Neonatal nephron loss during active nephrogenesis results in altered expression of renal developmental genes and markers of kidney injury.

Preterm neonates are at a high risk for nephron loss under adverse clinical conditions. Renal damage potentially collides with postnatal nephrogenesis. Recent animal studies suggest that nephron loss within this vulnerable phase leads to renal damage later in life. Nephrogenic pathways are commonly reactivated after kidney injury supporting renal regeneration. We hypothesized that nephron loss during nephrogenesis affects renal development, which, in turn, impairs tissue repair after secondary injury. Neonates prior to 36 wk of gestation show an active nephrogenesis. In rats, nephrogenesis is ongoing until day 10 after birth. Mimicking the situation of severe nephron loss during nephrogenesis, male pups were uninephrectomized at day 1 of life (UNXd1). A second group of males was uninephrectomized at postnatal day 14 (UNXd14), after terminated nephrogenesis. Age-matched controls were sham operated. Three days after uninephrectomy transcriptional changes in the right kidney were analyzed by RNA-sequencing, followed by functional pathway analysis. In UNXd1, 1,182 genes were differentially regulated, but only 143 genes showed a regulation both in UNXd1 and UNXd14. The functional groups "renal development" and "kidney injury" were among the most differentially regulated groups and revealed distinctive alterations. Reduced expression of candidate genes concerning renal development (Bmp7, Gdnf, Pdgf-B, Wt1) and injury (nephrin, podocin, Tgf-ß1) were detected. The downregulation of Bmp7 and Gdnf persisted until day 28. In UNXd14, Six2 was upregulated and Pax2 was downregulated. We conclude that nephron loss during nephrogenesis affects renal development and induces a specific regulation of genes that might hinder tissue repair after secondary kidney injury.

S-ketamine and intranasal application: alternatives for the castration of male suckling piglets?

BACKGROUND: The intramuscular injection of ketamine and azaperone was proposed as a suitable anaesthesia for male suckling piglets for surgical castration. However, this can be opposed by massive defensive movements, hypothermia and tachycardia during castration and a long recovery period. The aim of the present study was to test whether the use of S-ketamine and/or a change in the route of application from intramuscular to intranasal could reduce stress responses and the duration of recovery compared to the intramuscular route and the use of racemic ketamine. Seventy-eight healthy, five-day-old male piglets were randomized to six treatment groups in a blinded experimental study, matched by litter and weight. Experimental groups were A (15 mg kg-1 S-ketamine + 2 mg kg-1 azaperone, i.m., surgical castration), B (15 mg kg-1 R/S-ketamine racemate + 2 mg kg-1 azaperone, i.m., surgical castration), C (30 mg kg-1 S-ketamine + 2 mg kg-1 azaperone, i.n., surgical castration), D (15 mg kg-1 R/S-ketamine racemate + 2 mg kg-1 azaperone, i.m.; not castrated), E (positive control group; no anesthesia, surgical castration) and F (negative control group; no anesthesia, not castrated). RESULTS: S-ketamine reduced the defensive movement score during castration to a similar extent to racemic ketamine when administered intramuscularly but not via the intranasal route. However, the effects of S-ketamine (both routes) on the increase in cortisol levels and decrease in body temperature were similar to those induced by racemic ketamine. A reduction of the long recovery time known for ketamine-azaperone anaesthesia could not be achieved with S-ketamine in the given dosage, regardless of the route of application. The intranasal administration of ketamine was difficult with the available formulation as the necessary amount exceeded the capacity of the nose cavity. CONCLUSIONS: Neither the use of S-ketamine nor intranasal administration can be suitable alternatives for the anaesthesia of male suckling piglets for castration.

Topical vapocoolant spray reduces nociceptive response to ear notching in neonatal piglets.

