Flock Health Research Articles

Incubation, hatchery practice and the welfare of layer hens

For modern layers to achieve optimum production performance and welfare state, the entire production process needs to be managed to achieve target bodyweight, body composition and flock uniformity. In addition to genetic improvements, flock health, environment, nutrition and on-farm husbandry practices, incubation and hatchery practices have become a focal point for producing optimum chick quality. Chick quality is a collective term involving chick size and anatomical features, physiology, robustness and liveability over the first week after placement. Chick quality is a key focus for hatcheries as this has been positively correlated with overall flock performance, especially egg production, shell quality, liveability and animal welfare. Recent advances in incubation have focussed on the benefits of all-in–all-out (single-stage) machines. Innovation in incubation systems is completely conducted today by international manufacturers, and is largely driven by the meat chicken industry. Disposal of male layer chicks has increased as a consumer welfare concern, and while investment in research and legislation changes are focussed towards providing or driving new solutions, there are currently no commercial options for industry to deal with this problem before incubation or hatch. Chick transport systems and equipment have also significantly improved in recent years, providing optimum conditions to ensure temperature uniformity and minimal moisture loss during transit before placement, thus optimising chick quality. Together, recent improvements in incubation equipment and hatchery practice can produce commercial layer chicks that are healthy, of high quality, and are then in an optimal physiological state and condition to achieve their genetic potential.

Causes of death in sheep in Rio Grande do Sul, Brazil: analysis of 523 cases (2004-2019)

ABSTRACT: The increase in the commercialization of sheep products requires an equivalent improvement in flock health and rapid disease identification. Data regarding the cause of death in sheep were reviewed from the database of the “Setor de Patologia Veterinária” from the “Universidade Federal do Rio Grande do Sul”, from January 2004 and December 2019. Epidemiological features, such as breed, sex, and age, in addition to the clinical and pathological features, were analyzed. During this period, tissues from 523 sheep were evaluated, in which a conclusive diagnosis was obtained in 457 (87%) of the cases. The majority of sheep were from the metropolitan mesoregion of Porto Alegre. The most common breed was Texel 171/523 (33%). From all the conclusive diagnoses, 158/457 (35%) corresponded to infectious non-parasitic diseases, 117/457 (26%) were caused by toxic etiology, 95/457 (21%) were infectious parasitic diseases, 42/457 (9%) were included in the nutritional and metabolic category, 38/457 (8%) were in the “others” category, and 7/457 (1.5%) were congenital defects. The age of sheep included in this study ranged from 1 day to 7 years. Among cases with conclusive diagnosis, the main cause of death was haemonchosis with 83/457 (18%) of cases, followed by pneumonia 29/457 (6%), Baccharis sp. poisoning 25/457 (5%), and bluetongue 22/457 (5%).

An update on joint ill in sheep.

This focus article has been prepared by Vanessa Swinson of the APHA Small Ruminant Expert Group.

Evaluation of different litter materials on haematogical and serum biochemical indices of intensively managed finisher broiler chickens

