[Effect of a multimodal pain management protocol and age on wound healing after thermal disbudding of female German Holstein calves]. / Einfluss eines multimodalen Schmerz­managements sowie des Alters zum Zeitpunkt des Eingriffes auf die Wundheilung nach thermischer Zerstörung der Hornanlage bei weiblichen Deutsch-Holstein-Kälbern.

INTRODUCTION: Hot-iron disbudding of calves is a stressful and painful procedure and leaves a burn wound. Pain management procedures and the effects of hot-iron disbudding on biochemical markers of pain perception and stress response have been widely investigated in recent years. The aim of this study was to investigate the potential effects of pain management and age of the calf on the healing of burn wounds caused by disbudding. 327 healthy female German Holstein calves were included in this randomised, triple-blinded, prospective study. Calves were either disbudded at the age of four to 10 or 15 to 28 days using a gas-powered hot iron. Each calf was randomly allocated to one of nine possible treatment groups (BG). All calves received either the active ingredients to be tested (xylazine hydrochloride with 0.2 or 0.05 mg / kg body mass (BM) intramuscular for sedation, procaine hydrochloride (2 %) each 8 ml locally on both sides subcutaneously (SC) to the cornual nerves, meloxicam with 0,5 mg / kg BM SC for anti-inflammatory purposes) or an identical amount of saline solution (placebo). Calves in the group `thermE` and `ScheinE` received only placebo. In group `ScheinE` disbudding was simulated and in `thermE` it was carried out. The calves were clinically monitored starting one day before and ending 28 days after the procedure and the burn wounds were assessed. Both the rectal temperature and parameters of wound healing changed significantly during the study period and had characteristic profiles over time. Wound healing was not influenced by the different analgesic protocols, indicating that a multimodal analgesia does not pose a risk for wound healing after thermal disbudding. There were no observed differences between the age groups. The results of this study show, that disbudding of young calves and a multimodal pain management protocol does not affect wound healing in calves.

INTRODUCTION: L'ébourgeonnage thermique des veaux est une procédure stressante et douloureuse qui laisse une brûlure. Les procédures de gestion de la douleur et les effets de l'ébourgeonnage thermique sur les marqueurs biochimiques de la perception de la douleur et de la réponse au stress ont été largement étudiés ces dernières années. Le but de cette étude était d'étudier les effets potentiels de la gestion de la douleur et de l'âge du veau sur la cicatrisation des brûlures causées par l'ébourgeonnage. 327 veaux Holstein allemands femelles en bonne santé ont été inclus dans cette étude prospective randomisée en triple aveugle. Les veaux ont été soit ébourgeonnés à l'âge de 4 à 10 jours ou de 15 à 28 jours à l'aide d'un thermocautère à gaz. Chaque veau a été réparti au hasard dans l'un des neuf groupes de traitement possibles (BG). Tous les veaux ont reçu soit les principes actifs à tester (chlorhydrate de xylazine à 0,2 ou 0,05 mg/kg de masse corporelle (BM) par voie intramusculaire pour sédation, chlorhydrate de procaïne (2 %) 8 ml localement des deux côtés par voie sous-cutanée (SC) jusqu'aux nerfs cornuaux , méloxicam à 0,5 mg/kg de masse corporelle SC à visée anti-inflammatoire) ou une quantité identique de solution saline (placebo). Les veaux du groupe « thermE ¼ et « ScheinE ¼ ont reçu uniquement un placebo. Dans le groupe

[Cortisol concentrations in sheep before, during and after sham foot trimming on a tilt table - the suitability of different matrices]. / Kortisolkonzentrationen bei Schafen vor, während und nach der simulierten Klauenbehandlung im Kippstand ­ Eignung verschiedener Matrices.

