Effects of including two sources of copper hydroxychloride in diets for growing-finishing pigs

Recent research conducted at the University of Illinois Swine Research Center demonstrated positive effects of feeding copper hydroxychloride to weanling pigs, including improved growth performance and positive changes in intestinal health. It is, however, not known if copper hydroxychloride would also elicit positive effects in growing-finishing pigs. Additionally, it is also not known if the positive effects of copper hydroxychloride are obtained regardless of the origin of the mineral, or if the response is specific to the product produced by a specific supplier. Therefore, an experiment was conducted to test the hypothesis that inclusion of copper hydroxychloride in diets for growing-finishing pigs would improve growth performance, and secondly that the origin of the copper hydroxychloride is not important for the outcome.

Experimental Procedures

A total of 96 pigs, with an average body weight of approximately 28 kg, were randomly allotted to 3 treatments. There were 4 pigs per pen and 8 replicate pens per treatment for a total of 24 pens used in the experiment. Pigs were fed for approximately 12 weeks in a 3-phase feeding program, in which grower diets were fed for the initial 35 days, early finisher diets were fed for 28 days, and late finisher diets were fed for 23 days. In each phase, a basal diet primarily based on corn and soybean meal was formulated to meet or exceed estimated requirements for nutrients (Table 1). Two additional diets were formulated by adding 150 mg per kg of copper hydroxychloride, originating from either source 1 or source 2, to the basal diet. Pigs were provided ad libitum access to feed during the experiment and were weighed at the start and conclusion of each phase. Growth performance data were summarized for each phase and for the overall duration of the experiment.


No differences were observed for average body weight of pigs at any point in the experiment (Table 2). In the grower phase, pigs fed copper hydroxychloride from source 1 had greater (P < 0.05) ADG than pigs fed the diet without copper hydroxychloride, but no differences in ADG were observed during the finishing phases, nor for the overall experiment duration. In the grower phase, pigs fed diets containing copper hydroxychloride from source 1 tended (P < 0.10) to consume more feed than pigs fed the basal diet, but there were no differences in ADFI during the finishing phases. Gain to feed ratio was unaffected by dietary treatment.

            The pigs in the study had excellent health status, and mortality was low. All but 3 pigs remained on trial for the entire experiment duration. The overall ADG and G:F in the study were quite high, and this was likely due to the limited number of pigs per pen and the high health status of the pigs used in the experiment. Under commercial conditions, pigs are often health challenged, which results in reduced growth performance compared with what was observed in this experiment. If pigs have intestinal diseases, it is possible that copper hydrocychloride will have a greater positive impact on growth performance than was observed in this experiment.

Key Points

  • Pigs fed diets containing copper hydroxychloride tended to eat more during the growing phase, and subsequently, pigs fed copper hydroxychloride from source 1 had greater ADG during this phase. There was no effect of copper hydroxychloride on the growth performance of finishing pigs in the present experiment.
  • All pigs used in the present experiment were of high health status, and it is possible copper hydroxychloride will elicit a more pronounced response in pigs reared under the stress of commercial conditions.

Table 1. Composition of basal diets for pigs in grower, early finisher, and late finisher phases1

Ingredient, %


Early finisher

Late finisher

Corn 69.20 74.70


Soybean meal 25.00 20.00


Choice white grease 3.00 3.00


Ground limestone 0.84 0.77


Dicalcium phosphate 1.05 0.80


L-Lysine HCl, 78% 0.25 0.17


DL-Methionine, 98% 0.06 0.00


L-Threonine, 98% 0.05 0.01


Sodium chloride 0.40 0.40


Vitamin mineral premix 0.15 0.15


c c c


1Two diets were formulated in addition to the basal diet for each phase, in which 150 mg/kg of a single source of copper hydroxychloride (source 1 or source 2) was added to each diet in a premix form. Each premix contained 25.88% of one source of copper hydroxychloride (58% Cu) and 74.12% corn and was added to the diet at a rate of 0.10% at the expense of corn.

Table 2. Growth performance of pigs fed a basal diet containing no added copper hydroxychloride, a diet containing 150 mg/kg copper hydroxychloride from source 1, or a diet containing 150 mg/kg copper hydroxychloride from source 2



Source 1

Source 2



BW at d 0, kg 27.68 27.63 27.64 1.304 0.999
BW at d 35, kg 60.54 63.99 62.56 1.869 0.439
BW at d 63, kg 91.11 96.19 93.97 2.402 0.344
BW at d 86, kg 118.88 123.76 121.84 2.670 0.443
ADG d 0 – 35, kg 0.939b 1.039a 0.998ab 0.0243 0.029
ADG d 35 – 63, kg 1.092 1.150 1.127 0.0255 0.291
ADG d 63 – 86, kg 1.207 1.198 1.212 0.0305 0.950
ADG, d 0 – 86, kg 1.060 1.118 1.095 0.0215 0.189
ADFI d 0 – 35, kg 1.684 1.862 1.804 0.0498 0.055
ADFI d 35 – 63, kg 2.629 2.844 2.800 0.1009 0.305
ADFI, d 63 – 86, kg 3.383 3.472 3.382 0.0722 0.608
ADFI, d 0 – 86, kg 2.446 2.612 2.549 0.0576 0.147
G:F d 0 – 35, kg 0.559 0.560 0.554 0.0106 0.905
G:F d 35 – 63, kg 0.419 0.405 0.405 0.0092 0.487
G:F, d 63 – 86, kg 0.357 0.345 0.359 0.0066 0.299
G:F, d 0 – 86, kg 0.435 0.428 0.432 0.0050 0.623
s s s s s s