Sexual Dimorphism for Coping Styles Complements Traditional Methods for Sex Determination in a Multivariety Endangered Hen Breed

Sex determination is key to designing endangered poultry population conservation and breeding programs when sex distribution departs from Hardy–Weinberg equilibrium. A total of 112 Utrerana chickens (28 per variety, partridge, black, white, and franciscan) were selected for hatching day sexing. Sex assignation was performed through 10 methods. Three sex assignment criteria comprised criteria found in literature, opposite criteria to that in the literature, and composite criteria combining methods reporting the highest predictive success from the previous ones. This study aims to determine which method combinations may more successfully determine sex across the four varieties of Utrerana endangered hen breed to tailor noninvasive early specific models to determine sex in local chicken populations. Although the explanatory power of the three assignation criteria is equal (75%), assignation criteria 2 resulted to be the most efficient as it correctly assigns males more frequently. Only methods 3 (English method), 5 (general down feathers coloration), 7 (wing fan), and 10 (behavior/coping styles) reported significant differences regardless of the variety, hence, are appropriate for early sexing. Sex confirmation was performed at 1.5 months old. Identifying sex proportions enhances genetic management tasks in endangered populations, complementing more standardized techniques, which may result inefficient given the implicit diversity found in local populations

A Nondestructive Eggshell Thickness Measurement Technique Using Terahertz Waves

Eggshells play a number of important roles in the avian and reptile kingdom: protection of internal contents and as a major source of minerals for developing embryos. However, when researching these respective roles, eggshell thickness measurement remains a bottleneck due to the lack of a non-destructive measurement techniques. As a result, many avian and reptile research protocols omit consideration of eggshell thickness bias on egg or embryo growth and development. Here, we validate a non-destructive method to estimate eggshell thickness based on terahertz (THz) reflectance spectroscopy using chicken white coloured eggs. Since terahertz waves are reflected from outer air-eggshell interface, as well as the inner eggshell-membrane boundary, the resulting interference signals depend on eggshell thickness. Thus, it is possible to estimate shell thickness from the oscillation distance in frequency-domain. A linear regression-based prediction model for non-destructive eggshell thickness measurement was developed, which had a coefficient of determination (R2) of 0.93, RMSEP of 0.009, RPD of 3.45 and RER 13.67. This model can estimate eggshell thickness to a resolution of less than 10 μm. This method has the potential to expand the protocols in the field of avian and reptile research, as well as be applied to industrial grading of eggs

Effects of on-farm hatching on short term stress indicators, weight gain, and cognitive ability in layer chicks

Layer chicks are usually transported early in life, experiencing immediate post-hatch food and water deprivation and various transport-related stressors with potentially negative long-term consequences for learning, cognition and welfare. In contrast, as chicks are only temporarily exposed to these stressors, the experienced stress could be sub-chronic which may improve cognitive flexibility. The aim of this exploratory study was therefore to investigate the acute and long-term effects of on-farm hatching (OFH) compared to conventional hatching. Dekalb White layer chicks were subjected to either OFH (n = 47) with ad libitum access to feed and water or temporary post-hatch resource deprivation and eight hour transport (RDT; n = 42). Physical and behavioural measures were collected to examine short-term effects of the treatment procedures. To determine longer term effects, treatment differences in learning and cognitive flexibility were assessed in a Y-maze using several paradigms (reversal, attentional-shift, extinction) between 4 and 12 weeks of age (WOA). Compared to OFH chicks, RDT had: greater corticosterone levels after transport (F1,19 =8.15, p = 0.01, RDT (16.24 ± 1.20 ng/mL) vs. OFH (8.13 ± 1.20 ng/mL) and post-recovery (F1,19 =4.93, p = 0.04; RDT (11.69 ± 1.35 ng/mL) vs. OFH (5.31 ± 1.37)), and lower body mass after resource deprivation and transport (F2258 =9.7, p < 0.001, RDT (33.14 ± 0.33 g) vs. OFH (37.62 ± 0.28 g)). Performance of activity behaviours (foraging, drinking, resting, wing-assisted running) after transport exhibited treatment by time interactions. Additionally, a tendency for OFH being heavier than RDT chicks was observed up to 11 WOA. The majority of birds learned the initial association in the Y-maze between a reward and location (77% of n = 19 RDT and n = 29 OFH chicks) or light stimulus (91% of n = 12 RDT and n = 11 OFH chicks). Subsequently, a number of chicks reached the learning criterion in the location reversal (24% of n = 13 RDT and n = 24 OFH chicks) and the light-to-location attentional-shift (47% of n = 11 RDT and n = 10 OFH chicks), and most of these chicks succeeded in the following extinction paradigm (80% of n = 3 RDT and n = 7 OFH chicks). No treatment effects were detected in any phase of cognitive testing. In conclusion, treatment affected behaviour and health parameters suggesting RDT animals were recovering from resource deprivation and transport. Continued treatment differences in body mass throughout rearing demonstrated long term effects as well although no effects on initial learning and cognitive flexibility were identified. Future work is needed to determine what mechanisms are responsible for the observed health and behavioural differences

