Effect of age at castration on behavioural response to subsequent tail docking in lambs

Objective To investigate the effects of age at castration on the subsequent behavioural response to tail docking. Study design Randomised prospective blinded experimental study. Animals Forty‐five male lambs were admitted to the study at birth. Methods The lambs were allocated into two groups for castration by rubber ring at 1 (1D, n = 20) or 10 (10D, n = 25) days of age. Following castration both groups of lambs were tail‐docked by rubber ring at between 26 and 34 days of age. Their behavioural responses to tail docking were recorded by video for 30 minutes before (n = 11) and 30 minutes after (n = 45) tail docking. Statistical differences were tested using anova with Mann‐Whitney post‐hoc testing. Results Two data sets were removed resulting in n = 19 and = 24 at 1D and 10D, respectively. A significant increase in the incidence of active and abnormal postural behaviour was seen in both groups after tail docking. Three behaviours were significantly different (p < 0.05) between the two groups. These behaviours were rolling, standing unsteadily and the total proportion of time standing with abnormal posture. These behaviours all had greater incidence in the lambs castrated at 1D of age. Conclusions Lambs castrated at 1D appeared to perceive a greater intensity of pain after subsequent tail docking than lambs castrated at 10D. Clinical relevance The timing of a single noxious stimulus in young animals can affect subsequent pain perception.     

Topical anaesthesia alleviates short-term pain of castration and tail docking in lambs

Objective To investigate the effect of a topical anaesthetic formulation on pain alleviation, wound healing and systemic levels of local anaesthetic actives in lambs undergoing castration and tail docking. Design Three placebo-controlled and/or randomised experiments were conducted using three groups of Merino lambs (n = 62, 68 and 19) undergoing routine castration and tail docking. Procedure Surgical castration, with either surgical or hot-iron tail docking, was performed with and without the application of topical anaesthetic (Tri-Solfen®) or placebo. The effects of this procedure were compared with those of rubber ring castration and tail docking, and of the handled but unmarked controls. Wound pain was assessed using calibrated Von-Frey monofilaments over a 4-h period, pain-related behaviour was assessed over 5 h, wound healing was assessed at 14 and 28 days, and the plasma levels of lignocaine and bupivacaine were determined. Results Rapid and up to 4 h primary hyperalgesia developed following surgical castration and tail docking in the untreated and placebo-treated lambs. It was absent in the castration wounds, and significantly reduced in the tail-docking wounds, of the treated lambs. Hot-iron docking was associated with mild and transient secondary hyperalgesia, which was abolished by the topical anaesthesia. There was a significant reduction in pain-related behaviours in treated lambs, which were not significantly different in their behaviour to the sham-operation handled controls. Plasma lignocaine and bupivacaine levels were below the toxic thresholds in all tested lambs. Conclusion Topical anaesthesia alleviates wound pain and significantly reduces pain-related behaviours in lambs undergoing surgical castration plus surgical or hot-iron tail docking, without a negative effect on wound healing or a risk of systemic toxicity.     

Effects of acute pain reduction methods on the chronic inflammatory lesions and behaviour of lambs castrated and tail docked with rubber rings at less than two days of age

Lesions were produced by castration and tail docking of two-day-old Dorset-cross lambs with elastrator rings with (RRla) and without (RR) local anaesthetic or after destruction of the innervation by crushing close to the ring (Brr). The lesions were monitored twice weekly for six weeks and the behaviour of handled controls (H), RR and RRla lambs was recorded for two 3 h periods 10, 20, 31 and 41 days after treatment. There was no significant effect of castration and tail docking, with or without pain reduction methods, on daily liveweight gain. In the Brr lambs, the dead tails were cast 10 days earlier than from RR and RRla lambs. The time taken for the scrotal lesion to reach maximum severity was halved in Brr and RRla lambs, although the maximum severity of the lesion was unaffected by the methods of pain reduction. During the four 6 h behavioural observation periods, RR lambs showed a significant increase in the mean (+/- sd) frequency of foot stamping (RR13 +/- 13; H2 +/- 2.5), tail wagging (61 +/- 26; 15 +/- 6), head turning to the scrotum and inside hind-leg (12 +/- 10; 1 +/- 1). Less abnormal behaviour was found after RRla than after RR treatment. This unexpected finding may be evidence of long-lasting increases in pain sensitivity after an episode of intense acute pain in young animals.     