Attempts made to improve broiler production had been focused more on feed with little or no consideration on the impact of litter quality which is a major concern in chicken production not only because it affects the flock health and productivity, but also because it may act as potential reservoir and transmission vehicle for pathogens and potential pathogens. Since blood is considered as an important material for the evaluation of health status in animals, there is need therefore, to investigate the impact of different litter materials on the hematological and serum biochemistry of broiler finisher chicken. A56-day feeding trial was conducted to evaulate the effect of different litter materials on the haematological and serum biochemical indices of intensively managed finisher broilers. Four different litter materials were used for the experiment viz wood, shaving, Groundnut hulls; coconut husks and rice hulls. Wood shavings was used as the control owing to the fact that it is the most commonly used litter in this zone. The coconut husks were manually shred to extract the fibres which was used while the other materials were used as sourced. A toal of 120 broiler birds were used for the experiment, they were divided into four treatments (T1= Wood shavings, T2= Groundnut hulls, T3=Coconut husks, and T4=Rice hulls) of 30 birds each and sub divided into 10 birds per replicate. Each replicate was housed in a pen fitted with broding facilities. Feed and water were given ad libilum for eight weeks. At the end of the experiment blood was collected from the birds, three per treatment given a total of 12 birds. They were analyzed for haematological and serum biochemical indices. Haemoglobin values compared favourably (P>0.05) with that of the control. PCVvalues of T2 and T3 compared favourably well with that of control but significant differences existed (P<0.05) between the PCV value of T4 and the other treatments. The lymphocytes and neutrophils were not affected by the bedding materials showing that the litter conditions did not adversely affect the health and welfare of the birds. Serum protein, serum albumin and serum globulin were not affected by treatements (P>0.05) resulting in better protein efficiency ratio recorded in all the treatments. Serum electolytes calcium and phosphorus levels recorded in this study shows no adverse effect on the integrity of the liver in boosting cataion/anaion exchange. The haematological and serum biochemical indices recorded in this study showed no notable health challenges on the birds.

Impact of Flock Health Clubs

Sheep farming is an important part of UK agriculture with significantly more breeding females than either the pig or cattle sectors. Whether grazing alongside arable rotations or utilising the marginal uplands, sheep farms arguably play a key role that is embedded within UK rural society. However, research led by University of Nottingham has identified various challenges and barriers that have affected relationships between UK sheep farmers and the veterinary profession. In response to these findings, Flock Health Clubs were developed as an initiative that aimed for improved and cost-effective sheep farmer–veterinary interaction. We report quantitative and qualitative data that assess the impact of Flock Health Clubs and indeed show tangible improvements in both farmer–veterinary surgeon relationships and measures of flock health and welfare.

Estimates of on-farm antimicrobial usage in broiler chicken production in the United States, 2013-2017.

Antimicrobial use is a key selective force behind the emergence of resistant bacteria. Therefore, optimizing strategies for more efficacious and targeted antimicrobial use is an essential component of efforts to combat antimicrobial resistance. To bolster stewardship programmes in animal agriculture, processes are needed for the systematic collection of on-farm antimicrobial use data. The objective of this study was to develop a system for collecting on-farm antimicrobial use data from the US broiler industry and to have it be representative of the largest commercial broiler producers in the United States that comprise the vast majority of national broiler production. Participation was voluntary. Data were collected for the period 2013 through 2017 and are reported on a calendar year basis. Using statistics from USDA:NASS as a denominator, the data supplied by participating companies accounted for approximately 81.7% of broiler production in the United States in 2013 and increased to approximately 87.2% in 2017. The data that were submitted for 2017 are based on approximately 7,897,339,357 chicks placed, 7,541,449,430 chickens slaughtered and 48,225,124,865 pounds liveweight produced. The use of antimicrobials in the hatchery decreased substantially between 2013 and 2017; the approximate percentage of broiler chicks placed that received hatchery antimicrobials decreased from 93% in 2013 to 17% in 2017. Medically important in-feed antimicrobial use decreased substantially. For example, in-feed tetracycline use decreased approximately 95% between 2013 and 2017. Medically important water-soluble antimicrobial use decreased substantially for most antimicrobials. Between 2013 and 2017, water-soluble penicillin use decreased approximately 21%, water-soluble tetracycline use decreased approximately 47%, and water-soluble lincomycin use decreased approximately 28%. While a reduction in antimicrobial amounts used may be an important indicator of improved stewardship, reducing the need for antimicrobials through improved disease prevention should be considered a more important objective and a better indicator of overall flock health and optimal antimicrobial use.

Deaths of weaned lambs with visceral Listeria ivanovii infections

Listeriosis in humans and ruminants is most frequently associated with Listeria monocytogenes, with Listeria ivanovii only occasionally identified, mostly causing abortion in sheep. Between September 2018 and January 2019, visceral...

