The purpose of this study was to examine vitamin A and E in equine nutrition and especially in relation to forages. A literature review was conducted to examine factors that influence the level of vitamins present in forage, the vitamin A and E requirement of horses, and the absorption of vitamin A and E in horses. The influence of DM level on alpha-tocopherol and beta-carotene content in ensiled forage was investigated in a controlled ensiling study using baled silage and haylage. The results from the ensiling study were combined with data of vitamin A and E concentrations collected from literature. Calculations were done to theoretically establish how well the vitamin content in ensiled forage can cover the maintenance requirements of vitamin A and E in horses.

EVA, Equine Viral Arteritis, was diagnosed for the first time in 1953 in USA. The disease gained international interest in 1984, when there were several outbreaks of abortion at Thoroughbred studs in USA. EAV, Equine Arteritis Virus, is an RNA virus in the Arteriviridae family. There is only one serotype of EAV but several strains and the strains have different virulence. EAV is transmitted in two different ways: by aerosols, or by venereal transmission.

Most descriptions of stereotypic behaviours have in common that these repetitive behaviours only has been observed in captive animals and therefore it has been proposed that stereotypies exist because we house animals in environments that are sub-optimal to them. Some scientists claim that performance of stereotypies in itself decreases the animal's welfare due to costs in time, energy and health and a poorer quality of life. Other scientists assert that individuals performing stereotypies may have a better welfare compared to the rest of the animals in the same environment, since these individuals have developed strategies to cope with stress. Studies have estimated the prevalence of abnormal behaviours in horses to 18-30 % of the population. Several studies on cribbing have revealed a prevalence of 4-5 %, although some results indicate that more than 10 % of the horse population performs this stereotypy.

Claw diseases are common diseases in modern dairy production. They are painful for the cow and costly for the producer. Differences in the prevalence of claw disease depending on housing system have previously been observed. This raises the question if there are genotype by environment (GxE) interactions for claw diseases in different housing systems. To investigate this claw trimming records for Swedish Red dairy cattle (SR) and Swedish Holstein cows (SH) were retrieved from the Swedish Dairy Association.

The dog is unique in the way that the adult weight can vary 100 folds between the different breeds. Despite this, most of the breeds reach adult size before two years of age. For the large-breed dogs this means a very rapid growth when some of them can have a weight gain of up to 150 times their birth weight. The most rapid growth occurs when the puppies are between three to six months old and that kind of rapid growth during such a short period of time makes these large-breed puppies very sensitive to deficits and excesses of energy, nutrients and minerals. Some examples can be excess of energy, excess or deficit of minerals such as calcium and phosphorus or deficits of protein. The rapid growth can also make the large-breed puppies predisposed to some diseases affecting the skeletal and joints.

The histiocytic diseases are generally rare in dogs and not much is known about the disease. The disease complex that includes both a reactive form and a tumour form, is however common in certain breeds, among them the Bernese Mountain Dog. As the literature is very limited on the subject of histiocytic diseases, my aim with this thesis has been to gather current knowledge of these diseases. I have also attempted to estimate the frequency of the diseases among the Swedish Bernese Mountain Dogs and investigate if they appear to be more common among certain families..

By limiting our horse?s freedom of movement, we restrict their opportunity to forage, which is one of their most important needs. If their need of forage is not fulfilled it can lead to frustration, which might manifest itself in abnormal behaviour, like the oral stereotypies for example crib-biting. It is a held belief that the horse swallows air while crib-biting, which they don?t, and that swallowed air causes colic, and the belief that other horses can copy the behaviour, leads to the use of many methods to prevent the behaviour.

Cattle used for meat production can be held outside all year round and due to the legislation they should have access to shelters or other buildings for protection against the elements giving them a dry and clean bedding. There are different opinions concerning their need of protection and the question about necessity of shelters for cattle is of current interest due to a less profitable economy in meat production and the investment costs for shelters. The aim of this study was to acquire more knowledge about the natural behaviour of cattle concerning their use of shelters. The basis of the study was a series of questions regarding when animals choose to stay in shelters, if shelters were used less when they had access to protecting vegetation, how temperature and weather conditions affected the use of shelters and the influence of distance between shelter and feed. Behavioural studies was conducted at five different farms where six groups of suckler cows and heifers of following breeds and crossbreeds were observed; Aberdeen Angus, Charolais, Hereford, Scottish Highland Cattle, Simmental and the Swedish breeds SKB and SRB.

