Experimental alveolar echinococcosis in pigs, lesion development and serological follow up

Liver lesions were found in 6/6 pigs 7 months after oral inoculation with 5000 or 35,000 Echinococcus multilocularis eggs. However, lesion morphology differed considerably among the animals. The largest lesions (3–8 mm in diameter) were found in a single pig and smaller lesions (1.5–3 mm) in three pigs. These lesions were clearly circumscribed and had pronounced central necroses and dystrophic calcifications. In contrast, most of the smallest (usually <1.5 mm in diameter) found in two other pigs, had small compact fibrotic areas and blurred borders with obvious fibrous infiltrations into the interlobular tissues. E. multilocularis specific DNA was detected by PCR in all lesion types, but metacestode viability, as assessed by in vivo intraperitoneal inoculations in jirds, could not be demonstrated. Within 1 month post inoculation, all pigs developed specific IgG antibody responses against a battery of different antigens (metacestode, cyst fluid, and protoscoleces-derived native E. multilocularis and E. granulosus antigens, affinity purified Em2G11 antigen, antigen B, recombinant Em II/3–10 antigen). Two different reaction patterns were recorded. In the two pigs with the small lesions, pronounced reactions against all crude antigens with peaks 3–5 months p.i. and clearly elevated levels until the end of the experiment were noted. In all other pigs, antibody reactions remained low in all cases. In conclusion, we demonstrated two types of E. multilocularis metacestode development in pigs with distinct immunological response patterns.     

Progesterone and pregnancy status of buffaloes treated with a GNRH agonist

The primary aim of the present study was to establish whether the treatment with a GnRH agonist on Day 5 after AI may result in the formation of an accessory corpus luteum, greater progesterone secretion, and the increased likelihood of pregnancy success in buffaloes. The study was conducted during a period of increasing daylight length when progesterone secretion is suppressed and embryonic mortality is relatively high in buffaloes. In Experiment 1, treatment with a GnRH agonist (buserelin, 12 μg) on Day 5 after AI induced acute increases in circulating concentrations of LH, FSH and oestradiol-17β. Pregnant buffaloes (n = 14) at Day 40 following AI showed an increase (P < 0.01) in milk whey progesterone concentration between Day 5 (310 ± 55 pg/ml) and Day 15 (424 ± 50 pg/ml). The non-pregnant buffaloes (n = 7) showed a decrease (P < 0.01) in progesterone level from Day 5 (410 ± 87 pg/ml) to Day 15 (188 ± 30 pg/ml) following AI. In Experiment 2, the treatment with buserelin (12 μg) on Day 5 after AI induced ovulation in 62% of the buffaloes (31/50) and these buffaloes showed a progressive increase in milk whey progesterone concentration on Day 10, 15 and 20 of pregnancy. Buffaloes that did not ovulate, recorded a relatively constant milk whey progesterone level from Day 10 to Day 20 following AI. Milk whey progesterone concentrations increased after the administration of the GnRH agonist in 97% of the pregnant buffaloes and 68% of the non-pregnant buffaloes. The diameter of the largest follicle in buffaloes that ovulated (ovulated n = 31) (8.9 ± 0.04 mm; range 4.2 – 13.0 mm) did not differ significantly from the diameter of the largest follicle in buffaloes that did not ovulate (not ovulate n = 19) (8.7 ± 0.04 mm; range: 4.0 – 12.0 mm). The latter observation suggested that notional ovulatory size follicles in buffaloes are heterogeneous with respect to stage of follicle maturation and capacity to respond to plasma LH. The present study showed that treatment with a GnRH agonist on Day 5 following AI provides a strategy to increase progesterone secretion and the likelihood of pregnancy in buffaloes mated during periods of increasing daylight length.     