INTRODUCTION: Matrices that can be collected non-invasively for quantification of a stress response in sheep have received little attention in the veterinary literature. This study examines the suitability of blood, tears and saliva for determining a stress response in sheep undergoing sham foot trimming on a tilt table. The cortisol concentration of blood, tears and saliva and the concentration of cortisol metabolites in faeces were measured in 13 healthy Meat Merino ewes once a day for six days. Sham foot trimming on a tilt table was used as the stressor and was done during a one-hour period on day 4; cortisol concentrations of blood and tears were measured at 0, 10, 20, 30, 40 and 60 minutes. Cortisol concentrations of blood (maximum at 30 minutes) and tears (maximum at 40 minutes) increased during the procedure and then decreased. There were significant correlations between cortisol concentrations of blood and tears (p = 0,04) during sham foot trimming (area under the curve, 0 to 60 minutes). Over the entire 6-day study period, significant correlations were seen between the cortisol concentrations of blood and tears (r = 0,55; p.

INTRODUCTION: Les marqueurs qui peuvent être collectés de manière non invasive pour quantifier une réponse au stress chez le mouton ont fait l'objet de peu d'attention dans la littérature vétérinaire. Cette étude examine la pertinence du sang, des larmes et de la salive pour déterminer une réponse au stress chez des moutons subissant un parage fictif des pieds sur une table basculante. La concentration de cortisol dans le sang, les larmes et la salive ainsi que la concentration de métabolites de cortisol dans les fèces ont été mesurées chez 13 brebis Meat Merino saines une fois par jour pendant six jours. Le parage fictif des pieds sur une table inclinable a été utilisé comme facteur de stress et a été effectué pendant une période d'une heure le jour 4; les concentrations de cortisol dans le sang et les larmes ont été mesurées à 0, 10, 20, 30, 40 et 60 minutes. Les concentrations de cortisol dans le sang (maximum à 30 minutes) et les larmes (maximum à 40 minutes) ont augmenté au cours de la procédure puis ont diminué. Il y avait des corrélations significatives entre les concentrations de cortisol dans le sang et les larmes (p = 0,04) lors du parage fictif des onglons (aire sous la courbe, 0 à 60 minutes). Sur l'ensemble de la période d'étude de 6 jours, des corrélations significatives ont été observées entre les concentrations de cortisol dans le sang et les larmes (r = 0,55 ; p < 0,001), le sang et la salive (r = 0,53 ; p < 0,001) et les larmes et la salive (r = 0,78 ; p < 0,001). La concentration fécale de métabolites de cortisol était significativement augmentée au jour 5 (p 0,05), mais la concentration de cortisol des autres supports n'a pas changé de manière significative au cours de la période d'étude de 6 jours. Le parage fictif des pieds sur une table basculante a été considéré comme un facteur de stress aigu chez les moutons en raison de l'augmentation des concentrations de cortisol dans le sang, des larmes et de l'augmentation des concentrations de métabolites de cortisol dans les selles. La concentration de cortisol dans les larmes était similaire à celle du sang et, par conséquent, la collecte de larmes représente une alternative viable et non invasive au sang pour les tests de cortisol. Le délai des pics entre la concentration maximale de cortisol dans les larmes et le sang doit être pris en compte lors de l'interprétation des résultats.

[Thermographic monitoring of skin surface temperature associated with hot-iron disbudding in calves]. / Einsatz der Thermographie zum Monitoring der operationsbedingten Hitzeentwicklung während der thermischen Enthornung von Kälbern.

INTRODUCTION: The goal of this study was to determine the skin surface temperatures of the head using thermography in 28 German Holstein heifer calves at the time of hot iron disbudding. Calves were divided into group 1 (hot-iron disbudding, n = 14) and 2 (sham disbudding, n = 14). Thermographic measurements were made at eight locations of the head (area surrounding both horn buds, both horn buds, muzzle, mucous membranes of the muzzle, both eyes) at nine time points (- 60 min (basal value), time of disbudding, 5, 30, 60, 90, 120, 240 and 480 min after disbudding) using a high-end thermographic camera (ThermoPro TP8, Firma DIAS Infrared GmbH). The rectal temperature was measured 60 min before and 5, 240 and 480 min after disbudding. The statistical software SAS version 9.4 was used for analysis. Skin surface temperatures and rectal temperature correlated at several locations (rp ≥ 0.45; p ≤ 0.05). The maximum temperature (approx. 67 ºC) was measured at the horn buds immediately after the hot-iron procedure. By five and 30 min after hot-iron disbudding, the temperature of the horn buds had decreased by up to 50%, whereas the temperatures at the other locations had increased significantly (p.

