How to manage weaning shock

Angora goat farmers have to strike a delicate balance between early weaning and the risk of weaning shock, and weaning their kids in time for the mating season. However, a new study indicates an unweaned kid doesn’t necessarily hurt a ewe’s reconception rate. Roelof Bezuidenhout spoke to Grootfontein researcher Jan Hoon.
Issue date : 22 August 2008

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Angora farmers often have problems when weaning kids. Surprisingly, a new trial aimed at finding solutions indicates unweaned kids don’t necessarily affect ewes’ reproductive rates. The study, funded by Mohair SA, was performed on Jannie Moolman’s farm Rusoord in Middelburg, Eastern Cape, using Jannie’s animals grazing on natural veld. Jan Hoon of Grootfontein Agricultural Development Institute explains, “We wanted to determine the effect of different weaning practices on the post-weaning growth of kids, the body-weight change of ewes from weaning until mating, the ewes’ milk production and their conception rate in the next breeding season.” he researchers kept records of four kidding seasons, from 2003/04 to 2006/07. Jan explains that weaning shock is one of the biggest problems in the Angora industry.

“The kid goes through a very critical growth stage between weaning and the young goat stage. A mortality rate of up to 12,5% has been reported in Angora kids within this period, compared to only about 3% in Merinos.” To lessen the trauma of early, artificial separation, farmers try to wean their kids as late as possible, but they also want the next mating season to start as early as possible. It’s believed the earlier in the year the kid is born, the healthier it will be. his means kids can’t be weaned later than February, because it’s accepted the ewe needs three to four weeks before the next mating season.

Some farmers try to minimise weaning shock by keeping the kids with the ewes while the ewes are mated. Others remove the mothers and replace them with dry ewes or kapaters. worry is that ewes’ reproduction will be compromised if the kids aren’t removed at a normal weaning age. ccording to the trial, however, “you can mate ewes while their kids are still with them without compromising reconception rate, although weaning does improve the ewes’ body weight at mating,” says Jan. “No difference was observed in the growth rate and only small differences in the kids’ hair production at second shearing, and none of them got pregnant.” flock of Angora ewes and their kids was randomly tagged and numbered individually at the start of the kidding season in August 2003.

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In the following years, ewes used in the project during the previous season formed the nucleus of the flock. Replacement ewes were added randomly. At weaning time each year, weaned kids were separated from their mothers, swapped kids were separated from their mothers but put with other ewes, and unweaned kids stayed with their mothers. In the 2004/05 kidding season, 10 ewes from each of the three groups that had kidded in the same week and had single kids, were identified and marked. Their milk production was recorded weekly from three weeks until six weeks after kidding and a bi-weekly until the next mating season. All the ewes’ body weights were recorded at weaning and at mating/scanning.

The kids’ body weights were recorded at weaning and monthly thereafter until the age of 10 months. The ewes’ conception and scanning percentages were determined by ultrasound. The individual kids’ hair production was recorded at second shearing in 2005, 2006 and 2007. The animals stayed in their groups until the kids’ final body weights were recorded at 10 months of age.

Interesting findings
 Ewes reached their peak milk production at four to six weeks after lambing. Milk production of the weaned group’s ewes stopped over the next four weeks, but the ewes of the other two treatments continued to produce small amounts of milk . From weaning to about 10 months, weaned and unweaned kids’ growth rates didn’t differ, but were both higher than those of the swapped kids. Growth rates declined after eight months of age and the start of the dry winter period and deteriorating grazing conditions.

The weaned ram kids had the highest average daily gain (ADG) and the swapped ewe kids the lowest. Overall, there was no difference in the average growth rate of the ram and ewe kids . Ewes from the weaned group had the highest body weight from weaning until mating . The unweaned and swapped groups had the best average conception and scanning percentages over the trial period. Despite the variation in these percentages, not weaning kids didn’t harm ewes’ reconception rate. The kids’ average hair production at second shearing was low, varied from 1,2kg and 1,27kg, a small difference.

Jan warns breeders to keep environmental conditions in mind when interpreting the study’s results. “During the trial, average to above-average rainfall probably let the ewes maintain enough body weight to conceive in the next mating season, despite the kids’ presence. In drier years, their reproduction rates might be worse.” E-mail Jan Hoon at [email protected]. |fw