Prevalence of vancomycin-resistant Enterococcus faecium (VREF) in pig faeces from slaughterhouses in Spain

A study to estimate the prevalence of vancomycin-resistant Enterococcus faecium in faecal samples from pigs at slaughterhouses in Spain was carried out between November 1998 and January 1999 with 900 samples taken from four abattoirs representing 9.7% of all pig slaughtered in 1998. Using a selective enrichment broth with vancomycin (8 μg/ml), 64 samples (7.1%; 95% CI: 5.5, 9.0%) had E. faecium vancomycin-resistant strains that showed minimal inhibitory concentrations of 256 μg/ml (62 strains) and 512 μg/ml (two strains). Results by farm showed that 43 of the 240 pig farms represented in the sampling had at least one faecal sample with vancomycin-resistant E. faecium.     

Abundance and phenotypic diversity of Escherichia coli isolates with diminished susceptibility to expanded-spectrum cephalosporins in faeces from healthy food animals after slaughter

Antimicrobial resistance (AR) is an increasing phenomenon but its quantitative estimation remains controversial. The classical resistance percentage approach is not well suited to detect either emergence or low levels resistance. One option is to shift the focus from strains to hosts. This approach is applied to test for phenotypic diversity associated with diminished susceptibility to expanded-spectrum cephalosporins (DSESC) in faecal Escherichia coli from healthy food animals in Spain.

We performed E. coli enumeration in faecal samples of broilers (82 pooled samples) and pigs (80 pooled samples) at the slaughterhouse level, using Coli-ID plates alone and supplemented with cefotaxime at two levels (1 and 8 μg/ml). Antimicrobial susceptibility of isolates was tested by the agar diffusion method. Clustering was carried out using these numerical values and Ward and UPGMA methods.

When using plates supplemented with 1 μg/ml of cefotaxime for DSESC E. coli detection, 93% (76/82) of broiler pooled samples and 36% (29/80) pig pooled samples tested positive. When using 8 μg/ml of cefotaxime, 67% (55/82) of broilers and 13% (10/80) of pigs were positive. Nevertheless, the relative abundance of this phenotype was low in both animal species (range 0–4.3%). Irrespective of the clustering method (Ward or UPGMA), a noticeable phenotypic diversity was detected, especially from the plates containing 1 μg/ml of cefotaxime.

We concluded that: (a) E. coli with phenotype DSESC are common in broilers and pigs but are less frequent in pigs, and (b) the host approach is the most appropriate method for antimicrobial resistance assessment when null or very low levels of antimicrobial resistant bacteria are expected.     

CpG-ODN enhances mammary gland defense during mastitis induced by Escherichia coli infection in goats

Seven healthy native goats in early lactation, weighing 30–40 kg, were used in this study. The right mammary gland of the seven does were infused with CpG-ODN at a dosage of 100 μg kg⁻¹ body weight on the day 5 postpartum (PP). The left glands were used as controls and infused with sterile phosphate-buffered saline (PBS). On day 8 PP, the same dosage of CpG-ODN or PBS was again infused. On day 9 PP, the mammary glands (both right and left) of the seven does were infused with 6 × 10⁶ colony-forming units (CFU) Escherichia coli and, at 0, 8, 16, 24, 48 and 72 h postinfection (PI), milk samples were collected from all glands. Goats were euthanized at 72 h PI and the mammary tissue harvested. Infusion with 6 × 10⁶ CFU ml⁻¹ E. coli induced acute mastitis. Histopathological evaluations showed that polymorphonuclear neutrophils (PMNs) were still present in alveoli at 72 h PI, but PMNs in the CpG-ODN-treated glands has disappeared. Bacteria counts in milk peaked at 16 h PI and CpG-ODN induced a significant decrease in viable bacteria from 16 h PI until the end of the experiment. This study showed that CpG-ODN promoted the expression of its specific receptor (TLR-9 mRNA) in mammary tissue, stimulated IL-6 production, reduced bacteria counts in milk, attenuated the impact of inflammation mediators on cells and significantly shortened the inflammation course. These results suggest that the CpG-ODN improved mammary gland defense and, thereby, had a beneficial effects against mastitis caused by E. coli infection in goats.     

