Animal-specific Factors Research Articles

Prevalence of paratuberculosis in Thuringian sheep and goat flocks

In Germany, only few data on the current distribution of paratuberculosis in sheep and goat flocks is available. The present study provides an overview of the distribution of Mycobacterium avium ssp. paratuberculosis (MAP) in 165 Thuringian sheep and goat flocks. Also, the study investigated the association between the MAP status of the flock and herd specific factors as well as the association between the individual measured value of ELISA and animal specific factors like age, body condition, sex, and animal species. To investigate the prevalence of MAP, serum samples from 2550 sheep and 1171 goats from 165 flocks (flock size 2 to 2879 animals) were serologically examined for MAP antibodies in 2021. Additionally, 1 to 6 environmental faecal samples were collected from every flock depending on the flock size. They were examined for the presence of MAP by using both bacteriological cultivation and a commercially available real-time-PCR. MAP antibodies were detected in 41 sheep (1.6%) and 29 goats (2.5%), which accounts to a detection of MAP antibodies in 20.6% of the 165 flocks (on herd level). The symptoms of paratuberculosis, weight loss with preserved appetite and altered fecal consistency, were observed in only four of the flocks. A positive association was identified between the detection of MAP or MAP-specific antibodies in a flock and flock size, as well as positive association between the measured value in the Elisa (s/p ratio) and the age of the animal. Furthermore, an association between an increasing s/p ratio of the ELISA and a decreasing body condition was found. Given what is known about the distribution of paratuberculosis in small ruminants, this disease should always be considered as a possible cause of weight loss and diarrhea. In case of high within-herd prevalence herd-specific control measures should be considered. In serological herd monitoring, animals with poor body condition should preferably be included in the sample, as the probability of being able to identify MAP positive animals is higher here.

Animal-to-Animal Variability in Partial Hippocampal Remapping in Repeated Environments.

Hippocampal place cells form a map of the environment of an animal. Changes in the hippocampal map can be brought about in a number of ways, including changes to the environment, task, internal state of the subject, and the passage of time. These changes in the hippocampal map have been called remapping. In this study, we examine remapping during repeated exposure to the same environment. Different animals can have different remapping responses to the same changes. This variability across animals in remapping behavior is not well understood. In this work, we analyzed electrophysiological recordings from the CA3 region of the hippocampus performed by Alme et al. (2014), in which five male rats were exposed to 11 different environments, including a variety of repetitions of those environments. To compare the hippocampal maps between two experiences, we computed average rate map correlation coefficients. We found changes in the hippocampal maps between different sessions in the same environment. These changes consisted of partial remapping, a form of remapping in which some place cells maintain their place fields, whereas other place cells remap their place fields. Each animal exhibited partial remapping differently. We discovered that the heterogeneity in hippocampal representational changes across animals is structured; individual animals had consistently different levels of partial remapping across a range of independent comparisons. Our findings highlight that partial hippocampal remapping between repeated environments depends on animal-specific factors.SIGNIFICANCE STATEMENT Context identification is a difficult problem. Animals are not provided with objective context identity labels, so they must infer which experiences come from which contexts. Different animals may have different strategies for performing this inference. We find that different animals have stereotypically different extents of partial hippocampal remapping, a neural correlate of subjective assessment of context identity.

Uncovering how animals use combinations of magnetic field properties to navigate: a computational approach.

Certain animal species use the earth's magnetic field (i.e., magnetoreception) in conjunction with other sensory modalities to navigate long distances. It is hypothesized that several animals use combinations of magnetic inclination and intensity as unique signatures for localization, potentially enabling migration without a pre-surveyed map. However, it is unknown how animals use magnetic signatures to generate guidance commands. While animal experiments have been invaluable in advancing this area, it is a difficult phenomenon to study in vivo or in situ. Modeling and simulation present a powerful complementary tool that can be used to investigate whether and how animals use magnetic signatures to navigate. This perspective article summarizes work we have conducted that systematically and mechanistically uses modeling and simulation to study the use of magnetic signatures. We have studied this phenomenon from simulated agents that navigate in simple and abstract environments, to physical devices that navigate in realistic environments. The results have consistently demonstrated that this is a plausible way in which animals might navigate, and provided early insights into the environmental and animal-specific factors that are most important to this navigation strategy.

