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You are here: Home / Publications / Bibliographies and Resource Guides / Information Resources on Spaying and Neutering Cats, Dogs and Related Wildlife / Early Spay-Neuter  Printer Friendly Page
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Information Resources on Spaying and Neutering Cats, Dogs and Related Wildlife
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Early Spay-Neuter

Anonymous (2001). When should bitches be neutered. The Veterinary Record 148(16): 491-493. ISSN: 0042-4900.
NAL Call Number: 41.8 V641
Descriptors: attitude of health personnel, dogs, ovariectomy, age factors, postoperative complications.

Aronsohn, M.G. and A.M. Faggella (1993). Surgical techniques for neutering 6- to 14-week-old kittens. Journal of the American Veterinary Medical Association 202(1): 53-55. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: Ninety-six kittens (48 males and 48 females) between the ages of 6 and 14 weeks were neutered. There were no important anesthetic complications, or complications during or after surgery. Pediatric neutering of kittens is a low-risk procedure when specific guidelines are followed. It is recommended that a complete preanesthetic evaluation be performed, a quiet and warm preoperative and postoperative environment be provided, handling of kittens be minimized, bleeding during surgery be meticulously controlled, fragile pediatric tissues be handled gently, kittens be offered food shortly after standing to prevent hypoglycemia, and dextrose be administered PO or IV if recovery is prolonged.
Descriptors: age factors, animals, castration, cat diseases, cats, cryptorchidism, female, intraoperative complications, male, postoperative complications.

Buff, S. (2001). Reproduction des carnivores domestiques: Sterilisation tres precoce: de nombreux avantages [Early neutering in dogs and cats: numerous advantages]. Le Point Veterinaire 32(221): 52-54. ISSN: 0303-4997.
NAL Call Number: SF602.P6
Descriptors: age, bones, castration, hysterectomy, mammary gland neoplasms, ovariectomy, prostate, young animals.
Language of Text: French; Summary in English.

Buff, S. (2001). Reproduction des carnivores domestiques. Sterilisation tres precoce: de nombreux avantages [Early neutering in dogs and cats: numerous advantages]. Le Point Veterinaire 32(221): 52-54. ISSN: 0335-4997.
NAL Call Number: SF602.P6
Descriptors: dogs, cats, sterilization, males, females, age, timing, canidae, carnivora, felidae, mammals, sex.
Language of Text: French.

Buff, S. and A.J. de Vargas Cheuiche (2002). Castracao e ovariectomia de filhotes: um procedimento com muitas vantagens [Early neutering of dogs and cats: numerous advantages]. A Hora Veterinaria 22(127): 58-60. ISSN: 0101-9163.
Descriptors: age, castration, kittens, male genital diseases, mammary gland neoplasms, puppies.
Language of Text: Portuguese; Summary in English and French.

Carrig, C.B., I.M. Gourley, and A.L. Philbrick (1972). Primary abdominal pregnancy in a cat subsequent to ovariohysterectomy. Journal of the American Veterinary Medical Association 160(3): 308-318. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: ovariectomy, cat diseases, pregnancy complications, postoperative complications.

Chalifoux, A., G. Niemi, P. Fanjoy, and B. Pukay (1981). Early spay-neutering of dogs and cats. The Canadian Veterinary Journal: La Revue Veterinaire Canadienne 22(12): 381. ISSN: 0008-5286.
NAL Call Number: 41.8 R3224
Descriptors: postoperative complications, gonadectomy, dogs, cats.

Dowling, S.P. (1997). Opposition to prepubertal gonadectomies in cats. Journal of the American Veterinary Medical Association 210(3): 321. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: risk of early spay neuter, lower urinary tract disease.
Notes: This letter provides comment on (Stubbs et. al., 1996).

Faggella, A.M. and M.G. Aronsohn (1993). Anesthetic techniques for neutering 6- to 14-week-old kittens. Journal of the American Veterinary Medical Association 202(1): 56-62. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: Forty-eight male and 48 female 6- to 14-week-old kittens were neutered by use of 4 anesthetic protocols. Preanesthetic disposition, depth of sedation, loss of resistance to handling, induction quality, induction time, sternal and stand times, and recovery quality were evaluated. Analgesia and muscle relaxation without supplemental inhalational anesthetics were evaluated in male kittens, and the time until extubation was recorded in female kittens. Intramuscular administration of tiletamine/zolazepam (TZ), midazolam/ketamine, atropine/midazolam/ketamine/butorphanol (AMKB), and atropine/midazolam/ketamine/oxymorphone (AMKO) produced rapid sedation and smooth induction into anesthesia. In male kittens, there were no significant differences in sedation, relaxation, induction time, or quality. Tiletamine/zolazepam administration induced the best analgesia, and midazolam/ketamine administration induced the least analgesia for castration. The recovery time in male kittens was longest with TZ and shortest with the opioid groups (AMKB, AMKO). In females, TZ produced significantly faster induction times, but the degree of sedation and relaxation after administration of injectable agents was not significantly different among the groups. More females given TZ could be intubated without supplemental inhalational agents than females in other groups. Extubation time was rapid in all groups, but the times until sternal and standing were significantly longer, and recovery quality was significantly poorer in females given TZ. In kittens given opioids, reversal of the opioid did not shorten recovery time or improve recovery quality.
Descriptors: analgesia, anesthesia, butorphanol, castration, cats, drug combinations, drug effects on heart rate and respiration, ketamine, midazolam, oxymorphone, preanesthetic medication, tiletamine, zolazepam.