The C bicarbonate dilution technique to determine energy expenditure in young bulls validated by indirect calorimetry

We explored the applicability of the ¹³C bicarbonate dilution technique for determination of energy expenditure (EE) in young bulls in comparison to whole body indirect calorimetry (IC). Twelve bulls of a F2 German Holstein x Charolais cross (4.5 months, 332 ± 16 kg BM) received a diet providing 1000 kJ ME d^− 1 kg BM^− 0.75 and 4.3 g crude protein d^− 1 kg BM^− 0.75. Bulls were housed in respiration chambers and received an intravenous bolus of NaH¹³CO₃ (A: 3 μmol kg BM^− 1 (n = 2), B: 7 μmol kg BM^− 1 (n = 4), C: 17.5 μmol kg BM^− 1 (n = 6), 99 at.% ¹³C) into the jugular vein to measure EE. Simultaneously, EE was determined by IC. After the ¹³C administration blood samples and breath gas were collected from the animals in the respiration chamber during a 24-h period (7.00–7.00 h). The recovery of ¹³C in breath CO₂ (% of ¹³C dose) was irrespective of NaH¹³CO₃ dose (A: 69.7 ± 2.7%, B: 70.5 ± 4.5%, C: 75.0 ± 4.9%; P > 0.05). Only small amounts of ¹³C were excreted in urine (3.4 ± 2.6%) and feces (2.0 ± 1.3%). The EE determined by the ¹³C bicarbonate method using breath and blood ¹³C recovery rates as correction factors was not different from that measured by IC (816 ± 81 [blood] or 827 ± 101 [breath] vs. 820 ± 90 kJ d^− 1 kg BM^− 0.75). Bland–Altman analysis showed a 95% confidence interval for EE of ± 99 and ± 109 kJ d^− 1 kg BM^− 0.75 based on blood and breath ¹³C recovery, respectively. In conclusion, the ¹³C bicarbonate dilution method is appropriate to obtain reliable estimates of EE in young bulls using blood CO₂ or breath CO₂ under standardized experimental conditions, i.e. in the fasting state.     

Effects of feeding linseed and linseed expeller meal to newly weaned piglets on growth performance and gut health and function

The effects were evaluated of the inclusion of full fat linseed (125 g/kg) (LS) or linseed expeller meal (85 g/kg) (LSM) in diets for weaned piglets on growth performance and parameters of gut health and function. The diets were fed to groups of 12 post weaning single housed piglets. Three of the five treatments (Control (C)+, LS+, LSM+) were challenged with an enterotoxigenic strain of E. coli on day 6. Two treatments were not challenged (C− and LS−). The main response criteria were daily feed intake, body weight gain, faecal shedding of the E. coli, faecal consistency score, faecal nutrient digestibility and gut wall morphology and histology of the jejunal mucosa on day 18/19 of the study. Over the total experimental period (day 0–18) feed intake and body weight gain were highest in treatment C− and lowest in treatment LSM+ (P < 0.05). Feed conversion ratio did not differ between treatments over the total experimental period. Over day 10–12 of the study, the faecal digestibility of dry matter, ash and energy was higher for treatments C− and C+ compared to treatments LS−, LS+ and LSM+ (P < 0.05). There was no significant difference in the faecal shedding of E. coli between treatments C+, LS+ and LSM+. Intestinal mucosal histology and morphology were only slightly affected by the dietary treatments. It was concluded that the use of full fat linseed or linseed expeller meal did not show to be functional ingredients in diets for post-weaning piglet in terms of supporting gut health.     

