Farm structures ... - Ch9 Crop handling, conditioning and storage: Further reading

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Chapter 10 Animal housing

The main purpose for man to keep livestock is to convert energy in feed into products which can be utilised by human beings, such as milk, eggs, meat, wool, hair, hides and skins, draught power and manure (fertilizer). Traditional, extensive livestock production involving indigenous breeds and low cost feeding will usually have low performance and can therefore only justify minimal, if any, expenditure for housing. However, where improved breeds, management and feeding is available it will usually be economically beneficial to increase the production intensity and to construct buildings and other livestock structures to provide for some environmental control, reduced waste of purchased feed stuffs and better control of diseases and parasites, but this rule is not invariable. It is, for example, difficult to identify an economic benefit in sheep production arising from any but the use of the least expensive buildings. At the other end, a relatively expensive farrowing house, providing a high level of environmental control, may improve the survival rate in piglets sufficiently to both justify the cost and add to the profitability of the production unit.

The planning and design of any structure for a livestock production system involves many alternatives for each of numerous variables and can therefore be turned into a complex and theoretical subject, but is usually far simpler in reality. However, every facet of the design, be it the production system, equipment, building materials, layout or location, will play a part in determining the profitability of the production and any variation in one of them may significantly affect the profitability on the whole. One special difficulty when designing livestock structures for tropical climates is that most research and development has, up to now, been concerned with the conditions in temperate or cold climates. Any recommendations derived from such experiments and applied uncritically in warm climates may result in an adverse environment for the animals and in very high building and operation costs.

Animal behaviour

Introduction

Understanding of domestic animal behaviour and man's relationship with farm animals may greatly contribute to increased economic benefit in animal husbandry and easier handling of the animals. The importance of animal behaviour aspects in the design of animal housing facilities generally increase with the intensity of production and the degree of confinement. Many modern farming systems greatly reduce the freedom for animals to choose an environment in which they feel comfortable. Instead they are forced to resort to an environment created by man.Animals that as far as possible can exercise their natural species-specific movements and behaviour patterns are less likely to be stressed or injured and will therefore produce better. In practical design of an animal production system and any buildings involved, many other factors such as feeding, management, thermal environment, construction and economics can be equally or more important, however.The animals can to some extent adapt their behaviour to suit a bad design and on a long term basis they can be changed by breeding and selection, but generally it will be much easier to fit the husbandry and building design to the animals. The life span of a building is usually 5 to I 5 years and that makes it clear that even a small increase in production or decrease in frequency of injury and disease, in waste of feed or in labour requirements for handling of the animals will repay all the thought and care that has been put into the design, lay-out and construction of the building. Furthermore it may cost as much to construct a building that is poorly designed and equipped for the animals as one that works well.

Behaviour Patterns

Farm animals are born with certain fixed behaviour patterns such as pecking in chickens and nursing in mammals, but most behaviour patterns develop through play and social contact with other animals of their kind and under the influence of environmental stimulation and genetic factors. Behaviour variation within a species is mainly caused by differences in the environment and between the sexes but breed, strain and individual variance also have an influence. Domestic animals show great ability to modify their behaviour patterns in relation to environments and to learn by experience.Animals often form a daily cycle of habits caused by the uniformity of husbandry, for example, the, regular variation in light during night and day relate to internal physiological rhythms. This is why cows Bather around the barn just before milking time. Some behaviour patterns change from season to season, partly as a response to the changing weather. Cows tend to be more active during the night in the hot season and spend less time lying down if outside in the wet season. Many domestic animals show a slight seasonal breeding pattern.Domestic animals under conditions of close captivity, frequently show abnormal behaviour such as stereotyped movements or inappropriate sexual behaviour, particularly if they are unable to escape from or adapt to the situation. However, many disturbed behaviours have more complex causes. For example, tail and ear biting in pigs may be associated with boredom, breakdown of social order, too high stocking rate, too low fibre content in the feed, malnutrition, poor ventilation leading to high humidity and temperature, no bedding, inadequate trough space and watering points, skin disease, parasites, teething problems etc.