Faggella, A.M. and M.G. Aronsohn (1994). Evaluation of anesthetic protocols for neutering 6- to 14-week-old pups. Journal of the American Veterinary Medical Association 205(2): 308-14. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: Ninety-nine 6- to 14-week-old pups were given anesthetic agents according to 10 anesthetic protocols. Mean quality rating scores were determined to compare anesthetic protocols. In male pups, IV administration of propofol (6.5 mg/kg of body weight) 15 minutes after IM administration of atropine (0.04 mg/kg) and oxymorphone (0.22 mg/kg) provided the best quality anesthesia. Intramuscular administration of midazolam (0.22 mg/kg) and butorphanol (0.44 mg/kg) instead of oxymorphone provided little sedation, but induced good analgesia. Atropine/oxymorphone/midazolam/xylazine, atropine/butorphanol/midazolam/xylazine, and tiletamine/zolazepam were unsatisfactory combinations for use in castration of 6- to 14-week-old male pups. In female pups, IV administration of propofol (3.4 mg/kg) 15 minutes after IM administration of atropine (0.04 mg/kg) and oxymorphone (0.11 mg/kg) was the most effective anesthetic protocol. Administration of the drugs according to this protocol enabled a pup to be intubated. Anesthesia was maintained with isoflurane in oxygen. If inhalational induction was preferred, IM administration of 13.2 mg of tiletamine/zolazepam/kg, 0.04 mg of atropine/kg and 0.11 mg of oxymorphone/kg, or 0.22 mg of midazolam/kg and 0.44 mg of butorphanol/kg may be used prior to mask delivery of inhalational anesthetics. In female pups, it was not advantageous to combine midazolam with oxymorphone, and use of high dosages of oxymorphone (0.22 mg/kg) or midazolam/butorphanol provided little sedation. Time of recovery after use of tiletamine/zolazepam was the longest for the combinations used, but did not adversely affect pups. Male pups were castrated via scrotal incisions, using hemostatic clips. Ovariohysterectomies were performed via a ventral abdominal midline approach, using hemostatic clips for ligation, five females developed signs of inflammation at the surgical site within 1 to 2 weeks after surgical, and were treated conservatively with warm compresses.
Descriptors: anesthesia, dogs, hysterectomy, orchiectomy, ovariectomy, analgesia, adverse effects of anesthetics, muscle relaxation, postoperative complications.

Goeree, G. (1998). Pediatric neuters can be technically challenging. The Canadian Veterinary Journal: La Revue Veterinaire Canadienne 39(4): 244. ISSN: 0008-5286.
NAL Call Number: 41.8 R3224
Descriptors: kittens, puppies, castration, ovariectomy.

Gourley, J. (1997). When to spay dogs and cats. The Veterinary Record 140(4): 104. ISSN: 0042-4900.
NAL Call Number: 41.8 V641
Descriptors: age, animals, methods of castration, cats, dogs, sex maturation, prepubertal gonadectomy.

Guarneri Boe, M.A. and D. Lange (1995). When to neuter: the controversy. Iowa State University Veterinarian 57(1): 6-9. ISSN: 0099-5851.
Descriptors: kittens, surgery, age, anaesthesia, postoperative complications, castration, cats.

Gunzel-Apel, A.R. (1998). Fruhkastration von Hunden und Katzen unter Tierschutzgesichtspunkten [Early castration of dogs and cats from the point of view of animal welfare]. Deutsche Tierärztliche Wochenschrift 105(3): 95-98. ISSN: 0341-6593.
NAL Call Number: 41.8 D482
Abstract: The castration of dogs and cats is regulated in section 6 of the German Law for Prevention of Cruelty To Animals (Tierschutzgesetz) dated February 17, 1993. Gonadectomy in juvenile and prepuberal as well as in adult vertebrates is only permitted by law in case of a medical indication or a special using of the animal. On account of his special knowledge, the veterinarian is made responsible by law for the estimation of the indispensibility and for the performance of castration. As early-age castration means usually the surgical removal of healthy gonads from a healthy organism, it is principally forbidden by law at present. The bill of June 30, 1995 points to the legitimation of castration for contraception. This does, however, not dispense the veterinarian from deciding in each individual case under consideration of unwanted side effects and consequences that can be caused by castration and early-age castration, respectively.
Descriptors: animal welfare, prepubertal gonadectomy, castration, ovariectomy, sex maturation, cats, dogs.
Language of Text: German, Summary in English.

Hart, B.L. and L. Cooper (1984). Factors relating to urine spraying and fighting in prepubertally gonadectomized cats. Journal of the American Veterinary Medical Association 184(10): 1255-1258. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: cats, castration, fighting, scent marking behavior.

