Herd Groups Research Articles

Combining Salmonella Dublin genome information and contact-tracing to substantiate a new approach for improved detection of infectious transmission routes in cattle populations

This study presents a new method for detection of between-herd livestock movements to facilitate disease tracing and more accurately describe network behaviour of relevance for spread of infectious diseases, including within-livestock business risk-carrying contacts that are not necessarily recorded anywhere. The study introduces and substantiates the concept of grouping livestock herds into business-units based on ownership and location in the tracing analysis of animal movement-based contact networks. To test the utility of this approach, whole core genome sequencing of 196 Salmonella Dublin isolates stored from previous surveillance and project activities was combined with information on cattle movements recorded in the Danish Cattle Database between 1997 and 2017. The aim was to investigate alternative explanations for S. Dublin circulation in groups of herds connected by ownership, but without complete records of livestock movements. The EpiContactTrace R-package was used to trace the contact networks between businesses and compare the network characteristics of businesses sharing strains of S. Dublin with different levels of genetic relatedness. The ownership-only definition proved to be an unreliable grouping approach for large businesses, which could have internal distances larger than 250 km and therefore do not represent useful epidemiological units. Therefore, the grouping was refined using spatial analysis. More than 90% of final business units formed were composed of one single cattle property, whereas multi-property businesses could reach up to eight properties in a given year, with up to 15 cattle herds having been part of the same business through the study period. Results showed markedly higher probabilities of introduction of infectious animals between proposed businesses from which the same clone of S. Dublin had been isolated, when compared to businesses with non-related strains, thus substantiating the business-unit as an important epidemiological feature to consider in contact network analysis and tracing of infection routes. However, this approach may overestimate real-life contacts between cattle properties and putatively overestimate the degree of risk-contacts within each business, since it is based solely on information about property ownership and location. This does not consider administrative and individual farmers behaviours that essentially keep two properties separated. Despite this, we conclude that defining epidemiological units based on businesses is a promising approach for future disease tracing tasks.

Strategies for screening young stock for antibodies \u2013 optimising numbers to test, cut-points, & predictive values for bovine viral diarrhoea virus

The antibody seroprevalence of young stock can be a useful indicator of recent or current infection in a herd. We examine the factors that contribute to the assessment of herd exposure to disease, via spot testing for antibody, using bovine viral diarrhoea virus (BVDv) as an example. A statistical distribution of seroprevalences for BVDv in beef herds identified three groups of herds: low, intermediate and high within-herd BVDv antibody seroprevalence. We tested two assumptions –the intermediate seroprevalence group of herds is assumed to be negative for BVDv at the herd level and alternatively if this group is assumed to be positive. We found that: The herd-level sensitivity and specificity are sensitive to the assumption regarding the herds with intermediate seroprevalence. If an appropriate cut-point is chosen, reducing the sample size from ten to five does not produce a large drop in herd-level test performance. Increasing the cut-point may be valuable at the outset of an eradication programme. Increasing the sample size and decreasing the cut-point is advantageous towards the end of an eradication programme, to minimise the risk of positive herds being misclassified. The framework presented here illustrates how seroprevalence screening may be understood and assessed.

A modelling framework based on MDP to coordinate farmers' disease control decisions at a regional scale.

The effectiveness of infectious disease control depends on the ability of health managers to act in a coordinated way. However, with regards to non-notifiable animal diseases, farmers individually decide whether or not to implement control measures, leading to positive and negative externalities for connected farms and possibly impairing disease control at a regional scale. Our objective was to facilitate the identification of optimal incentive schemes at a collective level, adaptive to the epidemiological situation, and minimizing the economic costs due to a disease and its control. We proposed a modelling framework based on Markov Decision Processes (MDP) to identify effective strategies to control PorcineReproductive andRespiratorySyndrome (PRRS), a worldwide endemicinfectiousdisease thatsignificantly impactspig farmproductivity. Using a stochastic discrete-time compartmental model representing PRRS virus spread and control within a group of pig herds, we defined the associated MDP. Using a decision-tree framework, we translated the optimal policy into a limited number of rules providing actions to be performed per 6-month time-step according to the observed system state. We evaluated the effect of varying costs and transition probabilities on optimal policy and epidemiological results. We finally identifiedan adaptive policy that gave the best net financial benefit. The proposed framework is a tool for decision support as it allows decision-makers to identify the optimal policy and to assess its robustness to variations in the values of parameters representing an impact of incentives on farmers' decisions.

