Animal - Open Space最新文献

In the postnatal period, neonatal adaptation in terms of cardiovascular, respiratory, metabolic, thermoregulatory, and immunological functions is required, thus demanding the establishment of baseline parameters for research on neonatal calves. Few longitudinal studies have presented a set of physiological reference values for neonatal calves. The objective of this study was to evaluate physical, haematological, and biochemical parameters in young Holstein heifers in order to obtain useful information on their neonatal adaptation. Twenty-eight healthy young Holstein heifers were assessed for the collection of blood samples by jugular venipuncture at the following time points: immediately after birth, and before colostrum intake (first day of life is D1), and D2, D7, D14 and D28 days of life. Two hours prior to morning milk feed, calves were sampled, after being physically examined to establish reference values for heart rate (HR), respiratory rate (RR), and rectal temperature (RT). Several changes in physical, haematological, and biochemical parameters, secondary to neonatal adaptation, were detected. The reduction in HR and RR over time represented the maturation of the cardiovascular and respiratory systems, respectively, and the increase in RT represented the development of thermoregulatory mechanisms. Colostrum intake was reflected in several parameters, including immunoglobulin absorption and alteration of the serum protein profile. In addition, changes in glucose and cholesterol concentrations reflected the activation of the calf’s metabolism. Changes in white blood cell parameters, such as an increase in lymphocyte count and decrease in neutrophil count, were associated with maturation of the immune system and the influence of cortisol levels at parturition, respectively. Changes in the red blood cell count parameters could be attributed to the replacement of erythrocytes from the foetal circulation. Variations in the physiological parameters of calves were observed during the first month of life; it is necessary to compare them with established age-specific reference ranges for a better clinical interpretation.

Precise methods for measuring livestock body and carcass composition are essential for both animal and meat scientists. The aim of this study was to calibrate the 11th rib cut dissection method for the estimation of crossbred beef-on-dairy bull empty body (EB) and carcass compositions against reference tissue and chemical postmortem measurements. Sixty-six (66) crossbred bulls from Angus, Limousin and Simmental sires (n = 22 each) crossed on Brown Swiss dams were serially slaughtered along growth from 58 to 534 kg BW. The muscle, adipose tissue and bone contents of the left 11th rib were determined by physical dissection. Linear regressions followed by leave-one-out-cross-validation were tested between rib dissection variates (with or without additional ones: BW or carcass weight, carcass grading or postmortem linear measurements) and reference EB or carcass chemical (water, lipids, proteins, minerals and energy) and tissue (muscles, adipose tissues and bones, only for final slaughter group of 514 ± 12 kg BW, n = 30) compositions. When all bulls are considered (serial slaughter group, n = 66), the inclusion of rib dissection variate together with BW or hot carcass weight allowed precise estimations of EB and carcass masses and proportions of water [R² ≥ 0.91, residual CV (rCV) ≤ 3.1%], lipid (R² ≥ 0.88, rCV ≤ 14.0%), protein (R² ≥ 0.23, rCV ≤ 3.7%) and energy (R² ≥ 0.89, rCV ≤ 7.7%). Slight further improvements in precision were achieved when carcass grading conformation or fat scores was added to the multiple estimative regressions. Crossbreed effect was significant on the intercept of most of the predictive equations. Especially ×Angus had higher intercepts for lipids, energy and adipose tissues and lower ones for water, proteins and muscles, when compared to ×Limousin and ×Simmental. Further developments using for example rib imaging analysis rather than physical dissection may contribute to large scale and high-throughput phenotyping of body and carcass compositions.

Live weight (LW) is a key and conventional indicator for monitoring and assessing overall animal performance and welfare, representing the progress through different physiological stages, while providing close indication of individual physical and health status. Measuring LW in practice is still, however, quite rare and infrequent under commercial sheep farming conditions, mainly because sessions are time-consuming, stressful either for the operator or the animals. A Walk-over-Weighing (WoW) system was tested in this experiment lasting 14 weeks (i.e. 3 weeks for acclimation and adaptation and 11 weeks for data collection). We validated its use for routine and frequent monitoring of growth rate in postweaned Merinos d’Arles ewe lambs (n = 100), reared under Mediterranean grazing conditions. The necessity for an initial adaptation period of the animals was confirmed. Also, the importance of conducting an effective data cleaning procedure of the raw database automatically collected by the WoW was corroborated. Adaptation of naive ewe lambs enabled the required voluntary passages across the weighing platform and a high volume of individual and daily data after 2–3 weeks. Close monitoring of individual growth was then possible after performing sound data cleaning. A good agreement was demonstrated between WoW LW and a reference LW value (measured with a standard static scale). At the individual level, even with the lowest number of LW values collected with WoW, it was possible to monitor variations in LW at daily intervals. The establishment of an early warning system to help farmer decision-making could therefore be possible. Our results show interesting prospects for more accurate and frequent monitoring of LW in grazing sheep without human intervention, compared to what is currently carried out on commercial farms.

