TRICHUROSIS EN TERNEROS EN EL DEPARTAMENTO LAS COLONIAS, SANTA FE

Trichuris spp. It is a nematode that affects the mucosa of the cecum and the colon of the ruminates. Clinical cases are rare and occur when the number of adult worms is high. The objective of this work is to report a clinical case of trichurosis in a batch of 40 breeding calves raised in a pen without vegetation cover and with a very humid floor. The food was supplied in feeders, but the animals also consumed the food that fell to the floor. Three animals died from the batch. At necropsy, more than 400 specimens of worms identified as Trichuris were recovered. This case warns of the importance of the diagnosis of parasitosis in intensive breeding.

PRODUCTIVE BEHAVIOR OF Dactylopius coccus Costa ON TWO CONFINED Opuntia ficus-indica (L.) Mill CULTIVARS

Recently, the commercial breeding of Dactylopius coccus in confined environments has been developed not to depend on seasonal production and ensure the supply chain. Previous studies have shown the technical viability of their breeding of i Opuntia in a repository also called "Nopaloteca". However, considering the genetic diversity of Opuntia in each region, it is necessary to evaluate alternative cultivars to maximize the efficiency of that production system. The evaluated cultivars were Esmeralda and Villanueva (Opuntia ficus-indica (L.) Mill.). Four height levels (m) within the “Nopaloteca” (N1: 0.5; N2: 1.0; N3: 1.5 and N4: 2.0) and two harvest indices (pre and post oviposition) were evaluated regarding their effects on the carminic acid concentration (CAC, %) and fresh weight (FW, g) of D. Coccus. The results showed no significant difference in the CAC of the D. coccus colonies in both cultivars (18 %); however, the highest FW was reached in the cv. Esmeralda with 6.3 g per cladode (p ≤ 0.05). The highest CAC was found in the N4 treatment (2.0 m) with 18.6 % (p ≤ 0.05); while the highest average FW values (p ≤ 0.05) were in the intermediate levels of the N2 (1.0 m) and N3 (1.5 m) treatments, with 6.4 and 6.1 g per cladode, each. The post oviposition phase harvest of D. coccus resulted in a higher CAC concentration (20.4 %); meanwhile, in the pre-oviposition phase, 15.6 % was harvested (p ≤ 0.05). Due to the productivity and quality obtained, the Esmeralda cultivar could be used as an alternative host for the intensive breeding of D. coccus in confinement, in north-central Mexico.

The First Report of mcr-1-Carrying Escherichia coli Originating from Animals in Serbia

The aim of this study was continuous monitoring of the presence of mcr-1 to mcr-5 genes in Enterobacterales isolated from cattle, pigs, and domestic poultry at intensive breeding facilities in Northern Vojvodina, Serbia, from 1 January 1 to 1 October 2020. Out of 2167 examined samples, mcr-1 was observed in five E. coli isolates originating from healthy turkeys. Four isolates belonged to the phylogenetic group B1, and one isolate to the phylogenetic group A. Detected E. coli serogenotypes (somatic O and flagellar H antigens) were O8:H25 and O29:H25. Core-genome multi-locus sequence typing (cgMLST) revealed three ST58 isolates clustering together in Clonal Complex (CC) 155 and two singletons of ST641-CC86 and ST410-CC23, respectively. Clonotyping revealed CH4-32 (n = 3), CH6-53 (n = 1) and CH4-24 (n = 1). In all isolates, the mcr-1 gene was located on a large IncX4 replicon type plasmid. Eight virulence-associated genes (VAGs) typical of avian pathogenic E. coli (APEC) (fyuA, fimH, hlyF, iss, ompT, sitA, traT, iroN) were detected in four isolates. These isolates were investigated for susceptibility to four biocides and revealed MIC values of 0.125% for glutardialdehyde, of 0.00003–0.00006% for chlorohexidine, of 4–6% for isopropanol and of 0.001–0.002% for benzalkonium chloride. All obtained MIC values of the tested biocides were comparable to the reference strain, with no indication of possible resistance. This is the first report of mcr-1.1-carrying E. coli from Serbia. Although only samples from turkeys were mcr-positive in this study, continuous monitoring of livestock samples is advised to prevent a spill-over from animals to humans.

Collateral damage: Identification and characterisation of spontaneous mutations causing deafness from a targeted knockout programme

Mice carrying targeted mutations are important for investigating gene function and the role of genes in disease, but the process of culturing embryonic stem cells during the making of a targeted allele offers opportunities for spontaneous mutations to arise. Identifying spontaneous mutations relies on the detection of phenotypes segregating independently of targeted alleles, and many phenotypes are easy to miss if not specifically looked for. Here we present data from a large, targeted knockout programme in which mice were analysed through a phenotyping pipeline. Twenty-five lines out of 1311 displayed different deafness phenotypes that did not segregate with the targeted allele. We have identified 8 different mutations causing deafness in 16 of these 25 lines and characterised the resulting phenotypes. Our data show that spontaneous mutations with observable effects on phenotype are a common side effect of intensive breeding programmes, including those underlying targeted mutation programmes.