OBJECTIVE: To evaluate the efficacy of a vapocoolant spray (VS) to provide local anaesthesia for piglets during ear notching. STUDY DESIGN: Randomized study. ANIMALS: Eleven 10 day old and forty 3-5 day old Large White piglets. METHODS: Temperature validation studies using thermocouples and a temperature data logger were conducted on dead and live tissue to determine optimal spray distance and duration to reduce tissue temperature to below 10 °C. A behavioural trial was conducted to assess efficacy for ear notching. Piglets were randomly assigned to one of four treatment groups: positive control (POS; n = 10), VS (n = 10), lignocaine (LIG; n = 10) and negative control (NEG; n = 10). Spray was administered to the margin of each ear, from a distance of 10 cm, and for a duration of 2 seconds immediately prior to ear notching. Behavioural observation was used to assess movement and vocal response, with responses categorized as no response (0) and response (1). RESULTS: Temperature and tissue validation studies indicated that a 2 second spray from 10 cm reduced tissue temperature to below 10 °C, and reduced response to stimulation of the skin with an 18 gauge needle (p < 0.001). There was a significant effect of treatment on response to ear notching (p < 0.001). The probability of a piglet to respond to ear notching was 98.7% for NEG piglets, compared with those treated with VS (5.3%), LIG (1.1%) and sham-notched piglets (0.9%). CONCLUSIONS AND CLINICAL RELEVANCE: This study contributes new data on the pain of ear notching in piglets. The application of a topical VS prior to ear notching reduced the antinociceptive response of piglets to the procedure, similar to that of a local anaesthetic. Cryoanaesthesia presents a simple and effective option for reducing the pain response to this simple husbandry procedure.

Internal fixation of fractured ribs in neonatal foals with nylon cable tie using a modified technique.

Nylon cable tie has been shown to be an effective and economical method for fixing fractured ribs in the neonatal foal. This article describes a modification of the previously described technique. Under general anesthesia, the fractured ribs were exposed and a hole was drilled in the dorsal and ventral fragments. The fracture was not reduced, leaving the fragments overriding each other. The nylon cable tie was passed through the hole in the dorsal fragment from the external surface of the rib. The free end of the cable tie was then passed through the hole in the ventral fragment from the external surface of the rib and the tie was tightened. This technique was used in 4 neonatal foals with no complications. The modification of the original technique represents a method to minimize soft tissue trauma, implant failure, and complications.

Technique modifiée pour la fixation interne de fractures de côtes chez le poulain nouveau-né avec des attaches de câbles en nylon. Cet article décrit une technique pour réparer les fractures de côtes chez le poulain nouveau-né en utilisant des attaches de câbles en nylon. Sous anesthésie générale, une incision verticale a été faite et les côtes fracturées ont été exposées. Une mèche de perceuse a été utilisée pour faire des trous dans les fragments dorsaux et ventraux des côtes fracturées, approximativement 5 à 10 mm de la ligne de fracture. Le câble a été introduit dans le trou du fragment dorsal et ensuite dans le trou du fragment ventral. Les attaches de câbles ont été resserrées. Les fractures n'ont pas été réduites et les fragments dorsaux chevauchaient les fragments ventraux. Cette technique a été utilisée sans complications chez quatre poulains nouveau-nés.(Traduit par les auteurs).

Routine Trimming and Therapeutic Farriery in Foals.

Hoof care in the first few months of life is serious business and should never be taken lightly. Farriery plays a vital role in both the development of the hoof and the conformation of the limb. Management of the feet and limbs during this period will often dictate the success of the foal as a sales yearling or mature sound athlete. A sound foot care program is time-consuming, whereas assembly-line trimming is quick and easy, but the former is much more beneficial.

Neonatal pinealectomy in rats - a simple micro-suction technique.

To determine the role of the pineal gland and its secretory product melatonin on various aspects of the functioning of the organism, the gland can be easily surgically removed in rats within 18 hours after birth. We performed pinealectomy in rats in a state of deep hypothermia under an operating microscope, using a micro-suction device of our own construction. The rats were induced into a state of suspended animation by placing them in the freezing compartment at minus 20 Celsius degrees. The cessation of respiration and heart beat lasted for about 15 minutes. During that time the pinealectomy was performed. In some cases there was minor hemorrhage that was easily controlled. There were no major side effects or mortality following surgery. All rats recovered within 15 minutes after the end of the procedure. The pinealectomy procedure described in this study is simple, rapid, effective and safe, and can be easily performed with instruments commonly available in most laboratories.

Composite tissue allotransplantation in newborns: a swine model.