Risks and disease aetiologies of compromised performance in commercial broilers kept at lower stocking density and limited antimicrobial use

ABSTRACT The health status of broilers raised at lower stocking density and limited antimicrobial use (but routine anticoccidials) was assessed in order to identify prevalent causes of disease, mortality and reduced performance. “Dead-on-farm”(DOF) broilers from 145 commercial flocks were investigated at two different time points (TP1:7–14 and TP2:28–35 days of age); per sampling, 6–10 DOF broilers were selected for post-mortem investigation and gross pathomorphological changes were assessed from 2717 birds in total. Post-mortem findings were substantiated by bacteriological, virological and parasitological investigations. Furthermore, production data of all flocks were collected and used to perform comprehensive statistical analysis. Overall, colibacillosis was found most important with a significant negative impact on flock health, productivity and profitability through all ages of broiler production. At TP1, primary reasons for mortality comprised yolk sac infections, generally found together with fibrinous polyserositis due to E. coli. Furthermore, femoral lesions, which correlated with increased flock mortality, were associated with detection of E. coli. At TP2, ascites was detected frequently in DOF broilers, correlating with increased production losses in the fourth and fifth weeks of life. No aetiological link between the presence of ascites and the detection of the investigated pathogens was observed, instead a positive correlation was noticed with altitude above sea level of the farm, and with the sex of the birds. Disease conditions could not be linked with the housing system. Presence of infectious bronchitis virus, avian reovirus and fowl adenovirus did not correlate with macroscopic lesions or a specific disease. RESEARCH HIGHLIGHTS In young broilers lesions of visceral organs due to bacterial infections dominated. Colibacillosis impacts broiler health, productivity and profitability independent of the age of birds. Disorders of the locomotor system were frequently observed throughout production. Older broilers frequently showed pathologic changes due to metabolic disorders. Overall, a shift from infectious towards metabolic disease conditions was noticed.

Migratory Sheep Farming Practices in Cauvery Delta Zone in Tamil Nadu

Migratory sheep, due to its movement, poses threat of spreading diseases among small ruminants. Considering this, the study was carried out to identify the focus area of extension intervention among the migratory sheep farmers to disseminate scientifically recommended practices which minimize disease risk and enhance flock health. The study was conducted following ex post fact research design at Venganur village, Cuddalore district, Tamil Nadu. Using a semi-structured interview schedule, data were personally collected from 30 migratory sheep farmers who were selected purposively. The findings were subjected to focussed group interview involving seven farmers. The results envisaged a wider difference among the farmers from 100 per cent non-adoption of balanced ration to 100.00 per cent adoption of deworming. Therefore, extension interventions need to be intensified to educate the farmers on technologies which help in disease prevention and control.

Flock health survey of Irish Texel society breeders and larynx examination in Texel sheep

BackgroundLaryngeal chondritis is a disease of undetermined aetiology, characterised by oedema, ulceration, abscessation and necrosis of the laryngeal mucosa and cartilage. The initial aim of the study was to document flock health issues identified by Irish pedigree Texel breeders using a questionnaire survey. Additionally, given the reports of breed predisposition for laryngeal chondritis in Texels, a further aim was to identify if laryngeal problems were perceived as an issue. Work was then conducted to identify if pre-clinical laryngeal mucosal pathology was identifiable in Texel sheep showing no overt clinical signs of respiratory disease and if associations existed between laryngeal measurements and laryngeal pathology.Thirty one larynges were collected from a Texel flock that previously had laryngeal chondritis diagnosed in fallen stock. Gross visual inspection was performed to identify and grade (0–5) laryngeal pathology. A series of measurements were then performed on larynges that had been formalin fixed. Associations between independent variables (larynx measurements) and the dependent variable (laryngeal pathology score) were examined.ResultsRespiratory disease was the most frequently identified health issue. Farmer-diagnosed ‘throat problems’ were reported by over 80% of respondents.Laryngeal pathology was noted in Texels showing no overt clinical signs of respiratory disease. Associations between laryngeal measurements and laryngeal pathology were identified relating to the angle between the cranial point of the cricoid cartilage and the vocal process of the arytenoid cartilage.ConclusionsMild laryngeal pathology was noted in animals with no overt clinical signs of respiratory disease. Future research should examine whether significant associations between laryngeal measurements and laryngeal pathology identified in the current study can be measured ante mortem, and whether such ante mortem measurements will allow early identification of sheep at risk of developing laryngeal chondritis.

