O Level Notes : Agriculture - Ruminants : Sheep Production

Proper management skills of indigenous and exotic breeds of cattle, sheep and goats is important. The farmer should be able to select breeds of animals that are suitable for his / her environmental conditions basing on the traits of breeds of the animal.

Sheep production

Important terms in sheep production

  • Ewe - a mature female sheep which has more than one lamb
  • Ram - is a mature male sheep
  • Wether - is a castrated male sheep
  • Hogget - is a young female sheep
  • Lamb - the young one of a sheep

Indigenous breeds of sheep

 

Black head Persian

The breed originated from Somalia and is a direct descendant of the Somali sheep but are now kept in Zimbabwe as indigenous breed.

Characteristic features of the breed

  • The blackhead Persian is a fat tailed breed.
  • Black head Persian is a polled breed.
  • The coat consists of hair and no wool
  • The breed has a black head with long pendulous ears, black neck while the whole body coat is white.
  • The breed is resistant to local diseases.
  • Skin is used in making leather gloves.
  • Is a hard breed that survive on poor grazing
  • The coat is resistant to piercing types of some grass seed such as black jack

Characteristic features of the breed

  • The sabi sheep are hardy suited to dry conditions.
  • They breed at any time of the year.
  • The breed is susceptible to blue tongue diseases.
  • The breed has a hairy coat and no wool.
  • The breed has a multiplicity of colours from black through all shades of brown to pure white.
  • Sabi sheep have a small body.
  • The Rams have an average weight of 60kg-65 kg and the Ewes ranges from 40kg-to 45 kg.

 

Cross breed sheep 

  • Wiltiper sheep have three main dominant colours namely brownish dun, black and white.
  • This breed was produced by crossing the black head Persian ewes with Wiltshire horn rams imported from United Kingdom.
  • Breed is similar to the Dorper and is a good mutton sheep.

 

 

Dorper

This breed is the result of crossing the black head Persian Ewe with the Dorset horn.

Characteristics features of the Dorper sheep

  • The breed does not have a tail.
  • ADorper is a fast growing meat producing sheep.
  • Rams weigh an average mass of 80kg-100 kg and the Ewe 50kg – 70 kg under good management when mature.
  • The breed has less fat on the carcass.
  • Dorper sheep are adapted to survive in the arid extensive climatic regions.
  • The breed has a high fertility and maternal instinct.

 

Exotic breeds of sheep

Characteristic features of the breed

  • Corriedale sheep breed is a cross breed of merino sheep and Lincoln.
  • Is a dual purpose breed which started inAustralia and New Zealand.
  • Produce good mutton and long, strong, good quality wool.
  • Good flocks will average 6kg of wool per sheep.
  • The Ewes have a good mothering ability but have restricted breeding season and cannot be served by the Ram at any time of the year.
  • Rams weigh 80-110 kg and ewes weigh 55-70 kg.

Characteristic features of the breed

  • The breed is characterized by all white body with black face and legs.
  • Good mutton sheep with short, good quality wool.
  • Have a limited breeding season with Ewes coming to heat in the autumn and lambing in the spring most of the time.
  • The breed have a good mothering ability.

Dorset Hornsheep

There are two types of Dorsetsheep namely horned and polled. Both horned and polled Dorset have white colour and are of medium size.

Dorset sheep

 

  • Dorset sheep have a prolific lambing.
  • The breed produces a good quality of meat.
  • Dorset Horn breed has a good mothering ability.
  • It is a medium sized breed.
  • Both male and female sheep have horns.

 

Polled Dorset breed

Characteristic features of Polled Dorset sheep

  • The breed had no horns.
  • The breed had short wool.
  • Their fleece is very white in colour.

 

Merino breed

Characteristic features of the merino sheep

  • This breed originated from German.
  • The breed have a good mothering ability.
  • The breed is large. The merino rams weigh 90kg-140kg and the ewes ranges from 60kg - 80kg under good management.
  • The breed is kept mainly for its wool which can be processed and used for making wool clothing such as blankets and jackets.

 

Sheep management practices

 

(i) Lambing

During Lambing, the farmer should always be with his ewes to give help when necessary. The farmer can manage the ewes by putting them in fenced paddocks for easy monitoring and during lambing when the water bag which surround the fetus bursts and the lamb should be born with in an hour of this happening. Normally this is the most critical time when the farmer should be there, the two front legs come out first followed by the head but it can happen that the head or a leg turned inwards and it becomes a problem. The ewe will need assistance to straighten the head or leg. After lambing the farmer should check again if the breathing system is not affected by any mucus which may be on the nose of the lamb and if there is any, it should be removed by a clean piece of clothing. Soon after birth, it is a must that the lamb should suckle colostrum(the first yellow milk) from the mother. If the ewe is not accepting the lamb, the farmer should help the lamb to get the milk because it is from this first milk where the lamb only get protection against diseases as well as getting vitamins, proteins and minerals. Colostrum also have the ability to give energy to the lamb since it contains carbohydrates. It also helps in the cleaning of the digestive tract.

 

(ii) Care of lambs

  • Isolate ewes and their lambs in nearby paddocks up to 15 days to protect them from predatorssuch as dogs and jackals.
  • Orphans should be bottle fed with colostrum taken from another mother.
  • During the night, house the lambs in wind protected kraals to avoid cold weather which cause pneumonia
  • Feed lambs with protein concentrates such as sunflower seed cake mixed with maize meal.

 

(iii) Docking

This is the removal of the tail about 5cm from the body. It is done on lambs of wool breeds to reduce the problem of the sheep maggot. It can also be done on fat tailed sheep as it improves the quality of the meat.

Methods of docking

 

(i) Knife method

  • A sharp knife is used to cut off the tail of the lamb 5cm from the body.
  • Cut tails should be treated with antibiotic powder or iodine to prevent infection.
  • The knife should be sterilized in boiling water before use.

(ii) Rubber ring method

A rubber applicator is used to apply a tight rubber elastrator ring around the tail of the lamb where the tail is to be cut. This will cut off the blood supply from the tail and the bottom part of the tail withers and fall down within two weeks.

 

Castration

This is done to prevent males from breeding.

 

Methods of castration

(a) Use of a knife - to cut out the testes, a sharp knife is used to make incisions on the testicles to remove testicular tissue. This method is not recommended to animals that are housed in muddy conditions because the wound may be infected.

(b) Use of Budizzo – This is an instrument that crushes the spermatic cords on the reproductive organ of an animal.

(c) Use of rubber ring – The ring is placed on the scrotum above the testes and causes the whole scrotum to drop off after a few weeks.

 

Weaning

Lambs are usually weaned at two to three months of age. By this age, they are able to graze well. The best and easiest method is use of separate paddocks and kraals and the other alternative method is that of placing nose plates on the lambs for more than a week to prevent them from suckling.

 

Shearing

This is the cutting of wool normally done once per year. Shearing is done using a scissors or electricity driven shear. It should be done before the hottest time of the year to reduce heat stress in the animal and furthermore the wool will be dry by then.

 

Vaccination

Vaccination is the process of injecting vaccines into the animal's body so that the animal will be resistant to diseases. Sheep must be vaccinated against pulpy kidney which is caused by a bacteria. Vaccination of the sheep every year is recommended.