Risk factors for mortality in grow-finishing pigs in Belgium

The present study investigated risk factors for mortality in grow-finishing pigs of 137 pig herds belonging to one integration company during a period of 2.5 years. Mortality data, expressed as the number of dead pigs divided by the number of pigs placed in the fattening unit were investigated retrospectively. The following potential risk factors were evaluated: type of pig herd, season and year of placement in the fattening unit, pig density in the municipality, management practices (density of the pigs in the barn, origin of the pigs), housing conditions and feeding practices. The overall average mortality percentage was 4.70%. Three variables in a multivariable regression model were significantly associated with mortality: season of placement in the fattening unit, origin of the piglets and duration of the fattening period. Pigs placed in October, November and December, were at higher risk than pigs placed in other months. Herds that purchased pigs from a merchant, used pigs from other herds with an excess of piglets for filling their fattening units or herds that purchased pigs from more than five origin herds also suffered higher mortality. The mortality also increased in case of longer duration of the fattening period. This study documented for the first time that in addition to seasonal effects and a longer duration of the fattening period, purchasing feeder pigs from one or a limited number of herds is of crucial importance to achieve low mortality in the grow-finishing pigs.     

Mother–Offspring Interactions in Zebu Cattle

The knowledge of the interaction between mother and offspring might contribute to enhance the welfare of the offspring and to improve the reproductive efficiency of the cow. However, there is still little information available about such interaction in some cattle breeds. A series of observational studies were set up, addressing the mother–offspring relationships of Nelore, Guzerat and Gyr cattle breeds. Firstly, the behaviour of cows and calves around the time of parturition was described, and then, the underlying factors that affect the calves' survival and development were studied. Special attention was given to the failure or delay in the first suckling. The results together are indicative of genetic variability for some studied variables, indicating the possibility of selection for calf vigour (using latency to stand up and latency to suckle as its indicators) and maternal ability (using percentage of time in contact with the calves), in spite of the estimates of heritability were low and presented high standard deviation for all variables. The individual variability in their suckling behaviour and the efficiency in first suckling cannot be explained by a single isolated underlying factor. By now, there are some results available, although there are many questions without answers. The field is still open for the development of future research.     

Stolon Development and Cultural Production Practices of Winter-Grown Strawberries

ABSTRACT

The four experiments described here are part of a 5-year program focused on determining whether day-neutral and short-day strawberries would be suitable for commercial off-season/winter (temperate climate) production in greenhouses. All research was performed using container-grown plants fertigated through a capillary mat production system with heat supplied under the benches. The first experiment focused on stolon development. The second experiment investigated the influence of stolon removal on berry production and included the removal of flowers for the first three weeks. The third and fourth experiments were conducted as a comparison of university research (experiment 3) versus a commercial operation (experiment 4). In experiment one, of 13 cultivars, ‘AC Wendy’ plants produced significantly more stolons than the other cultivars. In experiment two, stolon production peaked at weeks 12 and 13, with ‘Chandler’ plants producing significantly more stolons (starting at week 9) than the other cultivars. At week 13, ‘Seascape’ plants produced more total berry weight than the other cultivars. The influence of stolon removal on total berry weight varied, with ‘Evie-2+’ plants (large crowns) producing higher total berry weight with the stolons on as compared to ‘Evie-2’ plants, which produced higher total berry weight with the stolons removed. In experiment 2, fruit production was low and was probably a result of deflowering for three weeks. Consequently, it may not be advisable to deflower during the ‘off-season’ for greenhouse-grown strawberries. In the final two experiments, which involved a commercial cooperator as well as the university greenhouse, it was found that of the five cultivars trialed, the same cultivars at both sites produced the maximum total berry weight. Stolon production differed at the two locations, but the optimal time for stolon removal was similar. Thus, it is recommended that for winter greenhouse production, stolons be removed initially at week 8 and then at weeks 11–12 of the production cycle.     

Development of Multispecies,Long-Term Monitoring Programs for Resource Management