BACKGROUND: Management of congenital limb aplasia or facial malformations could be improved by composite tissue allotransplantation (CTA), a technique that has never been performed in newborns. For this, however, the induction of donor-specific tolerance would be mandatory, as long-term immunosuppression is not acceptable in this non-lifesaving procedure. Induction of tolerance has been shown to be possible in a newborn CTA rat model but has never been tested in large-animal models. Our goals were to establish a model of CTA in newborn swine to see if tolerance could be obtained without immunosuppression and to assess rejection or tolerance properties via clinical and histologic examinations. MATERIALS AND METHODS: We applied a CTA heterotopic knee swine model. We performed two series of surgical procedures: Series 1 was 20 autografts in 6-day-old (1-10) 2,544 kg (1,140-4,060 kg) piglets; Series 2 was 10 allografts without immunosuppression between outbred animals aged 7.8 d (6-10) and weighing 2,770 kg (2,200-3,550 kg). RESULTS: In Series 1, six early deaths and two cases of vascular failure were observed. In Series 2, no spontaneous deaths were observed and all piglets presented clinical and histologic rejection. CONCLUSIONS: Our findings strongly suggest that newborn immunologic status is not sufficient for the development of tolerance in large animals without immunologic intervention. Complications and animal death after transplantation correlate with age and weight. Low rates for both vascular failure and postoperative death permit the use of this model in piglets weighing over 2 kg and aged more than 6 d for research on newborn CTA.

Feasibility of orthotopic fetal liver transplantation: an experimental study.

BACKGROUND: The use of livers from nonviable fetuses is particularly attractive for its potential to solve the current limitations of organ availability for the pediatric recipient. Therefore, it is essential to study the feasibility of orthotopic fetal liver transplantation. METHOD: We measured the hepatic and extra-hepatic anatomical structures of fetal and neonatal lambs and established an orthotopic liver transplantation model of the fetal lamb. RESULTS: Mean weight of the liver of fetal lambs at 142 to 145 days gestation was 34.75 g and the mean diameter of the portal vein was 3.03 mm, the supra-hepatic vena cava was 5.88 mm, and the infra-hepatic vena cava was 4.00 mm, which matched the corresponding sizes in neonatal lambs aged up to 2 weeks. Using standard surgical procedures we completed the vascular inosculation of fetal liver. However, all the newborn lamb recipients survived less than 24 hours. CONCLUSIONS: Orthotopic transplantation of the fetal liver is anatomically and technically feasible. However, perioperative issues need to be resolved prior to clinical application.

A surgical mouse model of neonatal pressure overload by transverse aortic constriction.

Cardiac disease is the main cause of death worldwide. Insufficient regeneration of the adult mammalian heart is a major driver of cardiac morbidity and mortality. Cardiac regeneration occurs in early postnatal mice, thus understanding mechanisms of mammalian cardiac regeneration could facilitate the development of novel therapeutic strategies. Here, we provide a detailed description of a neonatal mouse model of pressure overload by transverse aortic constriction (nTAC) that can be applied at postnatal days 1 and 7. We have previously used this model to demonstrate that mice are able to fully adapt to pressure overload following nTAC on postnatal day 1. In contrast, when nTAC is applied in the non-regenerative phase (at postnatal day 7), it is associated with a maladaptive response similar to that seen when transverse aortic constriction (TAC) is applied to adult mice. Once a user is experienced in nTAC surgery, the procedure can be completed in less than 10 min per mouse. We anticipate that this model will facilitate the discovery of therapeutic targets to treat patients or prevent pressure overload-induced cardiac failure in the future.

Effects of Oral Meloxicam and Topical Lidocaine on Pain associated Behaviors of Piglets Undergoing Surgical Castration.

The objective of this study was to find a practical means of reducing pain associated with surgical castration by evaluating the effects of oral meloxicam and topical lidocaine, separately and in combination, on behavioral indicators of pain in piglets. Two hundred thirty-five piglets were surgically castrated between three and seven days of age. Immediately following castration, piglets received one of four treatments: (1) No pain mitigation (C; control; n = 58); (2) NSAID only (M; meloxicam; n = 59); (3) Topical anesthetic (L; lidocaine spray; n = 60); or (4) NSAID and topical anesthetic (X; meloxicam and lidocaine spray; n = 59). Behaviors were recorded by direct observation of individual piglets using five-minute scan samples over a five-hour period, for three days post-castration. Results of the experiment demonstrate the administration of oral meloxicam and topical lidocaine spray at the time of castration under the current methods did not mitigate pain associated with the procedure (P = 0.09; C: 2.1 ± 0.1, L: 2.4 ± 0.1, M: 2.1 ± 0.1 and X: 2.1 ± 0.1).

Umbilical surgery in calves.

