Post-weaning Phase Research Articles

Performance of expert fuzzy systems for prediction of rabbit feed intake after weaning.

The postweaning phase is stressful for rabbits due to maternal separation and the introduction of solid feed. Stress can be aggravated when animals are subjected to thermal discomfort. Therefore, thermal variables, such as air temperature, which influence the productive and physiological performance of animals, require greater control in this phase of life of rabbits to ensure their well-being and productive efficiency. Thus, the objective of the present study was to develop and compare fuzzy inference systems (FISs) with different configurations to predict the feed intake (FI) of New Zealand White (NZW) rabbits subjected to different thermal conditions after weaning. The experiment lasted 14 days, and twelve rabbits between 30 and 43 days old were used. The animals were housed in air-conditioned wind tunnels and subjected to air temperatures of 20, 24, 28 and 32°C. For the FIS configurations, Mamdani inference with five defuzzification methods (center of gravity (COG), bisector of area (BOA), largest of maximum (LOM), mean of maximum (MOM) and smallest of maximum (SOM)) and Sugeno inference with two defuzzification methods (weighted average (WA) and weighted sum (WS)), were evaluated. In both inference methods, the input variables (air temperature and time after weaning) were represented by triangular, Gaussian or trapezoidal functions. In turn, the output variable (FI, g) was represented by triangular, Gaussian or trapezoidal functions in the Mamdani FIS and by singleton functions in the Sugeno FIS. Thus, all developed FISs were validated, and their results were compared to the experimental data using statistical indices. As a result, adequate FI prediction performances were obtained for rabbits using both inference methods, regardless of the configurations used in their development. However, the smallest simulation errors were obtained using the Sugeno FIS with Gaussian inputs and WA defuzzification and is therefore a system with greater generalization capacity for unknown scenarios. Thus, the developed models can be used as a support system for decisions on the management of rabbits, aiding the efficient production and welfare of the animals, as well as the maintenance of thermal variables through the activation of installed climate systems inside the rabbit production environment.Trial registration number: 085/17. Date of registration: 14/12/2017.

Productive, Physiological, and Environmental Implications of Reducing Crude Protein Content in Swine Diets: A Review.

Pig production is one of the most important providers of high-quality proteins and amino acids (AAs) to human nutrition. In this sector, feeding has an important economic and environmental impact. A strategy to reduce production costs and negative sustainability effects is reducing dietary crude protein (CP) contents with or without AA supplementation. This review addresses the different aspects related to this strategy, particularly the effects on growth performance and pork traits in piglets and growing and finishing pigs, as well as the physiological molecular mechanisms' underlying effects. Insight is also provided into the effects of dietary CP reduction on the productive performances of alternative pig production systems and breeding boars and sows. Finally, an overview is conducted on the effects of dietary CP reduction on ammonia, odor, and greenhouse gas emissions arising from pig production systems. Overall, CP reduction may lead to production losses, albeit they can be, to some extent, hindered by adequate AA supplementation. Losses are particularly relevant during the post-weaning phase, whereas in finishing pigs, it may bring additional benefits, such as high intramuscular fat contents in some markets or improved gut barrier function with benefits to the animals' health and welfare, as well as decreased ammonia emissions to the environment.

Development of a pig wean-quality score using machine-learning algorithms to characterize and classify groups with high mortality risk under field conditions