Regulating appetite in broilers for improving body and muscle development - A review.

Appetite is the desire for feed and water and the voluntary intake of feed and is an important regulator of livestock productivity and animal health. Economic traits such as growth rate and muscle development (meat deposition) in broilers are directly correlated to appetite. Factors that may influence appetite include environmental factors, such as stress and temperature variation, and animal‐specific factors, such as learning period, eating capacity and preferences. Feed preferences have been reported to be determined in early life, and this period is important in broilers due to their fast growth and relatively short growth trajectories. This may be of importance when contemplating the use of more circular and sustainable feeds and the optimization of appetite for these feeds. The objective of this review was to review the biological mechanisms underlying appetite using data from human, animal and bird models and to consider the option for modulating appetite particularly as it relates to broiler chickens.

Reducing the incidence of acute puerperal metritis in primiparous cows by application of pegbovigrastim in a Holstein dairy herd

In dairy cows, immunosuppression occurs frequently during the periparturient period and is characterised by transient neutropenia and impaired polymorphonuclear neutrophil function. As a consequence, postpartum cows are more susceptible to production-related diseases such as mastitis, retained foetal membranes and metritis. Recently, it has been shown that a double injection with recombinant bovine granulocyte colony-stimulating factor covalently bound to polyethylene glycol (PEG rbG-CSF) increased polymorphonuclear neutrophil number and the exocytosis of myeloperoxidase by stimulating polymorphonuclear neutrophil, which also played a role in innate uterine immune defence. The aim of this randomised clinical study was to investigate the effects of two periparturient PEG rbG-CSF injections (IMR; Imrestor<sup>TM</sup>, Elanco Animal Health, Bad Homburg/Germany) on the incidence of acute puerperal metritis, number of antibiotic doses required for treatment of acute puerperal metritis as well as parameters of milking performance (i.e., milk yield, milk fat, milk protein, and somatic cell count on the first dairy herd improvement test day) in primiparous cows within a dairy herd with an elevated incidence of acute puerperal metritis. In total, 169 heavily pregnant heifers were randomly assigned to the treatment group (IMR: n = 82) who received 15 mg PEG rbG-CSF subcutaneously 10 ± 3 days before the anticipated calving date and within 24 hours after calving, or to the untreated control group (Co: n = 87). In total, data from 157 animals (IMR: n = 75, Co: n = 82) were analysed. Administration of PEG rbG-CSF reduced the incidence of acute puerperal metritis in primiparous cows significantly (IMR: 22.7%, Co: 43.9%, P = 0.003; relative reduction: 48.3%). Moreover, the number of antibiotic doses per calving required for treatment of acute puerperal metritis was significantly lower in the pegbovigastrim group (IMR: 0.32 ± 0.66, Co: 0.59 ± 0.75, P = 0.005). No significant differences regarding incidence of clinical mastitis, milk production or milk composition were observed. These results suggest that further research should be performed to identify herd- and animal-specific factors that can be predictors of the beneficial effects of pegbovigrastim in preventing uterine diseases.

Effect of herd health management on the prevalence of Postpartum Dysgalaktie Syndrome (PPDS) and the treatment incidence

The Postpartum Dysgalaktie Syndrome (PPDS) also known as metritis agalactia mastitis (MMA), is considered the most common disease of the sow after farrowing. The reasons for PPDS are multifactorial and are to be found in the areas of management and hygiene, feeding, water supply and animal specific factors such as body condition and age of the sows. In this study a veterinary herd health management was carried out in 28 pig farms with PPDS, with the aim to reduce the PPDS prevalence and animal treatment incidence (TI). In 20 of 28 problem farms the PPDS-prevalence could be decreased from 37.4% (± 21.8%) to 24.5% (± 14.1%). The TI was not significantly reduced. The most effective procedures to reduce the PPDS-prevalence were the use of a prepartal transition feed, optimizing the PPDSdiagnostic and the use of nonsteroidal antiinflammatory drugs (NSAID) and oxytocin in the PPDS-treatment.