Calves benefiting from umbilical surgery can be affected by several different conditions. However, the practitioner should be able to correct any of these conditions surgically, especially in young calves, as a field procedure. Like other aspects of veterinary practice, the individual must decide what services he/she wishes to offer clients in the field or clinic setting and which ones will be referred. The objective of this article is to equip practitioners who wish to treat umbilical masses surgically with the information they need.

Management of fractures in field settings.

Limb fractures are common in farm animals, are most commonly found in young stock, and often occur subsequent to trauma during dystocia or handling. Cattle are excellent patients for treatment of orthopedic injuries because they spend a majority of time lying down, have a tremendous potential for bone healing, are more resistant than other animals to contralateral limb breakdown and stress laminitis, and usually do not resist having orthopedic devices on their limbs. This article describes management of fractures, especially for cattle, in field settings; explains how the principles of external skeletal fixation are adapted for cattle; discusses the application of external skeletal fixation to individual bones, and reviews potential complications in the use of external skeletal fixation.

Surgery of the bovine large intestine.

Cecal dilatation in cows and large intestinal atresia in neonatal calves are the most important diseases of the bovine large intestine amenable to surgical correction under field conditions. Clinical symptoms, diagnostic steps, surgical and medical treatment, etiopathogenesis, and prognosis are discussed. Surgery for correction of cecal dilatation, with and without retroflexion or torsion, can be performed under field conditions. In contrast, only anal reconstruction after atresia ani or colostomy in the case of atresia coli are amenable to field surgery; more complicated bypass procedures with anastomosis for atresia coli are best performed in hospital settings. Correcting intestinal atresia is not recommended because of animal welfare and breeding hygiene issues; it should be undertaken for salvage purposes only.

Proximal tibial epiphysiodesis to reduce tibial plateau slope in young dogs with cranial cruciate ligament deficient stifle.

The purpose of this study was to evaluate the ability of proximal tibial epiphysiodesis to reduce the tibial plateau slope in young dogs with cranial cruciate ligament (CCL) deficient stifles. Of the 14 treated dogs, eight had a bilateral injury, for a total of 22 joints. After physical and radiographical examination and measurement of tibial plateau slope, all of the dogs underwent surgery. Insertion of the screw was placed in the most proximal part of the tibial plateau, in its medio-lateral centre, aiming to the tibial shaft and using a K wire predriven as a guide; correct position of the screw was confirmed with intraoperative fluoroscopy or radiography. In all of the dogs the tibial slope was decreased at the time of physis fusion and the degree of change depended on the age and the breed of the dog at the time of surgery. The minimum change was 4 degrees and the maximum was 24 degrees. There was a statistically significant difference between tibial slope measured before surgery compared to tibial slope measured at the last follow-up visit after surgery. This study shows that the partial proximal tibial fusion in dogs with ACL injuries was effective in reducing the tibial slope during the residual growing time to such an extent to stabilize the joint, provided that the surgery had been carried out when there was still residual growing potential. The technique appeared to be mini-invasive and malalignment complications could be avoided by correct and precise insertion of the screw.

Evaluation of sutureless scrotal castration for pediatric and juvenile dogs.

OBJECTIVE To determine complication rates associated with sutureless scrotal castration (SLSC) performed in a large number of pediatric and juvenile dogs and investigate whether procedure duration differed from that of traditional prescrotal castration (TPSC). DESIGN Prospective case series and clinical trial. ANIMALS 400 shelter-owned dogs that underwent SLSC and 18 shelter-owned dogs that underwent TPSC between 2 and 5 months of age. PROCEDURES In the first phase of the study, SLSC was performed for 400 dogs, which were monitored for ≥ 24 hours after surgery to identify surgery-related complications such as hemorrhage, signs of pain, self-trauma, swelling, and dermatitis at the incision site. In the second phase, the durations of 18 SLSC and 18 TPSC procedures were measured and compared. RESULTS No hemorrhage-related complications were identified in any dog during SLSC in the first phase. Complications were all minor and self-limiting and included peri-incisional dermatitis (9/400 [2.3%]), skin bruising (4/400 [1.0%]), and swelling (1/400 [0.3%]). No self-trauma was observed for any dog, nor did any dog require additional analgesic treatment after surgery. Procedure duration was significantly briefer for SLSC (mean ± SD, 1.0 ± 0.2 minutes) than for TPSC (3.5 ± 0.4 minutes). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that SLSC as evaluated was safe and significantly faster than TPSC when performed in healthy 2- to 5-month-old dogs. The SLSC technique has the potential to improve morbidity and mortality rates as well as financial costs associated with castration, particularly in high-quality, high-volume spay and neuter programs.