The possibility of pre-birth microbiota colonisation remains controversial in the scientific community. Due to the placenta’s characteristics in pigs, the umbilical cord is the sole way for mother-foetus microbial transmission to occur. Studies on this topic have demonstrated conflicting results; some of these discrepancies might be due to differences during sampling, DNA extraction, bioinformatics and data analysis. The aim of this study is to assess a workflow for characterising the umbilical cord blood microbial profile by adjusting for the contaminating sources of bacterial DNA during the extraction procedure. The results show that among 735 amplicon sequence variants (ASVs), 568 ASVs were contaminants, while 165 ASVs were true samples. Using this workflow, we could distinguish the contaminant ASVs introduced during bacterial DNA extraction and amplification. With the results of the present study, however, we cannot confirm the pre-birth bacterial transfer by the umbilical cord blood due to the lack of samples representative of the contaminants in the surrounding sampling environment. Nevertheless, the present study can be used as a reference to address low microbial biomass, particularly with umbilical cord blood.

This study investigated the repeatability and influences of the time of the day (TOD) and horn status on cortisol responses to ACTH administration in heifers. Sixty-four heifers were subjected to three ACTH challenges. The first challenge (C1) took place at the age of 2 mo. Balanced for peak cortisol responses at C1, the heifers were assigned to one of two rearing conditions: horned (H+) or disbudded (H−). At the age of 15 months, the second (C2) and third (C3) challenges took place, 7 d apart from each other at the same TOD. For cortisol analysis, saliva was sampled in 30-min intervals from 30 min before to 150 min after each ACTH injection. The area under the curve (AUC) of cortisol was calculated with respect to the ground (AUC_G) and to the increase (AUC_I). Between C2 and C3, AUC values did not differ (P > 0.10), intra-class correlation coefficients (ICCs) indicated poor repeatability (AUC_G: ICC = 0.24 and AUC_I: ICC = 0.26) and no correlations were found. The TOD had no effect on AUC values in C2 (P > 0.1), while in C3, they were greater in the morning than in the afternoon (for both AUC_G and AUC_I, P < 0.05). The H+ and H− heifers showed similar cortisol responses in C3, but in C2, horned heifers had greater AUC levels (P < 0.05). From C2 to C3, AUC values increased and decreased for heifers tested in the morning and afternoon, respectively. This was more pronounced in H+ than in H− heifers (interaction effect P <0.05). The results indicate poor to lacking repeatability for ACTH challenges performed within the same physiological state. While TOD and horn status partly contributed to the cortisol responses’ variance, the poor repeatability critically questions the use of repeated ACTH challenges for stress research in cattle.

Coccidiosis is one of the major challenges in the poultry industry, leading to reduced animal performance and welfare and increased mortality. Currently, ionophores and chemicals are used to treat coccidiosis. However, the outbreak of resistant Eimeria strains and the growing customer demand for more sustainable products have prompted the need to identify nutritional strategies for coccidiosis control. In this study, we reviewed the efficiency of the supplementation of a combination of functional amino acids (arginine, threonine and glutamine) with grape extract polyphenols in broilers challenged with coccidiosis via a meta-analysis based on five independent trials. We observed that supplementation partially improved the performance of broilers affected with coccidiosis when compared with infected, untreated animals. In addition, there was no significant difference between the effect of supplementation of the combination of functional amino acids with grape extract polyphenols and that of anticoccidial drugs on animal performance when considering the overall trial period. This meta-analysis suggests that supplementing with a combination of functional amino acids with grape extract polyphenols could improve performance in broilers affected with coccidiosis. However, further research to understand the mechanisms involved is needed.

Because of their intense metabolism, lactating sows are highly sensitive to high ambient temperature which induces a reduction in their voluntary feed intake and milk production, which decreases piglet weaning weight. This also results in an increase in mobilisation of body reserves that may impair reproduction after weaning. The aim of the study was to quantify, on the basis of a quantitative analysis of the literature data, the effect of ambient temperature on the performance and physiology of lactating sows, with the perspective of integrating this knowledge in sow nutrition decision support tools. A literature database with 38 publications and a total of 227 observations was built in order to adjust prediction equations according to temperature, using a Mixed linear or quadratic model with random effect of publication, for different criteria such as feed intake, litter and piglet growth rate, milk production, maternal body reserve mobilisation, respiratory rate (RR) and core body temperature. The first criterion with the highest response to temperature was RR which increased by 175 % between 22 °C and 32 °C. The second most affected criterion was feed intake which was reduced by 36 % between 22 °C and 32 °C, and the third one was milk production which was reduced by 20 % between 22 °C and 32 °C. The equations obtained from the meta-analysis were incorporated into a nutrition model, based on InraPorc®, in order to predict, in the context of climate change, the effect of temperature on feed intake, milk production, energy and aminoacid utilisation, and body reserve mobilisation. The simulations performed using this model clearly indicate that nutrient requirement of sows per kg feed is affected by variation in ambient temperature due to seasons or to expected climate change. In practice, the integration of these new equations in nutritional models will enable feed composition to be better adapted to the season and to the geographical location of farms.

