Abstract
Hand-rearing neonatal ruminants can be a challenge, especially for those animals with small body mass. Nutrient intake must begin early and be adequate to prevent weight loss and subsequent organ compromise. There is a limited time period in which an animal can accept a bottle and nurse on it effectively before its body stores are depleted.
If neonatal ruminants do not begin active nursing behavior within a reasonable period of time, gastric tube feedings can be used on a limited basis. Copper sulfate placed on the back of the tongue is required to stimulate closure of the esophageal groove so that milk bypasses the rumen and goes directly to the abomasum. Repeated tubing may cause pharyngeal and esophageal trauma, safe copper levels may be exceeded over time, and the risk of milk induced rumenitis increases over time. Additionally, if an attempt is being made to initiate normal suckling behavior from a bottle, repeated manual restraint in order to pass a tube will be counterproductive.
Placing a feeding tube percutaneously into the abomasum provides an avenue for direct feeding, which eliminates the need for copper sulfate, insures that formula is delivered into the abomasum rather than the rumen, reduces the stress due to manual restraint during conventional tube feeding and allows delivery of adequate nutrients regardless of the nursing behavior of the animal. A technique described by Ensley et al.1 for placement of abomasal feeding tubes via nasal cannulation has the advantage of being a nonsurgical procedure and thus not requiring anesthesia, but requires manufacture of specialized equipment. However, percutaneous placement of a feeding tube allows the animals head to be free of any apparatus and may facilitate more rapid transition to bottle feeding.
Case #1
A maxwell duiker (Cephalophus maxwelli), which had weighted 1.02 kg at birth, was removed from its dam at 6 days of age due to weight loss and maternal neglect. At that time, the animal weight 788 g, was dehyrdrated and thin, and the abdomen felt empty on palpation. Initial attempts at bottle feeding were unsuccessful. Due to it compromised condition, percutaneous abomasal tube placement was performed. The animal was anesthetized via isoflurane via face mask, intubated with a 3.0 mm cuffed endotracheal tube and maintained on 3–5% isoflurane in 2 L/mO2 with intermittent positive pressure ventilation for 70 min. An 18-ga, 2.5-inch spinal needle was placed into the left femoral intraosseous space for administration of fluids and antibiotics. An abomasal feeding tube was placed using the technique described below. Direct abomasal feeding with 5% dextrose in lactated ringers solution began 4 hr later. Subsequently a formula of whole cows milk, colostrum and fluids was used. Volume infused into the abomasum increased to 15 ml per feeding every 3–4 hr over the next 4 days. In addition, attempts were made to get the animal to begin nursing from a bottle. On day 6 after placement of the tube (11 days of age), the animal was consistently taking formula orally. On day 7 the animal was anesthetized and the tube was surgically removed. The i.o. catheter remained in place through 15 days of age. Amikacin sulfate (Amiglyde-V, Fort Dodge Animal Health, Fort Dodge, Iowa 50501 USA) 10 mg/kg i.o., s.i.d. and sodium ampicillin (Ampicillin Sodium USP, Apothecon, Princeton, New Jersey 08540 USA) 50 mg/kg i.o., t.i.d was administered for 10 days followed by ampicillin 50 mg/kg s.c., b.i.d. for an additional 10 days. Solid food was offered beginning at 8 days of age and the animal was eating consistently at 7 wk of age, at which time it weighed 3.3 kg.
Case #2
A 293-g, female, larger Malayan chevrotain (Tragulus napu), was born to a dam with a history of repeated maternal neglect of offspring. Within 6 hr of birth an abomasal feeding tube was placed in the animal using the technique described below. The calf was anesthetized with isoflurane via facemask and an i.o. catheter consisting of a 22-ga, 1.5-inch needle was placed in the left femur. Formula, consisting of 100% cow’s colostrum, was begun 4 hr after tube placement at a rate of 2 ml every 3 hr for four feedings. The formula was then changed to colostrum, Esbilac® (PetAg Inc, Elgin, Illinois 60120 USA) and Multi-Milk® (PetAg) in a ratio of 1 ml colostrum to 1 ml of a mixture of 100 ml Esbilac + 13 g Multi-Milk. Over the ensuing 4 wk the volume delivered through the tube was increased to 9 ml 5 times per day. No attempt was made to initiate bottle feeding. The animal was encouraged to eat solid foods consisting of an herbivore pellet, kale and carrots and to drink water starting on day 5. Amikacin 10 mg/kg s.i.d. and sodium ampicillin 50 mg/kg t.i.d. were administered i.o. for 3 days. Subsequently, the amikacin was administered i.m. for 5 days and the ampicillin s.c., t.i.d. for 13 days followed by the ampicillin being given 20 mg/kg s.c., b.i.d. for an additional 8 days. Penicillin G Benzathine and Penicillin G Procaine (Flo-Cillin, Fort Dodge Animal Health, Fort Dodge, Iowa 50501 USA) 50,000 IU/kg was administered s.c., s.i.d. from day 25–34. The animal’s weight when the feeding tube was removed at day 28 was 670 g.
Percutaneous abomasal tube placement: The animals are placed in right lateral recumbency to facilitate clipping and surgical preparation of the left dorso-lateral abdomen. A 1- to 2-cm paramedian skin incision, dorsal lateral to the 8th-10th rib is made. Blunt dissection through muscle layers is performed until the peritoneum is encountered and penetrated. The abomasum is blindly grasped by passing a tissue forceps or hemostat ventrally along the body wall cranio-medial. When the abomasum is encountered it is grasped and gently retracted toward the incision from underneath the rumen. A stay suture is placed in the wall of the abomasum and an incision is made into the lumen so that an appropriate size catheter or feeding tube can be placed. The feeding tube is directed caudally towards the pylorus, a purse string suture is placed around the tube and through the wall of the abomasum. If a Foley catheter is used it is partially inflated at that time. One suture is placed through the serosa of the abomasum to attach the abomasum to the body wall, and then peritoneum and muscle layers are closed in routine fashion around the tube. The tube is sutured to the animal’s back in two sites. A sterile dressing is placed over the incision and around the base of the tube and a light body wrap is applied over that. The end of the tube is closed with an adapter and an injection cap.
Discussion
Mother reared maxwell duikers typically gain 30–70 g/day in the first 2 wk of life. The fact that the animal in this report had lost almost 25% of its body wt in the first week meant that it was severely calorically challenged and in danger of an imminent crisis. Usually animals that are this stressed are presented comatose, hypoglycemic and close to death. In these cases immediate rehydration and early nutrient delivery is essential for survival. It is our experience that waiting for an animal to learn to nurse at this stage often results in death. Teaching or developing an appropriate nursing behavior takes time and cannot be reliably used with animals that are “on the edge.” The abomasal feeding tube allowed for appropriate feeding while bottle training ensued.
Chevrotain birth wt range from 260–320 g for healthy neonates. Mother reared calves gain 30–50 g/day and double their birth wt within 10–14 days. Previous attempts at hand rearing underweight babies or those that had experienced maternal neglect and weight loss, using conventional methods, were usually unsuccessful. In this case, the calf was removed for abomasal feeding tube placement and hand rearing before its health became compromised. Nutrient delivery began within 12 hr of birth before weight loss or dehydration could occur. Subsequent weight gains were less than a mother reared animal but adequate for growth.
Literature Cited
1. Ensley, P.K., B.S. Saunders, and K.C. Fletcher. 1977. Use of an indwelling nasoabomasal tube for feeding of weak neonatal exotic ruminants. J Am Vet Med Assoc 171:9:984–987.