Social Rank Order

Domestic animals are highly sociable and naturally form groups. Males and females form separate groups, except during the breeding season, and the young tend to form small groups in the proximity of the female group.When strange adult animals meet for the first time they are likely to fight to establish dominance-subordinance relationships. The resulting pecking order or social rank order in which one or two animals are invariably dominant is usually formed quickly. Physical age and weight are the main factors determining social rank, but sex, height and breed can also be of influence. The group can live in relative harmony as long as each animal knows its place and gives way to animals of higher rank. However, the order is seldom strictly hierarchic or static. Some animals of low rank may dominate others whose positions are normally higher and fast growing and maturing animals may move up the ladder.Introduction of new animals in a group or mixing of groups will normally lead to fighting until a new social order is formed and this may cause a growth check as wellas injury.The normal response to aggressive behaviour in a group with established social order is for the subordinate animal to move away. The building layout must allow space for this and narrow passages and corners where one animal can be trapped by another should be avoided in pens and yards. The order is usually stable provided the group is small so that all animals in it can remember each others position, i.e. fewer than 60 to 80 cows, 12 to 15 pigs or about 100 chickens.

Design of animal housing, its furnishing and equipment, usually employ either of the following methods:

a A choice of environment is provided for the animals and their preference for the different facilities is recorded.
b The behaviour of animals in an experimental environment is studied and the result is compared to the behaviour of animals in a reference system, on a free range, or that of their wild relatives. Often the study is confined to activities like resting, eating, standing/walking, but sometimes the frequency of other behaviour patterns, such as investigative, agnostic, sexual, care-giving, caresoliciting, eliminative, etc. is included.

In addition productivity and frequency of injury and disease is recorded.

Animal Behaviour and Building Design

Below are some examples of how animal behaviour can influence the design of structures. More examples will be given when housing facilities for the various species are described later in this chapter.

Cattle normally live in herds, but when giving birth, the cow attempts to find a quiet, sheltered place away from the disturbance of other cows and humans. The cow needs to be alone with her calf for some time after birth for the cow-calf bond to be established. A cow, confined in a loose housing system, who is approaching calving, should therefore be removed from the herd and put in an individual pen.

Hens spend considerable time in the selection of a nest, which is on the ground. Nesting is characterized by secrecy and careful concealment. Hens in deep litter systems therefore, sometimes lay eggs on the floor instead of in the nestboxes, especially if the litter is quite deep or there are dark corners in the pen.

To avoid this, plenty of fresh litter is provided in the nests, and they are kept in semi-darkness and designed with a rail in front so that birds can inspect the nests prior to entry. An additional measure is to start with the nestboxes on the floor and slowly raise them to the desired level over a period of days.

Sows are nest builders and should be transferred to clean farrowing pens one to two weeks before giving birth, and given some bedding so that they can build a nest. Oestrus, especially in gilts, is increased by the smell, sight and physical presence of a boar. Gilts and sows awaiting mating should therefore be kept in pens adjoining the boar pen.

Cattle prefer to be able to see while drinking, therefore more animals can drink at once from a long, narrow trough than from a low round one. With cattle (and hens) feeding is typically a group activity, therefore space at the feed trough must be provided for all the animals at one time. At pasture, uncle sized feed or water troughs can result in inadequate feeding and watering of the animals which are lowest in rank, because these animals will likely be excluded from the trough, but they will still tend to leave with the rest of the herd after feeding or watering.

To prevent waste of feed a trough should be designed to suit the particular behaviour pattern each species exhibits while feeding i.e. pecking in hens, rooting with a forward and upward thrust in pigs, wrapping their tongue around the feed (grass) and jerking their head forward in cattle.

Artificially reared calves bunt the bucket instead of the cows udder, and this requires a sturdy holder for the bucket. The habit of suckling each other is a problem in dairy calves. The problem can be reduced by making the calves suckle harder and longer for their feed by using a rubber teat rather than a bucket and by giving them access to dry feed. Assuming intersuckling is not a problem, a group pen for calves is more natural than individual pens and helps ensure normal activity and resting.

Sheep are vigilant and tight flocking, and respond to disturbance by fleeing. When designing handling facilities these characteristics should be taken into account. A race should be straight, level, fairly wide, without blind ends, and preferably have close-boarded sides. Sheep which are following should be able to see moving sheep ahead, but advancing sheep should not see the sheep behind as they will tend to stop and turn around. Sheep move best from dark into light areas and dislike reflections abrupt changes in light contrast and light shining through slats, grates or holes. Handling facilities should be examined from the height of the sheep's eye level rather than the human to detect flaws in the design.

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