The relationship between tail biting in pigs, docking procedure and other management practices

The tail length (docked, tipped or undocked) and tail status (bitten or unbitten) of 27,870 pigs from 450 units was recorded at six UK abattoirs. A farm survey of the final finishing stage was used to investigate the relationship between management practice and tail biting. This showed that docking was the most important factor influencing the probability of being not bitten, with 2.4% of docked and 8.5% of long-tailed pigs being tail-bitten. The following factors reduced the probability of long-tailed pigs being tail-bitten; light straw provision, use of natural ventilation or artificially controlled natural ventilation (ACNV), mixed sex grouping, meal or liquid feeding, and use of double or multi-space feeders. Docked and long-tailed pigs provided with light straw and natural ventilation/ACNV had levels of tail biting of 1.2% and 4.3% respectively; 3.9% of docked pigs with artificial ventilation and no straw were tail-bitten. Long-tailed pigs fed via double or multi-space feeders also had 3.9% of tails bitten.     

The advantages of using a combination of LDL and glutamine in comparison with TRIS egg yolk and Equex® STAMP extenders in the cryopreservation of canine semen

Twenty semen samples taken from 5 dogs were frozen in liquid nitrogen at ?196 °C in four different extenders: one control extender based on 20% egg yolk, 6% LDL alone (low density lipoproteins: the active cryoprotective principle in chicken egg yolk), 6% LDL combined with 20 mmol glutamine, and Equex® (a reference extender that we wish to compare with the LDL-glutamine combination). After thawing, spermatozoal motility was evaluated using a HAMILTON THORNE CERROS 12 image analyzer; the percentage of motile spermatozoa was 27.7% in the egg yolk extender (p < 0.05), 49.9% with 6% LDL alone (p > 0.05), 54.7% in the 6% LDL + 20 mmol glutamine extender, and 47.9% with Equex® (p > 0.05). The motility parameters (VAP, VCL, VSL and ALH) were also superior in the 6% LDL + 20 mmol glutamine extender in comparison with the other extenders.Finally, the spermatozoa were generally better protected during freezing with the 6% LDL + 20 mmol glutamine association than with the egg yolk, 6% LDL, or Equex extenders in terms of the flagellar plasma membrane (HOS test), DNA (Acridine orange test), and acrosome integrity (Spermac® test: no significant difference). The Equex® extender obtained the best results for the acrosome, followed by 6% LDL + 20 mmol glutamine (FITC-PSA test: p < 0.05 between each extender).     

Concurrent parasitic infections of sheep: depression of Trichostrongylus colubriformis populations by a subsequent infection with Oestrus ovis

Concurrent infections of sheep with Oestrus ovis and trichostrongyles of the digestive tract are common in the field. Previous results have shown that a previous infection with O. ovis adversely affects worm populations of either Trichostrongylus colubriformis or Haemonchus contortus. However, no information was available to determine the influence of the succession of infections on the expression of interactions between these parasites located in remote anatomical sites. In order to investigate the role of these modulating factors, an experimental study was conducted on four groups of na?ve sheep, examining the consequences of a delayed infection with O. ovis on a pre-existing population of T. colubriformis. group T was infected four times with 4000 T. colubriformis larvae on days 0, 14, 28 and 42 of experiment; group O received multiple infections with O. ovis first instar larvae on days 42, 49, 56, 70 and 77; sheep from group TO received both infections and animals from group C remained as uninfected controls. Faecal egg counts and eosinophilia were measured weekly throughout the study. At necropsy (day 91), the mucosal cellular responses in the nasal cavities (septum, turbinates, ethmoid and sinus) and in the digestive tract (stomach and small intestine) from all animals were analysed from histological sections. Infection of the digestive tract with nematodes did not modify the biology of Oestrus populations, as measured by the number and weight of larvae. In contrast, infections with O. ovis after T. colubriformis infection was related to significant reductions (P < 0.01) in nematode egg excretion and worm burdens. These changes were associated with significant modifications in populations of mast cells, globule leucocytes and eosinophils in the respiratory and digestive tracts. These results indicate that an antagonistic interaction exists between the populations of O. ovis in the nasal cavities and T. colubriformis in the small intestine but that the order of succession of infections with the two parasites is not a major modulating factor for expression of interactions. They also confirm that parasitic infection in one particular anatomical site induces "at distance" inflammatory reactions of the whole mucosal system.     

