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Dive into the research topics where Isabelle D.M. Gangnat is active.

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Featured researches published by Isabelle D.M. Gangnat.


Poultry Science | 2018

Swiss consumers’ willingness to pay and attitudes regarding dual-purpose poultry and eggs

Isabelle D.M. Gangnat; Sabine Mueller; Michael Kreuzer; Ruth E. Messikommer; Michael Siegrist; Vivianne H.M. Visschers

Abstract Chick culling is an efficient and cost‐effective method in modern poultry farming, but it raises ethical concerns. Dual‐purpose poultry (DP), in which males are fattened and females are used for egg production, is currently the most realistic alternative to culling, as in ovo sexing is not yet viable for practical application. Consumers’ acceptance of DP products and their willingness to pay (WTP) for them have not been studied yet, and we expect that both aspects are closely related to the acceptance of and WTP for products from systems claiming beyond‐conventional animal welfare, such as organic products. Results from a survey conducted among 402 consumers at 8 Swiss supermarkets revealed that the practice of chick culling was largely unknown (75% of respondents). Generally, respondents’ knowledge about poultry production was low. The DP alternative was preferred to chick culling, but no preference emerged between DP and in ovo sexing. Furthermore, the WTP for DP products was proportionally lower for chicken than for eggs, probably because of the different price elasticity between these products. A regression analysis was used to determine the factors influencing consumers’ WTP for DP products. Consumers’ WTP was positively related to knowledge about poultry production, habits tied to purchasing organic or free‐range poultry products, and familiarity with DP products. Therefore, a combination of the DP alternative with an organic label is recommended.


Archives of Animal Nutrition | 2016

Carcass and meat quality of finished and non-finished Limousin heifers from alpine livestock systems differing in altitudinal origin of the forage.

Isabelle D.M. Gangnat; Michael Kreuzer; Andrea Liliana Clavijo McCormick; Florian Leiber; Joel Berard

ABSTRACT Effects of the alpine origin of the forage and of finishing on carcass and beef quality were quantified by modelling different alpine livestock system alternatives. Thirty-five Limousin heifers, initially weighing 383 ± 45 kg, were fed fresh grass at 400 or 2000 m above sea level, or a 1:1 mixture of alpine grass and lowland grass hay at 2000 m. After 9 weeks, the six heaviest and oldest animals per group were slaughtered. The remaining animals were finished for 8 weeks on a silage-concentrate diet in the lowlands to similar age and body weight as the first slaughtered group. Carcass and meat quality (M. longissimus thoracis) were assessed in various respects. The average daily gains achieved were of about 600 g/d and similar between forage-type groups. Dressing percentage was 53.5% in the alpine and 57.2% in the lowland group. Carcass conformation and fat cover scores did not differ between forage-type groups. The meat from the alpine groups had greater ultimate pH and smaller redness, yellowness and protein contents. Still, these differences were of minor practical relevance. There was no forage-type effect on water-holding capacity and shear force of the meat. The alpine systems enhanced the proportion of α-linolenic acid in intramuscular fat and decreased the levels of some volatile compounds in perirenal fat. Finishing resulted in compensatory growth, especially in the animals previously fed lowland grass. There was a trend for the finished compared with the non-finished groups towards greater carcass fat cover and intramuscular fat content. Additionally, ultimate pH was smaller and cooking loss was greater with than without finishing. Meat colour differences were also observed. Shear force was not affected by finishing. The finished animals had a smaller α-linolenic acid proportion in the intramuscular fat. In conclusion, the forage type had small effects on carcass and meat quality. Finishing did not substantially improve carcass and meat quality. The (alpine) grass-specific differences in fatty acid profile found in the unfinished cattle were not present in the finished animals.


Poultry Science | 2018

Carcass and meat quality of dual-purpose chickens (Lohmann Dual, Belgian Malines, Schweizerhuhn) in comparison to broiler and layer chicken types

Sabine Mueller; Michael Kreuzer; Michael Siegrist; K Mannale; Ruth E. Messikommer; Isabelle D.M. Gangnat