INTRODUCTION: Le but de cette étude était de montrer les températures de surface dans la zone de tête chez 28 veaux femelles Holstein allemandes autour de la période d'écornage en utilisant la thermographie. À cette fin, les animaux étudiés ont été divisés en deux groupes (1: écornage thermique (thermE), N = 14; 2: pseudo-écornage (ScheinE), N = 14). À neuf reprises (- 60 [valeur au repos], 0, 5, 30, 60, 90, 120, 240, 480 min) des mesures thermographiques ont été effectuées à huit endroits dans la zone de la tête (environs du bourgeon de corne gauche (UliHa), bourgeon de corne gauche (liHa), œil gauche (liAu), mufle (FM), muqueuse nasale (SHFM), œil droit (reAu), bourgeon de corne droite (reHa), environs du bourgeon de corne droit (UreHa)). Ces mesures ont été réalisés à l'aide d'une caméra d'imagerie thermique haut de gamme (ThermoPro TP8, société DIAS Infrared GmbH). De plus, la température interne du corps (ICT) a été enregistrée par voie rectale aux minutes - 60, 5, 240 et 480. L'évaluation statistique de chaque caractéristique a été effectuée avec SAS, version 9.4. À plusieurs endroits (reAu, liAu, SHFM, liHa), une relation entre les ICT mesurées par voie rectale et les températures de surface déterminées par thermographie a pu être démontrée (rp ≥ 0,45; p ≤ 0,05). La température maximale (env. 67 °C) a pu être constatée au niveau des bourgeons de corne directement après l'écornage thermique. Cinq et 30 minutes après l'intervention, la température au niveau des bourgeons de corne avait diminué jusqu'à 50%, tandis que les températures de surface des autres emplacements chez les veaux des deux groupes avaient augmenté par rapport à la valeur au repos (p.

[Thermographic examination of head surface temperatures of calves under field conditions]. / Thermographische Erfassung der Oberflächentemperatur im Kopfbereich von Kälbern unter Stallbedingungen.

INTRODUCTION: Thermographic examination of 157 German Holstein heifer calves was performed to investigate the feasibility of this technique for on-farm recording of surface temperature of the head and to examine potential factors that affect the recordings. Baseline values were obtained from six defined locations on the head including both eyes, both horn buds, the muzzle and the mucous membrane of the muzzle using a high-end thermographic camera (ThermoPro TP8, Firma DIAS Infrared GmbH). Evaluation of the influence of various factors on thermographic measurements showed that ambient temperature had the largest effect on surface temperature of the head (regression coefficient, 0.10 to 0.32, p ≤ 0.01) whereas humidity had no effect (in t-test p ≥ 0.33 over all locations). There was a no correlation between rectal temperature and surface temperature (rp ≤ 0.05). The surface temperature decreased with increasing age of the calves (regression coefficient, - 0.42 to - 0.14, p ≤ 0.01). The agreement between double readings made shortly after one another was excellent at all locations (r ≥ 0.95). The emission of infrared energy varied among different locations; the most infrared energy was emitted by the eyes and the least by the muzzle. Paired locations (eyes and horn buds) had symmetric emission patterns of infrared energy. Measuring the surface temperature of the head of calves in their normal barn environment using a standardised protocol was feasible and thus could potentially be used for monitoring calves under field conditions.

