Water restriction in goats during hot-dry season in the humid tropics: feed intake and weight gain

Abstract

SUMMARYTwelve non-pregnant female goats (West African Dwarf, WAD and Red Sokoto, RS) were used to investigate the effect of volumetric (0%, 33% and 67%) water restriction on feed intake and weight gain over a period of eight weeks. The goats are of 2 age groups: younger and older than 1 year. The experiment was arranged in a modified cross-over design with three treatment periods of 1 week each. In-between each treatment period was a 2-week wash-out period, when the effect of the previous was expected to have worn off. The average water intake (WI) was determined for the first 7 days of the experiment when all the animals were given water ad libitum. The 3 treatments were: (i) ad libitum supply of water every day; (ii) 33% reduction from average WI; and (iii) 67% reduction. Water drunk had positive and significant (p<0.001) correlation with feed intake in young and old WAD (r= 0.490 and 0.620 respectively) and RS (>1 year old; r= 0.615). All the four classes of goats showed positive highly significant (p<0.001) correlation between water drunk and daily weight gain (r= 0.408, 0.484, 0.555 and 0.422 respectively for WAD (<1 and >1 year old) and RS (<1 and >1 year old goats). RESUMEN Doce cabras no preñadas (West AfricanDwarf, WAD y Red Sokoto, RS) fueron empleadas para investigar el efecto de la restricción volumétrica (0%, 33% and 67%) del suministro de agua sobre la ingestión de alimento y ganancia de peso durante ocho semanas. Los animales se agruparon por edad en menores y mayores de un año. El experimento se dispuso según un diseño cruzado, modificado con tres periodos de tratamiento de una semana cada uno. Entre cada periodo se intercaló uno de lavado de dos semanas durante el que se eliminaba el efecto del experimento precedente. La ingestión media de agua (WI) fue determinada para los siete primeros dias del experimento durante los cuales a todos los animales se suministraba agua ad libitum. Los tratamientos fueron: (i) suministro de agua ad libitum, (ii) reducción del 33% sobre la ingestión media y (iii) 67% de reducción. El agua bebida mostró correlación positiva (p<0,001) con la ingestión de alimento en las cabras WAD jóvenes (r= 0,490) y mayores (r= 0,620) y para las RS de más de un año (r= 0,615). Todas las cabras mostraron correlación positiva (p<0,001) entre agua bebida y ganancia de peso (WAD:<1, r= 0,408 y >1, 0,484 y RS: <1, 0,555 y>1, 0,422).

Physiological and behavioral basis for the successful adaptation of goats to severe water restriction under hot environmental conditions

“…Imposition of water restriction enforced the animals to use different strategies, which applied much more economic use of water for maintaining the water balance and thermoregulation, and this switch was reflected by marked reduction in the water-to-feed intake ratio. A Similar sharp reduction in the ratio between water and feed intake in response to water restriction was also found by Ahmed and El Kheir (2004) in the Sudanese desert goats and Abioja et al (2010) in the West African tropical goats.…”

“…In contrast, in the present experiment, the reduction in FFI upon restricting FWI was proportionally much lower than the level of water restriction imposed. Similar moderate reduction in feed intake in proportion to considerable imposition of water restriction (33% and 67%) was found in breeds of tropical (Abioja et al, 2010) and desert goats (Alamer, 2009). In cows, with 50% drinking water restriction, the reduction in feed intake was 20% lower than that during when water was available ad libitum (Burgos et al, 2001).…”

“…Water restriction has been extensively studied in ruminants over the past five decades in order to evaluate and understand the physiological basis underlying their capacity to endure water shortage, as well as the effects of water restriction on feed intake and utilization (see Ahmed and El Kheir, 2004;Abioja et al, 2010;Rahardja et al, 2011 for recent studies on goats and Silanikove, 1992 for a review of older publications on ruminants). It is possible to maintain ruminants for longer periods (e.g., for entire season) on restricted water intake (Khan et al, 1978;Silanikove, 1992).…”

Water consumption when exposed to sun and shade for native goats in the semiarid of the State of Paraiba, Brazil

“…The values of this research to both Azul and Graúna were higher than the recommended by NRC (2007), which mentions that there must be a relation between dry matter and water consumption, which in this experiment should have a mean of 1.52 liters. ABIOJA et al (2010) reported that there is a positive correlation between the food and water consumption, and in the present study it may be observed that the Moxotó goats consumed less dry matter and water in relation to other animals. This high water consumption may also be explained by the type of food provided, which had a roughage: concentrate ratio of 47:53, and a high percentage of energy in the diet increases the water consumption ARAÚJO et al, 2010), but also to the environment where the animals were housed, subjected to high temperatures and low relative humidity (Table 1).…”

“…It is also the most abundant substance in living systems (NRC, 2007), and the percentage of water in the body of goats depends on the alimentation, the age of the animal and the amount of fat, protein and ash present in their bodies (ALVES et al, 2008;DIAS et al, 2008;ARAÚJO et al, 2010). Water requirements for goats vary with the seasons, air temperature, weight, stage of production, type and food intake (ABIOJA et al, 2010), and the animals at elevated temperatures increase water intake, and thus this must be offered to the animals on tropical climate in sufficient quantity and desirable quality (BRASIL et al, 2000;NRC, 2007), aiming to replace losses through perspiration and respiration, besides possible body cooling, through the water contact, colder than the body, with the mucous membranes of the digestive tract, and replace losses through urine, feces and in the milk production.…”