Entero-pancreatic neurons are responsible for the intestinal phase of pre absorptive insulin secretion

Insulin is a key hormone of the intermediary metabolism and its early secretion after a meal has a major role in the overall organism glucose sensitivity. Pre absorptive insulin secretion (PAIS) includes a cephalic phase (implicating oro-pharyngeal receptors) and an intestinal phase (implicating gastric and duodenal receptors). Entero-pancreatic (EP) neurons, which originate from the antral and the proximal duodenal intrinsic nervous systems, form varicosities in pancreatic ganglia and islets and may account for the intestinal phase of PAIS. To test this hypothesis, post prandial portal insulin and arterial glucose concentrations were compared in (i) intact pigs (IEP), (ii) pigs with gastric canula, (IEP + GC) and (iii) pigs with gastric canula and surgically interrupted EP neurons (XEP + GC) (n = 8). EP neurons section was achieved by sectioning the connective attachments between the pancreas and the proximal duodenum and the antrum. The test meal (800 ml of glucose 5%) was ingested voluntarily (IEP), or directly introduced into the stomach (IEP + GC, XEP + GC), to discriminate between the cephalic and the intestinal phases of PAIS. PAIS was significantly decreased in IEP + GC compared to IEP (AUC = 59 ± 21.2 vs 18 ± 6.6 μUI/ml/5 min for IEP vs IEP + GC, p = 0.04). PAIS was further nullified in XEP + GC (AUC = − 2 ± 8.1 μUI/ml/5 min). Glycemia was not modified in IEP, IEP + GC or XEP + GC. We conclude that EP neurons are responsible for the intestinal phase of PAIS since it disappeared in XEP + GC.     

The effect of dietary crude protein concentration and inulin supplementation on nitrogen excretion and intestinal microflora from finisher pigs

A 2 × 2 factorial experiment was used to investigate the interaction between dietary crude protein (CP) concentration (200 vs 140 g/kg) and inulin supplementation (0 vs 12.5 g/kg) on nitrogen (N) excretion and intestinal microflora from 16 boars (n = 4, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy and lysine. Pigs offered the high CP diets had a higher excretion of urinary N (P < 0.01), faecal N (P < 0.01) and total N (P < 0.001) than the pigs offered the low CP diets. Inulin supplementation increased faecal N excretion (P < 0.05) and decreased urine: faeces N ratio (P < 0.05) compared to the inulin free diets. There was no significant effect (P > 0.05) of dietary treatment on N retention. There was an interaction (P < 0.05) between dietary CP concentration and inulin supplementation on caecal E.coli. Pigs offered the diet containing 200 g/kg CP plus inulin decreased the population of E.coli compared to the inulin supplemented 140 g/kg protein diet. However, CP concentration had no significant effect on the population of E.coli in the unsupplemented diets. Inulin supplementation increased caecal bifidobacteria (P < 0.01) compared to the inulin free diets. In conclusion, inulin supplementation favourably altered N excretion and lowered the population of E.coli at high CP concentrations.     

Effect of rearing environment and age on gut development of piglets at weaning

Outdoor reared pigs are reported to be larger at weaning than indoor reared pigs and respond better to the weaning process. This may be due to enhanced gut development associated with increased size. Eighty sows were allocated to either indoor or outdoor farrowing on the basis of size, parity and past performance. Resulting litters were weaned at either 4 or 6 weeks of age. On days 26 and 40 of age, 40 (10/treatment) and 20 piglets (10/treatment still unweaned) were killed to measure intestinal morphology. Data were analysed as a 2 × 2 factorial using the GLM procedures of Minitab 12.2. Pigs reared outdoors were larger than those reared indoors at both weaning ages, pigs weaned at 6 weeks were heavier than those weaned at 4 weeks, 8.4 versus 7.4 kg at 4 weeks and 12.9 versus 10.5 kg at 6 weeks respectively (± 0.25, P ≤ 0.001). There were no differences in small intestine size relative to body weight due to rearing environment and no differences in gut morphology. When corrected for body weight, 6 week pigs had heavier small intestines than 4 week pigs, 0.39 (± 0.010) versus 0.34 (± 0.007) g/cm length, respectively (P ≤ 0.001). Six week unweaned pigs had similar villus heights to 4 week unweaned pigs but wider villi (P < 0.05) and deeper crypts, for example, at the 25% site crypt depths were 236 and 193 μm (± 7.7/5.5) respectively (P < 0.001). Hence increased piglet size due to outdoor rearing did not advance gut maturation whereas increased piglet size due to age did influence maturation of gut structure.     