Mortality during the post-weaning phase is a critical indicator of swine production system performance, influenced by a complex interaction of multiple factors of the epidemiological triad. This study leveraged retrospective data from 1723 groups of pigs marketed within a US swine production system to develop a Wean-Quality Score (WQS) using machine learning techniques. The study evaluated three machine learning models, Random Forest, Support Vector Machine, and Gradient Boosting Machine, to classify groups having high or low 60-day mortality, where high mortality groups represented 25 % of the groups among the study population with the highest mortality values (n=431; 60-day mortality=9.98 %), and the remaining 75 % of the groups were of low mortality (n=1292; 60-day mortality=2.75 %). The best-performing model, Random Forest (RF), outperformed the other ML models in terms of accuracy (0.90), sensitivity (0.84), and specificity (0.92) metrics, and was then selected for further analysis, which consisted of creating the WQS and ranking the most important factors for classifying groups as high or low mortality. The most important factors ranked through the RF model to classify groups with high mortality were pre-weaning mortality, weaning age, average parity of litters in sow farms, and PRRS status. Additionally, stocking conditions such as stocking density and time to fill the barn were important predictors of high mortality. The WQS was developed and correlated (r = 0.74) with the actual 60-day mortality of the groups, offering a valuable tool for assessing post-weaning survivability in swine production systems before weaning. This study highlights the potential of machine learning and comprehensive data utilization to improve the assessment and management of weaned pig quality in commercial swine production, which producers can utilize to identify and intervene in groups, according to the WQS.

Digestive physiology of rabbits in the pre- and post-weaning phases

This review aimed to address all relevant parts of the digestive physiology of rabbits, before and after weaning, with a view to enabling greater understanding of these phases and reducing the mortality of kits. The biggest bottlenecks in Brazilian rabbit farming are linked to the period from birth to weaning, a time when the animals are more sensitive to environmental adverse events, requiring more rigid and efficient management due to their immune system being not fully developed. Throughout the period in which kits are with the females, many physiological changes occur, mainly in their gastrointestinal tract (GIT), which changes over time, depending on the type of food intake; in order to achieve its full capacity to utilize food, the intestine needs to undergo an adaptation from milk-based to solid diet. Thus, the digestive system in the intrauterine phase, in the nursing kits, and in the weaned babies will be covered. Therefore, understanding the physiology of baby rabbits proves to be of great value in reducing the mortality rate, so that management becomes more practical, providing producers with different problem-solving alternatives, in addition to greater profit.

The Post-weaning Growth of Lambs from Crossbreeding Between Garut Ewes with Dorper Rams

This study investigates the performance of post-weaning growth of Garut lambs and the results of crossing Garut ewes with Dorper rams. This research phase occurred in the post-weaning phase period of 3–7 months using 168 lambs consisting of 85 Garut lambs and 83 crossed Dorper lambs in the post-weaning phase with an average body weight of 15.15±3.23 kg. The lambs were assigned to a factorial completely randomized design (2 x 2 factorial experiment). They were then divided into two groups based on breed (Garut and Crossed Dorper) and two sex groups (male and female). Data observed included feed consumption, as fed feed consumption, dry matter (DM) consumption, DM consumption per body weight, crude protein (CP) consumption, total digestible nutrient (TDN) consumption, average daily gain (ADG), and feed conversion. Results showed that consumption of as fed, DM, CP, TDN, and ADG were higher (<i>P</i><0.05) in crossed Dorper lambs than in Garut lambs; a total ADG of crossed Dorper, Garut, male, and female lambs were 106.92±11.68, 79.25±10.02, 102.49±17.54, and 86.79±14.48 g/day, respectively. Male lambs showed higher results (<i>P</i><0.05) in as-fed feed consumption, DM, DM consumption per body weight, CP, TDN, and ADG than female lambs. The feed conversion of crossed Dorper lamb and male lamb was lower (P<0.05) than that of Garut and female lamb. There was an interaction between male breed and sex at seven months ADG and feed conversion at 4 and 7 months. Sheep from Garut ewes crossed with Dorper rams improved the growth performance of their offspring.

Functional adaptation of the infant craniofacial system to mechanical loadings arising from masticatory forces.