Data Driven Enhancements to the Intestinal Integrity (I2) Index: A Novel Approach to Support Poultry Sustainability

Background: Optimizing the intestinal integrity of poultry flocks through a comprehensive index measure, such as the intestinal integrity (I2) index, could help to promote sustainable production in the poultry industry. The I2 index is a tool for assessing the intestinal health of flocks based on flock level health and performance data, captured by Elanco Animal Health’s global surveillance system, i.e., the Health Tracking System (HTSi). The objectives of this study were to evaluate the relationships between the proposed I2 index and each of the following four performance parameters: average daily gain (ADG), feed conversion ratio (FCR), European production efficiency factor (EPEF), and percent livability; and compare the ability of the proposed I2 index to predict these performance parameters with the current I2 index. Results: The proposed I2 index was found to produce a greater range and increased variation in flock level I2 index scores as compared with the current I2 index. The proposed I2 index was found to predict the four performance measures at least as well as the current I2 index, and the results suggested that the proposed I2 index could be superior at predicting ADG, EPEF, and percent livability. Conclusion: Our results highlight the strength of data-driven approaches in the development and improvement of comprehensive health metrics.

Housing and Management of Turkey Flocks in Canada.

Simple SummaryRelatively little is known about how farmers house and manage turkey flocks. To address this knowledge gap, a cross-sectional survey on housing and management practices of turkey flocks was conducted among farmers in Canada. Data were collected from 53 hen flocks (64%) and 30 tom flocks (36%), giving a total of 83 turkey flocks across the country. Flock age ranged between 7–14 weeks (interquartile range). The majority of turkey flocks were kept in indoor barns with automated ventilation. Bedding was provided to all flocks, and litter management was mostly focused on avoiding wet litter (e.g., adding dry litter or heat to avoid caking litter). Practices related to feed/water management and environmental control were relatively consistent between farms. More variation was observed between farmers in terms of flock health management and biosecurity practices. These results can benchmark current management practices within the Canadian turkey farming sector and present a foundation for future research.An increased understanding of the turkey sector and how farmers manage flocks can help maintain and improve the health and welfare of turkeys. We conducted a cross-sectional survey among turkey farmers in Canada to gain information regarding general farm characteristics, housing aspects (incl. lighting, ventilation), litter management, feed and water management, flock characteristics, and flock health management. The survey was distributed to 500 farmers through the Turkey Farmers of Canada in April–December 2019. A total of 83 final responses (response rate approx. 20%) were used for a descriptive analysis to determine the frequency of housing and management practices (77 commercial flocks, 6 breeder flocks). Hen flocks (n = 53) had a median age of eight weeks (IQR: 7–12 weeks) and tom flocks (n = 30) had a median age of 12 weeks (IQR: 9–14 weeks). Turkey flocks within Canada are typically kept in indoor barn systems on a concrete floor (87.5%), with bedding (e.g., straw, wood shavings) provided (100%). The majority followed a brood and move growing system (68.8%), and a large proportion of farmers indicated that they raised turkeys under the ‘Raised Without Antibiotics/Antibiotic Free’ or the ‘Responsible Use of Antibiotics’ certification (70.5%). Possible room for improvement could be found in terms of litter management and biosecurity practices, however, further research is needed to make clear recommendations.

An investigation of micronutrient supplementation in weaner lambs to improve growth rates in southeast Australia.