To evaluate the effect of dietary protein level (13.0% and 9.5% CP) and duration of fasting on the enzymatic activity of cathepsin B in live muscle and pig, 44 fattening pigs weighing 138 ± 9 kg were reared to slaughter (171 ± 9 kg). The feed allowance was set at 3.2 kg/day. Two weeks prior to slaughter, subjects on each diet were randomly assigned to one of two different fasting treatments (no fasting or 48 h fasting). After this treatment, an individual longissimus dorsi (LD) muscle sample was taken from each pig by biopsy at the level of the third lumbar vertebra and frozen in liquid nitrogen until analysis. Then, the subjects within each diet × fasting interaction were assigned to different fasting times before slaughter (4 or 28 or 52 h). One day after slaughter, LD and semimembranous muscle (SM) samples were taken from each carcass, kept at 4 °C for 24 h and then frozen in liquid nitrogen. The activity of cathepsin B was measured in muscle homogenates by colorimetric method. Dietary CP did not affect cathepsin activity in LD obtained in vivo and daily live weight gain up to slaughter. Compared to the absence of fasting, a cathepsin activity greater than 18% in LD was observed after 48 h of fasting (P < 0.01). Cathepsin activity in LD and SM sampled after slaughter was not affected by dietary protein level and fasting 2 weeks prior to slaughter. Compared with 28 h fasting, feeding exclusion for 52 h prior to slaughter increased cathepsin activity in the LD and SM muscles by 18% (P < 0.05) and 12% (P = 0.07) respectively. The preslaughter fasting length had no effect on fresh meat quality parameters (pH at 1 and 24 h post mortem, colour, drip losses, cooking losses).

The fasting heat production (FHP; net energy expenditure under maintenance) is a key value to determine the net energy value of the feed and is calculated from measurements in respiratory chambers or predicted as a function of the metabolic BW (MBW). This study aimed to determine the influence of body composition on the FHP of broilers through a modeling approach. Six experiments (Exp 1–6) were conducted to develop (Exp 1–4) and externally validate (Exp 5 and 6) predictive models. In Exp 1–4, broilers of a single genetic line in floor pens were subjected to three dietary treatments to induce differences in body composition. The FHP (calorimetry chambers) and the body protein-to-fat ratio (PFR; Dual-Energy X-ray Absorptiometry) were recorded at nine time points between 7 and 55 days. Linear models were adjusted (considering the pen as the experimental unit), starting with a model containing the MBW as the sole predictor. Further modifications were tested by including the PFR and the age of the birds. A random split with a refitting approach was applied. Four models were internally validated and refitted to the whole data. They considered the FHP a function of the MBW (or BW) and the PFR, including or not the age of the birds, and showed high precision (R² > 0.98) and accuracy (error < 2.5%). All models demonstrated that birds at the same BW and age have higher FHP the leaner they are. Body protein and fat are positively and negatively correlated to FHP, respectively. In Exp 5, broilers of two genetic lines fed three dietary treatments were tested for FHP and body composition at 22 and 41 days. In Exp 6, broilers fed continuous dietary treatments in a dose–response design were tested for FHP and body composition at 17, 20, and 41 days. The models were tested on the data from Exp 5 and 6 considering the treatments as the validation unit. The four selected models showed high prediction precision (validation R² > 0.92) and accuracy (model prediction error < 3%) and were validated externally. In conclusion, at the same age and BW, the higher the PFR, the higher the FHP. Including the PFR improved the strength of the models.

A dataset of 100 pigs, from the Piétrain NN Français line raised at the AXIOM boar testing station in 2020, was used. The farm was equipped with an automatic feeding system, recording individual weight and feed intake at each visit. We used a dynamic linear regression model to characterise the evolution of the energetic allocation factor (α_t) which represents the link between the cumulative net energy available (estimated from feed intake) and cumulative weight gain during the fattening period. The data were imported using an R script to estimate the allocation factor for a given animal. The dataset and R script are useful resources to study feed intake, growth dynamics and the relationship between these two variables.