The morphology and biomechanics of infant crania undergo significant changes between the pre- and post-weaning phases due to increasing loading of the masticatory system. The aims of this study were to characterize the changes in muscle forces, bite forces and the pattern of mechanical strain and stress arising from the aforementioned forces across crania in the first 48 months of life using imaging and finite element methods. A total of 51 head computed tomography scans of normal individuals were collected and analysed from a larger database of 217 individuals. The estimated mean muscle forces of temporalis, masseter and medial pterygoid increase from 30.9 to 87.0 N, 25.6 to 69.6 N and 23.1 to 58.9 N, respectively (0-48 months). Maximum bite force increases from 90.5 to 184.2 N (3-48 months). There is a change in the pattern of strain and stress from the calvaria to the face during postnatal development. Overall, this study highlights the changes in the mechanics of the craniofacial system during normal development. It further raises questions as to how and what level of changes in the mechanical forces during the development can alter the morphology of the craniofacial system.

304 What does Prop 12 mean for the swine industry

Abstract California’s Proposition 12, also known as the Farm Animal Confinement Initiative, has been fully implemented as of January 1st, 2024. This measure regulates the minimum space requirements for egg-laying hens, dairy calves raised for veal, and breeding pigs in order for the associated products to be sold within the state of California. Suppliers of these covered products need to be accredited by specific, third-party certifying agents to be certified as ‘Prop 12 compliant’. For the swine industry, the spotlight is on the housing of any female breeding pig over the age of 6 mo. These animals must be in an enclosure that allows them to lie down, stand up, turn around, and fully extend their limbs without touching the sides of their stalls or another animal (24 square feet of floor space per animal). These regulations also limit the duration of time producers can house animals in closed crates before farrowing to 5 d. While these housing regulations do not apply during the nursing phase, research contexts, during veterinary treatment or immediately before slaughter, they do apply in the post-weaning phase. This means that the animals cannot be confined for heat-checking or breeding to be considered ‘Prop 12 compliant’. These housing standards have no minimum herd size and apply to those in commercial or private farms if there will be products produced and sold. With any change to the standard operating procedures of animal husbandry, there will be some growing pains. These issues can be addressed when considerations are given to the group composition (age and size of sows), pen mixing practices (pre or post breeding), feeding schedule [collective (trough, floor fed) or individual (electronic sow feeding, free access stalls)], and, pen structural quality (flooring, enrichment). This measure will have considerable economic and ethical implications related to barn renovations, animal care staff training, and husbandry practices for the swine industry.

Influence of Jerusalem artichoke tuber as a prebiotic on the nutrient utilization, weaning stress indicators and immunocompetence of crossbred calves during the pre- and post-weaning phases

This study explored the potential prebiotic properties of pulverized Jerusalem artichoke tuber (JAP) in pre- and post-weaned calves. Accordingly, 24 fifteen-day-old calves were randomly assigned to four groups (n = 6). The groups received JAP supplementation at levels of 0 (CON), 1 (JAP1), 2 (JAP2), and 3 (JAP3) percent of dry matter intake (DMI) during the first 60 days of the 120-day experiment. Two 6-days digestion trials were conducted: one during the 4th week of the experiment (pre-wean), and the second during the tenth week (post-wean). Additionally, serum concentrations of cortisol and epinephrine were measured in both the pre- and post-weaning phases to assess the stress levels. Immunocompetence of the calves during both the stages was evaluated through lymphocyte proliferation response. In the pre-weaning phase, the calves supplemented with JAP had better (P < 0.05) protein intake and digestion compared to the control group. In the post-weaning phase, the JAP supplemented groups exhibited significantly (P < 0.05) improved digestibility coefficients for dry matter, organic matter, crude protein, ether extract, and neutral detergent fibre. Although cortisol levels didn't show significant differences (P > 0.05) between the groups during both pre-weaning and post-weaning stages, the post-weaning stage did reveal a significant reduction (P < 0.05) in epinephrine levels in JAP1 compared to the other groups. Additionally, JAP supplementation enhanced (P < 0.05) the calves' response to lymphocyte proliferation during the post-weaning phase. Considering the improved nutrient digestibility, enhanced systemic immunity, and reduced epinephrine levels observed in the JAP supplemented groups, our findings suggest that JAP may have promising potential as a prebiotic for calves.