A producer survey by questionnaire assessed supplements used in sheep and reasons for use. This was followed by field trials on eight sheep properties in SE NSW to determine the effect of commonly used commercially available supplements on growth rates of Merino and crossbred lambs. On each property, 450 lambs were selected at weaning and randomly allocated to nine groups of 50 sheep (eight treatment and a control group). Supplements were applied as per manufacturer's recommendation every 6-12 weeks. At each application, all sheep were weighed and data on general flock health and management were collected. All but one of the survey respondents (n = 77) had used supplements in their sheep at some stage. The reasons for use were most commonly for general health and production benefits (n = 21; 26.9%) and to prevent or treat specific diseases/deficiencies (n = 7; 9.0%). The average daily weight gains (ADWG) of the lambs over the trial period varied from 0.074 kg to 0.213 kg/head/day. Statistical analysis showed that overall there was not a significant difference (P = 0.587) between ADWG among lambs that received supplements and lambs that did not. Results of this study show that application of supplements were not linked to improved growth rates in clinically normal crossbred and Merino lambs under the trial farm conditions between weaning and 15 months of age. Effects of supplements on health and production in adult sheep and how supplement response can be best measured in sheep flocks (especially in relation to health and welfare) and linked to productivity requires further investigation.

Zoonotic risks of pathogens from sheep and their milk borne transmission.

Sheep were domesticated around 9000 BC in the Middle East, and since then milk from sheep gradually became very popular, not only for drinking but also for making cheeses and other dairy products. Nowadays, these dairy products are also important for people with an allergy to cow milk, and these products are an essential part of the local daily diet in regions of the world that are not suitable for cows and goats. Consumption of raw milk and raw milk products has a zoonotic risk, and with regard to sheep, the main pathogens associated with such dairy products are: Brucella melitensis, Campylobacter spp., Listeria spp., Salmonella spp., Shiga-toxin producing Escherichia coli, Staphylococcus aureus, tick borne encephalitis virus, and Toxoplasma gondii. Especially, young children, elderly people, pregnant women and immunocompromised (YOPI) persons, and those suffering from disease should be aware of the risk of consuming raw milk and raw milk products. This latter risk can be reduced by proper flock health management, prevention of contamination during milking, adequate milk processing, transport, and refrigerated storage. Only processes equaling pasteurization sufficiently reduce zoonotic risks from milk and milk products, but proper cooling is essential and recontamination must be prevented. Therefore, strict hygiene practices throughout the production process and supply chain especially for raw milk and raw dairy products, should be applied. Small scale production systems pose a greater risk compared to industrialized production systems because of a less protocolized and controlled production process. This manuscript describes zoonotic risks of pathogens from sheep and their milk borne transmission. Additionally, routes of contamination, possibilities for multiplication, and prevention measures thereof are described. We summarize some major human outbreaks caused by consumption of sheep milk and products made thereof, and finally discuss their implications.

Histomoniasis outbreaks in commercial turkeys in the southeastern United States: Proximity of broiler breeder farms as a potential risk factor in disease development

Summary Histomoniasis, an infectious disease of turkeys and other gallinaceous birds, has significant impacts on the health and welfare of infected turkey flocks. No preventatives or treatments for the disease are available. In the current study, the proximity of broiler breeder farms as a potential risk factor for histomoniasis in grow-out tom flocks was assessed using 2015 retrospective data provided by a commercial turkey integrator located in North and South Carolina. Company grow-out tom farms were grouped into potential “at risk” categories based on distance from broiler breeder farms. Presence of a broiler breeder flock within 1 mile of a grow-out tom farm placed that tom farm at a higher relative risk (RR) (RR = 3.45; 95% CI = 1.7519–6.8121; P-value = 0.0196) for occurrence of histomoniasis. There was no increased RR of histomoniasis at tom farms in distance categories beyond 1 mile from a broiler breeder flock. These results are consistent with variable transmission of Heterakis eggs harboring Histomonas from broiler breeder houses to susceptible turkey farms based on distance between farms.