Influences of carprofen and the experience of the surgeon on post-castration pain in lambs and young sheep

This study evaluated the influences of carprofen and the experience of the surgeon on post‐castration pain in lambs and young sheep castrated in the field. A total of 201, 1–6‐week‐old lambs with a mean body mass of 11.0 ± 2.4 kg (mean ± SD) were castrated after local application of 4 mL lidocaine (2%). Preoperatively lambs were given either 20 mg carprofen SC or an equal volume of saline in a randomized order. A further 34 sheep, aged 6 months, with a mean body mass of 36.0 ± 4.5 kg were castrated after local application of 7 mL lidocaine (2%). Preoperatively sheep received 2 mg kg^?1 carprofen SC or an equal volume of saline in a randomized order. Lidocaine was injected SC in front of, behind and into each spermatic cord. All surgery was performed using the same Burdizzo clamp (jaw 45 mm wide, handles 225 mm) either by students or experienced veterinary surgeons. Pain was assessed preoperatively and at 24, 48 and 72 hours after castration by two independent observers unaware of the treatment group. Observers scored pain using a visual analog scale (100 mm) after applying gentle pressure onto the scrotal region ( Thornton & Waterman‐Pearson 1999 ). Swelling of the scrotal region was scored as ‘severe’, ‘present but not severe’ and ‘not present’. The VAS scores were compared using a Mann–Whitney test, p < 0.05 was considered significant. Swelling was compared using Fisher's exact test. In lambs, no significant differences in pain scores between those treated with carprofen or saline were noted by either observer (p > 0.48) at any of the three assessment times. However, the number of lambs with severe or present swelling of the scrotal region was significantly lower in those receiving carprofen (8% versus 18%, p = 0.028). Lambs castrated by students showed significantly higher pain scores (23% versus 13%, p < 0.001 at 24 hours; 20% versus 13%, p = 0.0062 at 48 hours; 16% versus 10%, p = 0.0088 at 72 hours) and significantly more swelling (18% versus 8%, p = 0.0189) of the scrotal region than those castrated by veterinary surgeons. Young sheep receiving carprofen preoperatively had significantly lower pain scores (12 mm versus 25 mm, p = 0.037) 24 hours after surgery compared to sheep receiving saline. No scrotal swelling was obvious in sheep. Juvenile sheep but not lambs, receiving carprofen preoperatively showed reduced pain scores up to 24 hours after surgery. Carprofen reduced swelling of the scrotum in lambs. Lambs castrated by experienced surgeons scored lower VAS scores at all times and showed less swelling of the scrotal region.     

Do psychological and physiological stressors alter the acute pain response to castration and tail docking in lambs?

Objective To investigate whether events that may be stressful to young lambs, including simulated infection or social isolation, modulate pain experienced by lambs following castration and tail docking (C/D). Study design Randomised, controlled, prospective study. Animals Fifty male lambs born to 46 second‐parity Mule ewes. Methods Lambs were allocated randomly to one of four groups, experiencing either a potential stressor or handling on day 2 after birth, followed by C/D or handling only on day 3. Quantitative sensory testing (QST) data [mechanical nociceptive thresholds (MNT), Semmes Weinstein filaments (SW), response to cold] and serum cortisol concentration were measured at time points after application of treatments to lambs on days 2 and 3 after birth. The treatment groups were LPS, injection of bacterial lipopolysaccharide IV on day 2, C/D on day 3; ISOL, isolation from the dam for 10 minutes on day 2, C/D on day 3; CAST, handling only on day 2, C/D on day 3; CONT, handled only on days 2 and 3. Results Castration and tail docking caused transient hypoalgesia as measured by MNT and SW. Simulated infection and isolation caused hyperalgesia 3 hours after application, indicated by a reduction in MNT, however they did not alter the pain response to C/D compared to lambs in the CAST group. Injection of LPS and C/D caused increased serum cortisol concentration. The magnitude of the cortisol response to C/D was not altered by prior exposure to either LPS or isolation. Conclusions and clinical relevance LPS and isolation did not modulate the response to C/D but did cause hyperalgesia. This highlights the importance of flock health management and husbandry techniques to reduce the incidence of either systemic infection or psychological stressors in young lambs.     