Maternal Programming of Nursery Pig Performance and Gut Microbiome through Live Yeast Supplementation.

The supplementation of live yeast in pig diets is common in the post-weaning phase due to its prebiotic and probiotic effects, but little is known regarding the potential of feeding live yeast to gestating or lactating sows for transferring such benefits to their offspring through maternal programming. The objective of this study was to investigate the effects of live yeast supplementation in sow diets during late gestation and lactation on their reproductive performance and its impact on offspring performance and gut microbiomes in the post-weaning period. Three dietary treatments were imposed on 92 mixed-parity sows during late gestation and lactation based upon the inclusion level of live yeast in corn/soybean meal-based diets: Control (0% yeast), Low (0.1% yeast), and High (0.5% yeast). Nursery pigs in the Low group displayed the highest feed intake in the post-weaning period and greater total gain and average daily gain in comparison to pigs in the High group. The gut microbiomes of nursery pigs differed in composition according to maternal dietary treatment groups at days 4 and 28 post weaning, highlighting higher abundances of bacterial genera typically associated with fermentation roles in the gut microbiomes of offspring of yeast-fed sows. These results indicate that the supplementation of live yeast in sow diets, depending on the inclusion level, may result in beneficial performance and specific microbiome traits for their offspring in the post-weaning period.

A new selection criteria to optimize growth in animal breeding programs

Pedigree records and longitudinal measurements of live weight from 2628 buffaloes were analyzed. The aim of this research was to propose a new selection criteria, the Area Under the Growth Curve (AUGC), derived from a growth curve-based model. A hierarchical Bayesian approach with two levels was employed. In the first level, the growth trajectory was modeled using a fourth-degree polynomial, while in the second level, each parameter of the polynomial function was treated as a dependent variable influenced by environmental and genetic effects. The animal model included sex, dams’ parity and contemporary group (herd-year-season) as fixed effects, and relationships among animals as a random effect. Inference was conducted using Markov Chain Monte Carlo (MCMC) simulation algorithm. The proposed AUGC is interesting for use in selection programs because it allows breeders to identify heavier animals with lower risk in the production system. Additionally, that trait showed moderate to high heritabilities from weaning onwards, providing a useful new tool for cattle selection in the post-weaning phases.

3 Measuring feed intake in cows

Abstract In recent years, substantial progress has been made in understanding the sources of biological variation and genetic components of feed efficiency in growing animals consuming energy-dense mixed diets during the post-weaning phase. Much less is known about within-animal variation of feed efficiency for beef cows consuming moderate to low-quality forage diets common to most cow/calf production systems. Considerable evidence indicates the existence of a genetic by environment interaction for feed efficiency. Phenotype for feed intake and feed efficiency are most practically and cost effectively determined during the post-weaning growing stage. However, due to the additional nutrient sinks associated with gestation and lactation, and the cost, labor and technology required to measure economically relevant traits in mature cows, little is known about forage utilization efficiency in beef cows. The beef cow/calf segment of the industry represents, by far, the greatest opportunity to reduce beef production input costs and reduce the industry’s carbon footprint. We reason that selection tools for feed intake and feed efficiency developed over the last 20 years are effective for the post-weaning growing and finishing phases, although only marginally effective for beef cows consuming unprocessed, moderate to low-quality forage. In this session, we will discuss challenges, opportunities, and experiences associated with measuring forage intake and recovered energy in beef cows.