Field trials and tribulations: mortality, morbidity and liveweight following multivalent clostridial and Pasteurella vaccination of lambs on six English commercial sheep flocks

Objective: This field trial aimed to assess the effect of a multivalent clostridial and Pasteurella vaccine (Heptavac P Plus, MSD Animal Health, 2015), administered to lambs at two different time points, on lamb mortality (primary outcome), morbidity and growth rates (secondary outcomes) as compared to unvaccinated lambs.
 Background: This veterinary practice-based study was motivated by a knowledge gap identified during flock health planning activities and engagement between veterinarians and commercial sheep producers in a regional knowledge exchange programme in South West England. Common queries to the veterinary practice from sheep producers during summer to autumn 2012 included the value and timing of vaccinations to prevent disease associated with pasteurellosis. Discussions between veterinarians and consultants working in preventive sheep flock health planning stimulated a scientific literature search, which highlighted the lack of published data on field vaccine testing of Pasteurella components under British sheep commercial farming systems, and a lack of strong evidence in order to inform practical questions regarding the optimal timing of vaccinations aimed at preventing lamb mortalities in the pre-, peri- and post-weaning periods.
 Evidentiary value: A field vaccine trial was conducted on six commercial sheep flocks in South West England. From April 2013, across the six farms a total of 900 twin-born lambs (Ovis aries) were systematically randomly allocated into 1. unvaccinated, 2. early- (6 to 8-week-old) or 3. late- (18 to 20-week-old) vaccination groups. The study provides evidence to support recommendations for sheep producers regarding risks for clostridial disease in fully unvaccinated sheep flocks, supports the benefits of preventive ewe vaccination, and indicates that pre-weaning vaccination of lambs may be beneficial for reducing peri- and post-weaning losses on some flocks. The study highlights the challenges of identifying the reasons for mortality in grazing lambs, and provides new evidence to support the need for early intervention and treatment of ocular lesions in young lambs, in order to reduce their negative impact on lamb performance.
 Methods. During the 6-month trial, lambs were assessed for ocular lesions, orf lesions, clinical respiratory disease, lameness, diarrhoea, and ear tag losses. Monthly liveweights (kg) and mortalities were recorded. Lambs were removed from the study when they reached producer-defined finishing objectives, ≥46 kg liveweight or when they died.
 Results: Overall, low levels of mortality and disease outcomes were observed in both control and vaccinated lambs. A mortality rate of 33 deaths per 1000 lambs at-risk, 0.8% lameness (95% CI 0.6–1.1), 1.7% diarrhoea (95% CI 1.4–2.2), 3% ocular disease (including ocular discharge and/or entropion) (95% CI 2.2–3.2), and 2.6% orf lesions (95% CI 2.2–3.1) were recorded over the trial period. A higher proportion of mortalities occurred in unvaccinated or partially vaccinated lambs (n=23; 76.7%), as compared to trial lambs that had received a primary vaccine course (n=7; 13.3%). A small proportion of mortalities (n=3; 10.0%) occurred in lambs whose vaccination status could not be confirmed No clinical signs of respiratory disease were recorded during veterinary or producer assessments of control or vaccinated trial lambs. Mixed-effects models found significant between-farm and time differences in liveweights (p<0.001) but no significant effect of vaccination status on lamb growth rates. A dramatic decrease in lamb growth rates across all farms coincided with the weaning period – this was also the period in the study were the majority of grazing lamb mortalities were identified in flocks that routinely vaccinated their ewes against clostridial disease and pastuerellosis.
 Conclusion: A clear trend was found with fewer mortalities occurring in lambs that received a multivalent clostridial and Pastuerella spp. vaccination course compared to unvaccinated lambs. The reasons behind mortalities in grazing lambs were not diagnosed given the low submission of carcases for veterinary necropsy examination that was attributed to carcase scavenging and decomposition. No significant effects of vaccination were found on lamb growth rates or clinical outcomes. However, a secondary finding was the significant negative effect of ocular conditions (including discharge and entropion) on growth rates of lambs aged 6 weeks and over – supporting the need for early recognition and intervention in order to reduce animal welfare and production impacts.
 Application: We highlight study findings, field experiences and discuss some of the practical challenges and considerations in design and conduct of field vaccine trials used to inform evidence-based veterinary practice. The study will be of interest to veterinary surgeons, sheep producers, flock health and agricultural consultants, pharmaceutical agencies and advisors, researchers and those engaged in applied studies in animal health and welfare, veterinary epidemiology, preventive health management researchers, and participants and advisors in field vaccine trial design and development.
 