Effects of age on the electroencephalographic response to castration in lambs anaesthetized with halothane in oxygen from birth to 6 weeks old

ObjectivesTo characterize changes in the cerebro‐cortical response of lambs to rubber‐ring castration during the first 6 weeks of postnatal life.AnimalsCoopworth‐Texel cross ram lambs between 3 hours and 44 days of age.MethodsThe electroencephalogram (EEG) and heart rate responses to rubber ring castration were compared. Anaesthesia was induced via a face mask and maintained with halothane in oxygen (e′_Hal = 1.2%). Once a stable plane of anaesthesia had been achieved, data collection of EEG and electrocardiogram (ECG) commenced, and the lambs were castrated 15 minutes later, using rubber rings. Heart rate was derived from the ECG and the median frequency (F₅₀), spectral edge frequency (F₉₅) and total power (p_tot) were derived from the EEG.ResultsCastration‐induced changes in F₅₀ increased from 2 ± 1.8% in the youngest lambs to a maximum of 33 ± 8.9% in the 36 ± 0.5 day‐old lambs. Changes in F₉₅ increased from ?7 ± 3% in the youngest lambs to a maximum of 16 ± 11% in the 36 ± 0.5 day‐old lambs. Linear regression analysis in lambs up to 10 days of age demonstrated a change in the response with age that was significantly different from zero for F₅₀ (r² = 0.28, p = 0.007) and F₉₅ (r² = 0.38, p = 0.001), but not for p_tot or heart rate.ConclusionThis study identified significant changes in the responsiveness of the lambs’ cerebral cortex to the noxious stimulation of castration over the first 7–10 days of postnatal life. The results suggest that mechanisms that suppress responses of the fetus to noxious stimulation may still be active in the first few days after birth.Clinical relevanceThis study documents changes in central nociceptive processing which may reflect the ability of neonatal animals to perceive pain.     

Evaluating a novel analgesic strategy for ring castration of ram lambs

Objective To evaluate the analgesic efficacy of the NSAIDs flunixin and meloxicam administered locally to the scrotum before ring castration. Study design Randomised, controlled, prospective study. Animals Forty eight single born male Merino lambs. Methods Lambs, aged approximately 4 weeks, were allocated to four groups for castration. Groups were: sham control; castration + saline; castration + flunixin; castration + meloxicam. Drugs (5 mL) were administered subcutaneously around the circumference of the scrotum immediately before castration. Cortisol, rectal temperature, haematology and plasma haptoglobin were measured before and up to 48 hours after treatment. Behaviour recorded by video for 12 hours after treatment was classified as pain avoidance behaviours in the first hour and postural behaviours in three 4 hour intervals. Results Ring castration (saline group) induced a bi‐phasic increase in cortisol with peaks at 90 minutes and 24 hours but no significant changes in haematology, haptoglobin or rectal temperature. Pain avoidance behaviours were increased and teat seeking decreased. Normal lying and normal standing postures were decreased and abnormal ventral lying, statue standing, abnormal standing and total abnormal postures increased. Flunixin decreased cortisol at 90 minutes (60.3 versus 117.3 nmol L^?1) and cortisol AUC (0–6 hours), decreased elevated leg movement (2.5 versus 5.4 events) and sum of pain avoidance behaviours (8.5 versus 16.7 events), improved time spent in normal ventral lying and decreased abnormal ventral lying and total abnormal postures compared to saline treated lambs. In a similar contrast, meloxicam caused non‐significant decreases in cortisol at 90 minutes, cortisol AUC (0–6 hours) and pain avoidance behaviours, and significantly improved the postural behaviours normal ventral lying (26.7 versus 15.4%) and normal standing (13.9 versus 7.5%), and reduced abnormal standing and total abnormal postures. Physiological and behavioural responses associated with ring castration for both NSAID treatment groups were generally greater than sham controls. Conclusions and clinical relevance Locally administered NSAIDs provided partial analgesia for ring castration.     

