Sow’s milk contains about 80 percent water, and therefore it is often assumed that suckling piglets cover their daily water requirements without supplemental water. As a result, on many farms, farrowing crates are not equipped with a water delivery system for piglets, and water is provided for the first time only after weaning. In such cases, it is quite common to observe piglets trying to reach the water devices installed for sows. Nevertheless, most experts agree that supplemental water actually benefits suckling piglets, and these benefits greatly outweigh the cost of providing water for piglets in farrowing crates.
Dehydration during the first few days after birth is a common cause of death in newborn pigs, especially among light and weak piglets that fail to consume enough milk. It has been suggested that provision of drinking water may reduce pre-weaning mortality from dehydration, especially when environmental temperature is excessive. It should be noted that water loss (mainly from evaporation) in piglets housed under common heaters is about 155 g/day per kg body weight, and that piglets housed at 28 C (82.4 F) consume four times more water than piglets housed at 20 C (68 F). Therefore, when milk intake is limited or environmental temperature is excessive, a source of fresh drinking water should be provided to reduce dehydration and sustain life.
Dehydration during the first few days after birth is a common cause of death in newborn pigs, especially among light and weak piglets that fail to consume enough milk.
Supplemental water may also be beneficial to suckling piglets suffering from diarrhea, which causes severe water loss from the gut. In experimental studies, diarrhea caused severe dehydration, significant body weight loss, and increased mortality. Surviving piglets were able to withstand dehydration by adjusting intra- and extra-cellular body water. Thus, it is strongly recommended to provide electrolytes in addition to drinking water in pigs suffering from acute diarrhea to prevent severe dehydration.
Sow’s milk is relatively high in protein (30 percent) and ash (25 percent). As fresh water is required for urinary excretion of excess nitrogen and minerals, a potential deficit could, at least theoretically, reduce milk intake and growth in suckling piglets. It is interesting to note that newborn pigs are able to drink water within the first 2 hours after birth, indicating a need for water in addition to that supplied by sow’s colostrum or milk.
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It is also essential to provide drinking water to suckling piglets that actively consume solid feed. It has been demonstrated that piglets with free access to water eat more creep feed than piglets without supplemental water (3,215 versus 2,166 g/pig, respectively). The importance of drinking water in supporting vigorous intake of dry feed increases with weaning age. In production systems practicing very early weaning, creep intake is rather trivial and, thus, the effect of water on feed intake is minimal. But, in production systems that wean pigs about 3 to 4 weeks of age, creep intake can be substantial, and supplemental drinking water must always be provided.
Water for weaned pigs
At the time of weaning, pigs without previous experience in drinking fresh water are required to distinguish thirst from hunger and operate different devices (i.e., drinkers and feeders) to satisfy these needs via unfamiliar media (i.e., water and dry feed). This requirement for an abrupt change in drinking and feeding behavior is in sharp contrast with the way piglets used to cover their needs before weaning with sow’s milk. This argument gives ground to the notion of providing fresh water and creep feed to suckling pigs, although results in terms of pre-weaning growth performance are often less than satisfactory.
During the first couple days post-weaning, piglets weaned at an early age (less than three weeks) consume little if any dry feed. Thus, to satisfy their hunger they tend to fill up with water beyond their physiological needs. It is not uncommon for newly weaned pigs to drink up to 4 liters of water per day during the first few days post-weaning. Pigs that fail to locate or learn how to use drinkers should be encouraged to drink from bowls filled with water to prevent dehydration. During the rest of the first week, weaned pigs reduce their intake of water as they start to consume more feed.
Growing piglets
By the end of the first week, and assuming that feed intake has reached a linearly increasing pattern, water intake parallels feed intake. During the following weeks, water intake ranges from 2 to 4 liters per kg of dry feed, but most often it averages around 3 liters per kg of feed. Allowances should be made for wastage or abnormally high requirements for water during hot season or disease outbreaks. Average water intake during the first, second and third week post-weaning (for piglets weaned at three weeks of age) is expected at about 0.5, 1.0 and 1.5 liters per pig, daily. Studies indicated that water intake may be predicted based on feed dry matter intake using the following equation, which is very close to the 3:1 (water:feed) practical rule.
Water intake (liters/day) = 0.149 + (3.053 × feed intake, kg/day)
Weaned pigs housed under constant light conditions tend to drink more during “day” hours (8 a.m. to 5 p.m.) than during “night” hours. Also, weaned pigs drink most of their daily water ration in association with a meal. In young pigs, 85 percent of drinking takes place within 10 minutes of a meal.
It is advisable to monitor daily water intake per room using a simple water meter. A graph of water intake against time provides a visual aid in detecting irregular patterns of water intake that could be used as an indication of an imminent disease outbreak. For example, pigs start to drink more water at the onset of fever or diarrhea, before any visual symptoms become apparent. However, a distinction must be made for abnormal patterns in water intake due to elevated room temperature. To this end, monitoring daily temperature (minimum/maximum or average) along with daily water intake could prevent false alarms. Finally, water intake records from the first week post-weaning should be used with caution for monitoring health.