Characterizing Interpersonal Influence for Grassland Conservation Behaviours in a Unique Population

ABSTRACTInterpersonal communication can influence the decisions people make about engaging in conservation behaviours. In-depth interviews with Tibetan pastoralists serve as the basis for examining interpersonal communication patterns and sources of interpersonal influence about grassland conservation behaviours. Herding and family groups are key collectives; salient sources of information vary across types of information. Salient individuals are those with credibility and means control: community leaders, elders, veterinarians, and government officials. Explicit information about conservation comes from religious leaders. The findings have significant implications for understanding the function and nature of interpersonal influence in unique population groups regarding conservation actions.

Comparison of milk production and herd characteristics in New Zealand herds milked once or twice a day

To attract and retain quality staff, dairy farming must be competitive with industries offering conventional work hours. Full-lactation once-a-day (OAD) milking can improve staff working conditions. The aim of the present study was to compare the characteristics of OAD herds relative to a peer group of herds milked twice-a-day (TAD). Data were sourced from the Dairy Industry Good Animal Database, pairing OAD and TAD herds within 25 km, 20% herd size, and 14 days of planned start of calving. Aggregated data from these herds were extracted for the dairy production years 2007–2008 through 2015–2016. In 2015–2016, 9% of all herds tested in New Zealand were milked full-lactation OAD. Results are presented from –4 to 4 years, with 0 as the year of switching to OAD. Results indicated that herds adopting full-lactation OAD milking experienced an 11% decrease in total farm milksolid (MS; fat kg + protein kg) production (kg MS/herd) in Year 0 but, by Year 3, the prior level of production was regained. However, OAD herds remained 11% behind their TAD peer group, due to both OAD and TAD herds increasing production at a rate of 2171 kg MS/year in Years 0–4. The annual herd replacement rate was 20% for both groups. Differences also included a higher 6-week calving rate (82% TAD, 87% OAD), and a divergence in herd breed, with an increase in Jersey and a decrease in Holstein–Friesian genetics for the OAD herds from Year –2. Cows in OAD herds were less likely to be removed due to not being pregnant, but more likely to be removed due to low production or udder health. Milking interval × year interactions were significant for milk volume and liveweight breeding values, with OAD herds having lower values at Year 4. The main conclusion is that to retain an equivalent level of profitability, farm expenditure must be permanently reduced on the adoption of OAD by the initial production decrease multiplied by the long-term milk price. Farmers considering OAD should evaluate the trade-off between the ability to decrease costs to offset any decreased production and impacts on labour and/or lifestyle.

Culling in served females and farrowed sows at consecutive parities in Spanish pig herds

BackgroundThe objectives of our study were 1) to characterize culling and retention patterns in parities 0 to 6 in served females and farrowed sows in two herd groups, and 2) to quantify the factors associated with by-parity culling risks for both groups in commercial herds. Lifetime data from first-service to removal included 465,947 service records of 94,691 females served between 2008 and 2013 in 98 Spanish herds. Herds were categorized into two groups based on the upper 25th percentile of the herd means of annualized lifetime pigs weaned per sow: high-performing (> 24.7 pigs) and ordinary herds (≤ 24.7 pigs). Two-level log-binomial regression models were used to examine risk factors and relative risk ratios associated with by-parity culling risks.ResultsMean by-parity culling risks (± SE) for served females and farrowed sows were 5.9 ± 0.03 and 12.4 ± 0.05%, respectively. Increased culling risks were associated with sows that farrowed 8 or fewer pigs born alive (PBA). Also, farrowed sows in high-performing herds in parities 2 to 6 had 1.5–5.6% higher culling risk than equivalent parity sows in ordinary herds (P < 0.05). Furthermore, sows in parities 1 to 6 that farrowed 3 or more stillborn piglets had 2.2–4.8% higher culling risk than for sows that did not farrow any stillborn piglets (P < 0.05). For served sows, culling risk in parity 1 to 6 sows with a weaning-to-first-service interval (WSI) of 7 days or more were 2.2–3.9% higher than equivalent parity sows with WSI 0–6 days (P < 0.05). With regard to relative risk ratios, served sows with WSI 7 days or more were 1.56–1.81 times more likely to be culled than those with WSI 0–6 days.ConclusionProducers should reduce non-productive days by culling sows after weaning, instead of after service or during pregnancy. Also, producers should pay special attention to sows farrowing stillborn piglets or having prolonged WSI, and reconsider culling policy for mid-parity sows when they farrow 8 or fewer PBA.