Examination of the migration of first instar larvae of the parasite OEstrus ovis (Linne 1761) [Diptera: OEstridae] in the upper respiratory tract of artificially infected lambs and daily measurements of the kinetics of blood eosinophilia and mucosal inflammatory response associated with repeated infection

Twelve lambs were divided into two groups: Group C control, non-infected, and Group O infected once a week for 5 weeks with OEstrus ovis L1 through the same nostril. The first objective of this experiment was to check whether larvae moving through a given nostril remain in the same side nasal cavity or might to spread in both nasal cavities. It has been observed that larvae invade and spread through the entire nasal cavities. The only possible passage way between both sides is via the choanae and velum palatinum. The second objective was to follow the kinetics of blood eosinophilia. A primary peak in eosinophil numbers was noted 4 days following infection, with a higher peak following the second infection. After that, no major changes were seen. Nevertheless, the numbers of eosinophils were always higher than in control animals until the end of the follow-up. The third objective of the study was an enumeration of reactive cells (mast cells, globule leucocytes, and eosinophils) in the mucosae of the upper and lower respiratory tract after necropsy of the animals of the two groups. As observed in previous experiments, there was a large accumulation of these cells in mucosae of the upper respiratory tract. It was also worth noting a significant accumulation of eosinophils in the tissues of the trachea, bronchae and lungs even though OE. ovis was not present there. This "distant" eosinophilic reaction may have important consequences on patho-physiology of other parasites living in these locations: eosinophils have the potential to kill them even though these cells are not activated by their specific antigens.     

Regulation of Teladorsagia circumcincta and Trichostrongylus colubriformis worm populations by grazing sheep with differing resistance status

In an experiment lasting 4 years, changes in the Teladorsagia circumcincta and Trichostrongylus colubriformis populations were compared in lambs and adult sheep with differing resistance statuses. Two flocks of 30 rams (resistant R and susceptible S) grazed separate pastures and 8 rams were slaughtered in the middle and at the end of each grazing season. Five groups of tracer lambs were added each year to estimate the pasture infectivity and were killed for worm counts. The availability of animals with differing resistance statuses (rams and tracer lambs) and differing levels of infection made it possible to investigate the number, size and fecundity of worms of these two species. The inflammatory response was measured in the rams by counting the globule leukocytes, mast cells and eosinophils in the fundic, pyloric and intestinal mucosa. In the tracer lambs, the daily egg production by the female worms of both species was negatively correlated with the worm burden. Worm length accounted for 60 and 70% of the variation in the number of eggs in utero for T. circumcincta and T. colubriformis respectively. Worm length was closely associated with the resistance status of the host; there were greater differences between lambs, and S and R rams for T. colubriformis. T. circumcincta worm lengths were not affected by the worm number. Globule leukocyte counts were related to the worm burdens, and mast cell counts to worm length in the R and S rams. The number, size and fecundity of the worms may well be regulated by similar mechanisms in both species, but T. colubriformis seemed to be more intensively regulated than T. circumcincta. This finding could be useful in devising more effective methods of parasite control.     

