Copper is an essential micronutrient for animals. It is involved in cellular respiration and connective tissue development as well as being an essential component of several enzymes. High doses of copper—about 20 times the nutritional requirement—have been shown to improve growth performance in pigs. This may be because copper has an antimicrobial effect in the intestinal tract.

When supplemental copper is added to pig diets, it is usually in the form of copper sulfate. However, another form called tribasic copper chloride (TBCC) has been shown to be equally effective and may be  more bioavailable, but it is not yet known how much TBCC should be fed to optimize performance. Therefore, an experiment was conducted to determine the effects of adding 100 or 200 mg/kg TBCC to diets fed to weanling pigs.

A total of 150 weanling pigs with an average initial body weight of 10.22 kg were fed a common Phase 1 diet for 14 days after weaning. On day 14 post weaning, pigs were randomly allotted to 3 dietary treatments. The control diet was based on corn and soybean meal, and two additional diets consisted of the control diet plus 100 mg/kg TBCC, or the control diet plus 200 mg/kg TBCC. The TBCC that was used in this experiment was IntelliBond® C from Micronutrients, Indianapolis, IN. Pigs were fed their respective diets for 28 days. Individual pig weights were recorded at the beginning of the experiment, after 14 days and at the conclusion of the experiment. Average daily gain (ADG), average daily feed intake (ADFI), and average gain:feed ratio (G:F) were calculated.

Diarrhea scores were assessed visually every other day using a score from 1 to 5.

1 = normal feces
2 = moist feces
3 = mild diarrhea
4 = severe diarrhea
5 = watery diarrhea

Over the period of days 14-28, ADG, G:F, and final weight were greater (P ≤ 0.05) for pigs fed diets containing 100 or 200 mg/kg TBCC compared with pigs fed the control diet (Table 1). Final body weight on day 42 was also greater (P ≤ 0.05) for pigs fed diets containing 100 or 200 mg/kg TBCC compared with pigs fed the control diet. No differences in growth performance were observed between diets containing 100 mg/kg TBCC and diets containing 200 mg/kg TBCC.

In the overall four week period, pigs fed diets containing 100 or 200 mg/kg TBCC had less severe (P < 0.05) diarrhea scores than pigs fed the control diet (Table 2). In addition, pigs fed 100 mg/kg TBCC had diarrhea on fewer (P < 0.05) days than pigs fed 200 mg/kg TBCC or the control diet.

• Adding 100 or 200 mg/kg TBCC in the form of IntelliBond® C (Micronutrients, Indianapolis, IN) to weanling pig diets increased average daily gain, gain to feed ratio, and final body weight over the period from days 14 to 28 post-weaning.
• Final body weight at 42 days post weaning was greater in pigs fed 100 or 200 mg/kg TBCC than in pigs fed the control diet.
• Adding 100 or 200 mg/kg of TBCC to diets reduced the diarrhea score over the four week experimental period.

Table 1. Growth performance of pigs fed diets without additional copper or with 100 mg/kg or 200 mg/kg of tribasic copper chloride (TBCC)¹

^a,bMeans within a row that do not have a common superscript differ, P < 0.05.
¹The TBCC used in the experiment was IntelliBond^® C, Micronutrients, Indianapolis, IN

Table 2. Diarrhea score and frequency (number of pen days with diarrhea score) of diarrhea of pigs fed diets without additional copper or with 100 mg/kg or 200 mg/kg of tribasic copper chloride (TBCC)¹

Diarrhea score = 1, normal feces, 2, moist feces, 3, mild diarrhea, 4, severe diarrhea, 5, watery diarrhea. Pen days = number of pens × the number of days of diarrhea scoring.

^a,bMeans within a row that do not have a common superscript differ, P < 0.05.
¹The TBCC used in the experiment was IntelliBond® C, Micronutrients, Indianapolis, IN

This report is based on unpublished research by Charmaine Espinosa and Hans H. Stein.