Commercial Genetic Lines Research Articles

Ischemic myelomalacia associated with fibrocartilaginous embolism in multiple finishing swine.

Fibrocartilaginous embolism of the spinal vasculature with resultant myelomalacia has been described as a sporadically occurring condition in various species.1,2,4–7,11–15 A case with an unusually high prevalence of fibrocartilaginous embolism in swine is reported. Approximately 1,800 grow–finish swine were housed in 3 similar slatted confinement building each containing 600 head as part of an 18,000-sow farrow-to-finish operation. Each building was filled sequentially at 2-week intervals, with pigs in each buildings having no more than a 2-week age spread. Feeding and management practices were similar for each building. The pigs were derived from a heavily muscled, high-lean commercial genetic line selected for rapid growth. Production records indicated that these pigs had experienced no significant clinical disease and had a high growth rate during the 18-week grow–finish feeding period. Pigs were sorted for slaughter as they reached the target market weight of 126 kg. Within 24 hours after sorting for slaughter, 3 of 100 pigs were found to be recumbent with posterior paresis, which progressed to paralysis. As subsequent groups were sorted and removed, a few individuals among the remaining pigs developed similar symptoms. All 3 buildings contained similarly affected pigs. Representative animals from each affected group were submitted for postmortem examination. A total of 25 of 1,800 pigs were affected, of which 9 were submitted for necropsy 24 to 36 hours after development of clinical signs. Pigs in other grow–finish facilities of the operation were not affected. When presented, the pigs were unable to stand on their hind limbs. The degree of neurological deficit varied from severe paresis to complete paralysis; lesser-affected individuals retained minimal withdrawal reflex to a deep pain stimulus. There was a mild increase in packed-cell volume, consistent with dehydration, and moderate elevation of serum creatine kinase levels, consistent with muscle trauma of recumbency, in 3 animals sampled. Levels of sodium, potassium, bicarbonate, chloride, calcium, phosphorus, magnesium, urea nitrogen, creatinine, total protein, albumin, alkaline phosphatase, aspartate aminotransferase, and gamma glutamyltransferase were within normal ranges. A consistent finding at necropsy was severe distention of the urinary bladder. No other gross lesions were observed. Microscopic examination of the spinal cords demonstrated

Growth and development of aquilegia in relation to temperature, photoperiod and dry seed vernalization

A selected genome pool of commercial cultivars and genetic lines of Aquilegia × hybrida were grown in greenhouses and evaluated for their growth and flowering responses to temperature, photoperiod and dry seed vernalization. ‘Blue Shades’, ‘Pink Shades’, ‘Blue-White’, ‘Rose-White’ and ‘White’ flowered 4–5 months from sowing when grown at 9–13 °C night temperature. Day temperatures of 16–19 °C induced earlier flowering than day temperatures > 24 °C. Commercial cultivars ‘Blue Jay’, ‘Dove’, ‘Musik-Blue-White’ and ‘Musik-Red-White’ did not flower during these studies. Higher crown number per plant was correlated with lower day temperatures. Dry seed vernalization at 4 °C induced slightly earlier flowering in ‘Blue-White’ and ‘Rose-White’. Extending the photoperiod to 14 h in the early phases of the growth cycle delayed flowering. Certain genetic lines of aquilegia may be suitable for spring forcing if the seed is vernalized and plants are grown at night temperatures of 9–13 °C.

Comparison of Macrophage Function in Several Commercial Broiler Genetic Lines

The present study was conducted to establish baseline profiles of various macrophage functions in four commercial broiler genetic lines designated as Lines 1, 2, 3, and 4. All experiments were carried out between 2 to 3 wk of age. Total numbers of peritoneal exudate cells per bird collected 42 h after a single i.p. injection of Sephadex-G50 were comparable among the lines. Line 1 produced fewer macrophages along with reduced phagocytosis of opsonized SRBC, whereas Line 4 macrophages were depressed in unopsonized SRBC phagocytosis. Macrophages from Lines 2 and 4 killed internalized Escherichia coli earlier man macrophages from Lines 1 and 3. Supernatants from lipopolysaccharide-treated macrophages from Lines 1 and 2 exhibited significantly higher cytolytic activity against LSCC-RP9 tumor cells when compared with supernatants from Line 3 and 4 macrophages. The current study demonstrates genetic variation among the four broiler lines for mononuclear phagocytic system functions.