ABSTRACT Currently, there is an intensive ethical discussion about the practice of culling day‐old layer cockerels. One solution to avoid this practice could be using dual‐purpose types, where males are fattened for meat and females used for egg production. The aim of the present study was to compare fattening performance, carcass conformation, and composition as well as meat quality of Lohmann Dual, a novel dual‐purpose type, and 2 traditional dual‐purpose types (Belgian Malines and Schweizerhuhn) with 2 broiler types and 1 layer type (Lohmann Brown Plus). Broilers included a conventional line (Ross PM3) and a slower‐growing line (Sasso 51) fulfilling requirements of organic farming. Nine birds of each type were fed on a conventional broiler diet. Feed intake and metabolizability of nitrogen and energy were recorded per pen (n = 3), the latter through excreta sampling. For each bird, carcass conformation was assessed, and weights of body, carcass, breast meat, legs, wings, and inner organs were determined. Additionally, breast angle, an indicator for carcass appeal, and skin color were recorded. Meat quality assessment included determinations of thaw and cooking loss, shear force, meat color, and proximate composition of the breast meat. None of the dual‐purpose types (20 to 30 g ADG) performed as well in growth as the intensively growing broiler line (68 g ADG). However, Lohmann Dual could compete with the slower‐growing broiler line (slower growth but better feed efficiency, similar in carcass weight and breast proportion). Also breast angle was quite similar between Lohmann Dual (100°) and the extensive broiler type (115°C) compared to the intensive broiler line (180°). Meat quality was most favorable in the intensive broilers with the smallest shear force and thawing loss, whereas meat quality was not different between the other types. The Schweizerhuhn performed only at the level of the layer hybrid, and the Belgian Malines was ranked only slightly better.


Journal of the Science of Food and Agriculture | 2017

Effect of nursing or mentoring by adult cows on physical activity, performance and meat quality of fattening beef calves kept on alpine pastures

Isabelle D.M. Gangnat; Pierre-Alain Dufey; Paolo Silacci; Jessika Messadene-Chelali; Michael Kreuzer; Joel Berard

BACKGROUND Compared with weaned calves, nursed calves benefit from access to milk as nutrient-dense feed and mentoring by their dams. Both may be decisive for growth under difficult conditions such as grazing on alpine pastures, where experience could play an essential role. These factors were investigated separately by comparing nursed calves with calves weaned at 3 months of age and grazing with or without a mentor cow (n = 8 calves). RESULTS Weaned calves with mentor cows spent less time lying and walked more than nursed calves. Irrespective of whether they had a mentor cow or not, the weaned calves grew slower than the nursed calves (357, 428 and 1324 g day-1 respectively). This also adversely affected slaughter weight, dressing percentage, conformation and fat cover at slaughter. In general, mentoring had no effect. Meat quality did not differ whether weaned calves were mentored or not. Nursed calves were superior in intramuscular fat content, tenderness and water-holding capacity. CONCLUSION The availability of milk appeared to be much more important to the calves under demanding grazing conditions than did mentoring. The differences in growth rate were accompanied by unexpectedly large differences in meat quality, showing that early weaning was not suitable for this system.© 2016 Society of Chemical Industry.


Animal Production Science | 2018

Meat and carcass quality of Dexter cattle compared with that of suckler, Charolais-cross calves: a preliminary study

K. Giller; Isabelle D.M. Gangnat; P. Silacci; J. Messadene-Chelali; Michael Kreuzer; Joel Berard

Tenderness, flavour and colour are the most important quality traits of beef that are influenced by breed and age. Suckler calves (SC) produce very tender, high-quality meat. Extensively growing, small-framed breeds are known for high-quality beef, but information about the particularly small Dexter cattle (D) is yet unavailable. Eight D and seven Charolais-crossbreed SC were kept for 11 weeks on alpine pastures to be able to compare their meat quality. The SC were kept with their dams. The animals of the two breeds were slaughtered at different ages (D: 15 months and SC: 7 months) consistent with their respective production system conventions. Although this meant that age and breed effects were confounded, slaughter took place at the same carcass fatness score, thereby avoiding a confounding effect on meat quality. Quality of the carcass and of two muscles (M. biceps femoris, M. longissimus thoracis) was analysed. Despite being older, D had lower body and carcass weights, dressing percentage and bodyweight gains than SC. Dexter meat was darker than SC meat. Shear force did not differ between D and SC in the M. longissimus thoracis but was higher in the M. biceps femoris from D than from SC. Sensory analysis by a trained panel demonstrated an overall preference for D meat, associated with more favourable flavour and juiciness. Tenderness was not rated differently. Despite the unfavourable darker colour of D compared with SC meat, its characteristic flavour might attract consumers in a high-price niche market. For a more comprehensive characterisation, sensory evaluation of additional muscles is required. Additional measurements on a larger number of animals and muscles are required.


