Assessment of comfort and well-being in farm animals

The assessment of comfort and well-being in farm animals is discussed in terms of physical damage, physiological responses and behavior. Injuries may be due to the physical environment or contact, such as aggression, with other animals. Animals may reduce the frequency of injuries by modifying their behavior. Evaluation of injuries requires a methodical assessment of specific areas of the body and examination of the facilities and behavior of the animal to determine cause. The physiological response of an animal is dependent upon its psychological response. The adrenal medullary and cortical responses represent distinct strategies that may occur simultaneously or independently of each other. Stress frequently results in suppression of immune responses, although some aspects of the immune system are enhanced. Inadequate or excessive motivation results in behavioral problems and facilities must accommodate the behavior of the animals. Methods of preference-testing have been improved to evaluate factors in the environment and assess motivation for specific behaviors more reliably. All of the methods used to assess comfort and well-being must consider the animal's ability to adapt to different environments. Although it remains difficult to assess comfort and well-being across systems, improvement within a system can be demonstrated.     

Noroviruses and sapoviruses in man and farm animals

Noro- and Sapoviruses belong to the virus family Caliciviridae and are important causative agents of acute epidemic gastroenteritis in man. In many cases transmission of Noro- and Sapoviruses occurs via contaminated food or water and the respective diseases are therefore designated as food borne. Recently, the presence of Noro- and Sapoviruses in farm animals has attracted increasing attention. Clinical symptoms were observed after experimental infection of cattle and swine with members of the two virus groups. Thus far it is not known, whether virus transmission from animals to man does occur.     

Learning and the training of farm animals

The focus of learning studies shifted considerably about 30 years ago. Research moved away from using farm species as experimental animals (that is, as a tool) in which to study learning theory, to a genuine interest in the learning abilities and training processes of individual species. Growing use is being made of operant conditioning and other learning techniques to assess how animals learn from experience and their ability to control their environment to improve their well-being. The processes involved in extinguishing undesirable behaviors and establishing behaviors more compatible with farming operations, the use of handling during early sensitive periods, and the careful habituation of animals to intensive farming conditions and modern automated systems complement the on-going genetic selection of farm animals more suited to modern farms. Learning is an important way for animals to cope with and adapt to changing environments and, as such, is fundamental to their general well-being. Learning in farm animals is of vital concern to veterinarians, agricultural engineers, and those involved with animal husbandry and welfare.     

Epigenetics and transgenerational inheritance in domesticated farm animals

Epigenetics provides a molecular mechanism of inheritance that is not solely dependent on DNA sequence and that can account for non-Mendelian inheritance patterns. Epigenetic changes underlie many normal developmental processes, and can lead to disease development as wel. While epigenetic effects have been studied in wel-characterized rodent models, less research has been done using agricultural y important domestic animal species. This review wil present the results of current epigenetic research using farm animal models(cattle, pigs, sheep and chickens). Much of the work has focused on the epigenetic effects that environmental exposures to toxicants, nutrients and infectious agents has on either the exposed animals themselves or on their direct offspring. Only one porcine study examined epigenetic transgenerational effects; namely the effect diet micronutrients fed to male pigs has on liver DNA methylation and muscle mass in grand-offspring(F2 generation). Healthy viable offspring are very important in the farm and husbandry industry and epigenetic differences can be associated with production traits. Therefore further epigenetic research into domestic animal health and how exposure to toxicants or nutritional changes affects future generations is imperative.     

Epigenetics and transgenerational inheritance in domesticated farm animals

Epigenetics provides a molecular mechanism of inheritance that is not solely dependent on DNA sequence and that can account for non-Mendelian inheritance patterns. Epigenetic changes underlie many normal developmental processes, and can lead to disease development as well. While epigenetic effects have been studied in well-characterized rodent models, less research has been done using agriculturally important domestic animal species. This review will present the results of current epigenetic research using farm animal models (cattle, pigs, sheep and chickens). Much of the work has focused on the epigenetic effects that environmental exposures to toxicants, nutrients and infectious agents has on either the exposed animals themselves or on their direct offspring. Only one porcine study examined epigenetic transgenerational effects; namely the effect diet micronutrients fed to male pigs has on liver DNA methylation and muscle mass in grand-offspring (F2 generation). Healthy viable offspring are very important in the farm and husbandry industry and epigenetic differences can be associated with production traits. Therefore further epigenetic research into domestic animal health and how exposure to toxicants or nutritional changes affects future generations is imperative.     

Leptin as an indicator for carcass composition in farm animals

The function of leptin in livestock species has been intensively studied during recent years. Due to the associations between plasma leptin concentrations and body fat, leptin could be used as an indicator for the in vivo evaluation of carcass composition in breeding programs. This review specifically discusses leptin mRNA expression in several fat tissues, the relationship between plasma leptin and body fat and the influence of fasting on this association. It also refers to the limitations of the use of plasma leptin concentrations as a predictor for selection purposes in breeding animals. Furthermore, single nucleotide polymorphisms in the leptin gene have some effects on carcass traits and the leptin gene is considered to be a candidate gene for a marker‐assisted selection. However, these results are very inconsistent across various populations and need to be confirmed in future studies before leptin can be used efficiently in breeding programs and management.     