Herron, M. (1972). The effect of prepubertal castration on the penile urethra of the cat. Journal of the American Veterinary Medical Association 160(2): 208-211. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: castration, cats, male, penis, testosterone, time factors, urethra.

Hilsenroth, R. (1999). Pediatric neutering of dogs. Canine Practice 24(1): 24. ISSN: 1057-6622.
NAL Call Number: SF991.A1C3
Descriptors: puppies, castration, age.

Hoskins, J.D. (1999). Paediatrics: puppies and kittens. The Veterinary Clinics of North America: Small Animal Practice 29(4): 837-1027. ISSN: 0195-5616.
NAL Call Number: SF601.V523
Descriptors: pediatrics, young animal diseases, congenital abnormalities, cat diseases, dog diseases, newborn animals, veterinary practice, mycoses, helminthoses, myiasis, protozoal infections, viral diseases, bacterial diseases.

Howe, L.M. (1999). Prepubertal gonadectomy in dogs and cats. I. Compendium on Continuing Education for the Practicing Veterinarian 21(2): 103-111, 176. ISSN: 0193-1903.
NAL Call Number: SF601.C66
Descriptors: puppies, kittens, castration, ovariectomy, preanesthetic medication, anesthesia, body heat loss, clinical examination, fluid therapy.

Howe, L.M. (1999). Prepubertal gonadectomy in dogs and cats. II. Compendium on Continuing Education for the Practicing Veterinarian 21(3): 197-201, 267. ISSN: 0193-1903.
NAL Call Number: SF601.C66
Descriptors: puppies, kittens, ovariectomy, castration, tattooing, postoperative complications.

Howe, L.M. (1997). Short-term results and complications of prepubertal gonadectomy in cats and dogs. Journal of the American Veterinary Medical Association 211(1): 57-62. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: OBJECTIVE: To determine short-term results and complications of prepubertal gonadectomy in cats and dogs. DESIGN: Prospective randomized study. ANIMALS: 775 cats and 1,213 dogs. PROCEDURE: Animals undergoing gonadectomy were allotted into 3 groups on the basis of estimated age (group 1, < 12 weeks old; group 2, 12 to 23 weeks old; group 3, > or = 24 weeks old). Complications during anesthesia, surgery, and the immediate postoperative period (7 days) were recorded. Complications were classified as major (required treatment and resulted in an increase in morbidity or mortality) or minor (required little or no treatment and caused a minimal increase in morbidity). An ANOVA was used to detect differences among groups in age, weight, body temperature, and duration of surgery. To detect differences in complication rates among groups, chi 2 analysis was used. RESULTS: Group 1 consisted of 723 animals, group 2 consisted of 532, and group 3 consisted of 733. Group-3 animals had a significantly higher overall complication rate (10.8%) than group-1 animals (6.5%), but did not differ from group-2 animals (8.8%). Differences were not detected among the 3 groups regarding major complications (2.9, 3.2, and 3.0% for groups 1, 2, and 3, respectively), but group-3 animals had significantly more minor complications (7.8%) than group-1 animals (3.6%), but not group-2 animals (5.6%). CLINICAL IMPLICATIONS: In this study, prepubertal gonadectomy did not increase morbidity or mortality on a short-term basis, compared with gonadectomy performed on animals at the traditional age. These procedures may be performed safely in prepubertal animals, provided that appropriate attention is given to anesthetic and surgical techniques.
Descriptors: age factors, cats, dogs, adverse effects of hysterectomy, orchiectomy, ovariectomy, population control, postoperative complications.

Howe, L.M. and P.N. Olson (2000). Prepubertal gonadectomy: early-age neutering of dogs and cats. In: P. Concannon, E. England and J. Verstegen (editors), Recent Advances in Small Animal Reproduction, International Veterinary Information Service: Ithaca, NY.
Online: http://www.ivis.org (requires login)
Descriptors: online article, early-age neutering, side effects, recovery times, pet overpoulation, gonadectomy, risks, benefits, veterinarians.

Howe, L.M., M.R. Slater, H.W. Boothe, H.P. Hobson, T.W. Fossum, A.C. Spann, and W.S. Wilkie (2000). Long-term outcome of gonadectomy performed at an early age or traditional age in cats. Journal of the American Veterinary Medical Association 217(11): 1661-1665. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: OBJECTIVE: To determine long-term results and complications of gonadectomy performed at an early age (prepubertal) or at the traditional age in cats. DESIGN: Cohort study. ANIMALS: 263 cats from animal shelters. PROCEDURE: Cats that underwent gonadectomy were allotted to 2 groups on the basis of estimated age at surgery (traditional age, > or = 24 weeks old; prepubertal, < 24 weeks old). Adoptive owner information was obtained from shelter records, and telephone interviews were conducted with owners to determine physical or behavioral problems observed in the cats after adoption. Follow-up information was obtained from attending veterinarians for cats with complex problems or when owners were uncertain regarding the exact nature of their cat's problem. RESULTS: Compared with traditional-age gonadectomy, prepubertal gonadectomy did not result in an increased incidence of infectious disease, behavioral problems, or problems associated with any body system during a median follow-up period of 37 months. Additionally, the rate of retention in the original adoptive household was the same for cats that underwent prepubertal gonadectomy as those that underwent traditional-age gonadectomy. CONCLUSIONS AND CLINICAL RELEVANCE: Prepubertal gonadectomy may be performed safely in cats without concern for increased incidence of physical or behavioral problems for at least a 3-year period after gonadectomy.
Descriptors: prepubertal gonadectomy, cats, animal welfare, animal behavior, age factors, follow-up studies.

