Ultrasonographic examination of pregnant ewes: From early diagnosis of pregnancy to early prediction of dystocia

Ultrasonographic examination has been established as the most valuable method for early and accurate pregnancy diagnosis in ewes. Early and accurate diagnosis of pregnancy is particularly useful for correct health management of flocks during gestation. It is also important to study pregnancy processes and foetal development with a non-invasive method, as ultrasonographic examination, because various events might affect normal development of foetus and viability of offspring. Evaluation of normal physiological pregnancy progress and outcome, as well as pregnancy disorders and peri-parturient disorders are significant in sheep health management. Hence, ability to perform pregnancy diagnosis and to identify common pathological conditions of pregnant ewes is of importance to clinicians active in sheep practice. Further, monitoring of foetal growth during pregnancy is useful for those working with sheep. Moreover, various disorders of pregnant ewes (e.g., pregnancy toxaemia) can lead to dystocia and it would be beneficial to predict such cases, if any of these disorders has been diagnosed. In all the above circumstances, ultrasonographic examination can support the veterinarian in reaching a diagnosis and in taking decisions for management of each situation. © 2016 Elsevier B.V

Ultrasonographic examination of the uterus of ewes during the post-partum period

Objective of this article is to review use of ultrasonographic examination in the uterus of ewes during the post-partum period. The technique has been employed for elucidating the process of uterine involution in that species, as well as in the diagnosis of various clinical entities. In general, there is a progressive, significant reduction in the size of the uterus, especially during the first week after lambing, in the size of the uterine lumen and the size of the caruncles of the endometrium. In cases of post-partum metritis, principal uterine characteristics that can be assessed by means of ultrasonographic examination for diagnosis and evaluation of the disorder are uterine distention, asymmetry of the organ, distention of uterine lumen, presence, quantity and texture of uterine content, thickness of uterine wall, localisation of inflammatory foci on the uterine wall, texture of uterine wall, alterations in uterine wall vascularisation and confirmation of uterine involution completion. The technique may also be applied for evaluation of the effect of treatment in cases of the disease. © 2016 Elsevier B.V

Gastrointestinal trichostrongylosis can predispose ewes to clinical mastitis after experimental mammary infection

Objective was to study, in an experimental model, the possible role of gastrointestinal nematode infection in predisposing ewes to mastitis during the lactation period. Twenty-four ewes (A or B [n = 12]), free from nematode and trematode helminths, were used. Group A animals received 5000 third-stage larvae of a trichostrongylid helminth cocktail and group B ewes were unparasitised controls. Animals in group A developed gastrointestinal trichostrongylosis confirmed by >500 epg in faecal samples; mean epg of group B ewes were <20 (P < 0.001). Ewes were challenged by deposition of Mannheimia haemolytica into the teat duct. In group A, 7 ewes developed clinical and 5 subclinical mastitis; no ewe in group B developed clinical mastitis, but only subclinical (12 ewes) (P = 0.002). M. haemolytica was isolated from 132/132 and 121/132 udder samples from group A or B, respectively (P < 0.015); increased leucocyte numbers were recorded in 66/66 and 61/66 samples, respectively (P = 0.023). During post-mortem examination, mean number of helminths in gastrointestinal content was 2523 and 7.5 in group A or B, respectively (P < 0.001); within group A, proportions of Teladorsagia and Haemonchus were significantly greater in ewes that developed clinical mastitis than in others which did not (0.709 and 0.162 versus 0.662 and 0.136, respectively; P < 0.035). M. haemolytica was isolated from 36/36 and 19/36 udder tissue samples from group A or B, respectively (P < 0.001). In ewes with subclinical mastitis (in group A or B), inducible-lymphoid-follicles were observed in the teat, which were not observed in ewes with clinical disease. Total pathology scores summed over all days were 127 and 73 for group A or B ewes, respectively (maximum possible 192; P < 0.05). In general, there was positive correlation between intestinal helminth counts and pathology score (P < 0.001) and between Teladorsagia counts and pathology score (P = 0.002) in ewes that developed clinical mastitis. It is concluded that, in view of bacterial challenge, gastrointestinal trichostrongylosis and particularly Teladorsagia infection, might lead to clinical mastitis, through various pathogenetic pathways. © 2017 Elsevier B.V

Clinical, ultrasonographic, bacteriological, cytological and histological findings during uterine involution in ewes with pregnancy toxaemia and subsequent reproductive efficiency

