Diagnosing disease and deficiencies
Diseases and parasites can severely limit production and in severe cases lead to death. Livestock owners need to be aware of diseases that commonly occur in their environment. This also includes an awareness of signs or symptoms of diseases that may be new; including diseases that are exotic to Australia. The following table indicates normal ranges for important cattle functions.
Normal beef cattle functions
|Body temperature (daytime rectal average)||38.6°C|
|Puberty (age at first cycle)||12–24 months|
|Oestrus (duration)||14 hours (10–18 hours)|
|Return to oestrus after calving||41–60 days|
|Length of cycles if not pregnant||21 days (18–24 days)|
|Gestation period (conception to calving)||282 days (272–295 days)|
Diagnosing the causes of ill-health
Animal diseases are complex to diagnose. To the untrained eye, the symptoms of many diseases look similar. Determining what disease is present and what action to take is a job for a professional. Compiling comprehensive information about the affected animals, the whole herd, and the progress of the disease will greatly assist your vet or stock inspector with diagnosis and advising courses of action.
The most important predisposing factor to many situations is inadequate nutrition. Animals that are suffering from malnutrition are more susceptible to diseases and parasites than healthy animals. Animals with access to good nutrition also have a greater ability to develop an effective immune response to diseases. In the case of malnutrition there three main causes:
- insufficient feed
- a lack of one or more nutrients in the diet
- an imbalance of one or more nutrients in the diet.
For more information about beef cattle nutrition see Nutrition.
With some experience it is easy to recognise the main external parasites affecting livestock: ticks, buffalo fly and lice. However, determining whether an animal is affected by internal parasites is not so easy. Faecal testing will determine whether an animal is infested with worms, the types of worms, and to what extent.
To a certain extent, diseases and other causes of ill-health can be broadly categorized according to their main impact. Following are some common symptoms and possible causes. More information on specific diseases is available at A-Z list of significant animal pests and diseases.
Table 1. Symptoms and diseases and other conditions that cause them
|Sudden death||clostridial (blackleg, tetanus)
cyanide (prussic acid) poisoning
|Fever and possible death||three-day sickness (bovine ephemeral fever)
|Body abnormalities||blight or pink-eye
|Failure to reach growth targets||phosphorus
Source: Adapted from Dowling and McKenzie 1993
Source: Excerpt from ‘Managing a beef business in the subtropics’, 2004, pp 112–113