Howe, L.M., M.R. Slater, H.W. Boothe, H.P. Hobson, J.L. Holcom, and A.C. Spann (2001). Long-term outcome of gonadectomy performed at an early age or traditional age in dogs. Journal of the American Veterinary Medical Association 218(2): 217-221. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: OBJECTIVE: To determine long-term results and complications of gonadectomy performed at an early age (prepubertal) or at the traditional age in dogs. DESIGN: Cohort study. ANIMALS: 269 dogs from animal shelters. PROCEDURE: Dogs that underwent gonadectomy were allotted to 2 groups on the basis of estimated age at surgery (traditional age, > or =24 weeks old; prepubertal, < 24 weeks old). Adoptive owner information was obtained from shelter records, and telephone interviews were conducted with owners to determine physical or behavioral problems observed in the dogs since adoption. Follow-up information was obtained from attending veterinarians for dogs with complex problems or when owners were uncertain regarding the exact nature of their dog's problem. RESULTS: Prepubertal gonadectomy did not result in an increased incidence of behavioral problems or problems associated with any body system, compared with traditional-age gonadectomy, during a median follow-up period of 48 months after gonadectomy. Rate of retention in the original adoptive household was the same for dogs that underwent prepubertal gonadectomy as those that underwent traditional-age gonadectomy. Infectious diseases, however, were more common in dogs that underwent prepubertal gonadectomy. CONCLUSIONS AND CLINICAL IMPLICATIONS: With the exception of infectious diseases, prepubertal gonadectomy may be safely performed in dogs without concern for increased incidence of physical or behavioral problems during at least a 4-year period after gonadectomy.
Descriptors: animal behavior, early age gonadectomy, ovariectomy, orchiectomy, prepubertal gonadectomy, dogs, animal shelter, questionnaires.

Hughes, A. (2000). Early neutering of dogs. The Veterinary Record 147(20): 584. ISSN: 0042-4900.
NAL Call Number: 41.8 V641
Descriptors: age factors, dogs, sterilization, prepubertal gonadectomy.

Ingo, N. (2000). Kutyák és macskák korai kasztrációja orvosi szempontból [Early castration of the dog and the cat seen from a medical point of view]. Magyar Allatorvosok Lapja 122(9): 569-570. ISSN: 0025-004X.
Descriptors: castration, companion animals, veterinary surgery, non-drug therapy.
Language of Text: Hungarian.

Juhr, N.C. (2001). Die fruehkastration von Hunden aus der sicht der verhaltenskunde [Early castration of dogs from the point of view of behavior]. Tieraerztliche Umschau 56(4): 199-200. ISSN: 0049-3864.
NAL Call Number: 41.8 T445
Descriptors: dogs, castration, sterilization method, behavioral problems, urine marking.
Language of Text: German.

Kustritz, M.V. (2002). Early spay-neuter: clinical considerations. Clinical Techniques in Small Animal Practice 17(3): 124-128. ISSN: 1096-2867.
NAL Call Number: SF911.S45
Abstract: Early spay-neuter is ovariohysterectomy or castration of puppies or kittens 6 to 14 weeks of age. Pediatric animals may have an enhanced response to relatively low doses of anesthetic agents. Animals should be fasted no more than 3 to 4 hours before surgery to prevent hypoglycemia, and hypothermia should be avoided. Heart and respiratory rates must be monitored carefully throughout anesthesia. Pediatric gonadectomy surgeries are quick with minimal bleeding. Anesthetic recovery is rapid. No significant short-term or long-term effects have been reported. Prepuberal gonadectomy is most useful for humane organizations and conscientious breeders wishing to preclude reproduction of pet dogs and cats while placing animals at a young enough age to optimize socialization and training.
Descriptors: anesthesia, animals, cats, dogs, orchiectomy, ovariectomy.

Kustritz, M.V. (1999). Early spay-neuter in the dog and cat. The Veterinary Clinics of North America: Small Animal Practice 29(4): 935-943. ISSN: 0195-5616.
NAL Call Number: SF601.V523
Abstract: Early spay-neuter refers to the surgical sterilization of 8- to 16-week-old animals. Anesthetic and surgical techniques for the dog and cat are described. Pros and cons of prepubertal gonadectomy are discussed, and the veterinary literature is reviewed.
Descriptors: surgical sterilization, prepubertal gonadectomy, anesthesia, veterinary surgery, dog, cat, age factors.