Clinical effects of isoflurane and sevoflurane in lambs

Objective To compare isoflurane and sevoflurane in lambs undergoing prolonged anaesthesia for spinal surgery. Study design Prospective randomised clinical study. Animals Eighteen Scottish blackface lambs 3–6 weeks of age and weighing 10–17 kg. Methods After intramuscular medetomidine, anaesthesia was induced and maintained with either isoflurane (group I) or sevoflurane (group S) delivered in oxygen. Meloxicam, morphine, a constant rate infusion of ketamine and atracurium were given intravenously (IV) during surgery. Lungs were ventilated to maintain normocapnia. with peak inspiratory pressures of 20–25 cmH₂O. Ephedrine or dextran 40% was administered when mean arterial pressure (MAP) was <55 mmHg. Intrathecal morphine, and IV meloxicam and edrophonium were injected before recovery. Time to loss of palpebral reflex (TLPR) upon induction, cardiorespiratory variables, time at first swallowing and other movement, tracheal extubation, vocalisation, spontaneous head lifting (>1 minute), reunion with the ewe, and the number of MAP treatments were recorded. Statistical analysis utilised anova , Mann–Whitney, t‐test or Pearson’s correlation test as relevant. p < 0.05 was considered significant. Results End‐tidal carbon dioxide (mean ± SD) was significantly lower in group S (5.5 ± 0.6 kPa) than in group I (5.8 ± 0.5 kPa) while MAP (70 ± 11 mmHg) and diastolic arterial blood pressure (60 ± 11 mmHg) were higher in group S than in group I (65 ± 12 and 54 ± 11 mmHg, respectively). No differences were found with TLPR and MAP treatments. Time (median, range) from end of anaesthesia to ewe‐lamb reunion was briefer (p = 0.018) in group S (48, 20–63 minutes). Conclusion Isoflurane and sevoflurane are both suitable for maintaining general anaesthesia in lambs although sevoflurane, as used in this study, allows a more rapid reunion with the ewe. Clinical relevance The principal advantage of sevoflurane over isoflurane during prolonged anaesthesia in lambs is a more rapid recovery.     

Effects of concentrate feeding systems,genotype and sex on productive performance and meat quality of Norwegian lambs

Abstract

Two factorial experiments, I and II, were carried out in this study using 84 lambs (140±1.24 days old, 40.00±0.75 kg live weight) divided into six groups. Two levels of concentrate supplementation; restricted (0.4 kg concentrate/lamb/day) or ad libitum, two breed types; Norwegian White lamb or Nor-X and two sex types; ram or ewe lambs, were investigated. In experiment I, a 2×2×2 factorial arrangement of treatments (level of supplementation, sex, and breed) was imposed whereas a 2×2 arrangement of treatments (level of supplementation and breeds) was studied in Experiment II. Each of the two experiments lasted for four weeks. Lambs on ad libitum access to concentrate grew at 231 g d^–1 and 125 g d^–1 faster than those on restricted access in Experiment I and II, respectively. Moreover, ram lambs grew at 64 g d^–1 faster than ewe lambs. Lambs on ad libitum access to concentrate had about 5 kg heavier carcasses than that on restricted access. Ewe and ram lambs on ad libitum allowance to concentrate had 4.2 kg and 5.6 kg, respectively, higher carcass weight than those on restricted allowance. The two levels of concentrate supplementation had limited effects on the meat sensory qualities. Meat taste intensity increased with level of concentrate supplementation. Difference in meat tenderness between ram and ewe lambs was only evidenced on ad libitum concentrate feeding. Irrespective of stage of growth (Experiment I vs. II) and concentrate supplementation level, Nor-X lambs were superior to Norwegian White lambs with respect to carcass conformation scores. Based on results from sensory assessments of meat, ram lambs should be slaughtered before October to avoid off-flavour on meat.     

Effects of local anesthesia and intravenous naloxone on the changes in behaviour and plasma concentrations of cortisol produced by castration and tail docking with tight rubber rings in young lambs.

The reliability of some behavioral and physiological indices used for the recognition and assessment of acute pain in lambs after castration and tail docking has been examined. Changes in the indices were measured after blocking neural activity with local anaesthetic (lignocaine) and after an opioid antagonist (naloxone) was administered. Six lambs, aged less than one week, were allocated randomly to each of six treatments. (i) control handling and blood sampling; (ii) castration plus tail docking with tight rubber rings; (iii) local anaesthesia; (iv) local anaesthesia followed by castration and tail docking; (v) intravenous naloxone only (0.2 mg kg-1); and (vi) intravenous naloxone followed by castration and tail docking. Local anaesthesia eliminated the behavioural and plasma cortisol changes which usually follow castration and tail docking. Naloxone had a limited effect on the increase in cortisol but altered the behaviour. The results support the view that such indices are useful for assessment of the response to acute pain and that, although endogenous opioids do reduce pain in young lambs after castration and tail docking, the effect is small.     