Identification of Ehrlichia ruminantium (Gardel strain) IFN-gamma inducing proteins after vaccination with a killed vaccine

IFN-γ is considered as a key factor in protection against heartwater of ruminants, caused by the obligate intracellular bacterium Ehrlichia ruminantium. In this study, a better definition of the molecular masses of IFN-γ inducing proteins of the Gardel strain of E. ruminantium was obtained by the use of continuous flow electrophoresis (CFE) and sensitized polyclonal lymphocytes. Out of 15 E. ruminantium CFE fractions tested within the 14–39 kDa region, eight were commonly reacted to by all goats. Interestingly, half of these fractions fall within the 23–29 kDa region, shown previously to contain polymorphic B-cell epitopes. Thus, the results suggest that this region also contains T-cell epitopes potentially involved in protection. Also, several proteins were found to be more immunogenic than the serologically immunodominant MAP1 protein. Finally, high activity within the 15–19 kDa region was observed, which confirms previous work done with CD4+ T-cell lines obtained from cattle immunized with a South African strain of E. ruminantium. The proteins falling within the molecular weight ranges defined in this study may have potential as vaccine antigens.     

Effect of acid addition to pig liquid feed on its microbial and nutritional characteristics

An in vitro study was performed to describe the effect of addition of acid products to liquid feed on the course of fermentation. A standard grower diet with added extra lysine, methionine, and threonine was formulated. Three experimental treatments were prepared: the grower diet, ‘Control’; the grower diet + 4.8 g solid acidifier Boliflor® FA 2300S/kg liquid feed, ‘FA2300S’; and the grower diet + 2.0 g formic acid/kg liquid feed, ‘Formic’. Feed and water (1 to 2.75) were incubated in bioreactors with a volume of 1 l at 20 °C. A sample was taken after 0, 6, 24, and 48 h of incubation. After 48, 55, 72, 79, and 96 h of incubation, 90% of the mixture was removed and replaced with fresh feed and water. A sample was taken at 96, 102, and 108 h of incubation. Enterobacteriaceae counts were highest in the ‘Control’ diet and lowest in the ‘Formic’ diet at all sampling times. From 96 to 108 h of incubation,  5–19% total lysine, threonine, and methionine, and  26–42% free lysine, threonine, and methionine disappeared. Addition of 2.0 g formic acid or 4.8 g Boliflor® FA 2300S per kg pig liquid feed impeded a blooming of Enterobacteriaceae during the first hours of fermentation but had no effect on amino acid degradation. A disappearance of, mainly, free amino acids occurred during fermentation of liquid feed as prepared in the present study.     

The coccidia of sheep and goats in Senegal

A survey of the coccidia in domestic sheep and goats was undertaken to ascertain the type of Eimeria species and the number of different coccidial species in individual faecal samples. Simultaneously the prevalence and the oocyst output was investigated in 2234 sheep and 577 goats during a 12-month period. Eight Eimeria species were encountered in sheep: E. ahsata, E. crandallis, E. faurei, E. intricata, E. ovina, E. ovinoidalis, E. pallida and E. parva.

In goats the following species were found: E. ahsata, E. arloingi, E. christenseni, E. crandallis, E. faurei, E. intricata, E. ninakohlyakimovae and E. parva.

The prevalence in sheep was 94% and in goats 85%, multiple parasitism was the rule. No seasonal fluctuation was observed in the prevalence or oocyst output. The sheep and goats' oocyst output was moderate, the mean for both being in the range of 1000–5000 oocysts/g of faeces.     