Levy, J.K. (1997). Pros and cons of prepuberal gonadectomy. Journal of the American Veterinary Medical Association 210(7): 891. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: age of castration, benefits of early spay-neuter, surgical techniques, lower urinary tract disease.
Notes: This letter provides comment on (Dowling, 1997).

Lieberman, L.L. (1997). Pros and cons of prepuberal gonadectomy. Journal of the American Veterinary Medical Association 210(7): 891. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: feline urologic syndrome, age of gonadectomy, shelter management.
Notes: Comment on article from J Am Vet Med Assoc. 1997 Feb 1; 210(3):321 (Dowling, 1997).

Lieberman, L. (1987). A case for neutering pups and kittens at two months of age. Journal of the American Veterinary Medical Association 191(5): 518-521. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: dogs, cats, gonadectomy, age, young animals.

Lussier, B. (2001). La sterilisation en bas age chez le chien et le chat [Prepuberal gonadectomy in dogs and cats]. Le Medecin Veterinaire Du Quebec 31(2): 82-85. ISSN: 0225-9591.
Descriptors: anesthesia, prepubertal gonadectomy, surgical method, dogs, cats.
Language of Text: French.

Mackie, W.M. (2000). Early age neutering: perfect for every practice. Proceedings of the North American Veterinary Conference: Small Animal and Exotics Edition,Orlando, FL, Eastern States Veterinary Association: Gainesville, FL, Vol. 14, p. 653-655.
NAL Call Number: SF605.N672
Descriptors: dogs, cats, prepubertal gonadectomy, shelters, anesthesia.

May, C. (1998). Orthopaedic effects of prepubertal neutering in dogs. The Veterinary Record 142(3): 71-72. ISSN: 0042-4900.
NAL Call Number: 41.8 V641
Descriptors: radius, ulna, castration, surgery, dogs, prepubertal gonadectomy.

Olson, P.N. (2000). The history and politics of early spay neuter. Proceedings of the North American Veterinary Conference: Small Animal and Exotics Edition, Orlando, FL, Eastern States Veterinary Association: Gainesville, FL, Vol. 14, p. 657-658.
NAL Call Number: SF605.N672
Descriptors: dogs, cats, prepubertal gonadectomy, age factors, historical background.

Olson P.N. (2003). Prepuberal gonadectomy (early-age neutering) of dogs and cats. In: M.V. Root Kustritz (editor), Small Animal Theriogenology, Butterworth Heinemann: St. Louis, p. 165-181. ISBN: 0-7506-7408-3.
Descriptors: animal health, animal welfare, bodyweight, gonadectomy, penis, prepuce, surgical operations, urethra, vulva.

Olson, P.N. (1993). Prepubertal gonadectomy. California Veterinarian 47(4): 5-6. ISSN: 0008-1612.
NAL Call Number: 41.8 C12
Descriptors: pets, animal welfare, complications, young animals, castration, ovariectomy, cats, dogs

Olson, P.N., M.V. Kustritz, and S.D. Johnston (2001). Early-age neutering of dogs and cats in the United States (a review). Journal of Reproduction and Fertility Supplement 57: 223-232. ISSN: 0449-3087.
NAL Call Number: 442.8 J8222 Suppl.
Abstract: Prepubertal gonadectomy, often referred to as early-age neutering, has increased in popularity in the United States. The procedure is often used at animal care and control facilities, where puppies and kittens are neutered as early as 7 weeks of age or before adoption. Although the anaesthetic and surgical procedures appear to be safe, studies continue to evaluate the long-term effects on health and behaviour. Early-age neutering is one technique that is used to combat pet overpopulation, a problem whereby millions of unwanted healthy dogs and cats are euthanased each year. Although neutering animals is helpful in controlling pet overpopulation, other factors must be considered. In addition, many animals are relinquished to shelters when they show inappropriate behaviours, because owners and veterinarians are unable to modify animal behaviour. This review discusses early-age neutering in the United States, and includes the review of scientific studies that have evaluated this procedure in puppies and kittens. Early-age neutering does not stunt growth in dogs or cats (a once-held belief), but may alter metabolic rates in cats. The anaesthetic and surgical procedures are apparently safe for young puppies and kittens; morbidity is lower and recovery is faster than in adult animals. To date, adverse side effects are apparently no greater in animals neutered at early ages (7 weeks) than in those neutered at the conventional age (7 months).
Descriptors: anesthesia, prepubertal gonadectomy, cats, dogs, possible adverse effects, castration, orchiectomy, orchidectomy, hysterectomy, animal behavior.

Patel, C.M. and D. Yates (2003). Evaluation of an anaesthetic protocol for the neutering of eight- to 12-week-old puppies. The Veterinary Record 152(14): 439-440. ISSN: 0042-4900.
NAL Call Number: 41.8 V641
Descriptors: aging, adverse effects of anesthesia, inhalation anesthetics, intravenous anesthetics, animal, castration, dogs.

Poole, C. (1997). Early neutering of cats and dogs. The Veterinary Record 141(23): 608. ISSN: 0042-4900.
NAL Call Number: 41.8 V641
Descriptors: animal welfare, cats, dogs, female, male, sterilization, adverse effects.