Distribution and repeatability of nematode faecal egg counts in dairy goats: a farm survey and implications for worm control

The aims of this study were to characterise trichostrongyle egg excretion in dairy goat flocks under various epidemiological conditions, and to assess the relative importance of animals in their first lactation and goats with high levels of milk production on the total egg output of the flock. The repeatability of egg excretion was estimated on 4 different dates in 14 dairy goat farms in France. Egg outputs were positively skewed on most farms suggesting an aggregated distribution of parasites. Within-year repeatability coefficients ranged from 0.29 to 0.82 suggesting that, on most farms, animals with high egg excretion on one occasion are likely to show high rates of excretion on other occasions. Comparisons of egg outputs from the selected subgroups showed that the high producing goats contributed prominently to egg excretion, particularly at times of peak parasitism. Results from goats in their first lactation were more equivocal. These results provide a rationale for anthelmintic strategies in dairy goats based on phenotypic characters.     

Control of gastrointestinal parasitism with nematodes in dairy goats by treating the host category at risk

Infections of the gastrointestinal tract with parasitic nematodes remain one of the main limiting factors in grazing dairy goats. The usual mode of control of these parasitic diseases has up to now been based on the repeated use of anthelmintics. However, the prevalence rates of anthelmintic resistances, in particular to benzimidazoles, are now particularly high in the French dairy goat production. This situation makes it mandatory to reconsider the usual mode of control of these nematodes and to look for short term, alternative solutions which combine the control of gastrointestinal infections and management of anthelmintic resistances. One of the possible options is to leave a part of the flock without treatment during the grazing season in order to maintain alleles of susceptibility to anthelmintics within the worm populations. Previous epidemiological observations identifying the categories of host populations at risk are presented which provide the rationale for targeted applications of treatments. The results of assays on experimental flocks and from farm surveys examining the advantages and drawbacks of selective treatments are presented. The value of these results in combination with other alternative solutions of control are discussed in order to use minimum treatments with maximum benefits.     

Consequences for body composition at farrowing and nutrient partitioning during lactation of a choice-feeding regime during rearing and pregnancy in gilts of different genotypes

The potential conflict between reproductive functions and the drive to deposit body protein may impair productive performance in modern gilts of lean genotype. To study the response of the gilt to this conflict, a choice-feeding experiment was carried out to measure the nutrient intake selected by breeding gilts and responses in reproductive and lactation performance. Using a 2 × 2 factorial design, gilts of two different genotypes (24 of NPD 402, expected higher body protein/lipid ratio (L) or 24 of Camborough 23, expected lower body protein/lipid ratio, (F)) were either choice-fed (C) by offering both a low (120 g crude protein (CP)/kg) and a high protein (218 g CP/kg) feed during rearing and pregnancy or fed conventionally (R) single feeds, ad libitum during rearing and restricted during pregnancy. Choice-fed gilts selected mainly the low protein feed (0.92 of total feed intake) regardless of genotype and had lower protein intakes than R gilts prior to puberty. However, in pregnancy, due to higher feed intakes, C gilts had higher dietary protein and energy intakes than R gilts. C gilts were heavier, and had greater back-fat and eye muscle depth at farrowing than R gilts, but had smaller litter sizes (P < 0.01). During lactation, dietary treatments were reallocated so that gilts received either a low (LE, maintenance + 45 MJ/day) or a high (HE, maintenance + 67 MJ/day) digestible energy intake. Litter size was standardised within 2 days of farrowing. LE gilts had greater decreases in weight and back-fat and eye-muscle depth during lactation than HE gilts, but dietary lactation treatment had no effect on litter performance. The choice-feeding regime which resulted in heavier gilts with greater back-fat and eye-muscle depth at farrowing did not produce any advantage in terms of partitioning of nutrients towards milk production, as indicated by litter performance, irrespective of gilt genotype. F gilts had greater piglet growth rates than L gilts and also had a higher milk protein concentration. A greater number of L than F gilts failed to complete the experiment for health reasons. Treatment effects on glucose tolerance at day 13 of lactation were not significant. Choice-feeding was therefore not found to be suitable for determining nutrient requirements of modern lean-genotype gilts which would improve reproductive performance.