Inclusion of Saccharomyces cerevisiae var. boulardii RC009 and Pediococcus pentosaceus RC007 as a Probiotic Additive in Pigs’ Postweaning Diets and Its Effect on Meat Composition, Carcass Characteristics, and Fatty Acids Profile after Slaughter

The postweaning is recognized as one of the most challenging stages of pig growth that can affect their lifetime productivity. The aim of the study was to evaluate the inclusion of Saccharomyces cerevisiae var. boulardii RC009 and Pediococcus pentosaceus RC007 as a probiotic additive in pigs’ postweaning diets and its effect on meat composition, carcass characteristics, and fatty acids profile after slaughter. The following three treatments (550 animals each) were included: T1: control balanced diet (CD), T2: CD with S. boulardii RC009 (1 × 109 CFU/kg feed), and T3: CD with P. pentosaceus RC007 (1 × 109 CFU/kg feed). The additive was administered throughout the postweaning phase (49 d), and then the pigs were moved to a fattening house where they no longer received probiotics in the feed. At 115 ± 5 kg, the animals were transferred to the slaughterhouse. Analyses of carcass composition, muscle depth, protein content, total fat and ash, drip and cooking water loss, and fatty acids were performed. Pigs consuming the probiotic additives had improvements in some of the production parameters. According to our results, we could observe that some modifications in meat composition after slaughter were observed in the group of pigs that consumed the probiotic additives during the postweaning, which could be considered as an improvement in meat quality. Pigs consuming probiotics had higher percentages of essential omega-3 fatty acids such as linolenic acid, and pigs consuming S. cerevisiae var. boulardii RC009 increased lean percentage and reduced the eicosanoic contents in meat. Also, an improvement in water retention capacity was observed in both groups treated with probiotics. While these results are promising, further studies are needed to evaluate the possible effect of these additives closer to slaughter, as well as their combined use.

Effect of Post-Weaning Concentrate Feeding Prior to Forage Finishing on Intramuscular Fat Deposition

The objectives of this study were to examine the effects of feeding high-concentrate diets post-weaning (PW) prior to forage finishing on (1) changes in ultrasound intramuscular fat deposition and lipogenic/lipolytic gene expression during the post-weaning phase and (2) carcass characteristics and fatty acid composition after forage finishing to 487 kg. Steers were randomly assigned to one of four treatments (PW0, PW40, PW80, and PW120) at weaning to examine the time of high-concentrate feeding prior to forage finishing. The ultrasound intramuscular fat content was greater (p &lt; 0.05) for PW120 compared to those for PW0, PW40, or PW80 at the end of the post-weaning phase. Feeding high concentrates (PW120) up-regulated (p &lt; 0.01) the mRNA expression of fatty acid transporters and lipogenic genes and down-regulated lipolytic genes in the LM compared to PW0. Carcasses from PW120 were graded 83% Choice (p = 0.025), whereas carcasses from other post-weaning treatments (PW0, 40, or 80) were graded 25, 36, and 54% Choice, respectively, at the final harvest. The total fatty acid content of the muscle at slaughter was greater (p = 0.0004) for PW120 than PW0, PW40, and PW80. Feeding high-concentrate diets to steers post-weaning for 120 day enhanced early intramuscular fat deposition without causing major changes to the fatty acid composition of the longissimus muscle after forage finishing.

Utilizing productivity and health breeding-to-market information along with disease diagnostic data to identify pig mortality risk factors in a U.S. swine production system.