Lamb mortality in Meknes province (Morocco)

Two studies were carried out: a preliminary study based upon 220 flocks visited twice to collect data on sheep-flock management and losses, and a second intensive 2 year (1984–1986) study carried out on 16 of the 220 flocks in one country.

Mean annual lamb mortalities were 17.6% (1984–1985) and 31.3% (1985–1986), and varied significantly according to nutrition. Pre-parturient deaths represented 27.3% (1984–1985) and 18.9% (1985–1986) of total deaths. The percentage of parturient deaths was very low (0.4%) for both years. Of the lambs necropsied, starvation/exposure complex contributed most to lamb mortality. Enteritis and septicemia represented the second most important cause. Of the enteritis cases, 18.5–63.2% of the samples analyzed were positive for Escherichia coli: 38.5% of the septicemia cases were positive for E. coli in 1985–1986 but none were positive in 1984–1985. E. coli K99 isolates were rare. Only one Salmonella isolate was made in 1985–1986. There were 16 cases (12.2%) of pneumonia in 1984–1985 and two cases only (1.5%) in 1985–1986. Of the cases examined, 18.8% were positive for Pasturella hemolytica and 25% were positive for Pasturella multocida in 1984–1985.

Its appears that lamb mortality can be reduced by improvement of nutrition and health care in many of these flocks. Further work should be done to provide information on the causes of lamb pneumonia as well as the potential for vaccination against lamb diarrhea (i.e. E. coli in these flocks.     

Prolactin signaling in porcine adrenocortical cells: involvement of protein kinases

Prolactin (PRL) was found to have a stimulatory effect on adrenal steroidogenesis in vivo and in vitro in several species including pigs. PRL signal transduction pathways, however, in adrenocortical cells are poorly recognized. Therefore, the goal of this paper is to ascertain the involvement of protein kinase C (PKC) and tyrosine kinases in PRL signaling in porcine adrenal cortex. Adrenals were harvested from locally slaughtered mature gilts. Cortical cells were dispersed by sequential treatment with collagenase. The cells were seeded into 24-well culture plates at a density of 3×10⁵/mL. Cells were incubated with or without PRL (500 ng/mL), ACTH (5 nM—a positive control), tyrosine kinase inhibitor—genistein (1; 2.5 or 5 μM), PKC inhibitor—sphingosine (20–1000 nM) and PKC activators—diacylglycerol (DiC8; 10–100 μM) and phorbol ester (PMA; 1–1000 nM). All incubations were performed for 8 h (95% air and 5% CO₂, 37°C). PRL and ACTH (P<0.05) increased cortisol and androstenedione (A₄) secretion. DiC8 and PMA mimicked the stimulatory effect of PRL. Sphingosine (P<0.05) suppressed basal and PRL-stimulated steroid secretion. Genistein inhibited (P<0.05) PRL-stimulated cortisol secretion and enhanced (P<0.05) basal and PRL-stimulated A₄ secretion. Moreover, PKC activation was assessed by measuring the specific association of [³H]phorbol dibutyrate ([³H]PDBu) with adrenocortical cells after treatment with PRL or ionomycin (a positive control). PRL (within 2–3 min) and ionomycin (within 2–5 min) increased (P<0.05) specific binding of [³H]PDBu to the porcine adrenocortical cells. In addition, PRL did not augment the cortisol and A₄ secretion by PKC-deficient adrenocortical cells. In conclusion, presented results support the hypothesis that PKC and tyrosine kinases are involved in PRL signaling in adrenocortical cells in pigs. Moreover, activation of PKC is associated with the increased secretion of cortisol and A₄.     