Evaluation of social and environmental sustainability for potential alternatives to culling of cockerels

Tuppkycklingar av värphybrid-typ avlivas inom en dag efter att de kläckts eftersom de inte anses lönsamma att behålla för produktion av kött. Denna praxis har ifrågasatts allt oftare under senare tid vilket resulterat i utveckling av alternativa tillvägagångssätt. I detta arbete har tre av dessa alternativ beskrivits och granskats i syfte att besvara frågan om vilket alternativ som är mest socialt och miljömässigt hållbart: 1) könsbestämning av ägg 2) uppfödning av tuppkyckling till slakt och 3) användandet av dual purpose-höns. Könsbestämning av ägg i syfte att möjliggöra bortsortering av tuppembryon visade sig vara möjligt genom flera olika tekniker. Säkerhet i identifiering och tidpunkt under inkubation då teknikerna kunde användas skiljde sig åt vilket också påverkade möjligheten att nyttja de bortsorterade äggen. Resultaten från de enkätstudier vilka inkluderades i detta arbete visade att könsbestämning av ägg föredrogs framför det nuvarande förfarande och störst acceptans uppvisades för de tekniker där könsbestämningen skedde innan inkubation. De två andra alternativen, uppfödning av tuppkycklingar till slakt och användandet av dual purpose-höns, karakteriserades av en lägre produktionseffektivitet jämfört med konventionella slaktkycklingar och värphöns. De tidigare nämnda enkätstudierna påvisade en relativt hög acceptans för dessa alternativ men de visade också att uppfödning av tuppkycklingar inte föredrogs framför det nuvarande förfarandet. Kött och ägg från produktionsformerna förväntades enbart kunna marknadsföras som nischprodukter. Med hänsyn till de aspekter som lyfts i detta arbete framstod könsbestämning av ägg som ett mer hållbart alternativ eftersom det accepterades av allmänheten och potentiellt kunde innebära ett tillskott av livsmedel för humankonsumtion utan avkall på resurseffektivitet.Male chicks from layer breeds are killed within one day after hatching because they are not considered profitable to use for meat production. This practice has been questioned more frequently recently, resulting in the development of alternative approaches. In this paper, three of these approaches have been described and reviewed in order to answer the question of which alternative is the most socially and environmentally sustainable: 1) sex determination of eggs 2) fattening of cockerels and 3) use of dual purpose chicken. Sex determination of eggs which enable sorting out eggs containing male embryos proved to be possible through several different techniques. Precision and time during incubation when the techniques could be used differed, which also affected the possibility of utilizing the sorted out eggs. The results from the survey studies included in this paper showed that the sex determination of eggs was preferred over the current procedure and the greatest acceptance was demonstrated for the techniques where the sex determination occurred before incubation. The other two options, fattening of cockerels and the use of dual purpose chicken, were both characterized by a lower production efficiency compared to conventional broilers and layers. The before mentioned survey studies showed a relatively high acceptance for these alternatives but they also showed that fattening of cockerels was not preferred over the current practice. Meat and eggs from the productions were expected to be marketed only as niche products. Taking into account the aspects highlighted in this paper, gender determination of eggs appeared as the more sustainable alternative because it was accepted by the society and could potentially pose an addition of food for human consumption without reduced resource efficiency

Sintesi delle Pubblicazioni : Anni 1988 - 1995

Repertorio delle pubblicazioni scientifiche negli anni dal 1988 al 1995 dei docenti e ricercatori della Facoltà di Medicina Veterinaria. Digitalizzazione effettuata nel 2018 a cura della Biblioteca di Veterinaria "Ercolani". La digitalizzazione è stata autorizzata da Clueb, editrice della pubblicazione cartacea