INTRODUCTION: Un total de 157 veaux femelles provenant d'un troupeau de 1 500 vaches holstein ont été examinées au moyen d'une caméra thermographique haut de gamme (Ther-moPro TP8, Firma DIAS Infrared GmbH). Le but de la présente étude était d'étudier la faisabilité de cette technique pour l'enregistrement à la ferme de la température de surface de la tête de veaux laitiers et d'examiner les facteurs potentiels qui affectent les enregistrements. Tous les veaux ont été doucement tenus par une personne formée afin de normaliser la procédure. Les valeurs de base ont été obtenues à partir de six endroits définis sur la tête, y compris les deux yeux, les deux boutons de corne, le mufle et la muqueuse du museau. L'évaluation de l'influence de divers facteurs sur les mesures thermographiques a montré que la température ambiante avait le plus grand effet sur la température de surface de la tête (coefficient de régression, 0,10 à 0,32, p ≤ 0,01) alors que l'humidité n'avait aucun effet (dans le test t, p ≥ 0,33 sur tous les lieux). Il n'y avait pas de corrélation entre la température rectale et la température de surface (rp ≤ 0,05). La température de surface diminuait avec l'âge des veaux (coefficient de régression, -0,42 à -0,14, p ≤ 0,01). La concordance entre les lectures doubles faites peu de temps après les autres était excellente dans tous les sites (r ≥ 0,95) L'émission d'énergie infrarouge variait selon les endroits. L'énergie infrarouge la plus importante a été émise par les yeux et la plus faible par le mufle. Les sites appariés (yeux et cornes) présentaient des profils d'émission symétriques d'énergie infrarouge. La thermographie peut être utilisée chez veaux Holstein pour la détection de différentes température de surface de la tête.

Evaluation of arterial digital blood flow in dairy cows with claw horn disruption lesions using Doppler ultrasonography.

Vascular changes play an important role in the pathogenesis of claw horn disruption lesions in cattle. The aim of the study was to measure arterial blood flow in the hind limbs of German Holstein cows with claw horn disruption lesions. A 10-MHz linear transducer was used to assess blood flow in the interdigital artery in the dorsal pastern region in the hind limbs of 11 non-lame and 33 lame German Holstein cows in which lameness was scored clinically. Qualitative and quantitative blood flow parameters were compared in affected limbs and unaffected contralateral hind limbs in lame cows and in the hind limbs of lame cows and non-lame cows. A pulsed-wave Doppler signal suitable for analysis was obtained in 78 of 88 limbs (33 affected and contralateral limbs, 22 limbs of control cows). Blood flow curve types 1 and 2 were predominant in the hind limbs of lame cows. Vessel diameter, end-diastolic velocity, and blood flow rate were significantly greater in lame cows than in non-lame cows and were numerically greater in moderately lame cows than in mildly lame cows. The differences in the qualitative and quantitative parameters between lame and non-lame cows were most likely caused by inflammation of the pododerm. The role of weight distribution between the paired hind limbs and the existence of claw horn disruption appeared to have an effect on the differences in local circulation in the affected and unaffected contralateral hind limbs in lame cows.

Glycaemic and insulinaemic responses of adult healthy warm-blooded mares following feeding with Jerusalem artichoke meal.