The narrow gap between norms and cooperative behaviour in a reindeer herding community.

Cooperation evolves on social networks and is shaped, in part, by norms: beliefs and expectations about the behaviour of others or of oneself. Networks of cooperative social partners and associated norms are vital for pastoralists, such as Saami reindeer herders in northern Norway. However, little is known quantitatively about how norms structure pastoralists' social networks or shape cooperation. Saami herders reported their social networks and participated in field experiments, allowing us to gauge the overlap between reported and emergent cooperation. We show that individuals' perceptions of reciprocal cooperation within their social networks exceeded actual reciprocity, although both occurred frequently and were concentrated within herding groups. Herders with more extensive cooperation networks received more rewards in an economic game. Although herders overestimated reciprocal helping, cooperation in this community was still extensive, suggesting that perceived norms potentially allow network structures promoting cooperation to emerge and be maintained.

Growth curves and nutritional requirements for maintenance of asymptotic weight of Nellore cattle

The objective of this study was to evaluate the growth curve of Nellore cattle raised in the Pantanal, Mato Grosso do Sul, in different groups of size (weight), sex, and birth season, as well as to estimate the nutritional requirements for maintenance of the asymptotic weigh. The nonlinear models were adjusted using the Gauss-Newton method, with information on weight and age of animals within each (total, upper, and middle) group. The asymptotic weight was influenced by sex (P<0.05) in all groups. Regarding maturity rates, females in the total herd and upper group were more precocious than males, whereas males and females in the middle group were similar. Animals born in the dry season of the year showed a greater asymptotic weight in the total herd and upper group, and significant difference was not observed only in the middle group. Regarding asymptotic weight for the growth curve of the total herd (318.5 ± 0.92 kg), the upper group (384.4 ± 1.74 kg) requires 15.1% more nutrients for their daily maintenance. The nutritional requirements for daily maintenance in the middle group (294.5 ± 1.00 kg) is 5.7% lower than in the total herd. The animals kept in the same herd (in the Pantanal conditions) showed different growth curves, as a function of the birth season and sex, indicating variations in growth and different energy requirements for their maintenance.

Molecular Identification of Cryptosporidium spp. in Iranian Dogs Using Seminested PCR: A First Report.

Cryptosporidium is a parasitic protozoon with a wide range of vertebrate hosts. Cryptosporidiosis has been reported from numerous countries, including Iran. Molecular identification can be applied to characterize Cryptosporidium, of which there are over 30 species and 50 genotypes. Herein, we report the genetic diversity of Cryptosporidium spp. in Iranian dogs for the first time based on 18S ribosomal RNA gene sequencing. One hundred forty fecal samples of herd dogs were collected from Isfahan, central Iran. The samples were concentrated using sucrose flotation and subjected to Kinyoun staining. DNA extraction of positive samples was performed, and molecular diagnosis was carried out using highly specific seminested PCR for the characterization of Cryptosporidium species. Finally, sequencing and DNA analysis were performed to identify Cryptosporidium species. A total of 2.14% of herd dogs were positive for cryptosporidiosis in both microscopy and molecular methods. In all cases, the causative agent was identified as Cryptosporidium parvum. Dogs associated with positive samples had been in close relationship with livestock. Cryptosporidiosis in the herd dogs in Isfahan could be due to their close contact with animals, particularly cattle and sheep. Given that dogs with cryptosporidiosis lack clinical symptoms, they are a potential source of zoonotic transmission of this disease as they are companion animals for humans. Dogs with cryptosporidiosis are a potential source of the zoonotic transmission of this disease.

