Analysis of nutrient concentrations in the diet, serum, and urine of giraffe from surveyed North American zoological institutions

Abstract

The objectives of the present research were to conduct a survey to investigate the health history and feeding practices of giraffe in captivity in North America and to obtain samples of hay, concentrate, browse, urine, and serum to compare across zoos, possible factors relating to the development of urolithiasis. Forty-one out of 98 institutions contacted responded, representing 218 giraffe. All responding zoos fed concentrate and alfalfa hay was the primary forage. Sixty-five percent of zoos fed browse and 43 different species of browse were listed. Six zoos reported a history of urolithiasis, seven reported wasting syndrome, and 10 reported sudden death. The median daily amount (as fed) of concentrate and hay offered were 5.45 kg (range of 2.73-9.55 kg) and 6.82 kg (range of 2.53-12.50 kg), respectively. The concentrate:hay ratio of the offered diet ranged from 0.22 to 3.47 with a median value of 0.79. Forty-three percent of the institutions offered a ratio greater than 1:1. Samples of concentrate and hay (six zoos), serum (five zoos), and urine (seven zoos) were obtained for chemical analyses. Analyzed nutrient content of the consumed diet, measured by weighing feed and orts for three consecutive days, met recommendations for giraffe, but was excessive for crude protein and P. Concentrate:hay and serum P were positively correlated (r=0.72; P<0.05). High dietary P content and a high level of concentrate relative to hay may be contributing factors to urolith formation and warrant further investigation.

Impact of two types of complete pelleted, wild ungulate feeds and two pelleted feed to hay ratios on the development of urolithogenic compounds in meat goats as a model for giraffes

“…The other 65% of the hay was offered at the PM feeding (1530). This mimics common practices in zoological institutions for giraffe, which typically involve concentrates fed once in a large quantity and hay fed throughout the day with the intention of stimulating rumination and minimizing stereotypic behaviours (Schmidt and Barbiers, 2005; Sullivan et al., 2010). Individual water consumption was monitored by weighing the amount of water added to water containers each day.…”

“…Urolith formation occurs when mucoproteins in the urine coalesce and precipitate with crystals in urine supersaturated with minerals (Belknap and Pugh, 2002). It has been documented in both goats (Gutierrez et al., 2000; George et al., 2007 and Sun et al., 2010a) and giraffes (Wolfe et al., 2000; Sullivan et al., 2010; Webb et al., 2010). If the stones become too numerous or too large, they can cause obstruction of the urethra, especially in castrated male ruminants (Pinsent and Cottom, 1987; Ewoldt et al., 2008).…”

“…Recently, two cases were reported at one institution of magnesium ammonium phosphate stones (Webb et al., 2010). Within the last 10 years, at least seven giraffes have had phosphatic urolithiasis reported as a cause of death, with stones including calcium magnesium phosphate in a carbonate form and struvite noted (Wolfe et al., 2000; Sullivan et al., 2010) and dietary Ca:P ratios of less than 1:1 have been reported (Schlegel et al., 2004). Incidences of death resulting from obstructive urolithiasis have not been reported among wild giraffes, although they may occur.…”

The effects of increased hay‐to‐grain ratio on behavior, metabolic health measures, and fecal bacterial communities in four Masai giraffe (Giraffa camelopardalis tippelskirchi) at Cleveland Metroparks Zoo

“…Urolithiasis is a metabolic disease caused by the trauma or blockage of the urethra and bladder from uroliths, or urine crystals (Smith, ). This condition has been documented in zoo giraffe, with 10 of 41 zoos surveyed reporting conditions related to urolithiasis, and multiple known deaths due to urolith obstruction (Smith, ; Sullivan et al, ; Wolfe, Sladky, & Loomis, ). One possible cause of crystal formation is an imbalance in calcium‐to‐phosphorus ratio (Ca:P) in diet (Smith, ).…”

“…Diets with higher hay‐to‐concentrate ratios produced a decrease in urine crystal count scores (considered a precursor to urolith formation) in meat goats (Sullivan et al, ). In a comparison of varying giraffe diets across five zoos, those with higher concentrate‐to‐hay ratios and thus, higher phosphorus levels tended to have higher serum phosphorus concentrations, which may result in greater risk for phosphatic uroliths (Sullivan et al, ). The rate of saliva secretion has been shown to be higher in cattle while feeding or ruminating than during rest (Bailey & Balch, ).…”