Objectives were to evaluate characteristics of uterine involution in ewes with pregnancy toxaemia during gestation and to study effects on subsequent reproductive performance. Pregnancy toxaemia was induced in ewes (A) by feeding an energy-deficient diet as confirmed by detecting β-hydroxybutyrate concentrations in blood indicative of this disorder. There was also a control group (C). Animals were evaluated until the 60th day post-partum using clinical and ultrasonographic examinations. Vaginal swab samples and uterine biopsy tissue samples were collected for bacteriological and cytological examination; biopsy samples were prepared for histological examination. Ewes were subsequently placed with rams and reproductive performance was ascertained. Post-partum, during the ultrasonographic examination of the uterus, ewes of Group A had caruncle and uterine lumen diameters, as well as a uterine thickness greater than ewes of Group C. Post-partum uterine blood flow volume was greater in ewes of the A than C group. Neutrophils predominated in vaginal samples, with the neutrophil proportion being less in ewes of Group A than C. There were no differences in the uterine involution process between groups. During the subsequent reproductive season, all the ewes of Group A lambed normally and produced viable lambs. It is concluded that there were no adverse effects on subsequent reproductive performance of ewes previously affected with pregnancy toxaemia, when appropriate health management was performed. © 2020 Elsevier B.V

Extensive countrywide field investigation of subclinical mastitis in sheep in Greece

The objectives of this work were (1) to investigate prevalence of subclinical mastitis, (2) to identify etiological agents involved, and (3) to study factors potentially predisposing ewes to subclinical mastitis. Milk samples were collected from 2,198 ewes in 111 farms with a total population of 35,925 ewes, in all 13 administrative regions of Greece, for bacteriological and cytological examination. Prevalence of subclinical mastitis was 0.260. Main etiological agents were staphylococci (Staphylococcus aureus and coagulase-negative species), which accounted for 0.699 of all isolates recovered; prevalence of staphylococcal mastitis was 0.191. In a multivariable mixed-effects analysis, the primary factor found to be associated with increased prevalence of subclinical mastitis was the management system practiced in flocks (flocks under a semi-intensive system had the highest prevalence). Other factors that were included in the multivariable model were the stage of lactation period (ewes in the 2nd month postpartum showed the highest prevalence) and application of postmilking teat dipping. In contrast, measures taken at the end of a lactation period (e.g., intramammary administration of antimicrobial agents) were not found to have an effect on prevalence of subclinical mastitis. The results confirmed the significance of subclinical mastitis as a frequent problem of ewes, with staphylococci as the primary etiological agent. The findings confirm the multifactorial nature of subclinical mastitis and indicate that its control should rely on many approaches. © 2018 American Dairy Science Associatio

Clinical, ultrasonographic, bacteriological, cytological and histopathological findings of uterine involution in ewes with uterine infection

The objectives of the study were (a) to study the characteristics of uterine involution in ewes that had developed subclinical uterine infection in the immediately post-partum period and (b) to evaluate effects of the infection in the subsequent reproductive performance of ewes. Uterine infection was induced in ewes (I, n = 10) by intrauterine inoculation of Escherichia coli; uninoculated controls were included (C, n = 12). Animals were examined at regular intervals before and post-inoculation. Clinical and ultrasonographic examinations were performed. Vaginal swab samples and biopsy uterine tissue samples were collected for bacteriological, cytological and histological examination. Finally, ewes were put to rams and reproductive performance was monitored. After challenge, it was ultrasonographically found that caruncular dimensions, myometrial thickness and diameter of uterine lumen were greater in I ewes. In these ewes, particular reduction of dimensions occurred during the second week post-partum, whilst in C ewes during the first week. The uterine artery diameter and the blood flow into the uterus were also greater in I than in C ewes. E. coli infection was more frequent and of longer duration in I than in C ewes: in 68.1% and 50.0% of ewes and 19.5 and 14 days, respectively. There was lower proportion of neutrophils and higher of lymphocytes in group I than in C. In inoculated ewes, there was histological evidence of uterine epithelial destruction, increased cellular infiltration, hyperaemia and extracasation, which persisted up to 42 days post-partum. During the subsequent reproductive season, all ewes in group I lambed normally and produced healthy and viable lambs. No significant difference in reproductive performance parameters were seen in I comparison to C ewes. It is concluded that the innate immunity of the uterus sufficed to counteract the bacterial infection, although the process of involution took longer than in healthy animals; moreover, the ultrasonographic examination is a useful means for assessment of the genital tract of ewes post-partum; finally, no adverse effects were noted in the subsequent reproductive performance of ewes. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Association of staphylococcal populations on teatcups of milking parlours with vaccination against staphylococcal mastitis in sheep and goat farms

