Weaning and the First 18 Months

NUTRITION – WEANING AND THE FIRST 18 MONTHS

The First 18 Months

Multiple studies have concluded that the body mass at first breeding, usually 18 months, has a critical effect on the lifetime reproduction and production capacity of the ewe. The target for raising ewe kids intended for breeding should be that the kid has reached a body mass of approximately 27kg by the time of first breeding. It is of particular importance to note that the cost incurred in the supplementation of small and young kids will ensure that animals will develop to their full potential, and will produce and reproduce more effectively for the rest of their lives. The graph below demonstrates the optimum lifetime kidding percentages which can be achieved. Increased hair production is also achieved and is discussed below.

kidding_over_livetime_crop

Graph of the effect of body mass at first kidding over lifetime kidding%

While pre-weaning growth rates of ram and ewe kids may be satisfactory, post-weaning growth rates, in kids that do not receive supplementary feeding after weaning, are often very poor. Kids that are weaned lose weight fast due to “weaning shock” and under normal Karoo conditions can take too long to regain their weaning mass. Low kidding percentages of two-toothed ewes frequently obtained by farmers as well as the high mortality rate that can occur from weaning until first mating is often due to this factor. During this period the mortality rate is on average 12, 5 % which is appreciably higher than in other types of small stock. The problem of unsatisfactory growth in newly weaned and young kids on natural grazing is usually due to an energy deficiency. The dramatic improvement in growth rates in these kids when supplemented shows the necessity for an effective supplementary feeding programme. This supplementary feeding should idealy be started before the kids (creep feed ) are removed from the ewes so that they have already adapted to the diet.

The effect of weaning and nutrition on the growth rate of kids is demonstrated in experiments carried out when feeding weaned (removed from mothers) and un-weaned (left to graze with mothers until natural weaning occurs) kids. 

  • In the experiments where the ewes and kids received supplementary feeding (80% milled lucerne and 20 % mealie meal) the average daily increase (ADI) of the un-weaned group was 33, 8 g compared with the 21,9 g of the weaned group.
  • When this trial was repeated with just lucerne hay the un-weaned kids increased by 17,7 g per day compared with the 9,6 g per day of the weaned kids.  
  • The daily gain of the un-weaned group on the lucerne/mealie meal ration was 54 % more than the weanedgroup. On the poorer ration (lucerne), the growth of the un-weaned group was 85% better than theweaned group.

The growth rate between the two feeding programmes confirms the big effect nutrition has on post-weaning growth and describes the phenomenon known as weaning shock.

The experiment was repeated under veld conditions as well as exchanging ewes to determine the ewe effect as well as nutrition .As a result of good rains before the commencement of the experiment, the veld was in above-average condition during the period of the experiment.

  • The effect of weaning the kids and effect of running with other ewes (exchanged) was determined. The ADI of the kids was calculated for the period from weaning (four months of age) until the age of seven months.
  •  The ADI of weaned kids was 10, 2 g and that ewes exchanged was 12, 4 g.
  • On the other hand, the ADI of the non-weaned group of 34 g was approximately 3X better than that of the weaned and exchanged groups. This dramatic difference was statistically highly significant.

From this it is clear that weaning does have an inhibiting effect on post-weaning growth. Further, the practice of swopping ewes in order to decrease stress during weaning, is of very limited value. 

When comparing the effect of weaning differences in rams and ewes

  • The ADI of the ram and ewe kids is almost the same when they are not weaned.
  • However, when they are weaned the daily increase of the rams is significantly higher than that of the ewe kids.

In practice it is therefore best not to remove the ewe kids together with the ram kids, but to delay this wherever possible until they are older (6-7 months old), before the next mating season.

Ewes wean their kids naturally at about five-and-a-half months. When poorer nutritional conditions on the veld are present it can be expected that the ewes will wean their kids naturally at an even earlier stage.

The additional input costs of feeding weaned kids does not only benefit in lifetime reproductive benefits but also improved mohair return.

 

Dr Mackie Hobson 

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