This study aimed to investigate the impact of the supplementation of a pre-biotic compound [Jerusalem artichoke meal (JAM)] on the glycaemic and insulinaemic response in healthy, non-obese warm-blooded horses. Six adult mares [mean body weight (bwt) 529 ± 38.7 kg; body condition score 5.1 ± 0.49/9] were used. In two equal meals per day, the horses received crushed oat grains (1 g starch/kg bwt per day) and meadow hay (2 kg/100 kg bwt per day) which together were likely to meet the energy recommendation for light work (GfE, ). Additionally, they received either 0.15 g fructo-oligosaccharides and inulin (FOS+INU)/kg bwt per day via commercial JAM or maize cob meal without grains as control (CON) in 2 × 3-week periods according to a crossover design. Blood was collected on d21 of the feeding period at different ante- and postprandial (PP) time points (-60, 0, 30, 60, 90, 120, 180, 240 and 300 min), and the plasma glucose and serum insulin levels were determined. Feeding JAM vs. CON did not change the PP peak of glucose or insulin (glucose: 6.3 ± 0.40 vs. 7.0 ± 0.87 mmol/l; insulin: 0.508 ± 0.087 vs. 0.476 ± 0.082 nmol/l) nor did it cause different AUCs until 120 and 300 min PP for glucose and insulin, respectively (AUC120 , glucose: 997 ± 41.6 vs. 1015 ± 41.63 mmol/l per minute, insulin: 49 ± 6.3 vs. 42 ± 6.3 nmol/l per minute; AUC300 , glucose: 1943 ± 142.3 vs. 2115 ± 142.3 mmol/l per minute, insulin: 94 ± 14.8 vs. 106 ± 14.8 nmol/l per minute; p > 0.05). Following JAM vs. CON feeding, glucose and insulin levels declined more rapidly until 240 min PP and tended to be lower (p = 0.053 and p = 0.056, respectively) at this time point. This result might be promising and should further be studied more detailed.

Evaluation of arterial digital blood flow using Doppler ultrasonography in healthy dairy cows.

BACKGROUND: Local circulatory disturbances have been implicated in the development of foot disorders in cattle. The goals of this study were to evaluate the suitability of the interdigital artery in the pastern region in both hind limbs using pulsed-wave (PW) Doppler ultrasonography and to investigate quantitative arterial blood flow variables at that site in dairy cows. An Esaote MyLabOne ultrasound machine with a 10-MHz linear transducer was used to assess blood flow in the interdigital artery in the pastern region in both hind limbs of 22 healthy German Holstein cows. The cows originated from three commercial farms and were restrained in a standing hoof trimming chute without sedation. RESULTS: A PW Doppler signal suitable for analysis was obtained in 17 of 22 cows. The blood flow profiles were categorised into four curve types, and the following quantitative variables were measured in three uniform cardiac cycles: vessel diameter, pulse rate, maximum systolic velocity, maximum diastolic velocity, end-diastolic velocity, reverse velocity, maximum time-averaged mean velocity, blood flow rate, resistance index and persistence index. The measurements did not differ among cows from the three farms. Maximum systolic velocity, vessel diameter and pulse rate did not differ but other variables differed significantly among blood flow profiles. CONCLUSIONS: Differences in weight-bearing are thought to be responsible for the normal variability of blood flow profiles in healthy cows. The scanning technique used in this report for evaluation of blood flow in the interdigital artery appears suitable for further investigations in healthy and in lame cows.

Factors associated with dust dispersed in the air of indoor riding arenas.

REASONS FOR PERFORMING STUDY: Environmental factors contribute to respiratory diseases in horses and man. During exercise, equine ventilation is increased, potentially increasing exposure of the airways to inhaled particulates. Currently, there is very little information on the quality of air in riding arenas. OBJECTIVES: To evaluate air quality and dust particle concentrations in indoor riding arenas before and after use for riding. STUDY DESIGN: Longitudinal study. METHODS: Air quality was assessed in 4 indoor riding arenas in Saxony-Anhalt, Germany on a monthly basis for 1 year. Concentrations of particles in 6 particle fractions from 0.3 to 5.0 µm were measured in air collected at 4 points in the riding arenas approximately at the height of the horses' (1.5 m) and riders' noses (2.5 m), before and after the arenas were used by one horse performing standardised riding session. RESULTS: There were significant differences in the numbers of particles between the arenas within months and between months within the arenas. Particle numbers were significantly influenced by the month and activities in the arenas before and after riding. The effect of the month on differences in the dust concentration may relate to surface watering. A significant increase in numbers of particles was observed after the riding session. Significant interactions were found between measuring heights and month within arena (P<0.01) and there was an interaction between measuring height and time points (before and after riding, P = 0.02). CONCLUSIONS: The amount of dust dispersed in the air increases during riding in indoor arenas and this appears to be influenced by footing material, direct connections between the arena and stables and season, possibly reflecting surface watering practices.