Richardson, E.F. (1992). Prepubescent spay and neuter program proposed [for cats and dogs]. California Veterinarian 46(6): 28-29. ISSN: 0008-1612.
NAL Call Number: 41.8 C12
Descriptors: surgical operations, complications, sexual maturity, ovariectomy, castration, cats, dogs.

Roken, M. (2002). Prepubertal kastration av katt -- mojlighet eller risk? [Prepubertal neutering of the cat -- a possibility or a risk?]. Svensk Veterinartidning 54(12): 577-585. ISSN: 0346-2250.
NAL Call Number: 41.9 SV23
Descriptors: age, anesthesia, animal behavior, body temperature, castration, drug excretion, drug metabolism, hemorrhage, hypoglycemia, kittens, morbidity, obesity, ovariectomy, recovery, risk, surgery, surgical operations, cats.

Romatowski, J. (1993). Early-age neutering, an "uncontrolled experiment". Journal of the American Veterinary Medical Association 203(11): 1523. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: castration, cats, dogs, postoperative complications, age factors.
Notes: Comment On: J Am Vet Med Assoc. 1993 Sep 1;203(5):591-3.

Root, M.V., S.D. Johnston, G.R. Johnston, and P.N. Olson (1996). The effect of prepuberal and postpuberal gonadectomy on penile extrusion and urethral diameter in the domestic cat. Veterinary Radiology and Ultrasound 37(5): 363-366. ISSN: 1058-8183.
NAL Call Number: SF757.8.A4
Descriptors: cats, gonadectomy, age, sexual maturity, penis, urethra, diameter, radiography, analytical methods, body parts, carnivora, developmental stages, dimensions, felidae, genital system, male genital system, mammals, maturity, sterilization, surgical operations, urinary tract, urogenital system, cystourethrography, puberty.

Root, M.V., S.D. Johnston, and P.N. Olson (1996). Effect of prepuberal and postpuberal gonadectomy on heat production measured by indirect calorimetry in male and female domestic cats. American Journal of Veterinary Research 57(3): 371-4. ISSN: 0002-9645.
NAL Call Number: 41.8 Am3A
Abstract: OBJECTIVE--To use indirect calorimetry to compare heat production between gonadectomized and sexually intact male and female cats. DESIGN--Male (n = 6) and female (n = 6) kittens were gonadectomized at 7 weeks or 7 months of age, or left sexually intact. Body heat production was measured by indirect calorimetry in all cats at 12, 18, and 24 months of age. ANIMALS--18 male and 18 female clinically normal domestic shorthair cats. PROCEDURE--Heat production was measured, using an open-circuit, respiratory, indirect calorimeter. All cats underwent calorimetry at 12, 18, and 24 months of age. The heat coefficient, a measure of resting metabolic rate, was calculated for each cat at each test; heat coefficient is defined as logarithm of heat (kcal/h) divided by logarithm of body weight (kg). RESULTS--Heat production did not vary with age in male or female cats. Heat coefficient was higher in sexually intact male and female cats than in gonadectomized male and female cats at 12, 18, and 24 months of age (12 months, females, P < 0.01, males, P = 0.04; 18 months, females, P < 0.01, males, P = 0.02; and 24 months, females and males, P < 0.01). CONCLUSIONS--These data suggest that resting metabolic rate in cats decreases after gonadectomy. CLINICAL RELEVANCE--A decrease in metabolic rate is synonymous with a decrease in caloric requirements. Gonadectomized animals fed in a manner similar to sexually intact animals may be predisposed to obesity and its sequelae.
Descriptors: calorimetry, cats, comparative study, dogs, orchiectomy, ovariectomy, sex maturation, reproducibility of results.

Root, M.V., S.D. Johnston, and P.N. Olson (1997). The effect of prepuberal and postpuberal gonadectomy on radial physeal closure in male and female domestic cats. Veterinary Radiology and Ultrasound 38(1): 42-47. ISSN: 1058-8183.
NAL Call Number: SF757.8.A4
Descriptors: cats, bone formation, growth, gonadectomy, puberty, sex-differences, age at gonadectomy, bone growth.

Root, M.V. (1995). The effect prepuberal and postpuberal gonadectomy on the general health and development of obesity in the male and female domestic cat. Dissertation, University of Minnesota: 179 p.
Descriptors: cat, obesity, gonadectomy.

Root, M. (1995). Early spay-neuter in the cat: Effect on development of obesity and metabolic rate. Veterinary Clinical Nutrition 2: 132-134. ISSN: 1076-3872.
Descriptors: early spay-neuter, cats, obesity, metabolic rate.

Root, M., S. Johnston, G. Johnston, and P. Olson (1996). The effect of prepubertal and postpubertal gonadectomy on penile extrusion and urethral diameter in the domestic cat. Veterinary Radiology and Ultrasound 37(5): 363-366. ISSN: 1058-8183.
NAL Call Number: SF757.8.A4
Descriptors: cats, gonadectomy, puberty, age, penis, urethra, diameter, radiography.