Validation of genomic predictions for wellness traits in US Holstein cows

The objective of this study was to evaluate the efficacy of wellness trait genetic predictions in commercial herds of US Holstein cows from herds that do not contribute phenotypic information to the evaluation. Tissue samples for DNA extraction were collected from more than 3,400 randomly selected pregnant Holstein females in 11 herds and 2 age groups (69% nulliparous, 31% primiparous) approximately 30 to 60 d before their expected calving date. Lactation records from cows that calved between September 1, 2015, and December 31, 2015, were included in the analysis. Genomically enhanced predicted transmitting abilities for the wellness traits of retained placenta, metritis, ketosis, displaced abomasum, mastitis, and lameness were estimated by the Zoetis genetic evaluation and converted into standardized transmitting abilities. Mean reliabilities of the animals in the study ranged between 45 and 47% for each of the 6 traits. Animals were ranked by their standardized transmitting abilities within herd and age group then assigned to 1 of 4 groups of percentile-based genetic groups of equal size. Adverse health events, including retained placenta, metritis, ketosis, displaced abomasum, mastitis, and lameness, were collected from on-farm herd management software, and animal phenotype was coded as either healthy (0), diseased (1), or excluded for each of the 6 outcomes of interest. Statistical analysis was performed using a generalized linear mixed model with genetic group, age group, and lactation as fixed effects, whereas herd and animal nested within herd were set as random effects. Results of the analysis indicated that the wellness trait predictions were associated with differences in phenotypic disease incidence between the worst and best genetic groups. The difference between the worst and best genetic groups in recorded disease incidence was 2.9% for retained placenta, 10.8% for metritis, 1.1% for displaced abomasum, 1.7% for ketosis, 7.4% for mastitis, and 3.9% for lameness. Odds ratio estimates between the highest and lowest genetic groups ranged from 1.6 (lameness) to 17.1 (displaced abomasum) for the 6 traits analyzed. These results indicate that wellness trait information of young calves and heifers can be used to effectively predict meaningful differences in future health performance. Improving wellness traits through direct genetic selection presents a compelling opportunity for dairy producers to help reduce disease incidence and improve profitability when coupled with sound management practices.

Breed characteristics associated with LEP gene polymorphisms in Holstein cattle

Genotyping of the leptin gene locus (LEP) (SNP: R25C, Y7F, and A80V) has been performed in the animals from two groups in the Holstein cattle herd. Groups 1 and 2 included the fourth to seventh lactation cows and the heifers, respectively. The objective of the surveys was to study the Holstein cattle polymorphisms of the leptin gene associated with the productive longevity according to the related literature data. It has been ascertained that the LEP gene (SNP: R25C, Y7F, and A80V) polymorphism in the Holstein animals determines the certain breed characteristics that can be used for introduction to marker assisted selection. (Particularly, a low (0.04–0.15) frequency of occurrence of the F allele is typical for the LEP-Y7F SNP; as for SNP LEP-A80V, a low frequency of occurrence (0–0.14) is typical for the homozygous animals with the VV genotype when compared to a rather high frequency of occurrence (0.36–0.45) in the heterozygous animals).

The power of women in dairying communities of eastern and southern Africa

ABSTRACTToday, African pastoralist communities are often viewed as male-dominated or ‘patriarchal’. This is/was, however, not always the case. This paper explores the role of women in non-Bantu-speaking herding groups of eastern Africa, such as the Maasai, Samburu and Nuer, whose socio-economic lifeways are/were largely centred on dairying activities. It touches on the archaeology of milk and briefly compares what is known about women’s roles in eastern Africa with that of women in southern African Khoe communities, who are traditionally associated with herding and dairying in the region. It demonstrates that women are/were respected milk managers in several pastoralist communities, controlling access and consumption, and that among the Nama Khoe of southern Africa they were powerful, well-respected members of a household unit and of the community. This is in contrast with notions of male-dominated pastoralism in eastern Africa and with the behaviours of Bantu-speaking stock keepers and farmers in southern Africa. In conclusion, the paper contemplates the potential time depth of strong women’s roles in dairying societies in Africa.

Smaller Saami Herding Groups Cooperate More in a Public Goods Experiment.