Italian Journal of Animal Science | 2017

Growth and slaughter performance of two dual-purpose poultry types compared with extensive broiler and layer types fattened for 67 and 84 days

Sabine Mueller; Lorena Taddei; Ruth E. Messikommer; Michael Kreuzer; Isabelle D.M. Gangnat

than that caused by recognized “enterohaemorrhagic” STEC serogroups such as O157 and O111. More widespread use of PCRor enzyme-linked immunosorbent assay-based screening tests for the presence of STEC of any serogroup in animal samples will undoubtedly result in increased detection of similar non-O157 outbreaks in the future. This will provide more accurate data on the epidemiology of human STEC disease.


Book of Abstracts of the 68th Annual Meeting of the European Federation of Animal Science | 2017

Performance of dual-purpose types in comparison to layer hybrids fed a by-product diet

Sabine Müller; Ruth E. Messikommer; Michael Kreuzer; Isabelle D.M. Gangnat

AIM Identify signals of fat deposition and adaptation through genome-wide scan of the Barbaresca fat-tail sheep. ANIMALS Barbaresca in an ancient Sicilian fat-tail sheep, highly endangered at present. Of the 35 000 heads of 1980, abour 1 300 are left nowadays in 20 flocks. The breed originated from crosses between Barbary sheep from North Africa and the Pinzirita breed at times of the Arab settling in Sicily (9th century). The breed is reared in a very restricted area in central Sicily on smalland medium-sized farms under a semi-extensive farming system. It is a dual-purpose breed: milk for cheese and meat. Barbaresca is one of the only two fat-tail sheep of Italy. METHODS Genotypic data were obtained with the OvineSNP50K array. Fst values of differentiation for 43072 markers were calculated in pairwise comparisons of Barbaresca with each of 13 Italian thin tail breeds. Fat-tail sheep still represent twenty-five percent of the world sheep population; they are predominant in pastoral, transhumant and low input systems. In Western countries and in high input systems they are generally endangered. Fat-tail sheep preserved genetic variability for functional adaptation. The identification of the genes with a role in the fat-tail phenotype contributes to the understanding of the physiology of fat deposition as well as the mechanisms of adaptation and is essential for maintaining future breeding options. Heritability estimates for the 1st litter size, pregnancy rate and whelping success were low (0.05-0.14)  Grading size and quality had moderate heritability estimates 0.27 and 0.21, respectively  Genetic correlations between animal grading size and fertility traits were unfavourable (from -0.15 to -0.53)  Grading quality and guard hair coverage had antagonistic relationships with all the studied fertility traits (from -0.21 to -0.54) Genetic parameters of fertility and grading traits in Finnish blue foxTrabajo presentado al: 68th Annual Meeting of the European Federation of Animal Science (EAAP). (Tallin, Estonia. 28 agosto - 2 septiembre).Trabajo presentado al: 68th Annual Meeting of the European Federation of Animal Science (EAAP). (Tallin, Estonia. 28 agosto - 2 septiembre).


Proceedings of the 4th International Symposium on Energy and Protein Metabolism and Nutrition, 9-12 September 2013, Sacramento, California, USA | 2013

Influence of different grassland vegetation types on ruminal protozoa and ammonia in beef cattle

Isabelle D.M. Gangnat; Johanna O. Zeitz; D. Warner; Michael Kreuzer; Florian Leiber

Grassland vegetation types, which vary in concentration of nutrients and plant secondary compounds, may influence ruminal metabolism differently. Ruminal protozoa play a major role in ruminal protein degradation to ammonia and are involved in fibre digestion. Their role in, and response to, concentrate-based diets is well known. However, the effects of extensive grass-based diets on the composition of the protozoa population in the rumen are poorly understood. The present experiment investigated whether feeding grass or hay harvested from different vegetation types influences ruminal nitrogen metabolism and protozoa populations in beef heifers.


The Journal of Agricultural Science | 2017

Physical activity, forced by steep pastures, affects muscle characteristics and meat quality of suckling beef calves

Isabelle D.M. Gangnat; F. Leiber; P.-A. Dufey; P. Silacci; Michael Kreuzer; Joel Berard


72nd Conference of the Society of Nutrition Physiology | 2018

Response to a diet composed of food inclustry by-products of late laying dual-purpose hens in comparison to layer hybrids

Sabine Müller; Ruth E. Messikommer; Michael Kreuzer; Isabelle D.M. Gangnat

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Florian Leiber

École Polytechnique Fédérale de Lausanne

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