There is growing interest among resource managers in implementing long-term wildlife monitoring. The process to develop such a program may seem daunting, however, because it requires determining the species, metrics, sampling methods, experimental design, and level of effort necessary to achieve the desired power for detecting meaningful changes. Failure to give these decisions proper attention often leads to suboptimal information for decisions and planning objectives. Our primary objectives were to develop alternative scenarios for a monitoring program, including power estimates and sampling effort required to detect population changes for small mammals on rangelands in southern Texas. Our secondary objective was to present a framework for developing customized monitoring programs for tracking wildlife populations over time. We trapped small mammals using ~ 28 000 trap nights each year from 2014 to 2016 resulting in 13 183 captures of nine species. We estimated abundances and occupancy in each year for each species and conducted power analyses using simulations. We used these results to develop four multispecies monitoring scenarios: two with distinctly different levels of effort with abundance as the focal metric and two for monitoring occupancy. The most effort-intensive scenario required trapping 40 grids for 6 consecutive nights each yr. With this effort, we predicted it would be possible to detect annual changes in abundance of ≤ 10% after 10 yr for four species and net declines in occupancy of ≤ 50% after 10 yr for five species with a power of 0.90. The least effort-intensive scenario required trapping 30 transects for 4 consecutive nights each yr. We predicted this effort would allow for the detection of annual changes in occupancy rates between 35% and 55% after 10 yr for five species. Our study is an example for land managers, providing general guidelines for developing rigorous, long-term monitoring programs specific to their objectives.     

Changes in Testicular Interstitial Connective Tissue of Hamsters (Mesocricetus auratus) During Ageing and After Exposure to Short Photoperiod

The testicular interstitium of Syrian hamster (Mesocricetus auratus) was studied during ageing and in testicular regression after exposure to a short photoperiod, in relation to the interstitial cells and their connective tissue. This tissue was assessed histochemically using Masson's trichrome technique and the expression of Heat Shock Protein 47 (HSP‐47) and collagen IV (α5) was assessed in Leydig cells. Finally, an ultrastructural analysis of some cells of the testicular interstitium was made. Leydig cells were positive for HSP‐47 and collagen IV (α5). Ageing did not change the parameters studied while the short photoperiod altered the synthetic activity of Leydig cells. The positivity index of these cells for HSP‐47 was significantly higher in the regressed testis, but was lower for collagen IV (α5). During ageing no change were observed. Ultrastructural Leydig cells showed a discontinuous basal lamina that did not change during ageing. The basal lamina was not identified in Leydig cells regressed by exposure to a short photoperiod. In conclusion; the intertubular connective tissue suffers little change with age. By contrast, in the testis regressed after exposure to a short photoperiod the studied parameters related to the intertubular connective tissue were altered. These changes are probably related with the low synthetic activity of regressed Leydig cell.     

Using 20-gauge percutaneous peripheral catheters to reliably collect serial 4-mL blood samples from conscious dogs

Objective To determine the reliability of collecting serial 4-mL blood samples over 13 h using a 20-gauge, cephalic catheter in conscious dogs. Design Prospective, observational study. Animals Twelve (6 males, 6 females) healthy, neutered, lean dogs. Procedure Percutaneous placement of a 20-gauge, 1.1 × 30 mm intravenous over-the-needle catheter into the cephalic vein was performed in each dog on three occasions. Catheter patency was maintained by intermittent flushing with 0.9% saline and 1 IU/mL heparinised saline solutions. Blood samples (4 mL) were obtained at 10 time-points over 13 h, with close monitoring of the dogs and the indwelling catheters. Blood volume, resistance on aspirating blood sample (minimal or marked resistance) and the methods used to improve blood flow were recorded. Results A high proportion (93%) of blood sample collections achieved the required 4-mL volume, and the remaining samples were greater than 1.5 mL. Of the 358 collections via the cephalic catheter, 311 (87%) were obtained with ‘minimal resistance’. The remaining collections had ‘marked resistance’ (n=47) and were associated with a loose catheter in 11% (5/47) and of unknown cause in 89% (42/47). After ‘marked resistance’ had been encountered and the catheter was flushed with saline and heparin solutions, subsequent sampling with ‘minimal resistance’ was frequently possible from the same catheter. Conclusion Use of a percutaneous, 20-gauge intravenous cephalic catheter allowed reliable serial collection of 4-mL blood samples over 13 h in conscious dogs.     

Effects of spring fertilizer nitrogen and sward height on production from perennial ryegrass/white clover swards grazed by beef cattle

An experiment was carried out to compare the effects of two compressed sward height treatments, each at two fertilizer nitrogen (N) treatments (0 and 50 kg ha⁻¹ in spring), on the date of turnout and liveweight gain of steers grazing a perennial ryegrass/white clover ( Lolium perenne/Trifolium repens ) sward sited on clay loam in south-west England. The sward height treatments were 6 cm all season, and 4 cm in the spring rising to 6 cm in June; these were maintained using continuously variable stocking with Hereford × Friesian steers. Cattle were turned out on average 11·5 days earlier on the 4-cm sward height compared with the 6-cm sward height treatment. Liveweight gain early in the season was lower on the 4-cm swards than on the 6-cm swards. Liveweight gain ha⁻¹ over the whole season was similar for the two sward height treatments. Fertilizer N did not affect turnout date or liveweight gain.