Canine echinococcosis in northwest Libya: assessment of coproantigen ELISA, and a survey of infection with analysis of risk-factors

In order to determine the prevalence and risk factors for canine echinococcosis in different endemic localities in the Tripoli area of northwest Libya, stray dogs were examined post-mortem, and owned dogs screened for Echinococcus granulosus infection using a standardised genus specific coproantigen ELISA. The prevalence of E. granulosus infection at necropsy in stray-dogs was 25.8% (15/58, 95% CI 15.3–39.0%), and 21.6% (72/334, 95% CI 17.3–26.4%) of owned dogs tested were positive by coproantigen ELISA. Sheepdogs appeared to have a significantly higher copro-positive prevalence (19/19 positive, p = 0.003), compared to 23.6% of other dog classes (e.g. 52/220 guard dogs and household pets). Worm burdens in necropsied dogs ranged from 29 to 2900 (mean 1064) and were positively correlated to coproantigen ELISA OD values (r_s = 0.87, p < 0.001), but negatively correlated with dog age (r_s = −0.69, p = 0.001). Dog age was a significant factor in copro-prevalence as there was an increasing coproantigen-positive tendency in younger dogs (≤5 years, p = 0.04). A total of 45/132 (34%, 95% CI 25.9–42.1%) of farms/homestead had at least one dog that was coproantigen positive. Overall copro-prevalence in dogs by locality varied, with Alkhums (Leptis-Magna) district having the highest copro-prevalence at 38.7% (24/62, 95% CI 26.6–50.8%) (p = 0.001). Coproantigen testing of a cohort of owned dogs before and approximately 15 months after praziquantel treatment showed a significant decrease in the coproantigen positive rate from 21.6% (72/334) to 9% (21/233) post-treatment. The overall E. granulosus coproantigen positive rate (‘re-infection rate’) within the same cohort of dogs was 22 % (10/45) by 15 months post-treatment. Significant risk factors for a copro-positive owned dog were associated with non-restraint of dogs, and owners that did not de-worm their dogs. Home slaughtering of livestock and lack of knowledge about E. granulosus transmission were also significant risk factors for a canine coproantigen positive result.     

Epidemiological studies of clinical and subclinical ovine mastitis in Awassi sheep in northern Jordan

Forty-six Awassi sheep flocks selected by stratified random sampling were subjected to a cross-sectional study to determine the prevalence of intramammary infections, to assess the influence of flock size and parity on the prevalence of somatic cell count (SCC) and to identify major udder pathogens. Of the 3472 udder halves examined, 29.8% had over 10⁶ SCC/ml and 0.03% had dry teats due to chronic mastitis. Flocks with 30–49 milking ewes (small flock size) were much younger (P < 0.001) than flocks with 50–99 ewes (medium) and flocks with ≥ 100 ewes (large). Pairwise analysis of the InSCC of both halves of the udders revealed significant mean differences for small and large flock size (P < 0.05), and for medium and large flock size (P < 0.001). Mean InSCC was lower (P < 0.05) in samples obtained from the left half compared with samples of the right half of the udder. Multiparous ewes had higher (P < 0.001) mean InSCC than primiparous ewes. Also, ewes with twin lambs had higher (P < 0.001) mean InSCC in the right half of the udder compared with single-lamb ewes. Samples collected in January (winter) had lower (P < 0.05) mean InSCC compared with samples collected in June. The most common organisms isolated from subclinical mastitis cases were coagulase-negative Staphylococci (17.8%), E. coli (13.6%), Streptococcus agalactiae (6.8%) and Staphylococcus aureus (6.8%). Of the 46 flocks, 20 were monitored monthly for 9 consecutive months to determine the incidence of clinical mastitis diagnosed by shepherds or/and sheep farmers with major pathogens. The incidence of clinical mastitis (expressed as the number of clinical cases per 100 ewe-months) were 2.1 ± 1.9 (SD), 1.9 ± 1.1, and 1.2 + 2.1 for small, medium and large flocks size strata, respectively. The overall population estimate was 1.7 ± 0.02 cases per 100 ewe-months. The most-common clinical isolates were S. aureus (22% of all clinical isolates) and E. coli (14.2%).     

