Influence of age on neutrophil function in foals.

Functional activities (phagocytosis and killing) of neutrophil leucocytes (NL) and immunoglobulin G concentrations were evaluated in six healthy foals from birth to 6 months of age. Peripheral blood NL were reacted with Streptococcus equisimilis in 20 per cent pooled equine serum for 30, 60 and 90 mins and functional activities of NL were determined using a fluorochrome microassay. Values for foal NL function were compared with those of healthy adult horses (n = 28). Foal neutrophil function was influenced by age. Killing capacity of NL decreased, whereas phagocytic capacity increased, until 113 days of age, after which a reversal in trends became apparent. Immunoglobulin G concentrations changed significantly over time and were lowest at 29 to 56 days of age. All foal values for NL function fell within the range of normal values established for healthy adult horses.     

Use of oral tolerance tests to investigate disaccharide digestion in neonatal foals.

Oral tolerance tests were performed on 13 neonatal foals to determine their ability to digest disaccharides on d 1, 3 and 5 postpartum. Foals were assigned randomly to treatments consisting of 20% (wt/vol) solutions of either maltose, lactose, or sucrose, dosed at 1 g/kg of BW, or glucose, dosed at .5 g/kg of BW. After a 2-h fast, an initial blood sample was collected via jugular catheter. Foals were administered the appropriate solution orally, and blood was collected every 15 min for 1 h and then every 30 min for 3 h. Plasma glucose increased after dosing with lactose or glucose but not with sucrose. Plasma glucose concentrations increased slightly on d 3 and 5 in foals dosed with maltose. These findings suggest that although lactose is well digested by neonatal foals, maltose is digested only slightly, and sucrose is not digested by d 5. Results of this experiment indicate that maltose and sucrose would not be suitable for inclusion in artificial diets for foals less than 1 wk old. Oral tolerance tests could be useful for determining the ability of premature or sick foals with lactose intolerance to digest alternate carbohydrate sources.     

Correction of cervical esophageal stricture in a dog by creation of a traction diverticulum.

A cervical esophageal stricture was corrected in a dog by creation of a traction diverticulum. Although abnormal esophageal motility persisted in the portion of the esophagus cranial to the stricture, the clinical effects of the stricture were ameliorated by the simple surgical procedure.     

Sex Preselection in Swine: Altered Sex Ratios in Offspring following Surgical Insemination of Flow Sorted X- and Y-Bearing Sperm

Flow cytometric sorting of X and Y chromosome-bearing sperm into separate populations, followed by surgical insemination into the isthmus of the oviduct of mature gilts, produced litters with phenotypic sex ratios skewed in the direction of male or female according to the predicted sex of the sperm population inseminated. The skewing of the sex ratio of the offspring was predicted from flow cytometric DNA reanalysis of flow sorted sperm populations. Gilts inseminated with intact, viable flow-sorted X-bearing sperm produced litters of off spring that were 74% female (P < .01). Gilts inseminated with intact, viable flow-sorted Y-bearing sperm gave off spring that were 68% male (P < .04). These results validate the use of DNA as a marker for pre-selecting the sex of offspring when used in conjunction with flow cytometric sorting of sperm .     

Heritability estimates of pregnancy rate in beef cows under natural mating

Observations of 3,029 matings over 17 yr on an Ozark upland range were used to estimate heritability of pregnancy rate in Angus, Hereford and Polled Hereford cows. Pregnancy rate, the percentage of cows exposed that produced a live calf in the spring, was transformed using the empirical logit transformation and then analyzed for each breed separately by weighted least squares using a mixed model procedure. A numerator relationship matrix for sires of cows was incorporated into the sire model to account for relationships among sires. Variation among years significantly affected pregnancy rate in all three breeds. Age of dam significantly affected pregnancy rate in the Angus and Hereford groups. Paternal half-sib estimates of heritability from the observed binary data (h2b) for pregnancy rate were calculated on first-calf heifers and mature cows for each breed. Respective h2b estimates for heifers and mature cows were .17 and .09 in the Angus group, .04 and .01 in the Hereford group and .05 and .05 in the Polled Hereford group. The heritability estimates when binary records were transformed to the probit scale (h2) were .04 +/- .003 and .02 +/- .001 for Angus, .01 +/- .002 and 0 for Hereford and .01 +/- .001 and .02 +/- .001 for Polled Hereford for heifers and mature cows, respectively. Heritability estimates in this study are in agreement with the literature, indicating little opportunity for improvement in pregnancy rate by selection within a breed.     

