Satiety splits drinking behavior into bouts: Organization of drinking in turkeys1

Abstract

The regulation of the drinking behavior of animals is usually overlooked, and the traits associated with it are not well defined. We used a unique data set of measurements of individual drinking behavior in turkeys 1) to validate the system of data generation, 2) to develop a methodology to allow clustering of drinking events and splitting behavior into bouts, and 3) to develop traits related to drinking behavior and its regulation and investigate how these traits may be affected by bird genotype. Visits to drinkers were generated by an electronic, custom-made equipment that automatically measures the individual drinking behavior of a large number of turkeys from 3 different genetic lines. The overall reliability of the electronic system was estimated from video observations and resulted in a predictability of 98.8% and sensitivity of 98.6%. A novel method based on mixture distribution models allowed clustering of drinking events and splitting behavior into bouts by estimating the shortest interval between visits to the drinker that was considered to be part of a bout (bout criterion). The method predicted that after the end of a given bout the probability of the bird initiating the next bout was low but increased with time since the last bout. As a result, drinking bouts were not randomly distributed but were predicated on the physiological principle of satiety, suggesting that they constitute biologically appropriate units for expressing drinking behavior. The applied method resulted in bout criteria estimates of 665, 672, and 602 s for genetic lines A, B, and C, respectively. On the basis of this methodology, a number of drinking behavior traits, such as bout duration and frequency, and water intake per bout were identified that revealed differences ( < 0.01) in the drinking behavior between the turkey genetic lines. Similarly, time accumulation patterns of drinking behavior traits within a day differed ( < 0.01) within and between genetic lines, suggesting that variation in drinking behavior exists and birds use different behavioral strategies to meet their water intake requirements. Development of drinking behavior over time was similar between the lines, suggesting conservation of this behavioral organization. As well as providing ideas about the regulation of drinking behavior, the developed behavioral traits may be of practical relevance because water utilization, along with feed efficiency, is part of overall biological efficiency.

The genetic basis of novel water utilisation and drinking behaviour traits and their relationship with biological performance in turkeys

“…In addition, both lines were selected for leg health and fitness traits. In a previous study, we used these lines to develop a methodology for estimating drinking bout criteria in turkeys [ 8 ].…”

“…At the start of the experiment, each bird was fitted with a passive radio-frequency identification (RFID) transponder on the leg, which recorded bird presence inside the drinker. Previous observations suggested that transponders did not affect the birds’ behaviour in any way [ 8 ]. Access to each drinker was regulated by a set of transparent plastic side partitions, which were adjusted to the birds’ size as they grew.…”

“…Although visits to a drinker were the recorded trait, previous work had suggested that aggregating such visits into a bout is more appropriate since only the latter is consistent with biological principles [ 8 , 10 ]. While separate visits to the water station could show a random pattern, drinking behaviour expressed in bouts can be easily segregated into drinking and non-drinking activity.…”

“…However, recent technological advances in automated recording of drinking and feeding have made such measures possible while maintaining the birds in social groups [ 7 ]. In a previous paper, we described the definition of drinking behaviour traits that were recorded by using a system developed by Aviagen that measures the water use in turkeys individually [ 8 ]. Originally, these traits were recorded at the level of visits to the water providing system, and included the amount consumed per visit, visit duration, number of visits per day and their distribution over time.…”

“…In this study, we used the system for recording water drinking that we described in [ 8 ] to measure and define drinking behaviour traits in commercial turkeys. The system generates water intake data as visits to a drinker for individual birds, which can be used to develop drinking behaviour traits of biological relevance.…”