Research indicates that at least one aspect of temperament in ostriches can be modified by selection. This could help farmers breed ostriches that adapt better to the intensive farming systems found on most commercial ostrich farms. Roelof Bezuidenhout reports.
The behavioural traits of male ostriches don’t seem to be selection criteria for egg production in females. Male temperament, however, can be affected by genetic variation, which may make it possible to change the temperament of ostriches by genetic selection, allowing them to better adapt to farming routines, without hampering egg production. This is according to Dr Helet of the Department of Animal Sciences, Stellenbosch University, who investigated the influence of management, behaviour and physiology on the reproduction efficiency of ostriches under commercial conditions. She cautions that extensive research on the genetic components of ostrich behaviour is still required. Dr Lambrechts investigated whether the shin colour of adult breeding males, and their extent of aggressive display, had any influence on the reproductive performance of their companion breeding females under commercial conditions. The study was conducted at the Little Karoo Agricultural Development Centre outside Oudtshoorn, using males aged between two and 12 years. Each male was evaluated monthly using a subjective scale to assign aggression and shin colour scores (See Measuring aggression). I n other domestic livestock species, such as beef cattle, extensive selection for temperament produced modern genotypes well adapted to general husbandry routines, but Dr Lambrechts points out that this is a new concept in ostrich husbandry. “Up to 1913, the SA ostrich industry focused on feathers,” she says. “Now meat, leather and feathers contribute about 45%, 50% and 5% respectively of income generated per slaughter bird.”
Commercial farming and behaviour
During the last few decades the intensification of commercial ostrich farming, and increased awareness of the animals’ welfare, have led to management programmes that integrate ostriches’ behavioural requirements to ensure an optimal breeding environment. “In commercial ostrich farming, early identification and integration of behavioural patterns may reduce stress, which may adversely affect reproductive performance,” says Dr Lambrechts.
Previous studies on ostrich behaviour focused on ostriches in their natural environments. “Ostriches are gregarious during non-breeding seasons,” she says. “But during breeding seasons, male and female behaviour changes considerably. Territorial behaviour in adult males, usually combined with aggression and vocalisation, increases. Males ram each other with their chests and kick, and perform display dances (cantling) to other males and intruders in or near their territories.” Similar behaviour is exhibited under commercial farming conditions. “Farmers use displays of territorial aggression and changes in shin colour as indications of a male’s readiness to breed,” says Dr Lambrechts. “Both traits were previously shown to be positively related to egg production in females.
Males appear to exhibit reproductive behaviour later than females. Colouration of the beak, thighs and shins only occurs after the onset of breeding, with males’ shins darkening from light pink to crimson red.” Crucially, Dr Lambrechts notes that overt aggression is considered abnormal and may hamper reproductive performance. “Farming ostriches commercially can be financially intensive,” she says. “A 2001 study showed that a 10% rise or fall in the number of day-old chicks hatched per female amounts to a 9,1% rise or fall in the cost of producing a chick. Selection for temperament to decrease overt male aggression may indirectly improve reproduction, decreasing costs.”
Environment and aggression
She studied how permanent environment (PE) and temporary environment (TE) contribute to variations in egg production. The PE represents factors that could contribute to the variation observed between breeding seasons which could be explained by the males’ genetics. The TE represents factors that could contribute to the variation observed within a breeding season, such as changes in management or climate. Females’ monthly egg production performance (EPP) varied