Estimation of the leucine and histidine requirements for piglets fed a low-protein diet.

Reduction of the CP content in the diets of piglets requires supplementation with crystalline essential amino acids (AA). Data on the leucine (Leu) and histidine (His) requirements of young pigs fed low-CP diets are limited and have primarily been obtained from nonlinear models. However, these models do not consider the possible decline in appetite and growth that can occur when pigs are fed excessive amounts of AA such as Leu. Therefore, two dose-response studies were conducted to estimate the standardised ileal digestible (SID) Leu : lysine (Lys) and His : Lys required to optimise the growth performance of young pigs. In both studies, the average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratio (G : F) were determined during a 6-week period. To ensure that the diets had sub-limiting Lys levels, a preliminary Lys dose-response study was conducted. In the Leu study, 60 35-day-old piglets of both sexes were randomly assigned to one of five treatments and fed a low-CP diet (15%) with SID Leu : Lys levels of 83%, 94%, 104%, 115% or 125%. The His study used 120 31-day-old piglets of both sexes, which were allotted to one of five treatments and fed a low-CP diet (14%) with SID His : Lys levels of 22%, 26%, 30%, 34% or 38%. Linear broken-line, curvilinear-plateau and quadratic-function models were used for estimations of SID Leu : Lys and SID His : Lys. The minimum SID Leu : Lys level needed to maximise ADG, ADFI and G : F was, on average, 101% based on the linear broken-line and curvilinear-plateau models. Using the quadratic-function model, the minimum SID Leu : Lys level needed to maximise ADG, ADFI and G : F was 108%. Data obtained from the quadratic-function analysis further showed that a ±10% deviation from the identified Leu requirement was accompanied by a small decline in the ADG (-3%). The minimum SID His : Lys level needed to maximise ADG, ADFI and G : F was 27% and 28% using the linear broken-line and curvilinear-plateau models, respectively, and 33% using the quadratic-function model. The preferred model to estimate the His requirement was the curvilinear-plateau model. However, a 10% reduction in the SID His : Lys level was associated with an 11% reduction in the ADG. In conclusion, the SID Leu : Lys level needed to maximise growth was 108% when using the quadratic-function model as the best-fitting model. The minimum SID His : Lys level required to optimise growth was 28% when using the curvilinear-plateau model as the best-fitting model.

Analysis of ordered categorical data with threshold models exemplified by plumage damage scores from laying hens differing in their genotype and rearing environment.

Plumage damage scores (PDS) were assessed in laying hens of 2 genotypes (Lohmann Tradition and Lohmann Silver) at the 45th and 70th weeks of age, with scores ranging from zero (no damage) to 6 (completely denuded). This ordinally scaled categorical characteristic was recorded from different body regions of 365 hens that had experienced different housing environments (2 enrichment levels) during their rearing and laying periods. The so-called threshold model is an option for analyzing repeated ordered categorical data from individual animals. This model represents a generalized linear mixed model if the linear predictor additionally includes the animal as a random effect. This paper is intended to fill the gap between the theoretical aspects of generalized linear mixed models and their practical application in animal science. A cumulative probit model was adapted for analyzing plumage damage. The variation among birds was considered as a random effect for the analysis of cumulative probabilities. The numerical implementation of the methodology was done based on the NLMIXED procedure of the SAS statistical program. A threshold model with inhomogeneous residual variances for the latent variable was used because less plumage damages were observed up to the 45th week of age compared to the 70th week of age. Differences in PDS were evident between genotypes, age, and enrichment levels during housing periods. However, neither of the 2 enriched environments proved consistent superiority or inferiority across all traits. Major plumage damage (PDS larger than or equal to 5) was observed for the breast region in 56.6% of all birds with the Lohmann Tradition genotype and in 34.4% with the Lohmann Silver genotype when we look at the mean over all treatments. The most severe plumage damage was observed at the 70th week of age for the traits breast and housing environment without additional enrichment.