Preliminary studies on the effectiveness of the novel pulicide, spinosad, for the treatment and control of fleas on dogs

Spinosad is a novel mode-of-action insecticide produced from a family of natural products derived from fermentation of the actinomycete, Saccharopolyspora spinosa. Separate studies were undertaken to determine the minimum effective dose of spinosad given orally for the treatment of experimentally induced flea infestations (Ctenocephalides felis) on dogs, and to assess any potential impacts of feeding canned or dry food at the time of dosing. Both were randomized block (blocked by gender and pre-treatment flea counts), blinded parallel-arm studies, with dogs selected on health and ability to maintain pre-treatment flea populations. For dose selection, 48 dogs were allocated among six groups (8 dogs/group; 4 males, 4 females): placebo-treated negative control, spinosad in gelatin capsules at 15, 20, 30 and 40 mg/kg administered per os; and topical imidacloprid (10 mg/kg) as a positive control. Placebo and spinosad treatments were administered on Days 0, 30 and 60, imidacloprid only on Day 0. In a second study to assess the impact of food type at the time of dosing, three groups were formed: placebo-treated control (8 dogs; 4 males, 4 females), spinosad (30 mg/kg) administered with canned food (8 male dogs, 8 females); and spinosad (30 mg/kg) with dry food (8 males, 8 females). Treatments were administered on Days 0 and 30. To assess post-treatment persistent efficacy, flea infestations were repeated at regular post-treatment intervals, beginning on Day 5 through Day 89 in the dose selection study and Day 58 in the impact of food type and dosing study. Flea counts were performed 48 h post-infestation by study personnel who were blinded to treatments. In the dose selection study, compared to geometric mean live flea counts in the control group, each spinosad dose was highly effective (99.8–100%) at 7, 14 and 21 days after treatment. Only the 30 and 40 mg/kg doses maintained high efficacy (97.2–100%) until 30 days after treatment, with no difference between the two. Imidacloprid was highly effective at Day 30, with significant difference only from the 15 mg/kg spinosad group. Because there was no significant difference between the higher spinosad rates, 30 mg/kg was selected as the optimal minimum effective dose. In the second study, spinosad was highly effective at all post-treatment flea counts (98–100%). Taken together, these studies demonstrate that repeated monthly oral treatments with spinosad at 30 mg/kg provide sustained control of C. felis on dogs. There were no treatment-related adverse events in either study, indicating that spinosad has potential to be used monthly as a safe and effective flea adulticide, providing sustained activity that matches that of currently used topical products.     

The effects of weaning age, diet composition, and categorisation of creep feed intake by piglets on diarrhoea and performance after weaning

This study investigated the effects of weaning age, diet, and classification of piglets as ‘eaters’ or ‘non eaters’ of creep feed in lactation, on production and diarrhoea after weaning. Four antimicrobial-free diets were offered in lactation and for 14 days after weaning: (i) wheat–soy based diet with animal and vegetable (‘mixed’) protein sources (COMM), (ii) heat-processed rice (HPR) with barley hulls and potato starch and mixed protein sources (RBHPS), (iii) HPR with sugar-beet pulp and mixed protein sources (RSBP), and (iv) HPR with mixed protein sources (R). Piglets were individually examined for diarrhoea daily for 14 days after weaning, and antibiotic treatments were individually recorded. Faecal swabs were taken on day 10 after weaning and scored for β-haemolytic Escherichia coli. There were significant main effects of weaning age and diet (both P < 0.001) on daily gain between weaning and 14 days after weaning. Pigs weaned later grew 50 g/day more than pigs weaned earlier, and pigs fed the COMM diet grew slower than pigs fed the rice-based diets. The number of antibiotic treatments was influenced by diet (P < 0.001), with most treatments (2.1) given to pigs fed the diet RBHPS. Faecal score was influenced by a weaning age and diet interaction (P < 0.01). There was no correlation (P > 0.05) between the number of antibiotics treatments and the E. coli score.