Aggregated diagnostic data collected over time from swine production systems is an important data source to investigate swine productivity and health, especially when combined with records concerning the pre-weaning and post-weaning phases of production. The combination of multiple data streams collected over the lifetime of the pigs is the essence of the whole-herd epidemiological investigation. This approach is particularly valuable for investigating the multifaceted and ever-changing factors contributing to wean-to-finish (W2F) swine mortality. The objective of this study was to use a retrospective dataset ("master table") containing information on 1,742 groups of pigs marketed over time to identify the major risk factors associated with W2F mortality. The master table was built by combining historical breed-to-market performance and health data with disease diagnostic records (Dx Codes) from marketed groups of growing pigs. After building the master table, univariate analyses were conducted to screen for risk factors to be included in the initial multivariable model. After a stepwise backward model selection approach, 5 variables and 2 interactions remained in the final model. Notably, the diagnosis variable significantly associated with W2F mortality was porcine reproductive and respiratory syndrome virus (PRRSV). Closeouts with clinical signs suggestive of Salmonella spp. or Escherichia coli infection were also associated with higher W2F mortality. Source sow farm factors that remained significantly associated with W2F mortality were the sow farm PRRS status, average weaning age, and the average pre-weaning mortality. After testing for the possible interactions in the final model, two interactions were significantly associated with wean-to-finish pig mortality: (1) sow farm PRRS status and a laboratory diagnosis of PRRSV and (2) average weaning age and a laboratory diagnosis of PRRS. Closeouts originating from PRRS epidemic or PRRS negative sow farms, when diagnosed with PRRS in the growing phase, had the highest W2F mortality rates. Likewise, PRRS diagnosis in the growing phase was an important factor in mortality, regardless of the average weaning age of the closeouts. Overall, this study demonstrated the utility of a whole-herd approach when analyzing diagnostic information along with breeding-to-market productivity and health information, to measure the major risk factors associated with W2F mortality in specified time frames and pig populations.

Dose-response of inactivated yeast in diets of late gestating and lactating gilts on immunoglobulin transfer and offspring preweaning growth performance.

Fifty gilts (initial body weight [BW] 190.7 ± 4.2kg) were recruited on day 85 of gestation and were used until day 19 of lactation to assess the dose-response of inactivated yeast via hydrolyzation (HY) inclusion on offspring growth and immunoglobulin (Ig) transfer prior to weaning. Gilts were assigned to one of the 5 experimental diets: a control with no HY (HY0) or inclusion of 0.25% (HY0.25), 0.5% (HY0.5), 1.0% (HY1.0), or 1.2% (HY1.2) HY. Gilts were weighed on days 85 and 110 of gestation and days 1 and 19 (weaning) after farrowing. Offspring were weighed on days 1 and 19 of age. On lactation day 1 (approximately 24h after farrowing), colostrum, gilt plasma, and plasma from 2 median BW piglets were collected and on day 19, plasma from each gilt and 2 median BW piglets per litter were collected for determination of Ig concentrations. Contrast statements were used to assess the linear, quadratic, cubic, and quartic effects of HY inclusion. The inclusion of HY had minimal effects on gilt BW or litter characteristics at birth (total number born and born alive, piglet birth weight). Lactation average daily feed intake of the gilts tended to increase then decrease with increasing HY inclusion (quadratic; P = 0.085). Piglet preweaning average daily gain (linear, quadratic, and quartic; P < 0.05) and BW at weaning (quadratic and quartic; P < 0.05) increased then decreased with increasing HY inclusion. On lactation day 1, colostrum and gilt plasma Ig concentrations were not affected by dietary treatment (P > 0.10) but piglet IgA and IgM decreased then increased with HY inclusion level (cubic; P < 0.05). On lactation day 19, piglet plasma IgG tended to increase with HY inclusion (linear; P = 0.099). In summary, increasing HY inclusion in late gestating and lactating gilt diets improved immune transfer in the first 24h after birth and piglet preweaning growth rates and BW at weaning. Therefore, maternal feeding of HY could be used as a strategy to improve offspring immunocompetence and BW at weaning, with possible carryover benefits for the postweaning phase.

Linear and Nonlinear Mixed Models to Determine the Growth Curves of Weaned Piglets and the Effect of Sex on Growth

