Eldoret Technical Training Institute

Eldoret Technical Training Institute students on their farm in Kapsaret, Uasin Gishu County in 2019. Most farmers don’t weigh their animals before sale.

| File | Nation Media Group

Here’s how to beat the pig carcass weight cheats

Livestock farmers’ issues are numerous and varied. They range from animal diseases, feeding, breeding, produce quantitation, marketing to pricing.

The matter is further complicated by the number of different species of livestock and production inputs involved in the business. The low level of knowledge and exposure between the farmers, input suppliers and buyers of produce further exacerbates the complexity of business dealings in farming.

One common issue of contention is the sale value of animals for slaughter. It is unfortunate to say most butchers and brokers are keen on reaping maximally from slaughter animals at the expense of the farmer.

I once shared the case of a farmer who had very nice bulls he was being offered Sh30,000 for each by brokers but he fetched Sh70,000 for each when he demanded scientific quantitation of the meat value of the live animals. Such a negotiation can only benefit the farmer when she knows reliable methods of determining the carcass value of a live animal.

Most butchers and livestock traders catch the farmers off-guard and use the visual estimation method. Except for the very experienced people, this technique is highly inaccurate, unreliable and subjective. It is also highly manipulated in favour of the buyer.

When the cattle trade brokers and butchers use the visual estimation method, they simply bull-doze the farmer to accept a price they have pre-determined. They take control of the farmer by confidently citing their experience with slaughter animals and meat trade. They also tell the farmer the quality of meat of their animals is poor.

My advice to farmers is that they must equip themselves with the knowledge and tools to carry out scientific quantitation of the meat value of their slaughter animals. It starts with being able to accurately estimate the weight of the animal, followed by understanding the carcass weight and the market price of meat. Carcass weight is the meat-on-bone weight after all the internal organs, hooves, skin and head have been removed. It varies between different species and ages of animals.

This being the festive season, it is time for animals to be slaughtered in larger than usual numbers to satisfy the demand for meat. Munyao from Ruai in Nairobi rears pigs. He called me last week to inquire how he could estimate the weight of his animals which were in big demand from pork eateries.

He was sure he was being given a raw deal by the various buyers because pigs of the same age group were showing highly variable carcass weights depending on the buyers.

Munyao had the habit of selling his pigs to buyers and then awaiting them to report the carcass weight after slaughter. He became suspicious when he sold to an established pork processor and the weight returned was almost double the highest he had got from the pork eatery buyers.

The farmer told me he did not have a pig live-weight scale and enquired if there were other ways of estimating the live weight of his animals before selling them for slaughter. The best method is to accompany the pigs to the slaughter house and confirm the weight but Munyao said that was too involving for him.

He was happy with the established pig processor but then they did not buy his pigs all the time since he was not consistently producing large enough numbers to enter into a contract.

There are four ways of quantifying the weight of slaughter pigs. The first is the visual estimate, which is highly unreliable and not recommended. Second is the use of a weighing scale. The cost of scales discourages small producers. Communal weighing is not recommended due to transmission of diseases.

I advise small producers to use the length and circumference measurement method instead. This is called the heart girth (GH) measurement.

The first technique here is straight forward and uses a calibrated pig weight measurement tape. The tape is calibrated in centimetres on one side and the corresponding animal weight on the other side. It is a fairly accurate measurement technique.

The tape is taken round the chest of the pig from the point of the shoulders down behind the elbows. The weight in kilo is then read off the tape.

Another technique is to measure the HG in centimetres and read off the weight in kilos from a weight conversion chart. The third technique involves measuring both the HG and the length of the pig in metres and calculating the weight in kilos. The length of a pig is measured from the middle of the base of the head between the ears to the base of the tail.

To measure the weight in kilos, record the HG and the length (L) in metres. Square the HG to get the girth result (GR). Multiply the GR by L and then by 69.3. You get the pig’s weight (W).

For example: Your pig has HG of 1.27 and L of 1.02. Square of HG is 1.27x1.27 = GR of 1.6129. GRx1.02x69.3 = 114kg live weight. The carcass weight of pigs is 70-85 per cent of the live weight depending on the live weight of the pig. In this case, it would be 114x70/100 = 79.8kg. This method is reported to be 97 per cent accurate in estimating a pig’s weight.


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