Kansas State University (KSU) research suggests that pigs fed supplemental levels of tribasic copper chloride (TBCC) had increased growth rates into the late finishing stage. The researchers found that adding supplemental copper to pig diets in the form of either TBCC or copper sulfate (CuSo4) improved growth in both the grower and early finishing periods.

Ultimately, copper-fed pigs weighed more and had higher hot carcass weights (HCW) compared to pigs fed a control diet that did not include copper. Pigs receiving the TBCC diet displayed the greatest overall advantage in the study, according to Kyle Coble, a KSU animal science graduate assistant, who conducted the research.

A total of 1,143 mixed-sex pigs were randomly allotted by pen to one of six dietary treatments in order to determine what effect the two copper sources would have on growth performance, carcass characteristics, pen cleanliness and overall economics.

Adding 250 ppm of copper derived from copper sulfate has been a routine practice in nursery pig diets for many years. It is believed that copper serves as an antimicrobial-like agent in the pig’s gut.

While added copper in nursery diets is common, previous research suggested that copper supplementation in late finishing may not provide growth advantages.

Because of the limited data available on the new TBCC source, the KSU researchers wanted to assess whether the product could offer improvements in finishing pig growth performance. Feeding diets high in byproduct ingredients, as well as supplemental copper, has been thought to increase manure buildup and pen washing time, so the researchers sought to gather data on this aspect as well. The study evaluated the effects of TBCC and copper sulfate on growth performance, carcass characteristics, pen wash time and economics of finishing pigs.

The study was conducted at a commercial research finishing site in southwest Minnesota. Pigs weighed 55.3 lb. when the 111-day study began. Prior to initiating the trial, pigs were fed on a common diet containing 186 ppm TBCC.

Pigs were housed in pens of 25-28 pigs/pen, with eight pens/treatment. The treatment diets included a corn-soybean meal-positive control diet, a high-byproduct diet with 30% distiller’s dried grains with solubles (DDGS) and 15% bakery meal (considered the negative control diet), or the negative control diet with 75 or 150 ppm copper from copper sulfate or TBCC. All diets contained 20 ppm of copper from copper sulfate in the premix, and were formulated on a standardized ileal digestible lysine basis at 0.05% below the estimated requirement during each phase. Treatment diets were fed in five phases. During the last phase, all diets contained 4.5 g/ton of ractopamine HCl (Paylean). Each treatment diet was sampled at the start and before the last day of each phase. Diets were analyzed for copper.

Pens of pigs were weighed and feed disappearance was recorded at days 27, 49, 71, 92 and 111. Pigs fed the positive control, corn-soybean meal or negative control, high-byproduct diet had similar average daily gain (ADG) overall; however, feed/gain was poorer for pigs fed the negative control. Adding copper to the diets increased ADG, average daily feed intake (ADFI) and final weight. Within copper sources, as TBCC inclusion in the diet increased from 0 to 150 ppm, ADFI increased from days 0 to 71, 71 to 111 and 0 to 111. As a result of this increased feed intake, ADG was also increased during these periods. Pigs fed increasing levels of copper sulfate had increased ADFI and ADG from days 0 to 71 and 0 to 111 (see graph).

Pig Performance

Final live weight for pigs fed 150 ppm TBCC was 12.8 lb. heavier than the negative control diet, and those fed 150 ppm copper sulfate were 7.1 lb. heavier. Increased final weight combined with no differences in carcass yield for the copper-fed pigs led to an increase in HCW for pigs fed increasing levels of copper. Specifically, pigs fed 150 ppm TBCC had 7.7-lb. heavier carcasses, and pigs fed 75 ppm copper sulfate had 3.1-lb. heavier carcasses.

The researchers found no differences in manure texture among dietary treatments, which suggested that the consistency of manure was not affected when copper was added to the diet.

An economic analysis was calculated on both a constant days-on-feed or constant market-weight basis to determine the value of feeding copper in two separate scenarios. When the economic advantages were calculated on a constant number of days-on-feed basis, there were no differences in total feed cost, revenue or income over feed cost (IOFC) between sources of copper. As added copper increased, feed cost and revenue increased, as well as cost per pound of gain.

Coble reports that the greatest numerical response in IOFC for the individual copper sources was $1.50/pig for pigs fed 150 ppm TBCC and $0.82/pig for pigs fed 75 ppm copper sulfate. When the economics were calculated on a constant weight basis, the greatest numerical advantage for each copper source occurred at 150 ppm for TBCC ($1.35/pig) and at 75 ppm for copper sulfate ($0.26/pig), due to the decrease in feed and facility cost.