Effect of transmucosal corn syrup application on postoperative blood glucose concentrations in kittens.

Objectives The aim of the study was to determine the effect of a common clinical practice, the transmucosal (TM) application of corn syrup, on postoperative blood glucose concentrations in kittens. Methods This study was designed as a randomized controlled trial. Seventy-five kittens between the age of 8 and 16 weeks scheduled for surgical sterilization by gonadectomy at an animal shelter were enrolled. Kittens were randomly assigned to either a routine treatment group that received the shelter's typical postoperative application of corn syrup immediately following gonadectomy or to a control group that did not receive typical treatment. Three blood glucose measurements were obtained per kitten: baseline reading prior to preoperative examination, immediately postoperatively and 20 mins postoperatively. The median values of the 20 min postoperative blood glucose reading for the control and treatment groups were compared using the Wilcoxon rank-sum test. Results Postoperative application of corn syrup to the oral mucosa of kittens did not result in significant elevations in blood glucose compared with controls. No kitten was hypoglycemic (⩽60 mg/dl) at any point during the study. Conclusions and relevance TM application of corn syrup did not affect postoperative blood glucose concentrations in kittens. Protocols that use routine TM administration of corn syrup in kittens should be re-evaluated.

Onfaloarterioflebite e onfalectomia em bezerro / Omphalophlebitis, omphaloarteritis and omphalectomy in a calf

O objetivo desse trabalho foi relatar um caso de onfaloarterioflebite em bezerro mestiço com oito dias de vida, apresentando aumento de volume umbilical associado à miíase. O hemograma revelou neutrofilia e hiperfibrinogenemia, sendo realizado também exame ultrassonográfico para avaliação do comprometimento de estruturas internas e confirmação diagnóstica. Devido à gravidade do quadro, optou-se pelo tratamento cirúrgico do animal, através da técnica de onfalectomia. No transoperatório, foi instituída terapêutica com antimicrobiano, antipirético, analgésico e mucolítico, além do internamento do paciente para continuidade da terapia sistêmica e realização de curativos. Após 72h da cirurgia, observou-se excelente cicatrização da ferida operatória e novos exames laboratoriais detectaram ausência de neutrofilia e hiperfibrinogenemia, possibilitando a alta médica, com recomendações de curativos diários na propriedade e retorno, após 10 dias, para reavaliação e retirada dos pontos. Este estudo reportou os achados clínicos e a abordagem terapêutica em um caso de onfaloarterioflebite em bezerro. A anamnese e o exame físico são fundamentais para o diagnóstico de onfalopatias e, quando associados à exames complementares, permitem ao veterinário a determinação das estruturas afetadas, possibilitando a instituição do tratamento mais eficiente e específico. O procedimento cirúrgico é um método terapêutico que apresenta resultados mais rápidos e melhores taxas de recuperação quando comparado ao tratamento clínico de forma isolada.

The objective of this study was to report a case of omphaloarteriophlebitis in an eight-day-old crossbred calf, presenting an increase in umbilical volume associated with myiasis. The blood count revealed neutrophilia and hyperfibrinogenemia, and an ultrasound examination was also performed to assess the impairment of internal structures and diagnostic confirmation. Due to the severity of the condition, we opted for the surgical treatment of the animal, using the omphalectomy technique. In the intraoperative period, therapy with antimicrobial, antipyretic, analgesic and mucolytic agents was instituted, in addition to the patient's hospitalization for continuity of systemic therapy and dressings. After 72 hours of surgery, excellent healing of the surgical wound was observed and new laboratory tests detected the absence of neutrophilia and hyperfibrinogenemia, allowing medical discharge, with recommendations for daily dressings on the property and return, after 10 days, for reassessment and removal of stitches. This study reported the clinical findings and therapeutic approach in a case of omphaloarteriophlebitis in a calf. Anamnesis and physical examination are fundamental for the diagnosis of omphalopathies and, when associated with complementary exams, allow the veterinarian to determine the affected structures, enabling the institution of the most efficient and specific treatment. The surgical procedure is a therapeutic method that presents faster results and better recovery rates when compared to clinical treatment alone.

Effect of post-natal castration on sepsis mortality in rats.

