Alkyl aryl ketone oxime O-ethers: A novel group of pyrethroids

The alkyl phenyl ketone oxime O-benzyl ethers are a new group of insecticidal compounds. Although they lack the ester linkage, they resemble the pyrethroids in general, and the esters of 2-phenylalkanoic acids, in particular fenvalerate, because they show similar physiological effects on isolated nerve preparations and on whole insects; they also show a similar pattern of change of biological activity in response to structural change. The compounds may exist as two geometric isomers, of which only the (E) series shows significant biological activity; this observation appears to have some bearing on the relationship between conformation and activity in the pyrethroid series as a whole.     

Factors associated with time under quarantine for swine herds in the voluntary phase of the Illinois pseudorabies eradication program

The association of herd characteristics and intervention strategies with time under quarantine was evaluated for 163 farrow-to-finish swine herds enrolled in the voluntary phase (1986–1987) of the pseudorabies virus (PRV) eradication program in the state of Illinois (USA). Vaccination was the intervention strategy used most widely (69% of herds), particularly in larger herds. Depopulation was used primarily when PRV seroprevalence was high, and test-and-removal when seroprevalence was low. Approximately 50% of the herds were released from quarantine within 3 years of developing a herd clean-up plan.

Multiple regression analysis using the Cox proportional hazards model indicated the following. Vaccination had a strong association with a longer time until release from quarantine (P<0.001). This is attributed to the lack of a vaccine differential test during this time, which made diagnosis of natural infection more difficult. Offspring segragation was associated with a longer time under quarantine (all herds: P=0.05; non-vaccinated herds: P=0.004). Delay in implementation of a herd clean-up plan was also associated with longer time under quarantine (all herds: P=0.012; non-vaccinated herds: P<0.001). Herds with higher seroprevalence at the time of agreement to a herd plan required a longer time under quarantine (all herds: P<0.001). This result was apparent for non-vaccinated herds (P=0.001), and thus is not merely a consequence of vaccination. Herds in areas with a high geographic density of quarantined herds required a longer time before release from quarantine (all herds: P=0.003), although this trend was not apparent for non-vaccinated herds (P=0.39). After taking PRV seroprevalence into account, there was no apparent association of time under quarantine with sow herd size (all herds: P=0.057; non-vaccinated herds: P=0.81) or confinement housing (all herds: P=0.19; non-vaccinated herds: P=0.91).     

Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. IV. Characterization of metacarpal, metatarsal, femur, humerus and turbinate bones of sows during three parities

The effect of early nutrition on subsequent bone development was studied using gilts that had previously been fed ad libitum or 75% ad libitum intake and 100 or 150% National Research Council-recommended daily Ca and P from weaning to 100 kg. During the three-parity reproductive study, sows were fed a 14% protein diet. Metacarpals and metatarsals were taken from sows culled due to lameness or failure to breed and from sows after completing three parities. Femur and humerus articular cartilage and turbinates were described at necropsy. Metacarpals and metatarsals were heavier and tended to have thicker walls when sows were previously fed ad libitum or fed 150% Ca and P. Energy intake produced the greater response. Metacarpal breaking strength was greatest for sows previously fed ad libitum. Metatarsals were not affected by energy intake. Stiffness, Young's modulus of elasticity (YME) and flexural modulus for metacarpals and metatarsals were not affected by energy intake. Previously fed Ca and P intakes did not affect any of the mechanical bone characteristics. Metacarpals were heavier, had a greater breaking strength, were more elastic and exhibited slightly less resistance to bending than the metatarsals. The ether extract, ash, Ca and P content and the Ca:P ratio of metacarpals and metatarsals were not affected by previously fed energy or Ca and P intakes. The ether extract content tended to decrease and the ash, Ca and P content tended to increase with age. Articular cartilage and turbinate scores were not influenced by previously fed energy or Ca and P intakes. The YME and flexural modulus were the only bone characteristics that were even poorly correlated (average r = .25) with soundness scores, suggesting that high values result in poorer soundness scores. Energy and Ca and P intakes during growth and development had only minimal effects on bone characteristics and no apparent effect on structural soundness and longevity of sows kept for three parities.     

Thyroid hormone concentrations in selenium deficient and selenium sufficient cattle

Selenium deficient calves when compared to selenium supplemented calves had increased plasma thyroxine concentrations and decreased plasma tri-iodothyronine concentrations. These changes in the selenium deficient calves were accompanied by significant increases in plasma urea and creatinine concentrations and decreased plasma alkaline phosphatase activity. The demonstration that low selenium status can cause imbalances in thyroid hormone metabolism may provide an explanation for some of the effects of the deficiency.