EEG changes in 4-week-old lambs in response to castration, tail docking and mulesing

OBJECTIVE: To interpret changes in EEG in relation to perceived pain of castration, mulesing and docking in lambs. DESIGN: Analysis of covariance (randomised block design) to determine the effects of treatment on eight bandwidths of the EEG frequency spectrum. PROCEDURE: Ninety-eight, 3- to 4-week-old lambs were subjected to one of seven treatments: castration, tail docking, mulesing, ear tagging, sham shearing, formalin injection (to induce lameness) and handling. EEG was recorded for 15 min before treatment, during treatment, and for 15 min after treatment. RESULTS: Consistently lower mean power values across all bandwidths of the EEG were found at the time of mulesing and docking than at handling and shearing (P < 0.01). Formalin injection resulted in lower power values than handling and shearing (P < 0.01). Castration had lower power values than handling and shearing. Similarly, for 15 min after treatment, mulesing and formalin injection had significantly lower power values than handling, shearing, ear tagging and castration (P < 0.05). CONCLUSION: The consistent effects associated with mulesing, docking and castration compared to handling, shearing and ear tagging suggest that mulesing at both the time of treatment and during 15 min after treatment results in a response that is similar to that of induced lameness. Docking and castration result in a response at the time of treatment that is similar to induced lameness and mulesing, but during 15 min after treatment is similar to the non-noxious control treatments. However, the depressing effects on the mean power values are the reverse of that anticipated from a previously developed pain model, highlighting the need for further research to develop this technology to evaluate pain associated with husbandry procedures.     

Effect of complete feed block with tree leaves rich in hydrolysable and condensed tannins on nutrient utilization,rumen fermentation and growth performance of lambs

Thirty lambs (Avishaan genotype, 10 weeks old, 14.0 ± 0.2 kg live weight) were randomly assigned into three equal treatment groups to study the effect of complete feed blocks (CFB; concentrate and roughage at 70:30 ratio) with three different tanniniferous tree leaves on intake and utilization of nutrients, rumen fermentation, microbial protein synthesis and growth performance. The treatments were T1 (Control), CFB1 with Vigna sinensis hay; T2, CFB2 with Acacia nilotica leaves rich in hydrolysable tannins (HT); and T3, CFB3 with Ziziphus nummularia leaves rich in condensed tannins (CT). The three CFBs were fed ad libitum to the respective groups of lambs for a period of 12 weeks. There was lower (p < .05) intake of dry matter (DM), total carbohydrates (TCHO) and fibre components in T2 compared with T1 and T3. However, the digestibility of nutrients except crude protein (CP) was higher in T2. Diet had no effect (p > .05) on the LW gain in lambs. Amongst the three groups, T3 showed enhanced N utilization with a comparable microbial protein synthesis, the lowest being in T2. The T2 group of lambs had higher propionate and lower non-glucogenic: glucogenic short-chain fatty acids ratio. It may be concluded that tanniniferous tree leaves at 30% of total mixed ration can meet the requirement of nutrients for desired post-weaning growth.     