Salmeri, K.R. (2000). Health effects of early-age neutering. In: Proceedings of the North American Veterinary Conference: Small Animal and Exotics Edition,Orlando, FL, Eastern States Veterinary Association: Gainesville, FL, Vol. 14, p. 659-660.
NAL Call Number: SF605.N672
Descriptors: dogs, cats, gonadectomy, age, adverse effects, secondary sex characteristics, weight gain, skeletal growth, behavior, gonadal hormones, urethral function.

Salmeri, K., M. Bloomberg, S. Scrugs, and V. Shille (1991). Gonadectomy in immature dogs: effects on skeletal, physical, and behavioral development. Journal of the American Veterinary Medical Association 198(7): 1193-1203. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: dogs, castration, ovariectomy, skeletal development, feed intake, liveweight gain, animal behavior, body fat, secondary sexual traits.

Spain, C., J. Scarlett, and K. Houpt (2004). Long-term risks and benefits of early-age gonadectomy in cats. Journal of the American Veterinary Medical Association 224(3): 372-379. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: OBJECTIVE: To evaluate the long-term risks and benefits of early-age gonadectomy, compared with traditional-age gonadectomy, among cats adopted from a large animal shelter. DESIGN: Retrospective cohort study. ANIMALS: 1,660 cats. PROCEDURE: Cats underwent gonadectomy and were adopted from an animal shelter before 1 year of age; follow-up was available for as long as 11 years after surgery (median follow-up time, 3.9 years). Adopters completed a questionnaire about their cats' behavior and medical history. When possible, the cats' veterinary records were reviewed. Statistical analyses were conducted to identify any associations between the occurrence of 47 medical and behavioral conditions and the cats' age at gonadectomy. RESULTS: Among male cats that underwent early-age gonadectomy (< 5.5 months of age), the occurrence of abscesses, aggression toward veterinarians, sexual behaviors, and urine spraying was decreased, whereas hiding was increased, compared with cats that underwent gonadectomy at an older age. Among male and female cats that underwent early-age gonadectomy, asthma, gingivitis, and hyperactivity were decreased, whereas shyness was increased. CONCLUSIONS AND CLINICAL RELEVANCE: Gonadectomy before 5.5 months of age was not associated with increased rates of death or relinquishment or occurrence of any serious medical or behavioral condition and may provide certain important long-term benefits, especially for male cats. Animal shelters can safely gonadectomize cats at a young age, and veterinarians should consider recommending routine gonadectomy for client-owned cats before the traditional age of 6 to 8 months.
Descriptors: prepubertal gonadectomy, cats, adoption, animal shelter, questionnaires, benefits, recommendations.

Spain, C., J. Scarlett, and K. Houpt (2004). Long-term risks and benefits of early-age gonadectomy in dogs. Journal of the American Veterinary Medical Association 224(3): 380-387. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: OBJECTIVE: To evaluate the long-term risks and benefits of early-age gonadectomy, compared with traditional-age gonadectomy, among dogs adopted from a large animal shelter. DESIGN: Retrospective cohort study. ANIMALS: 1,842 dogs. PROCEDURE: Dogs underwent gonadectomy and were adopted from an animal shelter before 1 year of age; follow-up was available for as long as 11 years after surgery. Adopters completed a questionnaire about their dogs' behavior and medical history. When possible, the dogs' veterinary records were reviewed. Associations between the occurrence of 56 medical and behavioral conditions and dogs' age at gonadectomy were evaluated. RESULTS: Among female dogs, early-age gonadectomy was associated with increased rate of cystitis and decreasing age at gonadectomy was associated with increased rate of urinary incontinence. Among male and female dogs with early-age gonadectomy, hip dysplasia, noise phobias, and sexual behaviors were increased, whereas obesity, separation anxiety, escaping behaviors, inappropriate elimination when frightened, and relinquishment for any reason were decreased. CONCLUSIONS AND CLINICAL RELEVANCE: Because early-age gonadectomy appears to offer more benefits than risks for male dogs, animal shelters can safely gonadectomize male dogs at a young age and veterinary practitioners should consider recommending routine gonadectomy for client-owned male dogs before the traditional age of 6 to 8 months. For female dogs, however, increased urinary incontinence suggests that delaying gonadectomy until at least 3 months of age may be beneficial.
Descriptors: prepubertal gonadectomy, adoption, animal shelter, questionnaire, complications, cystitis, urinary incontinence, behavior, benefits.

