Depending on how facility allows pigs to drink water, considerable amounts of feeds can be wasted, which may affect digestibility of nutrients by pigs. Therefore, the objective of this experiment was to test the hypothesis that different watering options affect concentration of net energy (NE) in a corn-soybean meal diet fed to growing pigs.
Experimental design
A total of 24 pigs (initial BW: 50.2 kg; SD = 3.2 kg) were fed a corn-soybean meal-based diet and were housed in groups of 4 pigs in 6 indirect calorimeter chambers. There were 3 treatments: 1) dry feeder plus a water nipple located outside the feeder, 2) wet-dry feeder with the water nipple inside the feeder, and 3) combined system with a water nipple both inside the feeder and also an outside nipple. Pigs were allotted to 1 of the 3 treatments using a replicated 3 × 3 Latin square design with 6 chambers and 3 periods. Therefore, there were 6 replicate chambers per diet for the 6 periods. Each chamber was equipped with a slatted floor, 4 stainless steel fecal screens, and 2 urine pans for total, but separate, collection of fecal and urine materials. The temperature and relative humidity inside the chambers were controlled and maintained at the same levels in all chambers.
Throughout the experiment, pigs were allowed ad libitum intake of feed. Diets were fed for 13 d, where the initial 7 d were considered the adaptation period to the diet. On d 8, gas analyzers started measuring O2 consumption and CO2 and CH4 production. Fecal and urine samples were also collected from d 8 to d 13; All collected fecal samples and 5% of the urine were stored at −20 °C immediately after collection. At 0700 h on d 14, pigs were deprived of feed for 36 h. This time was considered a fasting period to determine fasting heat production (FHP). Therefore, each period lasted 14.5 d.
Concentrations of O2, CO2, and CH4 were averaged within each collection period and diet. Total heat production (THP) from pigs fed diets during the collection period were calculated using the following equation (Brouwer, 1965):
THP, kcal= [(3.866 × O2 + 1.200 × CO2 – 0.518 × CH4 – 1.431 × Urine N)],
where O2, CO2, and CH4 were expressed as liter and urine N was expressed as g. The FHP from pigs fed during the fasting period was calculated as for the THP. Heat increment was calculated by subtracting FHP from THP and concentrations of NE in all diets were then calculated as (modified from NRC, 2012):
NE, kcal/kg = ME – (THP – FHP)/feed intake,
where metabolizable energy (ME) was in kcal/kg, THP and FHP were in kcal, and feed intake was in kg.
Results
There were no differences among the 3 watering options in feed intake, GE intake, feces weight, fecal GE output, urine GE output, total and fasting heat productions, ATTD of DM or GE or concentrations of digestible energy (DE), ME, and NE (Table 1). Weight of orts was greater (P < 0.05) for pigs fed the diet from the feeder without water than for pigs fed the diet with water in the feeder and in the outside nipple drinker. Weight of urine was also greater (P < 0.05) from pigs fed from the feeder without water or from the feeder with water and the outside drinking nipple than from pigs who only had water in the feeder.
Key points
- In this experiment, pigs were group-housed and allowed to drink water from 1) dry feeder plus a water nipple located outside the feeder, 2) wet-dry feeder with the water nipple inside the feeder, and 3) combined system with a water nipple both inside the feeder and also an outside nipple.
- Different watering options did not affect digestible energy, metabolizable energy, and net energy.
Table 1. The ATTD of DM and GE and concentrations of DE, ME, and NE in diet fed to pigs that were group-housed with different watering options, one-pig basis