Group living often entails a balance between individual self-interest and benefits to the group as a whole. Situations in which an individual’s vested interests conflict with collective interests are known as social dilemmas (Kollock 1998). More formally, a theoretical game becomes a social dilemma when an equilibrium of dominant strategies leads to worse outcomes for all players compared to a more cooperative but non-equilibrium strategy (Zelmer 2003; Cardenas and Carpenter 2008). For example, arms races, climate change, the Cold War, credit markets, eBay, exploitation of fisheries, irrigation scheduling, overpopulation, pollution, price wars, voting, water supply and welfare states all give rise to social dilemmas (Kollock 1998; Wydick 2008). Researchers have identified various mutually inclusive routes to solving social dilemmas, including interacting with kin and/or cooperative individuals, communication, coordination, exclusion, institutions, leadership, legislation, mobility, monitoring, parcelling out cooperation or access to resources, partner choice, partner control, policing, punishment, repeated reciprocal interactions, rewards, sanctions, and social norms (Trivers 2005; West et al.2007; Levin 2014; Raihani and Bshary 2015). Social dilemmas pervade the pastoralist way of life. Individual herders must balance their interests (e.g., generating income and managing the inherent risks of pastoralism) with the interests of their herding group and the wider community facing similar challenges (Naess et al.2012; Naess and Bardsen 2015). Pastoralists such as Saami reindeer herders in Norway face social dilemmas across a range of scales and have a variety of individual and collective strategies for solving them.

Parasites of sheep herding dogs in central Germany.

This paper reports on endoparasite infections diagnosed in 2012 by standard coproscopical techniques and coproantigen Giardia ELISA in 165 dogs used for sheep herding in 36 farms in central Germany. The overall prevalence of dogs with evidence of endoparasite infections was 27.3% (95% CI 20.6-34.7). The most frequently identified faecal forms were those of ascarids (Toxocara, 6.7%; Toxascaris 3.6%), hookworms (5.5%) and taeniid cestodes (4.2%), followed by those of Trichuris whipworms (3.0%), Capillaria aerophila (1.8%), Angiostrongylus and Crenosoma lungworms (1.2% each) and Cystoisospora canis coccidians (0.6%). Molecular identification demonstrated the seven dogs shedding taeniid eggs positive for Taenia (T.) species tapeworms (five, T. hydatigena; one, T. ovis; one Taenia sp.). Screening of the faeces with the coproantigen ELISA revealed Giardia specific antigen in 5.5% of the samples. The majority of the dogs had evidence of single endoparasite infections (22.4%) while evidence for infection with two or three parasites concurrently was found in six (3.6%) and two (1.2%) of the dogs, respectively. Dogs ≤ 1 year (n = 19) were parasitized more frequently (p < 0.05) with overall gastrointestinal parasites (63.2% vs. 20.5%), ascarids (36.8% vs. 6.8%) and Giardia spp. (21.1% vs. 3.4%) than older dogs (n = 146). Dogs which had been wormed within six months of examination tested less frequently positive for gastrointestinal helminths compared to dogs not wormed (11.1% vs. 25.0%; p = 0.0567). In addition, ear swabs taken from 43 sheep dogs in 2012 were examined, and Otodectes cynotis mites were extracted from one dog. Identification of ectoparasites collected by full body search and combing from 113 sheep dogs in the years 2011 to 2013 revealed infestation of fleas and ticks (each up to five specimens per dog) on 13 and 108 dogs, respectively, with nine dogs carrying both fleas and ticks. Archaeopsylla erinacei, Ctenocephalides (C) canis, C. felis and Pulex irritans fleas were identified from one, three, two and eleven dogs, respectively. Dermacentor reticulatus, Ixodes (I.) hexagonus and I. ricinus ticks were isolated from 16, eight and 95 dogs, respectively.