Parasitological survey to address major risk factors threatening alpacas in Andean extensive farms (Arequipa, Peru).

Extensive alpaca farming in the Colca Valley (Arequipa, Peru) is the most important resource for farmers who live in this remote area of the country. Grazing is the major available source of food, whereas forage production and supply are limited. Food availability is low during the dry season predisposing animals to parasitic diseases and reproduction failure. In this study, we looked into gaining an overview about flock health management and nutritional and parasitological status of different age groups in medium-large alpaca farms at the beginning of the dry season. A total of 20 herds were included in the survey and 288 fecal samples were collected and analyzed to determine prevalence and oocysts/eggs output level of the most common gastro-intestinal parasites that affect alpacas. Body condition scoring (BCS), was used to determine the nutritional status of sampled animals, belonging to different physiological classes (i.e. crias, tuis, lactating females, non-lactating females, males). Coccidiosis was the parasitic disease with the highest prevalence and output level. It was the most relevant parasitic disease in all classes and especially in young pre-breeding animals. Higher burdens were found in subjects with lower BCS. More specifically, the farms with higher cria mortality rates showed also a tendency to have higher prevalence values of Eimeria macusaniensis. An improved management of nutritional aspects and parasite control, in particular regarding the weaning phase, is expected to enhance the farming reproductive and productive performances of the alpacas in this region.

Shearing during late pregnancy increases size at birth but does not alter placental endocrine responses in sheep

Shearing during the latter half of pregnancy is a common practice to improve flock health and productivity. Previous studies have demonstrated that shearing pregnant ewes at mid or late pregnancy is associated with an increase in lamb birth weight. In the present study, we used singleton Polypay × Dorset pregnant sheep, to investigate the potential roles of placental function and changes in maternal metabolism in underlying this increased birth weight response. Two groups were randomly established and blocked at enrollment by animal BW, body condition score and subcutaneous adipose tissue depth. The groups were shorn (SH; n = 18) or not (C; n = 20) at gestational day (GD) 107 ± 1 (mean ± SEM). Weekly maternal plasma samples were collected between shearing and birth, but only six samples were assayed for progesterone, pregnancy-associated glycoproteins (PAG1), glucose and non-esterified fatty acids (NEFAs). At birth, sex, birth weight, and newborn body mass index (BMI) were recorded. Maternal BW during mid- to late-pregnancy was similar between groups. Shearing resulted in increased lamb birth weight and BMI (P < 0.05) regardless of fetal sex but did not affect the maternal concentration of PAG1 or progesterone from GDs 100 to 142. After shearing (GD100) and up to lambing, shorn females had higher circulating glucose concentrations (P < 0.05), but not NEFA, compared to the control group. Maternal circulating PAG1, progesterone, glucose or NEFA concentration across pregnancy did not differ according to lamb sex. Across pregnancy, birth weight was positively associated with PAG1 (P < 0.001), but not with progesterone concentrations. In conclusion, weight and BMI at birth were higher in both sexes upon shearing in singleton pregnancies. Despite PAG1 being associated with birth weight, late-pregnancy shearing did not alter the placental endocrine response. Whether other placental factors are altered upon shearing and may influence the increase in birth weight and BMI remain to be investigated.

