Ewe Age - Effect on Reproduction

Thursday, 26th April 2018

Many producers keep older ewes or buy in old Angora goat ewes.

  • How do these ewes perform when compared to younger ewes?
  • How does the body weight on the ewes affect reproduction
  • How the older ewes are best managed to maximise reproductive performance?

 

Research by Gretha Snyman at Grootfontein has helped answer some of these questions. From the results (see the graphs below) it is evident that:

 

  • The age of the ewe has a significant effect on reproduction of Angora goats.
  • The practice of keeping ewes older than seven to eight years of age in the breeding flock is detrimental for optimising overall productivity. Not only will it slow down genetic progress, but income of the current herd is also adversely affected by retaining unproductive older ewes.
  • To optimise productive and reproductive efficiency and rate of genetic progress, breeders should keep a maximum of 5 to 6 dam age groups.

 

The Effect of EWE AGE on:

 

  1. birth weight and weaning weight of kids

  1. 8 and 16 month weight of kids

The effect of  reduced kid (ewe replacement) weight at 8 and 16 months is the impact on future reproductive performance of these kids. The lower reproductive efficiency of young ewes is largely be ascribed to their lower body weight. A body weight of 25 to 27 kg at 18 months of age is generally regarded as a minimum to ensure that young ewes conceive and are able to carry their foetuses to parturition. However, 40 % of young ewes in this study had mating body weights of less than 25 kg; the range being from 15 to 45.8 kg, depending on the respective rearing environments. Young ewes with mating weights less than 25 kg also had lower survival rates of their kids.

Management of the ewes

Body weight, age of the ewe and management system all have a significant effect on reproduction of Angora goats.

Effect of age on body weight of ewe:

  • More ewes in this study that received either flushing treatment or were run on pastures before mating were pregnant at scanning than ewes that were run on veld without any supplementation before mating.

 

  • Ewes should not be underfed between days 61 and 120 of pregnancy.
  • In this survey, 84 % of the ewes that were run on veld without supplementation during pregnancy and was scanned pregnant, did eventually kid, compared to 92 and 93 % of the ewes that either received supplementation during the last part of pregnancy or were run on pastures.
  • POOR nutrition of Angora goats during the third trimester of pregnancy, could cause
  • Poor udder development
  • Delay the onset of milk and colostrum production.
  • Lead to poor mothering instinct.

Most veld types in the Angora goat areas are unable to fulfil the protein and energy requirements of late pregnant and lactating Angora goat ewes which is reflected in the trial - lower reproductive performance of ewes run continuously under veld conditions.

  • For management of the Pregnant and lactating ewe also see the SAMGA website:

https://www.angoras.co.za/page/pregnant_and_lactating_ewe#47

  • Flush Feeding

https://www.angoras.co.za/page/flush_feeding#42

  • Growth rate of Angora kids

https://www.angoras.co.za/article/growth-rate-of-angora-kids#279

  • Weaning and the first 18 months

https://www.angoras.co.za/page/weaning_and_the_first_18_months#46

 

REFERENCES/Extracted from:

INFLUENCE OF EWE AGE AND MANAGEMENT SYSTEM ON BODY WEIGHT AND REPRODUCTION

OF SOUTH AFRICAN ANGORA GOAT EWES.

M.A. Snyman, Grootfontein Agricultural Development Institute, Middelburg (EC)

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