Magnetic resonance imaging of hepatic neoplasms in the rat

Magnetic resonance imaging (MRI) at microscopic resolution was done on a live rat that had chemically induced hepatic neoplasms. Beginning at the anterior aspect of the liver, 16 contiguous transaxial slices (each 1.25 mm thick) were produced using three-dimensional Fourier transform sequences. The rat had been treated with diethylnitrosamine (200 mg/kg) at 70 days of age, and, subsequently, received periodic implants of 17a-ethynylestradiol for 60 weeks. Carr-Purcell-Meiboom-Gill (CPMG) sequences (repetition time = 2,000 and echo time = 20, 40, 60, 80 ms) were done to give quantitative measures of spin-spin relaxation times (T2). Pixel-by-pixel curve fitting from these multiple images yielded calculated T2 images. Histologic evaluation of three abnormal areas in the liver revealed solid and cystic hepatocellular adenomas. Although lesions were evident in early-echo images of the CPMG sequence, they were more apparent in the late-echo images. This was consistent with longer T2 relaxation times for the lesions. The voxels of dimensions (230 x 230 x 1,250 microns) permitted resolution of volume elements less than 0.07 mm3. This in turn permitted clear delineation of focal lesions less than 3 mm in diameter. The potential for MRI at microscopic resolution in toxicologic research is clearly demonstrated.     

Ammonia and greenhouse gas emissions from a straw flow system for fattening pigs: Housing and manure storage

Animal welfare and environmental protection are increasingly important. Housing systems must be found that offer animal welfare while minimizing the overall emissions of ammonia and greenhouse gases. The straw flow system is an animal friendly housing system for fattening pigs, which can be operated economically on commercial farms. Emissions from conventional slurry based pig houses have been intensively studied, but more research is needed into straw based systems. In this study, we quantified emissions of ammonia and greenhouse gases from a straw flow system with or without daily removal of slurry to an outside store. The effect of applying a solid cover during outside storage was also examined.

Emissions of NH₃, N₂O, CH₄, and volatile organic C (VOC) from a commercial straw flow system for fattening pigs in Upper Austria were measured between June 2003 and March 2004. Emissions of CH₄ during housing were 1.24 and 0.54 kg CH₄ per pig place per year without and with daily manure removal, respectively. The corresponding N₂O emissions amounted to 39.9 and 24.5 g N₂O per pig place per year, and NH₃ emissions to 2.10 and 1.90 kg NH₃ per pig place per year without and with daily manure removal. Emissions of CH₄, N₂O and NH₃, and of total greenhouse gases, from the straw flow system were lower than literature reference values for forced ventilated fully slatted floor systems. Daily removal of the manure to an outside store reduced emissions from the pig house.

Emissions during storage of pig slurry derived from a straw flow system were quantified between June 2004 and June 2005. Slurry was stored in pilot scale stores with or without a solid cover and emissions quantified by a large open dynamic chamber. The solid cover reduced NH₃ and greenhouse gas emissions by 30 and 50%, respectively. During cold climatic conditions stored pig manure emitted less NH₃ and greenhouse gases than when stored under warm climatic conditions. We recommend the use of separate emission factors for slurry storage in the colder and warmer periods in the national emission inventory, and the use of covers on pig slurry stores.

Overall, it is concluded that the straw flow system may combine recommendations of animal welfare and environmental protection.