular skeleton osteochondrosis lesions were both greater in horses with CSM. Osteochondrosis and nonosteochondrosis lesions were more severe on facets at sites of compression than on facets at noncompressed sites in horses with CSM. However, compression was also observed at sites with no articular facet lesions. The association of widespread osteochondrosis and spinal canal narrowing with CSM suggests CSM may represent a systemic failure in the development or maturation of cartilage and bone.     

Embryo transfer for conserving valuable genetic material from swine herds with pseudorabies

Embryo transfer was used to conserve genetic material from 2 swine herds seropositive for pseudorabies virus (PRV). Embryos (n = 805) were recovered from 38 PRV-seropositive Duroc sows in Iowa and, after 4 to 10 hours' culture and shipment to Illinois, were transferred to 34 recipients from a herd seronegative for PRV. All recipients remained seronegative for PRV, and 22 of the recipients farrowed 208 pigs (189 alive) that also were seronegative for PRV. There was no evidence of PRV in the embryo recovery medium or in the uterine and oviductal cells recovered with the embryos. Transfer of morulae resulted in higher (P less than 0.02) farrowing rates than did transfer of 4- to 8-cell embryos, but litter size was not affected.     

Necropsy and laboratory findings in free-living deer in South Dakota.

In a diagnostic survey of diseases in wild white-tailed deer (62 cases) and mule deer (12 cases) the most common findings were traumatic injury (20%), nontraumatic hemorrhage (13%), polioencephalomalacia (11%), and bacterial infections (9%). Although epizootic hemorrhagic disease was suspected in several cases, the virus was isolated from only 1 white-tailed deer.     

The neurologic examination of the horse for purchase.

The veterinarian needs to be able to incorporate an accurate neurologic examination as a portion of the pre-purchase evaluation. Subtle neurologic deficits may be hidden by musculoskeletal disease or missed as a result of lack of knowledge or understanding of these disorders. It is important to known which musculoskeletal disorders are commonly associated with neurologic disease to better assist the buyer with the decision about whether to purchase the animal.     

Reduction of the red blood cell mass of horses: toxic effect of heparin anticoagulant therapy

This study was designed to test the efficacy of heparin anticoagulant therapy in the horse and its effect on the formed elements of blood. Nine clinically normal, nontraumatized adult horses were subjected to 4 different heparin maintenance regimens (dosages of 320, 240, 160, and 40 U/kg of body weight). Porcine intestinal mucosa heparin (20,000 U/ml) was injected subcutaneously every 12 hours for 96 hours (total 9 times). A loading dose of one-third the maintenance dose was given IV just before the first heparin injection. Three control horses were given an equivalent volume of 0.9% saline solution. The 2 large doses of heparin (320, 240 U/kg) resulted in an extension of the therapeutic range for heparin anticoagulant therapy (1.5 to 2.5 X data base-line prolongation of the activated partial thromboplastin time [APTT]). The 160-U/kg dose maintained the APTT in the therapeutic range, and the 40-U/kg dose had no effect on the APTT. Heparin was shown to exert a profound influence on the RBC mass of the horse. Three of the heparin regimens (320, 240, and 160 U/kg) resulted in a significant decrease in RBC numbers, PCV, and total hemoglobin content. Platelet count also was reduced in the horses when given the 320 and 240 U/kg doses. The observed increase in the mean corpuscular volume was associated with decreasing RBC numbers. Plasma proteins, serum bilirubin, free hemoglobin (plasma), haptoglobin (plasma), and urine and fecal hemoglobin values remained unchanged in all groups. Heparin anticoagulation therapy with the smallest dose (40 U/kg) had no detectable effects on the measured values, nor did the saline solution.     

Conium maculatum (poison hemlock) toxicosis in a flock of range turkeys

Five 20-week-old tom turkeys from a flock of range turkeys were presented for examination; the flock had a history of salivation, tremors, paralysis, and increased mortality. Necropsy revealed numerous seeds identified as seeds from Conium maculatum (poison hemlock) within the crop, proventriculus, and gizzard. Histopathologic alterations were limited to catarrhal enteritis. Clinical signs of Conium maculatum toxicosis abated after the turkeys were removed from their range, which was infested with poison hemlock.