This study characterizes the growth of weaned Large White × Landrace hybrid piglets from 6 to 20 kg live body weight (BW) under real farm conditions. Batches of 50 castrated male pigs and 50 gilts were weighed repeatedly over two 6-week breeding cycles. The data was fitted to various linear (quadratic and exponential) and nonlinear (Gompertz, Richards, logistic, Von-Bertalanffy) mixed models to find the best-performing model. During the postweaning phase, animal growth was modelled, and the effect of sex on growth was determined by incorporating the variable, sex, into the mixed models and using t-tests for paired samples. The average BW at weaning was 6.86 kg, and the average BW by the end of the cycle was 19.46 kg, with an average daily gain (ADG) of 0.324 kg/day. Over the study period, the variable, sex, did not show a significant effect (p &lt; 0.05) on piglet growth. The nonlinear mixed models performed better than the linear mixed models, with the Gompertz (RMSE = 0.296) and Von-Bertalanffy (RMSE = 0.288) curves as the best-performing models. When fitted to the Gompertz curve, the data showed a maximum ADG of 0.508 kg/day on day 27 postweaning. Accordingly, nonlinear mixed models can provide useful information to farmers about the evolution of weaned piglet growth and can be used for the early detection of growth anomalies.

Strategies of virginiamycin supplementation in the postweaning phase on growth performance and carcass quality of beef cattle.

The present study evaluated the effects of supplementing VM in grazing cattle during the rearing phase on performance and carcass quality of beef cattle in the finishing phase. Two experiments with a randomized block design were conducted in consecutive years to contrast two post-weaning supplementation strategies using VM at 45 mg/100 kg body weight (BW). In the first year, treatments were protein supplement in the dry season and mineral supplement in the rainy season versus the addition of VM both in the protein and mineral supplements. In the second year, was contrasted with protein supplement in the dry season and protein-energy supplement in the rainy season. Performance, carcass traits, and carcass quality were evaluated at the end of both phases. In Year 1, adding VM in mineral supplement increased final backfat thickness (P=0.05), backfat gain (P=0.06), final rump fat thickness (P=0.02), and rump fat gain (P=0.01). In the finishing phase, VM-treated cattle had a greater dry matter intake (P=0.03) and tended to show a greater backfat thickness than non-treated cattle (P=0.07). In Year 2, no VM effects were observed on post-weaning phase performance and carcass traits. However, cattle-fed VM during the post-weaning phase tended to show a lower feed conversion ratio (P=0.09) and had a significantly higher gross feed efficiency (P=0.03) than non-treated cattle at slaughter. Virginiamycin supplementation during rearing on pasture improves performance and carcass fattening in the growth phase and has a residual effect in the finishing phase that may reflect greater backfat thickness and gross feed efficiency.

Detection and disease diagnosis trends (2017–2022) for Streptococcus suis, Glaesserella parasuis, Mycoplasma hyorhinis, Actinobacillus suis and Mycoplasma hyosynoviae at Iowa State University Veterinary Diagnostic Laboratory

BackgroundAccurate measurement of disease associated with endemic bacterial agents in pig populations is challenging due to their commensal ecology, the lack of disease-specific antemortem diagnostic tests, and the polymicrobial nature of swine diagnostic cases. The main objective of this retrospective study was to estimate temporal patterns of agent detection and disease diagnosis for five endemic bacteria that can cause systemic disease in porcine tissue specimens submitted to the Iowa State University Veterinary Diagnostic Laboratory (ISU VDL) from 2017 to 2022. The study also explored the diagnostic value of specific tissue specimens for disease diagnosis, estimated the frequency of polymicrobial diagnosis, and evaluated the association between phase of pig production and disease diagnosis.ResultsS. suis and G. parasuis bronchopneumonia increased on average 6 and 4.3%, while S. suis endocarditis increased by 23% per year, respectively. M. hyorhinis and A. suis associated serositis increased yearly by 4.2 and 12.8%, respectively. A significant upward trend in M. hyorhinis arthritis cases was also observed. In contrast, M. hyosynoviae arthritis cases decreased by 33% average/year. Investigation into the diagnostic value of tissues showed that lungs were the most frequently submitted sample, However, the use of lung for systemic disease diagnosis requires caution due to the commensal nature of these agents in the respiratory system, compared to systemic sites that diagnosticians typically target. This study also explored associations between phase of production and specific diseases caused by each agent, showcasing the role of S. suis arthritis in suckling pigs, meningitis in early nursery and endocarditis in growing pigs, and the role of G. parasuis, A. suis, M. hyorhinis and M. hyosynoviae disease mainly in post-weaning phases. Finally, this study highlighted the high frequency of co-detection and -disease diagnosis with other infectious etiologies, such as PRRSV and IAV, demonstrating that to minimize the health impact of these endemic bacterial agents it is imperative to establish effective viral control programs.ConclusionsResults from this retrospective study demonstrated significant increases in disease diagnosis for S. suis, G. parasuis, M. hyorhinis, and A. suis, and a significant decrease in detection and disease diagnosis of M. hyosynoviae. High frequencies of interactions between these endemic agents and with viral pathogens was also demonstrated. Consequently, improved control programs are needed to mitigate the adverse effect of these endemic bacterial agents on swine health and wellbeing. This includes improving diagnostic procedures, developing more effective vaccine products, fine-tuning antimicrobial approaches, and managing viral co-infections.