There is a paucity of information regarding staphylococcal populations on teatcups of milking parlours in sheep and goat farms. The objectives were to describe the populations of staphylococci on teatcups in milking parlours in sheep or goat farms in two field investigations throughout Greece and to potentially associate the findings with the use of anti-staphylococcal mastitis vaccinations in the farms visited during the two investigations. In a cross-sectional (255 sheep and 66 goat farms across Greece) and a longitudinal (12 sheep farms, four samplings, throughout lactation) study, swab samples were collected from 1418 teatcups (upper and lower part) for staphylococcal recovery, identification and assessment of biofilm-formation. A total of 328 contaminated teatcups (23.1%) were found in 105 sheep (41.2%) and 35 goat (53.0%) farms. Staphylococci were more frequently recovered from the upper than the lower part of teatcups: 269 versus 139 teatcups, respectively. After identification, 253 staphylococcal isolates were found: Staphylococcus aureus, Staphylococcus equorum, Staphylococcus lentus, and Staphylococcus capitis predominated. Of these isolates, 87.4% were biofilm-forming. The proportion of contaminated teatcups was smaller in farms where vaccination against anti-staphylococcal mastitis in general or vaccination specifically against mastitis caused specifically by biofilm-forming staphylococcal strains was applied, 19.7% or 10.9%, respectively, versus 25.5% in farms without vaccination. In the longitudinal study, contaminated teatcups were identified in 28 (58.3%) sampling occasions, with staphylococci being recovered more frequently from their upper part. The same species as in the cross-sectional study predominated. Of these isolates, 61.9% were biofilm-forming. In farms where vaccination against mastitis caused specifically by biofilm-forming staphylococcal strains was applied, the proportion of contaminated teatcups was smaller: 20.4% versus 48.3% in farms without vaccination. There were no differences in proportions of contaminated teatcups between sampling occasions. In conclusion, the great majority of staphylococci recovered from teatcups of milking parlours in sheep and goat farms included biofilm-forming isolates. Reduced staphylococcal isolation was noted in farms where anti-staphylococcal vaccination was performed; this was possibly the effect of reduced excretion of staphylococci in the milk of vaccinated animals. © 2021 by the authors

Extensive countrywide field investigation of somatic cell counts and total bacterial counts in bulk tank raw milk in goat herds in Greece

Dairy goat farming is an important sector of the agricultural industry in Greece, with an annual total milk production exceeding 450 000 l and accounting for over 25% of all goat milk produced in the European Union; this milk is used mainly for cheese production. Despite the importance of goat milk for the agricultural sector in Greece, no systematic countrywide investigations in the bulk-tank milk of goats in Greece have been reported. Objectives were to investigate somatic cell counts (SCC) and total bacterial counts (TBC) in raw bulk-tank milk of goat herds in Greece, study factors influencing SCC and TBC therein and evaluate their possible associations with milk content. Throughout Greece, 119 dairy goat herds were visited for milk sampling for somatic cell counting, microbiological examination and composition measurement. Geometric mean SCC and TBC were 0.838 × 106 cells ml-1 and 581 × 103 cfu ml-1, respectively. Multivariable analyses revealed annual frequency of check-ups of milking system and total milk quantity per goat (among 53 variables) to be significant for increased SCC; no factor emerged (among 58 variables) to be significant for increased TBC. Negative correlation of SCC with total protein was found; mean total protein content in the bulk-tank milk in herds with SCC >0.75 × 106 cells ml-1 was 5.1% lower and in herds with SCC >1.5 × 106 cells ml-1, it was 7.8% lower. Copyright © The Author(s), 2021. Published by Cambridge University Press on behalf of Hannah Dairy Research Foundation

Extensive countrywide field investigation of somatic cell counts and total bacterial counts in bulk-tank raw milk in sheep flocks in greece

Objectives were to investigate somatic cell counts (SCC) and total bacterial counts (TBC) in the raw bulk-tank milk of sheep flocks in Greece, to study factors potentially influencing increased SCC and TBC in the bulk-tank milk of sheep and to evaluate possible associations of SCC and TBC with milk content. Throughout Greece, 325 dairy sheep flocks were visited for collection of milk sampling for somatic cell counting, microbiological examination and composition measurement. Geometric mean SCC were 0.488 × 106 cells mL−1; geometric mean TBC were 398 × 103 cfu mL−1; 228 staphylococcal isolates were recovered form 206 flocks (63.4%). Multivariable analyses revealed annual incidence risk of clinical mastitis, age of the farmer and month into lactation period (among 53 variables) to be significant for SCC &gt; 1.0 × 106 cells mL−1 and month into lactation period at sampling and availability of mechanical ventilators (among 58 variables) to be significant for TBC &gt; 1500 × 103 cfu mL−1 . Negative correlation of SCC with fat, total protein and lactose and posi-tive correlation of SCC with added water were found. With SCC &gt; 1.0 × 106 cells mL−1, significant reduction of protein content (2%) was observed, whilst in flocks with SCC &gt; 1.5 × 106 cells mL−1, significantly lower annual milk production per ewe (42.9%) was recorded. © 2021 by the authors. Licensee MDPI, Basel, Switzerland