The effects of age, isoflurane and sevoflurane on atracurium in lambs

ObjectiveTo determine the effects of age, sevoflurane and isoflurane on atracurium-induced neuromuscular blockade in 3–16 week-old lambs.Study designProspective randomized experimental trial.AnimalsTwenty-six Scottish blackface ewe-lambs were anaesthetized for spinal surgery when either 3–6 (mean age 4.6 weeks; n = 18) or 12–16 weeks (mean age 13.7 weeks; n = 15) of age; seven animals were anaesthetized at both ages.MethodsAfter intramuscular injection of medetomidine (10 μg kg^?1) anaesthesia was induced in the younger lambs either with isoflurane or sevoflurane in oxygen delivered by mask, and in the older lambs with ketamine (4 mg kg^?1), and midazolam (0.2 mg kg^?1) administered intravenously (IV). In both groups anaesthesia was maintained with fixed end-tidal concentrations of either sevoflurane (2.8%) or isoflurane (1.8%) delivered in oxygen. Before surgery meloxicam (0.6 mg kg^?1), morphine (0.5 mg kg^?1) and ketamine (1 mg kg^?1 followed by 10 μg kg^?1 minute^?1) were administered IV. The lungs were ventilated mechanically to maintain normocapnia. Neuromuscular block was achieved with a loading dose (LD) of atracurium (0.5 mg kg^?1 IV). The peroneal nerve was stimulated (train-of-four every 12 seconds). Evoked responses in the digital extensor muscles were evaluated by palpation and observation. Maintenance doses (MD) of atracurium (0.17 mg kg^?1 IV) were administered when the first twitch (T1) returned. The onset and duration of LD action (T1 absent) and the duration of MD were recorded. Data were analysed using Student's t test, Mann–Whitney U test, repeated–measures anova, Wilcoxon's matched pairs test or Pearson correlation coefficient as relevant (p < 0.05).ResultsOnset of LD action developed significantly (p < 0.05) more rapidly in isoflurane compared with sevoflurane-anaesthetized lambs (55 ± 18 cf. 80 ± 37 seconds). Duration of action of LDs and MDs was longer (p < 0.05) in lambs aged 12–16 than 3–6 weeks (33 ± 5.4 cf. 25 ± 6.4 and 26 ± 4.2 cf. 18 ± 5.5 minutes) but were independent of the anaesthetic used.Conclusions and clinical relevanceThe effect of atracurium is age-dependent in lambs being prolonged in older animals. The onset of neuromuscular blockade is more rapid in isoflurane compared with sevoflurane-anaesthetized lambs.     

Undernutrition During Foetal and Post‐Natal Life Affects Testicular Structure and Reduces the Number of Sertoli Cells in the Adult Rat

To test whether undernutrition during foetal to pre‐pubertal life would have long lasting effects on testicular histology in adult male offspring, eleven adult Sprague–Dawley pregnant rats were divided into two groups: Control group, n = 4, fed ad libitum, during gestation and lactation (until 25 day post‐partum). Underfed group pregnant females (n = 7) were kept in cages where only dams had access to food (standard rat chow, 33.5% of ad libitum intake of Control group pregnant dams). After parturition, litters were adjusted to either 14 (Underfed group) or eight (Control group) pups. Mothers were weighed weekly. At 25 day of age pups were weaned, housed at four animals per cage, fed ad libitum and weighed weekly until euthanized at 100 day of age. Testes were processed for standard histology and morphometrical evaluation. At weaning, mother weight was lower in Underfedthan in Control group (mean ± SD): 214.1 ± 26.2 g vs 361.9 ± 33.1 g. Body weight at 100 days of age (254 ± 26.9 g vs 342.4 ± 10.2 g, p ≤ 0.001), testicular weight (1.29 ± 0.16 g vs 1.45 ± 0.13 g, p = 0.03), number of Sertoli cells per seminiferous tubule cross section (18.2 ± 1.2 vs 20.2 ± 1.3, p ≤ 0.01) and per testis (30.5 ± 4.2×10⁶ vs 36.0 ± 5.4×10⁶) were lower (p < 0.05) in Underfed than in Control group. This is the first report stating that foetal to pubertal subnutrition is accompanied by changes in testicular structure and lower Sertoli cell numbers in adult life, strongly suggesting lower daily sperm production.     

Performance and carcass measurements of ewe lambs reared in a feedlot and fed wheat (<Emphasis Type="BoldItalic">Triticum durum</Emphasis> Desf.) middlings total mixed rations in the summer season

The effect of total mixed ratios containing wheat middlings (WM) as a corn grain substitute on the growth performance and carcass traits of Comisana ewe lambs was evaluated. Forty ewe lambs, with average live body weight of 13 ± 0.3 kg (mean ± SEM), were allocated randomly to two isocaloric and isonitrogenous diets for 50 days. Control diet contained 400 g/kg of dry matter (DM) of corn as the main starchy source, whereas experimental diet contained 600 g/kg DM of WM. In vivo nutrient apparent digestibility of the two diets was determined using Comisana rams (mean body weight, 65 ± 2.3 kg) and indicated significant (P < 0.05) differences for neutral detergent fibre, acid detergent fibre, cellulose and hemicellulose fractions. Results from the trial using Comisana ewe lambs showed that growth traits were unaffected by dietary treatments as well as none of the carcass measurements examined (P > 0.05). These findings indicate that WM results as a suitable feed ingredient for growing ewe lambs that can be a satisfactory substitute to conventional grain source.     

