BIOEPAR's contributions to the IAHA videoconference

The IFOAM Animal Husbandry Alliance (IAHA) together with the Research Institute of Organic Agriculture (FiBL) organised a well-attended video conference on 21st and 22nd of September 2020. The importance of an «ultimate one health approach» in organic animal husbandry systems was emphasised.

Caroline Constancis, PhD student at BIOEPAR, presented the results of her thesis during two presentations: 

• Performance and health status of dairy calves reared with nurse cows, a 2-year study involving 3 cohorts

Abstract: The agro-ecological transition is based on “bottom up” innovation processes developed by agricultural stakeholders. The role of researchers is now to accompany this process by working closely with them. Since the 90s, groups of dairy farmers have been set up in many developed countries to exchange information about intensive grazing management. Within these groups, organic dairy breeders have experimented new cow-calf rearing practices, in which a specific batch of lactating cows is constituted in order to nurse and raise 2-4 calves each (usually replacement heifers) for several months on pasture. The objective of our study was to assess effects of this innovative rearing system on growth and health of the calves, with a focus on the risk of grazing parasite (gastrointestinal nematodes). On an experimental organic farm located in East of France, we designed a cow-calf rearing system in collaboration with farmers experienced on this practice. A 2-year study of 3 cohorts of 9, 16 and 23 calves was conducted from 2016 to 2019. We weighed, recorded all health events and measured different parasitic indicators at key times of the grazing season. Calves showed a fast and steady growth during the 2 years of follow-up, allowing a calving at 24 months old. Parasitic risks were low, with nurse cows playing a protective role towards infection. In addition, early immunity against gastrointestinal nematodes was developed in calves. Throughout the study, the calves did not receive any antibiotic nor anti-parasitic treatments. Only one calf died due to ruminal tympany. Rearing calves with nurse cows seems to be of real interest for their growth and health, and in particular the management of parasitic risks. Further studies in other farms are needed to validate these results.

• Risk factors for Cryptosporidium oocyst shedding in dairy calves reared with nurse cows in organic farms.

Abstract: New rearing practices of suckling dairy calves with nurse cows have been recently adopted by farmers but remain poorly documented regarding their impact on calves health, particularly for cryptosporidiosis. The objective of the study was to assess calf faecal shedding of Cryptosporidium spp. oocysts and to identify particular risk factors of shedding related to those practices. Between January and May 2019, the rearing practices of calves with nurse cows were described in 18 farms and 401 calves were sampled between 3 and 21 days of age to quantify faecal oocyst shedding of Cryptosporidium spp. (score 0 to 4). The risk of excretion (score 0 versus 1-4) was analysed using multivariate logistic regression models. Rearing usually consisted of a first phase with the dam, followed by an optional phase of artificial milk feeding, and lastly a phase of adoption by a nurse cow. On average, each nurse raised a group of 3 calves of close age with a median adoption age of 4 days. The oocysts shedding prevalence was 41.9% and the score was low (mean = 0.7). The risk of shedding increased when the calf was born at the end of the calving season (odds ratio = 6.19; 95% confidence interval = [3.16; 12.14]) or when the calf was in the barn during the first phase (4.09 [1.58; 10.61]). The risk of shedding was also higher for a calf adopted before 4 days of age (2.85 [1.10; 7.39]) or for a calf adopted with another calf shedding oocysts (3.43 [1.37; 8.58]). The end of the calving season and the indoor rearing for the first phase with the dam were confirmed as known risk factors in cattle farms. Early adoption and the presence of an infected calf in the adoption group were new risk factors related to these rearing practices.

Next IAHA meeting in Rennes 2021

The IFOAM Animal Husbandry Alliance, IAHA, is organising on the 6th and 7th of September 2021 a Pre-Conference in Rennes, France before the main Organic World Congress. A new programme will be available by the end of December 2020. 

The IAHA conference is linked to the Organic World Congress of IFOAM – Organics International, the umbrella organisation of the organic movement, initially planned for September 2020 but postponed to September 2021. The video conference was supported by FiBL, the Technical Institute of Organic Agriculture and Food (ITAB) France, the French National Research Institute for Agriculture, Food and the Environment (INRAE), GoodEarthGreatFood from New Zealand, IFOAM – Organics International and ICROFS. Furthermore, several CORE Organic (Coordination of European Transnational Research in Organic Food and Farming Systems) and Horizon 2020 EU projects contributed with papers or posters to the video conference: GrazyDaiSy; ProYoungStock, MIX-ENABLE; POWER; Organic-PLUS, RELACS and Polyfarming as well as the BIOBREEDING EUROPE Initiative.

Download the proceedings here.