PURPOSE: To investigate the influence of castration in early periods of development on survival to experimental acute sepsis. METHODS: Four groups of 10 (ten) Wistar rats were used. The groups were comprised of males (M), females (F), males castrated on the fourth day of life (CM) and males castrated on the fourth day of life with testosterone replacement (CMR). Sepsis was induced by ligature and cecal perforation in adult life. RESULTS: The analysis of death within 24 hours following sepsis induction showed greater mortality between the M and the CMR groups as compared to the CM and F (p=0.0180) groups. Multiple correspondence analysis (MCA) indicates an association between the M and the CMR groups for death within 24 hours as well as a relationship between the F and the CM groups for the absence of death and death up to 24 hours following sepsis induction. Statistical analysis of the Kaplan-Meier survival curve through log-rank demonstrates a significant difference among the four groups (p=0.0055) and between the M and the F (p=0.0005) groups. CONCLUSION: Data suggest a better survival to sepsis within 24 hours for the F and CM groups, the presence or absence of testosterone in early periods of post-natal life being responsible for these findings.

[Changes in the concentration of noradrenaline and adrenaline before and after castration of piglets with and without isoflurane anesthesia]. / Verlauf der Noradrenalin- und Adrenalinkonzentrationen vor und nach der Kastration von Saugferkeln mit und ohne Isofluran-Narkose.

Since the amendment of the animal welfare law in Germany in April 2006, castration of piglets without anesthesia is only allowed in the first seven days of life. However, neonates are capable of feeling pain and react more sensitive to pain than adults. Accordingly we expect that castration without anesthesia will be unaccepted in Germany in the future as castration without anesthesia will be forbidden in Switzerland from 2009 on. Denmark and The Netherlands strive for an embargo of the castration without anesthesia and Norway is already asking for an elimination of pain during castration. In Switzerland castration under isoflurane-anesthesia is considered to be a good alternative for the castration without anesthesia. Whether isoflurane-anesthesia is able to reduce stress caused by castration adequately or anesthesia, especially anesthetization that often provokes defensive reaction, is stress for the animal itself was tested in the following investigation. To get an objective statement about the stress of the animals, concentrations of epinephrine and norepinephrine were detected before and immediately after castration/fixation with or without anesthesia. Five day old, healthy animals were divided into four groups. Animals of group A (n = 10) were only fixed without anesthesia, animals of group B (n = 10) were fixed and castrated without anesthesia. In group C (n = 10) the animals were only fixed under anesthesia and the animals of group D (n = 11) were fixed and castrated under anesthesia. Norepinephrine-concentrations and epinephrine-concentrations did rise significantly in all piglets handled without anesthesia (group A and B) independently if castrated or only handled. The values of these animals were significantly higher than the values of the anesthetized animals after fixation/castration (group C and D). In contrast the norepinephrine-concentrations and the epinephrine-concentrations of all anesthetized animals (group C and D) were significantly lower after castration than the concentrations before castration. The catecholamine peak did not differ significantly between the groups of anesthetized animals. The significant increase of the catecholamines of the non-anesthetized animals can be explained by the stress caused by fixation and/or castration without anesthesia. Because of the anesthesia the catecholamine-concentration was reduced considerably during the fixation and/or castration. The results show that fixation and/or castration under anesthesia causes no stress for the piglets.

Effects of hypoglossal and facial nerve injuries on milk-suckling.

Functional roles of the perioral anatomical structures involved in breastfeeding were examined in newborn rat pups in which the hypoglossal (XII) and facial (VII) nerves had been resected at the neonatal stage. The XII nerve controls tongue movement and is comprised of two functionally distinct branches: the medial branch related to protrusion of the tongue and the lateral branch related to its retraction. Newborn rat pups with bilateral resection of either of the XII nerve components (main trunk: XII-trunk; medial branch: XII-med; lateral branch: XII-lat) failed to suckle milk and did not survive. Unilateral XII nerve-resected neonates showed different milk-suckling capabilities, which thus resulted in differences in survival rate (XII-trunk: 38%; XII-med: 24%; XII-lat: 92%) and postnatal growth during the postnatal 3 weeks until P21. Unilateral and bilateral resections of the VII nerve innervating the buccolabial musculature produced lowered suckling capabilities and retarded postnatal growth, although all pups showed 100% survival. The results indicate a crucial role of the tongue, especially of protruding muscular elements innervated by the XII-med nerve, in breastfeeding. The results also indicate differential effects of the VII and XII nerve components on suckling capability, survival, and postnatal growth of newborn rat pups.