Influences of non-genetic factors on early growth of Adilo lambs under smallholder management systems,southern Ethiopia

Stagnant early growth and mortality are the major impediments for sheep production in southern Ethiopia. We evaluated the effects of non-genetic factors on early growth performance of lambs in Halaba district with 467 lambs owned by 60 households. Body weights (kilograms) of lambs at birth, 30, 60, 90, 120, and 150 days were 2.30 ± 0.03, 4.45 ± 0.11, 6.94 ± 0.13, 10.4 ± 0.19, 13.3 ± 0.19, and 15.7 ± 0.20, respectively. The average daily gain (ADG; gram) from birth to 30, 60, 90, 120, and 150 days were 71.18 ± 8.18, 77.18 ± 2.19, 89.20 ± 1.98, 91.18 ± 1.51, and 90.68 ± 1.27, respectively. Season effect was significant (p < 0.05) for weight at birth, 30, and 120 days. Similarly, season of birth influenced (p < 0.05) ADG (gram) at all ages except from birth to 60 days. Single-born lambs were heavier over multiple births (p < 0.01), 90 (p < 0.001) and 120 days (p < 0.05) and higher (p < 0.001) ADG from birth to 90 days. There were significant interaction effects of parity by sex at birth (p < 0.01) and parity by type of birth (p < 0.001) and 90 days (p < 0.01). From the non-genetic factors estimated in this study, season and type of birth, and their interaction had a more profound effect at early growth of lambs, and they need to be considered in the improvement plan of sheep under Halaba arid to semi-arid environments. Efforts geared towards planned breeding, improved nutrition, and health would assist farmers to exploit these indigenous and adaptable sheep resources efficiently.     

A morphometric analysis of the changes with age in the skin surface wax and the sebaceous gland area of Merino sheep

SUMMARY Skin samples were collected from the midside of Merino ewes at 6 weeks, one year, and 3 years of age. The thickness of the surface wax and the number and area of sebaceous glands per unit length of skin were measured with an image analyser. Three-year-old sheep had a significantly (P < .05) thicker skin surface wax layer, (14.4μ± 1.45), than they did as lambs, (7.85μ± 0.88). Both the number (2.91 ± 0.15 per mm) and area (24.27 μ²/μ± 1.54) of sebaceous glands per unit length of skin of 3-year-old sheep were significantly less than in lambs, which measured 4.10 ± 0.15 per mm and 39.30 ± 4.14 μ²/μ respectively and one-year-old sheep, which measured 3.99 ± 0.21 per mm and 35.43 μ²/μ 3.65 respectively.     

Melatonin administration enhances the reproductive capacity of young rams under a southern Mediterranean environment

This study tested the effect of melatonin treatment, initiated in late February on reproductive traits of young rams. A total of 14 young Barbarine rams were used. Seven animals were treated with three melatonin subcutaneous implants (Melatonin) on 28 February while the remaining rams remained untreated (Control). After 60 days of melatonin administration, scrotal circumference reached average values of 32.1 ± 1.54 and 29.5 ± 1.0 cm for Melatonin and Control animals, respectively (P < 0.05). Semen characteristics did not differ between groups; melatonin treatment tended (P = 0.091) to increase sperm concentration 60 days after implantation when means reached 5.87 ± 0.703 and 4.61 ± 0.654 × 10⁹ spermatozoa/mL for Melatonin and Control rams, respectively. Melatonin treatment significantly affected total activity time, number of lateral approaches and mount attempts in comparison to controls. During a 6‐h sampling period, mean plasma testosterone concentrations increased as a result of melatonin treatment (P < 0.001) and testosterone pulse frequency averaged 3.45 ± 2.24 and 1.25 ± 1.0 (P = 0.086) for Melatonin and Control rams. Data clearly suggest that abrupt treatment of young rams with melatonin implants in winter is sufficient to improve reproductive traits.     