Investigation of Intestinal Parasites in Guardian and Herding Dogs of Gilanegharb Suburb, Iran

The present study was conducted to investigate the prevalence of canine gastrointestinal helminths in guardian and herding dogs of Gilanegharb suburb during March 2012 to April 2013. A total number of 138 fecal samples were collected. The overall prevalence of gastrointestinal helminths in the studied animals was 44.92%. The mean of prevalence the gastrointestinal helminths was as follows; Toxocara canis (17.39%), the most prevalent helminths in dogs, Ancylostoma caninum (7.97%), Taenia spp. (10.14%) and mixture of these infections (9.42%). Our findings also indicated that young dogs, under 1 year of age, show a higher overall prevalence than that of older dogs, over 12 months of age (P

Echinococcus canadensis transmission in the North

The Echinococcus granulosus complex (EG) is the causative agent of cystic echinococcosis (CE). Northern cervid Echinococcus was previously suggested to be the ancestor of the entire EG. During the last century, it was regarded to have three (or four) different, but often overlapping, transmission cycles in the circumpolar North: the original wolf–wild cervid (reindeer or elk)-cycle; the semi-synanthropic cycle involving sled and hunting dogs and wild cervids; and the synanthropic cycle involving herding dogs and semi-domesticated reindeer. Human infections mainly derived from the latter two cycles. In Fennoscandia, the synanthropic cycle has been eliminated during the last 50 years due to changes in reindeer husbandry methods; machinery making herding dogs largely redundant. Typical to human CE in the North has been the relatively benign nature of the disease compared with CE caused by E. granulosus sensu stricto. The metacestodes in humans and in the natural cervid hosts predominantly appear in the lungs. The causative agents have been identified as EG mitochondrial genotypes G8 and G10, now together with G6 (camel), G7 (pig) and G9 genotypes constituting the Echinococcus canadensis species. Based on recent findings in reindeer in Yakutia, G6 might also be recognised among cervid genotypes. The geographical distribution of both G8 and G10 is circumpolar, with G10 currently apparently more prevalent both in the Palearctic and Nearctic. Because of the disappearance of the working dog, E. canadensis in Fennoscandia is again highly dependent on the wolf, as it was before domestication of the dog. Pet and sled dogs, if their number further increases, may to a minor part participate in the life cycle. Human CE in the North was mostly diagnosed by mass chest tuberculosis radiography campaigns, which have been discontinued.

Number of pigs born alive in parity 1 sows associated with lifetime performance and removal hazard in high- or low-performing herds in Japan

Reproductive performance, lifetime performance and removal hazard were studied in commercial herds in order to detect prolific sows at an early-stage. Reproductive performance measurements that we assessed were number of pigs born alive (PBA) per litter, weaning-to-first-mating interval and farrowing rate (FR). Lifetime performance measurements included lifetime average PBA and lifetime average nonproductive days. In total, 213,514 parity records and 47,024 lifetime records of 96 herds were included. Sows were categorized into three groups based on the lower and upper 25th percentiles of PBA in parity 1:8 pigs or fewer, 9–12 pigs and 13 pigs or more. The herds were classified into high- and low-performing herds on the basis of the 50th percentile of pigs weaned per mated female per year. To compare the measurements between the sow groups taking account for the herd productivity groups, multivariate and single response models were applied to reproductive performance from first-farrowing and lifetime performance, respectively. A hazard model was fitted to survival data. Sows having 13 or more PBA in parity 1 had 1.0–1.4 more PBA per litter in all subsequent parities (P<0.05), 1.2–1.5% higher FR in parities 2–4 (P<0.05) and 3.4–3.7 higher lifetime average PBA than sows having 8 or lower PBA (P<0.01). However, there were no differences between the sow groups for weaning-to-first-mating interval in any parity (P>0.05). There were two-way interactions between the sow and herd groups for FR in parity 2 (P=0.01) and lifetime average nonproductive days (P=0.046). In low-performing herds, sows having 13 or more PBA in parity 1 had 3.9% higher FR at their next farrowings than sows having 8 or fewer PBA (P<0.05), although no such difference was found for high-performing herds (P>0.05). Sows in the low-performing herds with 13 or more PBA in parity 1 also had 2.3 fewer lifetime average nonproductive days than sows having 8 or fewer PBA (P=0.01), although again no similar difference was found for high-performing herds (P=0.96). The removal hazards for sows having 13 or more PBA in parity 1 were lower than those for sows having 8 or fewer PBA (P<0.01), with no difference in hazards between the herd groups (P=0.62). In conclusion, PBA in parity 1 may help predict a prolific sow or low PBA sow.