Artificial insemination (AI) has had a great influence on the development of pig production and is today widely practiced (Gerrit et al., 2005). With AI, genetic progress can at a short period of time be spread worldwide compared with using natural service and the best boars can be intensively used. This is also one of the biggest risks with AI; the impact of semen containing a genetic disease or contamination of pathogens can be enormous. Fortunately, it is a small risk of disease transmission due to many tests of the boars and the semen before use (Maes et al, 2008). It is important that the boars used for insemination have good breeding values along with good reproduction features and have good fertility results (Robinson et al., 2005).

This study was performed to examine whether horses that are kept alone in smallpaddocks are less likely to suffer injuries, compared to horses kept in biggerenclosures with the company of other horses, or not. In not yet published researchmaterial from 2005, risk factors associated with ?accidental injuries? versus ?wearand tear injuries? (represented by trauma injury and fetlock inflammationrespectively), were compared. That material, based on the results of 507 returnedquestionnaires from owners of horses in a Swedish insurance company, includedquestions about paddock/pasture confinement. The results from those questionswere then analyzed in this study in a so called case-control study, in which thegroups with trauma and fetlock inflammation were compared to a healthy controlgroup.The results show that the risk of fetlock inflammation is greater in a smallconfinement, OR for inflammation in a small paddock is 2,2 (95% KI 1,2-3,9)compared to a bigger paddock.

Artificial insemination (AI) has had a great influence on the development of pig production and is today widely practiced (Gerrit et al., 2005). With AI, genetic progress can at a short period of time be spread worldwide compared with using natural service and the best boars can be intensively used. This is also one of the biggest risks with AI; the impact of semen containing a genetic disease or contamination of pathogens can be enormous. Fortunately, it is a small risk of disease transmission due to many tests of the boars and the semen before use (Maes et al, 2008). It is important that the boars used for insemination have good breeding values along with good reproduction features and have good fertility results (Robinson et al., 2005).

Difficult calvings and stillbirths are problems in Swedish dairy production that result in large expenses for the farmers and welfare issues concerning the animals. A common opinion is that the live weight of SRB and SLB is increasing, and whether increased weights have caused the increase in calving problems has been discussed. The aim of this study was to investigate the relationship between the relative birth weight (calf/cow) and calving difficulty and stillbirth, respectively. The importance of breed and parity for the relative weight has been investigated, and comparisons with previous studies have been made to evaluate whether the relative weight has changed over the last decades or not. The study was based on 807 calvings, registered during the period 1993-2003 in the experimental dairy herd of the Swedish University of Agricultural Sciences (Jälla).

This thesis is focused on what impact stall confinement has on a horse?s mental and physical welfare. It was of great interest to get a gathered picture of how Swedish horseowners had experienced having their horses in stall confinement. A survey study was conducted to achieve this. The survey included twelve questions which for example investigated the horses? age at the time of stall confinement, the length of stall confinement and their sexes.

Canine dilated cardiomyopathy (DCM) is a disease with high morbidity and mortality and with a high prevalence in certain breeds. Predominatly large breeds are affected, such as Great danes, Newfoundlands, Deerhounds and Dobermanns. One exception is Cocker spaniels, where both American and English Cocker spaniels are affected in a quite high frequency. Cardiomyopathy is characterised as a disease that affects the myocardium and gives an impaired heart function. To diagnose DCM following criteria have to be observed: 1. Dilation of the left ventricle. 2. Reduced systolic heart function. 3. Increased sphericity of the left ventricle. To be certain of the diagnosis, alternative reasons for the symptoms such as lung- and heart diseases with other etiologies have to be excluded Two different types of DCM have been found upon histological examination.

The aim of these two studies was to investigate the possible physiological, behavioural and emotional changes that appear after human-horse interactions and also to find an explanation to why they occur. One aspect that is discussed is whether the wellbeing of humans can be coupled to interacting with horses and of how the animals respond to the interaction. The first study was performed on 9 horses and their owners, both parts being subjects to registrations during 4 different interaction treatments. The second study was performed on 6 horses with registrations only being performed on the horses during 2 different treatments. Nine horses underwent 3 different treatments all performed by their owners (H = stroking of the horses forehead, B = brushing and M = stimulation of the withers) in addition to a control round (K). Each treatment lasted for 4 minutes but observations were performed until after 45 minutes from start.