Energy requirements of early‐weaned Dorper cross‐bred female lambs

The net and metabolizable energy (NE and ME) requirements of Dorper cross‐bred female lambs with BWs of 20–35 kg were assessed in a comparative slaughter trial. Thirty‐five Dorper × thin‐tailed Han cross‐bred female lambs weaned at ~50 days of age (20.3 ± 2.15 kg BW) were used. Seven randomly selected lambs were slaughtered at the start of the trial (baseline group). An intermediate group consisting of seven randomly selected lambs fed ad libitum was slaughtered when the lambs reached an average BW of 28.5 kg. The remaining 21 lambs were allotted randomly to three levels of dry matter intake: ad libitum or restricted to 70% or 40% of the ad libitum intake. All the lambs were slaughtered when the sheep fed ad libitum reached a BW of 35 kg. Total body energy, nitrogen, fat, ash and moisture content were determined. In a digestibility trial, an additional 15 Dorper × thin‐tailed Han cross‐bred female lambs (28.7 ± 1.75 kg BW) were housed in metabolism cages and used in a completely randomized design experiment to evaluate the ME value of the diet at the three feed intake levels. The maintenance requirements for NE and ME were 245.5 and 380.3 kJ/kg metabolic shrunk body weight (SBW^0.75) respectively. The partial efficiency of energy use for maintenance was 0.645. The NE requirements for growth ranged from 1.18 to 5.18 MJ/d for the lambs gaining 100–350 g/d from 20 to 35 kg BW. Partial efficiency of ME for growth was 0.44. In conclusion, the current study suggests that the NE requirement for maintenance and growth of Dorper early‐weaned cross‐bred female lambs is lower than the current AFRC and NRC recommendations.     

An effective buprenorphine analgesic protocol increases post-operative adhesions in rats after laparotomy

The use of analgesics in post‐operative adhesion (POA) research is problematic due to POA‐inhibiting effects of anti‐inflammatory agents and bowel motility‐inhibiting effects of opioids, which may increase adhesion formation. This study was conducted to assess a buprenorphine (BUP) protocol for analgesic efficacy and its effects on POA formation in a rat cecal abrasion model. The protocol was approved by the University of Florida's Institutional Animal Care and Use Committee (IACUC). Forty‐one female Sprague‐Dawley rats were randomized into two groups (n = 20 or 21 group). Body weight, food and water intake were recorded daily from 2 days before until 7 days after surgery. Treatment rats received 0.05 mg kg^–1 BUP SQ at anesthesia induction and 0.3 mg kg^–1 BUP orally in flavored gelatin 6 hours after surgery. Control rats received saline placebo injection and plain gelatin. All rats underwent laparotomy and controlled cecal abrasion. At 3, 6 and 24 hours post‐operatively rats were individually observed in 10‐minutes periods for pain related behavior incidence: ‘twitch’ (contraction of muscles along dorsum and/or head), ‘back arch’ (cat‐like position with front legs extended and pushing backward), ‘writhe’ (flank contraction), and ‘stagger/fall’ (momentary loss of balance while grooming or ambulating), using the method of Roughan and Flecknell (Pain 2001,90, 65–74). On post‐op day seven rats were euthanized by CO₂ inhalation and POA evaluated (0 to 4 scale; ³Grade 2 = clinically significant.) BUP treated rats had lower mean pain scores than control rats at 3 hours (1.6 ± 1.7 versus 20.3 ± 13.5 (mean ± SD); p < 0.001) and 6 hours (2.1 ± 2.7 versus 23.7 ± 12.9; p < 0.001) but not 24 hours (1.5 ± 1.3 versus 4.9 ± 6.6; p = 0.35) post‐operatively. Predominant pain behavior was ‘writhe’ (flank contraction) in contrast to ‘twitch,’‘back arch,’ and ‘stagger/fall’ reported as most common pain indicators in other rat strains. BUP rats had greater mean adhesion incidence (2.4 ± 1.7 versus 1.4 ± 1.8; p < 0.03) and severity (90%³Gr.2 versus 65% of controls; p < 0.05). The BUP protocol appeared to provide effective analgesia for at least 24 hours post‐operatively. Strain of rat may affect pain related behavior. BUP should be used with caution after abdominal surgical procedures having high risk of POA formation.