Ann Crock, Dr. Arlin Karsten, Larry McMullen

When Iowa State University's (ISU) Larry McMullen looked at the first wave of results from a trial studying the effects of dietary phytase, he got a bonus lesson. McMullen's surprise finding was in how much less water the study pigs used compared to the typical water use at many commercial operations.

The Iowa Pork Industry Center is sponsoring the trial at Kirkwood Community College in Cedar Rapids, IA. McMullen designed the demonstration to evaluate the phosphorus content of manure from finishing pigs who receive phytase versus those who don't. The trial will be repeated four times and is expected to be concluded in early 2001.

30 Percent Less Water Use

Pens housing study pigs are equipped with Farmweld Jumbo Feeders and Farmweld DRIK-O-MAT® Wean-to-Finish Water Cups. In the trial's first replication finished in January of this year, water consumption for pigs during the finishing phase was .99 gallons per pig per day. That's about a 1/2 gallon per day or 30 percent less than what McMullen says he sees in traditional finishing facilities with nipple drinkers.

Water consumption for the first replication was measured by a single water meter for both the phytase group and the control group. Each pen at Kirkwood's facility has its own manure pit so slurry volumes and components can be evaluated on a group by group basis. For the second replication of the trial, McMullen added a second water meter to determine if the addition of phytase affects water consumption. Results from that trial were not available at the time of printing.

McMullen, an ISU extension swine field specialist, says he thinks the 1/2 gallon per pig per day savings is likely due to reduced water wastage. He says he wasn't worried that pigs' water consumption was restricted in anyway because performance results were good. The pigs were fed from roughly 115-118# to 260-270# and had average daffy gains of 2.01 for barrows and 1.95 for gilts. Feed:gain ratios were 3.3 for barrows and 3.0 for gilts. "If the pigs are not drinking enough, you'd see a reduction in performance," says McMullen. 'These pigs did pretty well."

Less Manure to Haul is a Bonus

Using less water makes sense environmentally and economically. It means less water to pump or purchase and less manure to haul. In Iowa, the going rate for transporting manure is $.01 per gallon, according to McMullen. A 1,000-head finishing unit that saves a half gallon per pig per day creates 500 fewer gallons of waste per day or 177,500 fewer gallons per year. That's a big volume of wastage that no longer has to be dealt with in a system. The water wastage savings in hauling expense alone would be $1,775 per year (355 operating days) for a 1,000-head unit. That's significant, says McMullen.

At Kirkwood, the water savings has indeed translated into less manure volume and less pit management. "We used to have to pull the plugs several times during a 16-week feeding period," says Dr. Arlin Karsten, director of the swine education program at Kirkwood. 'With the cups, we get almost all the way through the feeding period before we have to pull the plugs."

Reduced volumes of manure benefits Kirkwood's teaching program as well. "Because we are so close to Cedar Rapids, we have to haul a long distance and we pay over a penny per gallon to haul and inject manure," says Karsten. "Arty waste water volume saved means a direct savings to our program."

PERFORMANCE RESULTS
	PHYTASE GROUP (46 barrows from 118 to 269#)	CONTROL GROUP (53 gilts from 115 to 258#)
Average Daily Gain	2.01	1.95
Feed:Gain	3.3	3.0