In vivo kinetic study on uptake and distribution of intramuscular tritium-labeled polysulfated glycosaminoglycan in equine body fluid compartments and articular cartilage in an osteochondrial defect model

The uptake and distribution of intramuscularly (IM) administered tritium-labeled polysulfated glycosaminoglycan (³H-PSGAG) in serum, synovial fluid, and articular cartilage of eight horses was quantitated, and hyaluronic acid (HA) concentration of the middle carpal joint was evaluated in a pharmacokinetic study. A full-thickness articular cartilage defect, created on the distal articular surface of the left radial carpal bone of each horse served as an osteochondral defect model. ³H-PSGAG (500 mg) was injected IM, between 14 and 35 days after creation of the defects. Scintillation analysis of serum and synovial fluid, collected from both middle carpal joints at specific predetermined times up to 96 hours post-injection, revealed mean ³H-PSGAG concentrations peaked at 2 hours post-injection. ³H-PSGAG was detected in cartilage and subchondral bone 96 hours post-injection in samples from all eight horses. There were no statistically significant differences in ³H-PSGAG concentration of synovial fluid or cartilage between cartilage defect and control (right middle carpal) joints.

HA assay of synovial fluid revealed concentrations significantly increased at 24, 48, and 96 hours post-injection in both joints. The concentration nearly doubled 48 hours post-injection. However, no statistically significant differences were found between synovial concentrations of HA in cartilage defect and control joints.

³H-PSGAG administered IM to horses, was distributed in the blood, synovial fluid, and articular cartilage. HA concentrations in synovial fluid increased after IM administration of polysulfated glycosaminoglycan.     

Hypocalcaemia associated with high dose rates of zinc oxide to lactating dairy cows

Clinical hypocalcaemia was associated with single doses of three oi more days; supply of zinc oxide to dairy cows for facial eczema control. Experimental hand dosing of a single dose of zinc oxide (40 and 120 mg Zn/kg b wt) to Jersey cows caused a significant drop in serum calcium concentration at 24 h followed by a rise to concentrations higher than controls at subsequent samplings over four days. At the highest zinc dose rate, 78% of serum calcium values were equal to or lower than the lowest control value at 24 h post dosing. Serum magnesium concentrations had a reciprocal relationship to the calcium levels at all samplings. Serum zinc concentrations were most elevated over the 48 h post dosing, returning to normal levels at the fifth day. Following the highest zinc dose milk yields were reduced by approximately 1.5 kg milk/cow/day for 48 h. Similar results were obtained when cows grazed pasture on which large amounts of zinc oxide had been sprayed.     

Feeding fodder beet (Beta vulgaris L.) with either barley straw or pasture silage to non-lactating dairy cows

AIMS: To determine the suitability of diets containing either approximately 85% fodder beet (Beta vulgaris L.) with barley straw or 65% fodder beet with pasture silage when fed to non-lactating dairy cows, by measuring intakes, digestibility, rumen function including microbial growth, and N excretion.

METHODS: Holstein-Friesian cows fitted with permanent rumen fistulae were fed either 65% fodder beet with pasture silage (Silage; n=8) or 85% fodder beet with barley (Hordeum vulgare L.) straw (Straw; n=8) in an indoor facility over a 9-day period, for measurement of intakes, digestibility, rumen function and urine production. The cows were adapted to the diets over 2 weeks before the indoor measurements. Feed was available for about 6 hours/day, as practiced commercially for wintering non-lactating cows.

RESULTS: Five cows fed the Straw diet had to be removed from the trial because of acute acidosis; four on Day 1 of the measurement period and one on Day 7. One cow allocated to the Silage diet refused to eat fodder beet bulbs and was also removed from the trial. Two cows fed the Silage diet were also treated for acidosis. DM intakes were lower with the Straw than Silage diets (6.4 (SE 0.4) vs. 8.3 (SE 0.5) kg/day) and organic matter (OM) digestibility was lower with the Straw than Silage diets (77 (SE 1) vs. 83 (SE 1) g/100g). The N content of the two diets was 1.14 and 1.75?g/100?g DM and there was a net loss of N by cows fed the Straw diet (?22.7 (SE 7) g/day). Rumen microbial N production was much lower in cows fed the Straw than the Silage diet (6.6 (SE 1.3) vs. 15.8 (SE 0.7) g microbial N/kg digestible OM intake). Concentrations of ammonia in rumen liquid collected on Days 5–6 were below detection limits (<0.1?mmol/L) in 36/48 (75%) samples collected from cows fed the Straw diet and in 27/48 (56%) cows fed the Silage diet. Mean urinary N excretion was lower in cows fed the Straw than the Silage diet (52.0 (SE 5.8) vs. 87.7 (SE 5.9) g/day).