Estimation of genetic parameters based on individual and group mean records in laying hens.

(1) The study was conducted to estimate the heritability, genetic correlations and breeding values of laying hens based on individual records and group mean records. (2) Records of two pure lines from a commercial breeding programme of White Leghorns from three generations housed in single cages and in group cages were used. A total of 8483 and 8817 individual records of lines A and D, respectively, and a total of 1358 (line A) and 1161 (line D) group mean records were analysed. (3) An animal model using Restricted Maximum Likelihood (REML) was used to estimate variance components of individual records. Group mean records were analysed using the sire model, taking heterogeneity of error variance and correlated residual effects into account. Breeding values of sires were estimated based on the BLUP method using a multivariate sire model. Spearman Rank correlations were used to compare sire breeding values estimated from individual records and from group mean records. The traits studied were monthly egg production, cumulative production and egg weight. (4) Heritability estimates based on individual records were higher than from group mean records. Heritabilities for cumulative production records were higher than for monthly production, based on individual as well as group mean records. The estimates of genetic correlations between monthly egg production and cumulative production were moderate to high. Egg production and egg weight recorded individually were highly genetically correlated with those recorded on group means. Sire breeding values estimated from individual records showed high correlations with those from group mean records. (5) Differences in the ranking of sire breeding values estimated from individual vs group mean records were negligible, indicating that no genotype x environment interaction exists. Selection based on individual performance records of laying hens housed in single cages could give a good response on performance of laying hens housed in group cages. Cumulative egg production over periods 1 to 6 is the best trait for the selection programme.

Monthly model for genetic evaluation of laying hens. II. Random regression.

1. We investigated the use of monthly production records for genetic evaluation of laying hens, derived from a test day model with random regression in dairy cattle and compared it with other models. 2. Records of 6450 hens, daughters of 180 sires and 1335 dams, were analysed using a model with restricted maximum likelihood (REML): traits considered were monthly and cumulative egg production. Five models were studied: (1) random regression with covariates derived from the regression of Ali and Schaeffer (Canadian Journal of Animal Science, 67: 637-644, 1987) (RRMAS), (2) random regression with covariates derived from quartic polynomial (RRMP4), (3) fixed regression with covariates derived from Ali and Schaeffer (FRM), (4) multiple trait (MTM) and (5) cumulative (CM). 3. The models were compared on the basis of Spearman rank correlations of individual breeding values and sire breeding values estimated from subsets of full-sib split data. The hens (about 10% per generation) which ranked highest on their estimated breeding values from different models were compared phenotypically with their full records. 4. The estimates of heritability resulting from RRMP4 were biased upward from the estimates obtained from MTM, so this model was discarded. The heritabilities for monthly productions from RRMAS and MTM showed a similar pattern. They were high for the 1st month of production, decreased to their lowest value at about month 5 of production and increased again to the end of lay. 5. Spearman rank correlations between animal breeding values estimated by monthly models (RRMAS, FRM and MTM) were high, between 0.91 and 0.98, whereas those between estimates of monthly models and CM were lower, from 0.85 to 0.87. The correlations estimated either from intermittent months of measurements (odd vs even months) or full records were generally high, from 0.93 to 0.99. Information from odd months of production could be sufficient for cost-efficient recording schemes. The RRMAS generally had the highest correlation of sire breeding values between subsets of full-sib records, followed by MTM, RM and CM. Monthly models selected hens with higher productivity than the cumulative model. 6. In conclusion, genetic evaluation based on monthly production may be better than using cumulative production and RRMAS appeared to be the best among the models tested here.

Monthly model for genetic evaluation of laying hens 1. Fixed regression.