Dominance rank is associated with body condition in outdoor-living domestic horses (Equus caballus)

The aim of our study was to explore the association between dominance rank and body condition in outdoor group-living domestic horses, Equus caballus.Social interactions were recorded using a video camera during a feeding test, applied to 203 horses in 42 herds. Dominance rank was assigned to 194 individuals. The outcome variable body condition score (BCS) was recorded using a 9-point scale. The variables age and height were recorded and considered as potential confounders or effect modifiers. Results were analysed using multivariable linear and logistic regression techniques, controlling for herd group as a random effect.More dominant (p=0.001) individuals generally had a higher body condition score (p=0.001) and this association was entirely independent of age and height. In addition, a greater proportion of dominant individuals fell into the obese category (BCS≥7/9, p=0.005).There were more displacement encounters and a greater level of interactivity in herds that had less variation in age and height, lending strength to the hypothesis that phenotypic variation may aid cohesion in group-living species. In addition there was a strong quadratic relationship between age and dominance rank (p<0.001), where middle-aged individuals were most likely to be dominant. These results are the first to link behavioural predictors to body condition and obesity status in horses and should prompt the future consideration of behavioural and social factors when evaluating clinical disease risk in group-living animals.

Parasites and parasite management practices of organic and conventional dairy herds in Minnesota

The objective of this study was to describe the prevalence and practices used to manage internal helminth parasites and external arthropod parasites on organic and conventional dairy herds in Minnesota. All organic (ORG) dairy herds in Minnesota (n=114) and a convenience sample of conventional herds were invited to participate in the study. Thirty-five ORG herds and 28 conventional herds were visited once in summer and fall of 2012. Conventional dairy herds were split into small conventional (SC,<200 cows) and medium-sized conventional herds (MC, ≥200 cows) so that SC herds were comparable in size to the ORG herds. Dairy managers were surveyed to assess their farm management practices and perceptions about parasites, hygiene scores were recorded for adult stock, and fecal samples were collected from a nominal 20 breeding-age heifers to characterize abundance of internal parasites. Nonparametric tests were used to compare fecal egg counts per gram (FEC) among farms grouped by management systems and practices. Organic farms had more designated pasture and were more likely to use rotational grazing compared with conventional farms, but the stocking densities of animals on pasture were similar among farm types. The overall FEC were very low, and only a few individual ORG heifers had FEC >500 eggs/gram. Samples from heifers on ORG farms had significantly more strongyle-type eggs than those on SC and MC farms (ORG: 6.6±2.1; SC: 0.5±0.3; MC: 0.8±0.7), but egg counts of other types of gastrointestinal parasites did not differ significantly among the 3 herd groups. Fly control measures were applied mainly to milking cows and preweaned calves and were used on 88.6% of ORG herds, 60.0% of SC herds, and 91.7% of MC herds. Approximately half of the producers reported having seen skin conditions suggestive of lice or tail mange in their cattle during the previous winter (ORG: 48.6%, SC: 57.1%, MC: 53.9%). Although most conventional producers reported treating these skin conditions, most organic producers stated they had not treated them. In conclusion, gastrointestinal parasite egg counts were low overall at the time of the survey, and most surveyed producers did not perceive gastrointestinal parasites to be a problem for their animals’ health. Independent of the herd type, fly control was mostly targeted at the lactating herd and preweaned calves.

Saami reindeer herders cooperate with social group members and genetic kin

Cooperative behaviors evolve by ultimately increasing the inclusive fitness of performers as well as recipients of those behaviors. Such increases can occur via direct or indirect fitness benefits, theoretically explained by reciprocal altruism and kin selection, respectively. However, humans are known for cooperating with individuals who are not necessarily genetic relatives, which seemingly precludes kin selection as an explanation. Here, we aim to quantify the relative importance of kinship and social group membership as mediators of cooperative behavior. Using an experimental gift game, we test whether indigenous Saami reindeer herders in Norway give gifts to genetic relatives or to members of their cooperative herding group (the “siida”) or both. Membership of the same siida strongly increased the odds of gift giving. Kinship had a smaller, albeit positive, effect. Gifts were not preferentially given to younger family members, contrary to predictions relating to intergenerational resource transfers as a form of parental investment. These patterns suggest that social grouping can be at least as important as genetic factors in mediating cooperative behavior in this population. This is likely to reflect the importance of herding groups in day-to-day subsistence.