Stable-isotope microprofiling of wombat tooth enamel records seasonal changes in vegetation and environmental conditions in eastern Australia

We present the first high-resolution carbon and oxygen isotope profiles of carbonate in modern wombat (genera Vombatus and Lasiorhinus) tooth enamel and demonstrate that the carbon isotope ratios ( δ 13C) clearly preserve seasonal changes in diet and local environmental conditions. Our baseline study of δ 13C in tooth enamel and bone collagen from wombats that inhabited semi-arid, savannah, temperate and alpine environments in eastern Australia documented an offset of 5.2 ± 0.4‰ and 12.9 ± 0.3‰ from the animal's diet, respectively. Marsupial wombats are obligate grazers, whose teeth grow continuously. Sequential micro-analysis of δ 13C and δ 18O along the length of wombat incisors yielded a time-series of isotopic variation. The microprofiles of wombat tooth δ 18O are highly variable between and within sites. Notwithstanding, the δ 18O values were relatively high in wombat teeth from arid and semi-arid sites, and significantly lower in those from southern temperate and coastal regions. In contrast, the δ 13C of wombat tooth enamel correlates well with the local environmental setting and the seasonality of C 3 and C 4 grass growth. In areas with marked seasonal changes in the proportions of winter C 3 and summer C 4 grasses, wombat microprofile δ 13C values varied by up to 8‰. Importantly, at sites with predominantly C 3 or C 4 grasses all year, variations in microprofile δ 13C values are small (< 1.9‰), indicating that the relatively large seasonality in δ 13C we observe in wombat teeth must be primarily controlled by changes in diet, rather than animal-specific factors. This study shows that microprofiling of δ 13C in wombat incisors, in particular, provides a high level of isotopic detail which is not available from time-averaged isotope records from bone collagen, or bulk analysis of isotopes in tooth enamel. Wombat teeth are common in the Quaternary fossil record and, as such, they have the potential to be outstanding archives of palaeoecological information. For example the δ 13C of fossil wombat teeth could be used to define the changing proportions of C 3 and C 4 grasses in wombat diets through the Quaternary, which in turn reflect changes in the seasonality of precipitation, summer temperatures, and possible ecosystem modification by human activities.

An Analysis on Mortality Among Calves in Danish Dairy Herds

This study analysed the mortality among young calves born alive up to 180 days after birth, born in Danish dairy herds in 1998 and 1999. The objective of the study was to estimate the overall mortality and to analyse possible risk factors having an influence on the mortality. The data material comprised 914,000 recorded births of dairy race cows in 9,333 dairy herds including the following animal level information: Dates of birth and possible death, sex, breed, change of herd, size at birth, calving eas (dystocier), calving number of mother and the following herd level information: Herd size, milk production level, indicator of organic farming status, indicator of major change in herd size, and county. The effects of the animal and herd level factors on mortality in four periods after birth was investigated by a random effects model. The response being indicator of the calf dying during the period conditional on being alive at the beginning of the period. The four periods were defined as 1: 1?14 days, 2: 15?28 days, 3: 29?56 days, and 4: 57?180 days after birth. The three main breeds (Danish Holstein, Red Danish, and Jersey) were analysed separately. The observed overall mortality among heifers and bulls from day 1 to 180 after birth was 6.4%, respectively 7.8%. Among the animals not surviving 180 days a percentage of 45 died during the first 14 days. Although there is some variation between breeds, with Jersey having a higher level of mortality. The mortality of heifers is smaller than that of bulls. A small size of the calf at birth combined with a difficult delivery is increasing mortality, as well as the movement of an animal between herds increases its probability of not surviving. The management on the farm is assumed to be confounded by the yield level, as farms with higher yield level has a reduced mortality. There is some variation in mortality between counties, which may be related to differences in production and housing systems, which are not registered yet. As a conclusion, a number of production factors are documented to have an effect on calf mortality as well as some animal specific factors, which can help to focus on specific animals having an increased risk of dying prematurely. Abstracts – Oral presentations at 11th ICPD 225