Research at Utrecht University, the Netherlands, recently focused on the question whether the taste of water may or may not influence intake by pigs.
Head researcher Dr Arie van Nes presented the research at the recent International Pig Veterinary Society (IPVS) Congress in Cancún, Mexico. The reason to zoom in onto drinking water is because many pig farmers use the water system to apply medication or additives to improve pig health. The effects of additives on water palatability, however, are often ignored because pigs are not given a choice source of drinking water.
In their paper, the researchers wrote: "With respect to drinking water constituents guidelines for pigs are mainly based on possible adverse effects for pig health and not on water palatability. Furthermore, it is known that pigs have a different taste than man. In this study we will investigate the palatability of two water temperatures and two commercially available additives by measuring water consumption of weaned piglets."
Materials & methods
In total four types of drinking water were evaluated, using four groups of 22 pigs of about seven weeks of age:
- A = Control (11°C, pH= 7.3);
- B = Warm water (33°C);
- C = water with a commercially available organic acid compound (pH=3.7);
- D = water with this organic acid and essential oils (pH=3.6).
The four water types were supplied on four subsequent days from 1 pm until 6 pm. In the first hour, pigs were provided with one type of water in a closed drinker, after which it was changed for another in the second, third and fourth hour.
The order of supplied water types differed each day to prevent confounding by learning. After the hour had passed the water consumption was measured. The data were analysed with univariate and multivariate linear regression models. The best multivariate model was chosen after a stepwise backward procedure.
The pH and water temperature can be found in Table 1, the water consumption in Figure 1.
Table 1 - pH and water temperature
The mean water consumption was 0.21 litres/pig/hour (range 0.08-0.39). Mean water consumption did not differ between pens, but was affected by day, time of day and type of water. On the last day and during the first hour on each day more water was consumed.
Water consumption was not affected by temperature, but water C was consumed more than the other three water types and water D was consumed more than control.
The researchers concluded, "The organic acid compounds did not adversely affect the palatability of the drinking water in this study. Whether an increase of water uptake is seen in the long run remains unclear as pigs get used to the water taste. Furthermore, water types were not equal in sodium content which is the main driver for thirst and has certainly confounded our study results. Equaling sodium contents however would affect palatability too. The non-invasive setup used in this trial proved possible to test water palatability preference under field conditions. Recommendations for future trial designs will be presented."
Apart from Arie van Nes, the research was carried out by Tijs Tobias, Utrecht University and PorQ; and Manon Houben, PorQ.