Stocklin-Gautschi N.M., Hassig M., Reichler I.M., and A.S. Hubler M. (2001). The relationship of urinary incontinence to early spaying in bitches. Journal of Reproduction and Fertility 57(Suppl.): 233-236. ISSN: 0449-3087.
NAL Call Number: 442.8 J8222 Suppl.
Abstract: It is still controversial whether a bitch should be spayed before or after the first oestrus. It would be desirable to spay bitches at an age that would minimize the side effects of neutering. With regard to the risk of mammary tumours, early spaying must be recommended because the incidence of tumours is reduced considerably. The aim of the present study was to determine whether early spaying also reduces the risk of urinary incontinence. The owners of 206 bitches that had been spayed before their first oestrus and for at least 3 years were questioned on the occurrence of urinary incontinence as a result of spaying. At the time of the enquiry the average age of the bitches was 6.5 years, and the average age at the time of surgery was 7.1 months. Urinary incontinence after spaying occurred in 9.7% of bitches. This incidence is approximately half that of spaying after the first oestrus. Urinary incontinence affected 12.5% of bitches that were of a large body weight (> 20 kg body weight) and 5.1% of bitches that were of a small body weight (< 20 kg body weight). The surgical procedure (ovariectomy versus ovariohysterectomy) had no influence on the incidence, or on the period between spaying and the occurrence of urinary incontinence. Urinary incontinence occurred on average at 2 years and 10 months after surgery and occurred each day, while the animals were awake or during sleep. However, compared with late spaying the clinical signs of urinary incontinence were more distinct after early spaying.
Descriptors: early spay-neuter, complications, mammary tumor development, urinary incontinence, ovariectomy, ovariohysterectomy.

Stolla R (2002). Spaying before or after first heat? Pros and cons. Tierarztliche Praxis 30(5): 333-338. ISSN: 1434-1239.
NAL Call Number: SF603.V433
Descriptors: adverse effects, age, biological development, bitches, dermatitis, incidence, mammary gland neoplasms, neoplasms, oestrus, ovariectomy, puberty, urinary incontinence.

Stubbs, W.P. and M.S. Bloomberg (1995). Implications of early neutering in the dog and cat. Seminars in Veterinary Medicine and Surgery (Small Animal) 10(1): 8-12. ISSN: 0882-0511.
NAL Call Number: SF911.S45
Abstract: Early age neutering of dogs and cats is a safe and effective means of pet population control. The surgical techniques are similar to those already familiar to the veterinary practitioner and pose minimal risk to the animal patient. Advantages include a shorter operative time, better intra-abdominal visualization, and rapid animal patient recovery. Prepubertal gonadectomy does not seem to adversely affect skeletal, physical, or behavioral development in the dog and cat.
Descriptors: cats, dogs, surgery, orchiectomy, ovariectomy, time factors.

Stubbs, W.P., M.S. Bloomberg, S.L. Scruggs, V.M. Shille, and T.J. Lane (1996). Effects of prepubertal gonadectomy on physical and behavioral development in cats. Journal of the American Veterinary Medical Association 209(11): 1864-1871. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Abstract: OBJECTIVE: To determine the effect of prepubertal gonadectomy on physical and behavioral development in cats. DESIGN: Prospective controlled study of kittens randomly assigned to 3 treatment groups: group 1, neutered at 7 weeks of age; group 2, neutered at 7 months of age; and group 3, sexually intact controls. ANIMALS: 31 clinically normal male and female kittens. PROCEDURE: Age at distal radial physeal closure and mature radius length were determined radiographically. Six behavioral characteristics were recorded monthly. At 1 year of age, body weight was recorded and thickness of the falciform ligament was measured from a lateral abdominal radiographic view. Secondary sex characteristics were also examined at 1 year of age. RESULTS: There were no differences between group-1 and group-2 cats for any of the study variables. Sexually intact cats (group 3) weighted significantly less than group-2 cats and had less falciform fat and earlier distal radial physeal closure than cats of both neutered groups. Group-3 cats manifested greater intraspecies aggression, less affection, and greater development of secondary sex characteristics than neutered cats. CLINICAL IMPLICATIONS: Neutering cats at 7 weeks of age had similar effects on physical and behavioral development, compared with neutering at the more traditional age of 7 months. These data lend support to the concept of prepubertal gonadectomy, already performed by many animal shelters/humane organizations, as a method of enhancing the effectiveness of pet population control programs.
Descriptors: cats, gonadectomy, skeletal development, body-weight, animal behavior, body composition, early age neutering, radiography, sexual maturation, age factors.

Stubbs, W.P., K.R. Salmeric and M.S. Bloomberg (1995). Early neutering of the dog and cat. In: J. Bonagura and R. Kirk (editors), Kirk's Current Veterinary Therapy XII: Small Animal Practice, W.B. Saunders: Philadelphia, p. 1037-1040. ISBN: 0-7216-5188-7.
NAL Call Number: SF745.K57
Descriptors: pet overpopulation, prepubertal gonadectomy, animal shelters, surgical sterilization, dogs, cats, safety, risks.

Swift, B.J. (2000). Early neutering of dogs. The Veterinary Record 147(23): 667. ISSN: 0042-4900.
NAL Call Number: 41.8 V641
Descriptors: estrus, ovariectomy, dogs, health status, postoperative complications, time factors, urinary incontinence.

Theran, P. (1993). Early-age neutering of dogs and cats. Journal of the American Veterinary Medical Association 202(6): 914-917. ISSN: 0003-1488.
NAL Call Number: 41.8 Am3
Descriptors: dogs, cats, young animals, sterilization, overpopulation, preoperative care, surgery.
Notes: Paper presented at the AVMA Aimal Welfare Forum: Overpopulation of unwanted dogs and cats, Nov. 6, 1992, Chicago, IL.

 

 

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