Molecular survey and interaction of common respiratory pathogens in chicken flocks (field perspective).

Aim:The present study was designed for the detection of the most prevalent respiratory infections in chicken flocks and clarifying their interaction and impact on flock health.Materials and Methods:A total of 359 serum samples were collected from 55 backyard chickens and tested using commercial enzyme-linked immunosorbent assay kits to determine the seroprevalence of Newcastle disease virus (NDV), infectious bronchitis virus (IBV), influenza type A, Mycoplasma gallisepticum (MG), and Mycoplasma synoviae (MS). Molecular prevalence of NDV, IBV, low pathogenic avian influenza virus (LPAIV) H9N2, MG, and MS was carried out on swab, and tissue samples collected from 55 backyard flocks and 11 commercial broiler flocks suffered from respiratory infections using polymerase chain reaction (PCR) and reverse transcription-PCR.Results:Seroprevalence of NDV, IBV, Influenza type A virus, MG, and MS in chicken backyard flocks was 56.4%, 50.9%, 12.7%, 14.5%, and 3.6%, respectively. Specific antibodies against one or more respiratory viruses and mycoplasma were detected in 36.4% of backyard flocks, indicating concurrent viral infections. The molecular survey showed that 90.9% of chicken backyard flocks were infected with common respiratory viruses (NDV, IBV, and LPAIV H9N2) while 81.8% of commercial broiler flocks were infected. The molecular prevalence rate of NDV, IBV, and LPAIV H9N2 was 46.97%, 56.1%, and 19.7% in backyard flocks, respectively. Combined viral and bacterial infection represented 40% and 63.6% of the respiratory infections, resulting in enhanced pathogenicity and increased mortalities of up to 87.5% and 27.8% in backyard and commercial flocks, respectively. Mixed infection of IBV, LPAIV H9N2, and/or Escherichia coli is the most prevalent mixed infection in broiler flocks, inducing severe clinical outcomes. Avian pathogenic E. coli was, respectively, isolated from 40% of backyard flocks and 81.82% of broiler flocks. Staphylococcus aureus was isolated from three backyard chicken flocks mixed with other respiratory pathogens with elevated mortality. Mixed infection of E. coli and MG reported in 9.1% of broiler flock. MG was detected in 14.5% of backyard flocks and 9.1% of broiler flocks while MS was detected only in 3.6% of backyard chickens mixed with E. coli, and other viruses.Conclusion:Our results confirm that mixed infections are more commonly prevalent and associated with dramatic exacerbation in clinical outcomes than a single infection. Bidirectional synergistic interaction between these concurrently interacted respiratory pathogens explains the severe clinical impact and high mortality rate. The high prevalence of IBV (either as a single or combined infection) with LPAIV H9N2 and/or E. coli, in spite of intensive use of commercial vaccines, increases the need for revising vaccination programs and the application of standard biosecurity measures. Backyard chickens impose a great risk and threaten commercial flocks due to the high prevalence of viral respiratory pathogens.

Footrot control, farm assurance and antimicrobial stewardship — making use of opportunities to engage sheep farmers

Prompt treatment of individually lame sheep with parenteral and topical antibiotics without foot trimming remains the recommended best practice for footrot control, and is considered appropriate and justified antimicrobial use. Several antibiotic groups are licensed for footrot in sheep; all are effective but it would be prudent to use certain classes as a first-line treatment. Culling sheep with repeated lameness, separating at time of treatment and preserving the flock lameness status through quarantine procedures can also have a significant impact on lameness prevalence. Farm assurance visits and antibiotic use reviews facilitate farmer–veterinary surgeon interactions and provide an opportunity to improve flock productivity and welfare. A flock health assessment should include observation of groups of ewes to estimate lameness prevalence, examination of lame sheep to determine aetiology and a review of records to determine treatment practices.