Progress on gene transfer in farm animals

Transgenic pigs and sheep have been produced by the microinjection of single-cell zygotes and two-cell ova with linear molecules of mouse metallothionein I (MT) promoter/regulator fused to either the human growth hormone (hGH) or bovine growth hormone (bGH) structural genes. The foreign genes integrated into the chromosomes of 3 of 111 lambs or fetuses and 31 of 341 pigs or fetuses examined. Immunoreactive hGH or bGH was present in the plasma of two transgenic lambs and 19 transgenic pigs. The hGH concentration in plasma varied greatly among pigs and was unrelated to the number of gene copies that had integrated. Rate of growth was not enhanced in any of the transgenic pigs in comparison to their littermate controls. However, bGH and hGH exerted definite biological effects in transgenic pigs as evidenced by significantly depressed backfat measurements, elevated levels of insulin-like growth factor (IGF-I), stimulation of mammary development (by hGH) and reduction in porcine growth hormone (pGH) to nondetectable levels in plasma. Five of six founder transgenic pigs transmitted the MT-hGH gene construct to one or more progeny. Three progeny of a boar that expressed hGH also expressed the foreign gene.     

Specific immunity in farm animals to heartwater

The duration of immunity to heartwater normally varies from 6 months to 4 years. In Angora goats it may be difficult to produce a specific immune response with vaccination. Humoral immunity does not appear to play a role in the development of immunity. It has been suggested that cellular immunity may play a role, but the actual mechanism involved remains obscure. The specific immune response developing in farm animals following infection with Cowdria ruminantium is reviewed.     

The immunology of early pregnancy in farm animals

The mammalian conceptus undergoes development in the face of a functional immune system. This characteristic of viviparity creates opportunities and perils for the conceptus. In the period up to hatching from the zona pellucida, the conceptus appears immunologically inert with low expression of major histocompatibility complex (MHC) genes and little evidence for alterations in the function of maternal immune cells. The conceptus may benefit from cytokines produced by leucocytes resident in the reproductive tract or by other cells of the reproductive tract. One cytokine in particular, colony-stimulating factor 2, can promote preimplantation development and cause changes in conceptus function that increase the likelihood that the conceptus develops to term. It is not clear whether activation of specific types of immune responses in early pregnancy can enhance the likelihood of pregnancy success. Semen deposition causes inflammation in the reproductive tract, but there is little evidence that this process is beneficial to pregnancy unless the uterus was exposed to a prior inflammatory event. Around the time of placentation, the period of immunological inertness of the conceptus is replaced by a period of immune activation caused by the expression of interferon genes in ruminants and pigs and MHC class I genes in invasive trophoblast of the horse. The large-scale changes in the endometrium that occur as a result are likely to play an important role to ensure continued development of the conceptus. In contrast, other immune responses generated as a result of disease in the reproductive tract or other tissues (mastitis) can lead to death of the conceptus. Because of this hazard, as well as the possibility that cell-mediated immune responses against the conceptus could occur, the immune system is regulated by both the mother and conceptus to reduce immune responsiveness during pregnancy.     

Congenital and inherited renal disease of small animals.

Congenital renal diseases are present at birth and may be determined genetically; familial renal disorders occur in related animals with a higher frequency than would be expected by chance, and frequently are inherited. The most common familial disorders in cats and dogs include renal amyloidosis, renal dysplasia, polycystic kidneys, basement membrane disorders, and tubular dysfunction (Fanconi's syndrome). This article alerts the veterinarian to commonly observed congenital and hereditary conditions of the kidneys in small animals.     

A brief overview of transgenic farm animals

Transgenesis offers new possibilities to rapidly modify the genome of living organisms. The application of transgenesis to farm animals faces many problems, more than those observed in the transgenesis of laboratory animals, as there are currently many different techniques available to obtain transgenic animals, which all have problems regarding low efficiency and high costs. When these techniques are applied to farm animals the problems concerning transgenesis are multiplied. Two main techniques, male pronuclear microinjection and sperm mediated gene transfer, utilised in farm animal transgenesis, are briefly presented. The improvement of these techniques and the employment of other biotechnologies such as cloning, could expand the uses of transgenic farm animals for human health.     

Assessment of antibiotic use in farm animals in Rwanda

The irrational use of antibiotics in humans and animals is highly related to the emergence and increase of antibiotic-resistant bacteria worldwide. A cross-sectional survey aimed at evaluating the current level of practices regarding antibiotic use in farm animals in Rwanda was carried out countrywide. Interviews were conducted on 229 farmers rearing different types of animals. The study has revealed that almost all respondent farmers could name at least one antibiotic used in farm animals and peni-streptomycin was named by most of them (95.6%). The use of antibiotics in farm animals was observed in the majority of respondents (97.4%). It was found that 44.4 and 26.5% of respondents reported that they used antibiotics for disease prevention and growth promotion, respectively. The use of non-prescribed antibiotics in animals was also reported by more than the half of respondent farmers (55.6%). The majority of farmers had a moderate level of practices regarding antibiotic use in farm animals (73.5%), very few had a high level (26%) and only one respondent had a low level. The high level of practices in regard to antibiotic use in animals was associated with the location of the farm, the type of reared animals, and the rearing system. The results of this study give an insight into antibiotics usage practices in farm animals in Rwanda. The generated information can guide sensitizations and promotions of the prudent use of antibiotics among farmers in order to limit the increase of antibiotic resistance in the country.     

Protective effect of rhodanates in laboratory and farm animals]

Immunization with soluble or corpuscular antigens produces a rise in thiocyanate content of the blood of guinea-pigs, sheep, calves and fowls. Animal possessing a high thiocyanate concentration (2-3mg/100ml) usually have the highest antibody titres. Formation of humoral antibodies is increased by administration of thiocyanate during immunization, and there is significant correlation between thiocyanate concentration and antibody titre. In the intensive fattening of veal calves, the use of thiocyanate during the first 21 days of fattening has reduced mortality by up to 60%. Morbidity was halved during the 103 days of the fattening period. Illness was not only less common in the thiocyanate-treated group, but it was also milder. It is suggested that addition of thiocyanate to the food may also have a nutrient effect.