1. This paper addresses the possibility of using a monthly model for the genetic evaluation of laying hens, based on the definition of a test day model with fixed regression as used in dairy cattle, in which monthly records were treated as repeated measurements of the same trait. 2. Production records of 6450 hens, daughters of 180 sires and 1335 dams were analysed using an animal model with restricted maximum likelihood (REML). The traits considered were individual monthly egg production and cumulative egg production in 11 months. Four different models were fitted to various combinations of monthly and cumulative records. The covariates were derived from the regression of Ali and Schaeffer (1987). 3. Spearman rank correlations were computed to compare breeding values from different models. Two types of correlations were computed: between individual breeding values and between sire breeding values based on subsets of full-sib records. 4. The results indicated that a monthly model with nested covariates produced higher heritability and permanent environmental variance than the models with non-nested or without covariates. The estimates of heritability obtained from monthly model were lower than the estimates from the cumulative model. The monthly model resulted in higher correlations of sire breeding values between two subsets of full-sib records than those from cumulative models. 5. In conclusion, the monthly model with nested covariates appears to be better than the model with non-nested covariates or without covariate. Although the heritability estimates obtained from the monthly model were lower, the monthly model with nested covariates could be better than the cumulative model for genetic evaluation of laying hens in the 1st cycle of laying period when using either full or part records. The use of information from odd months of production could be of interest for the evaluation of full records.

Application of a nonlinear regression function to evaluate the kinetics of antibody response to vaccines in chicken lines divergently selected for multitrait immune response.

To evaluate the kinetics of immune response to vaccines in chickens, antibody response curves were approximated to the observed antibody ratios by using a nonlinear regression function. New parameters, the curve maximum (ymax) and the time of the maximum (tmax), were calculated. The method was applied to analyze the kinetics of the serum antibody response to Mycoplasma gallisepticum (MG) and Pasteurella multocida (PM) vaccines in White Leghorn lines selected, in replicate, for 10 generations for high (High) and low (Low) multitrait immune response. Chicks were immunized at 6 wk of age with both vaccines. Serum antibody levels were analyzed before (0) and 1, 2, 3, 4, 5, 12, and 21 wk postvaccination (wpv). The High lines displayed a significantly higher response than Low to both MG and PM. The difference in ymax between High and Low lines was 3.25-fold for PM response and 1.5-fold for MG response. Low lines had a significantly (P < 0.05) later tmax than High lines to MG, but not to PM. There was a significant (P < 0.05) positive correlation between the antibody responses to MG and PM, in High lines for the antibody ratios 0, 3, and 21 wpv and in Low lines for 0, 12, and 21 wpv. The ymax and tmax of antibody responses to the two vaccines were not correlated. The results on the kinetic differences of the antibody responses to MG and PM suggest that the kinetics and persistence of antibody reaction have different genetic regulation in response to each vaccine.

Simultaneous estimation of variances and covariances using REML and Henderson 3 in a selected population of White Leghorns.

1. Genetic and residual variances and covariances were estimated on performance data from 5943 lyaing hens from a 7 generation selection experiment for the traits: egg number up to day 270 (EN270), egg weight (EW), body weight at day 215 (BW), egg mass 100 g of food (EMFC), and residual food consumption (RFC) by a Henderson 3 and REML procedure. 2. Simultaneous REML estimates of all 30 components were obtained by a software package is based on numerical optimisation of the log likelihood using a multivariate animal model. Henderson 3 estimates were computed on the basis of a hierarchical sire-dam model. Estimates were generated beginning with a data set comprising only the first generation, and then successively adding one generation after the other. 3. REML estimates for heritabilities h2 on the basis of all performance records were 0.40, 0.75, 0.62, 0.21 and 0.22 for traits EN270, EW, BW, EMFC, and RFC, respectively. The corresponding Henderson 3 estimates were: 0.30, 0.57, 0.43, 0.21, and 0.20. 4. The results indicate that some REML h2 estimates are substantially different from those obtained by Henderson 3 once the data set included three generations as opposed to those based on Henderson 3.