Tracing the origins of SARS-COV-2 in coronavirus phylogenies: a review

SARS-CoV-2 is a new human coronavirus (CoV), which emerged in China in late 2019 and is responsible for the global COVID-19 pandemic that caused more than 97 million infections and 2 million deaths in 12 months. Understanding the origin of this virus is an important issue, and it is necessary to determine the mechanisms of viral dissemination in order to contain future epidemics. Based on phylogenetic inferences, sequence analysis and structure–function relationships of coronavirus proteins, informed by the knowledge currently available on the virus, we discuss the different scenarios on the origin—natural or synthetic—of the virus. The data currently available are not sufficient to firmly assert whether SARS-CoV2 results from a zoonotic emergence or from an accidental escape of a laboratory strain. This question needs to be solved because it has important consequences on the risk/benefit balance of our interactions with ecosystems, on intensive breeding of wild and domestic animals, on some laboratory practices and on scientific policy and biosafety regulations. Regardless of COVID-19 origin, studying the evolution of the molecular mechanisms involved in the emergence of pandemic viruses is essential to develop therapeutic and vaccine strategies and to prevent future zoonoses. This article is a translation and update of a French article published in Médecine/Sciences, August/September 2020 (10.1051/medsci/2020123).

Time-Budget of Horses Reared for Meat Production: Influence of Stocking Density on Behavioural Activities and Subsequent Welfare

Horses reared for meat production can be kept in intensive breeding farms where they are housed in group pens at high stocking densities. The present study aimed to evaluate whether the expressed behaviours correlated with stocking density, and to compare their time-budget with that of wild-living horses. An ethogram of 13 mutually exclusive behavioural activities was developed. Behavioural observations were performed over a 72 h period on group pens selected on the basis of stocking density and the homogeneity of breed, age, height at the withers, and time since arriving at the farm. Scan sampling (n = 96 scans/horse/day) was used on 22 horses. The mean frequency (%) ± standard deviation (±SD) for each behavioural activity was calculated to obtain the time-budget. The associations between time-budget and stocking density were evaluated using a bivariate analysis. The relationships were analysed by Pearson’s correlation coefficient (r). Our results show that locomotion, playing, and self-grooming positively correlated with a reduction in stocking density, indicating the potential to use these behaviours as positive welfare indicators for young horses kept in group pens. The data also revealed an unusual time-budget, where the main behavioural activity expressed was standing (30.56% ± 6.56%), followed by feeding (30.55% ± 3.59%), lying (27.33% ± 2.05%), and locomotion (4.07% ± 1.06%).

Evaluation of the environmental impact of two types of food in intensive farming of rainbow trout fry (Onchoryncus mykiss. Walbaum, 1792).

The environmental impact of two types of food distributed during the first phase of intensive breeding of rainbow trout (Oncorhynchus mykiss) fry at the station of the National Center for Hydrobiology and Pisciculture constitutes the main objective of this study. the method used for the evaluation of the impact of these two foods is the mass balance method based on the calculation of the quantities of nitrogen and phosphorus excreted according to the quantities of food ingested and the composition of the carcasses. The results obtained show that the weight growth of fry and the rate of nitrogen and phosphorus rejection during the experimental period are very different and vary depending on the type of food received.

Influence of the use of nurse sows on their lifetime performance

Using nurse sows is a common practice for intensive pig farming because large numbers of piglets per litter result from intensive breeding. This aim of this study was to compare reproductive parameters of nurse sows and non-nurse sows in relation to subsequent reproductive performance. The study evaluated 463 breeding sows that produced at least one litter. The sows were divided into two groups: non-nurse sows (350 sows) and nurse sows (113 sows) at their first farrowing. The average length of first lactation was 35.12 days for nurse sows and 29.79 days for non-nurse sows. At first parity, nurse sows weaned 5.18% more piglets than did non-nurse sows (P < 0.05). At second parity, nurse sows had 2.25% more live born piglets than did non-nurse sows. Nurse sows also had 9.59% more total live born piglets and they were removed from the breeding herd later (on average by 67.1 days) than were non-nurse sows. In conclusion, using sows as nurse sows in their first lactations provides a good solution when there are large numbers of piglets per litter, and this practice has no negative effect on sows’ subsequent reproductive performance.