CONCLUSION AND CLINICAL RELEVENCE: An over-wintering diet for dry cows comprising about 65% fodder beet with 35% pasture silage provided adequate nutrition, although there was some risk of acidosis. In contrast, the diet containing about 85% fodder beet with barley straw resulted in lower DM intakes, poor rumen function, negative N balance so that both nutrition and welfare were compromised.     

Production Characteristics and Size Variability of Channel Catfish Reared in Cages and Open Ponds1

Production characteristics of channel catfish (Ictalurus punctatus) reared in cages and open ponds were compared. Fish reared in open ponds had significantly better growth and food conversion ratios than fish reared in cages. Cages and open ponds stocked with fish which were closely graded in size produced fish with less size variability at harvest compared to ponds and cages stocked with nongraded and coarsely graded fish. The decrease in size variability at harvest was reflected in a greater proportion of marketable fish.     

Effects of thyroxine and growth hormone treatment of dairy cows on milk yield, cardiac output and mammary blood flow

Four cows received thyroxine injections (T4; 20 mg/d) and three cows received growth hormone injections (GH; 44 mg/d) for 4 d during successive 16-d experimental periods. Measurement was made of milk yield, protein yield, mammary tyrosine and phenylalanine uptake, blood plasma hormone concentrations, mammary blood flow and cardiac output. Milk yield increased by 25% with T4 and 21% with GH treatment. Milk protein content tended to decline during T4 treatment and increase following GH treatment. Cardiac output increased by 8.9 liter/min (20%) and 4.6 liter/min (10%) with T4 and GH injection. Mammary blood flow (half-udder) increased from 3.6 to 4.9 liter/min (35%) and from 3.3 to 4.4 liter/min (33%) with T4 and GH treatment, respectively. These increases calculated on a whole-udder basis, accounted for 28% (T4) and 48% (GH) of the increases in cardiac output. The proportion of cardiac output perfusing the (whole) udder increased to 19.1% (T4) and 18.7% (GH), increases of 17 and 30%, respectively. Heart rate increased with T4 (but not GH treatment) from 80 to 115/min. Ratio of blood flow to milk yield was not changed by either treatment. The proportion of cardiac output perfusing the udder likely plays a major role in facilitating the partitioning of nutrients for milk synthesis.     

Mycoplasma gallinarum infection in commercial layers and onset of fatty liver hemorrhagic syndrome

Fatty liver hemorrhagic syndrome (FLHS) was observed in each of three trials in which commercial layers were utilized to determine the effect of Mycoplasma gallinarum (MGn) on egg and eggshell quality parameters and egg production. In each of three trials, FLHS occurred 31-54 days later in MGn-inoculated hens as compared with the Mycoplasma-clean (control) hens. In trials 1 and 2, no therapeutic intervention was initiated to ameliorate FLHS. In trial 3, therapeutic intervention was instituted and consisted of the addition of 1 pound of choline chloride/ton of feed. Total mortality recorded throughout the duration of each trial and attributable to FLHS was not significantly different between the control and the MGn-inoculated treatment. However, FLHS-associated mortality in each of the three trials was numerically greater for the control treatment.     

Equine conjunctival pseudotumors

Five horses presented with unilateral pink, smooth, nonulcerated conjunctival masses with histologic features characteristic of inflammatory pseudotumors, i.e. proliferative inflammatory lesions clinically resembling true neoplasia. Although causes for the inflammatory lesions were not determined, based on the presence histologically of mononuclear (predominantly lymphocytic) inflammatory cell infiltrates and the absence of infectious agents, parasites or foreign bodies, an immune-mediated pathogenesis was suspected. Affected horses ranged from 5 to 8 years of age with no apparent breed or sex predilection. Conjunctival lesions were nodular in two cases and relatively flat and more diffuse in three cases. Third eyelid lesions were present in three cases and two affected eyes had corneal involvement. Based on findings from these five cases, the prognosis for equine conjunctival pseudotumors appears to be good when lesions are treated by partial or complete surgical excision, local administration of anti-inflammatory agents, or a combination of surgery and anti-inflammatory therapy.     

Integrated pest management in field vegetable crops in northern Europe — with focus on two key pests

Improvements in (1) insecticide application, (2) supervised control, and (3) pest forecasting systems have each helped to reduce considerably the amounts of insecticides required to control fly, caterpillar and aphid infestations in vegetable crops in northern Europe. By growing plants that are partially resistant to certain major pests, it is now possible to apply even less insecticide than the dose recommended for the crop. In crops where only small amounts of insecticides are applied, natural predators should prevent large increases in pest insect populations and natural parasitoids should reduce the numbers of pest insects entering subsequent generations. The possible impact of introducing transgenic plants and the use of physical (crop covers), cultural (crop rotation, undersowing) and microbial (e.g. fungi, bacteria and nematodes) methods of control are also discussed. The withdrawal of certain insecticides, as a result of environmental and commercial pressures, means that some crops may soon be without appropriate insecticides for controlling one or more of the major pest species. Whether such systems will be sustainable, remains to be seen.