Effect of Creep Feeding Supplementation on Growth Performance and Metabolic Characteristics of Nellore Heifers

The objective of this paper is to evaluate the effects of creep feeding supplementation during the preweaning phase on the growth performance and metabolic characteristics of Nellore heifers. Forty-two female Nellore calves (age = 100 ± 25 d; initial body weight (BW) = 113.4 ± 16.6 kg) were randomly assigned to the following treatments: control, where calves received mineral mix supplementation (n = 21); supplemented in creep feeding, where calves received 6 g/kg BW of a concentrate supplement (n = 21) during a period of 140 d. In the postweaning phase, all heifers received 6 g/kg BW of a concentrate supplement during a period of 210 d. Supplemented heifers had a greater average daily gain (ADG) than control heifers during the preweaning phase and, consequently, were heavier at weaning and at the end of the growing phase (p &lt; 0.05). However, preweaning supplementation did not influence (p &gt; 0.05) the body measurements or BW at the end of the growing period. Greater (p &lt; 0.05) rib fat was observed in supplemented heifers. Concentrations of metabolites were not affected by preweaning supplementation (p &gt; 0.05). Thus, supplementing heifers in the preweaning phase improved growth performance of weaning and body adiposity.

Tracing early life histories from Roman times to the Medieval era: weaning practices and physiological stress

In humans, breastfeeding and weaning depend on the infant’s needs and physiology but are also influenced by environmental and cultural factors. While infant feeding strategies vary across different regions and historical eras, the associated transition from breastmilk to solid foods is universally thought to be stressful. However, still little is known about infant feeding practices and possibly associated stress in former times. This also applies to the period of transition from classical antiquity to medieval times, which shaped modern Western civilization. To enhance the understanding of childhood nutrition and stress during this period, we first analyzed stable carbon and nitrogen isotopes in serial dentine samples from the first molars of 38 individuals buried in the region once known as the Roman frontier province of Raetia secunda, now encompassing Southern Bavaria. In addition, we investigated the presence of linear enamel hypoplasia (LEH), known to be a marker of unspecific physiological stress, within their dentition. We used this data to create isotope profiles that display dietary changes in comparison with the occurrence of LEH. We found highly variable δ15N and δ13C values and different shapes of isotope profiles which indicate different nutrition of breastfeeding individuals, complementary foods and post-weaning diets, and individual weaning patterns. For most individuals, the weaning process was completed between the ages of two and three. Interestingly, some females of non-local origin show longer weaning periods, likely displaying the influence of different cultural practices in other communities. We also found that LEH most frequently occurred in the post-weaning phase, which supports the assumption that children were at increased risk once breastfeeding had ceased completely. Furthermore, a change in the post-weaning diet in the seventh century coincided with an increased prevalence of LEH, indicating that the foods chosen or available during this time affected the susceptibility of children to stress. In conclusion, our study unveiled diverse infant feeding strategies practiced across various communities, both in different historical eras and geographical locations.