Preliminary outcomes on phenotypic and genetic parameter estimates for body weight of indigenous Tswana goats in Botswana.

The aims of this study were to estimate the genetic and phenotypic parameters for growth traits and evaluate genetic trends on 585 indigenous Tswana goats. The population was maintained under low input production system at the Department of Agricultural Research in Lesego ranch, Botswana, from 2005 to 2008. Data included birth weight (BW), weaning weight (WW), weight at 8 months (PW), yearling weight (YW), pre-weaning average daily gain (ADG) and two post weaning average daily gains (ADG2 and ADGYW). Data was analysed using general linear model of SAS to determine non-genetic effects. Estimation of genetic and phenotypic parameters were estimated using ASREML fitting an animal model that accounted for fixed effect of parity, sex, type of birth and year of birth. Least squares means for BW, WW, PW and YW were 2.88 ± 0.03, 12.15 ± 0.17, 16.52 ± 0.28 and 21.04 ± 0.32Kg, respectively, while those for ADG, ADG2 and ADGYW were 74.52 ± 1.41, 28.78 ± 1.55 and 33.66 ± 2.28 g/day, respectively. Estimates of heritability for BW, WW, PW and YW were 0.79 ± 0.11, 0.63 ± 0.14, 0.32 ± 0.13 and 0.48 ± 0.16, respectively. The genetic correlations for all the traits studied were positive and moderate to high (0.48 to 0.82) whilst phenotypic correlations ranged from 0.21 to 0.72. Positive average genetic trends of 12.32% (WW), 13.39% (PW) and 7.38% (YW) were attained. The results have demonstrated the potential of this breed to be improved through selection.

Investigating the regulatory effect of Shen Qi Bu Qi powder on the gastrointestinal flora and serum metabolites in calves.

Object: To investigate the effects of Shen Qi Bu Qi Powder (SQBQP) on the average daily gain, blood indexes, gastrointestinal microflora, and serum metabolites of calves. Methods: A total of 105 calves were randomly assigned to three groups (n = 35 per group): the control group (C, fed with a basal diet for 21 days) and two treatment groups (SQBQP-L and SQBQP-H, fed with the basal diet supplemented with 15 and 30 g/kg of SQBQP), respectively for 21 days. The active components of SQBQP were identified using LC-MS/MS. Serum digestive enzymes and antioxidant indices were determined by ELISA kits and biochemical kits, respectively. Serum differential metabolites were analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), while flora in rumen fluid and fecal were analyzed by 16S rDNA sequencing. Further correlation analysis of gastrointestinal flora and serum metabolites of SQBQP-H and C groups were performed with Spearman's correlation. Results: The principal active components of SQBQP mainly includes polysaccharides, flavonoids, and organic acids. Compared to the control group (C), calves in the SQBQP-H (high dose) and SQBQP-L (low dose) groups showed a significant increase in serum amylase (AMS) levels (P<0.001), while lipase content significantly decreased (P<0.05). Additionally, the average daily gain, T-AOC, and cellulase content of calves in the SQBQP-H group significantly increased (P<0.05). Proteobacteria and Succinivibrio in the rumen flora of the SQBQP-H group was significantly lower than that of the C group (P<0.05). The relative abundance of Proteobacteria, Actinobacteria, Candidatus_Saccharibacteria, Deinococcus_Thermus, Cyanobacteria, and Succinivibrio in the SQBQP-H group was significantly increased (P<0.05), while the relative abundance of Tenericutes and Oscillibacter was significantly decreased (P<0.05). Serum metabolomics analysis revealed 20 differential metabolites, mainly enriched in amino acid biosynthesis, ß-alanine metabolism, tyrosine, and tryptophan biosynthesis metabolic pathways (P<0.05). Correlation analysis results showed that Butyrivibrio in rumen flora and Oscillibacter_valericigenes in intestinal flora were significantly positively correlated with average daily gain, serum biochemical indexes, and differential metabolite (-)-Epigallocatechin (R>0.58, P<0.05). Conclusion: SQBQP can promote calves weight gain and enhance health by modulating gastrointestinal flora and metabolic processes in the body.

Theileria orientalis Ikeda infection does not negatively impact growth performance or breeding soundness exam results in young beef bulls at bull test stations.

Introduction: Theileria orientalis Ikeda genotype is an emerging cattle disease in the US. Since 2017, when T. orientalis Ikeda was discovered in beef cattle in two counties in Virginia, cattle infections have risen to include ~67% of Virginia counties and 14 states. Consistent with New Zealand studies, many infected herds in Virginia were >90% positive upon initial testing without overt evidence of infection. Central bull tests present a unique opportunity to study the effects of T. orientalis Ikeda infections, as bulls from multiple source herds are consolidated. The objective of this study was to determine if infection with T. orientalis Ikeda affected the average daily gain (ADG), adjusted yearling weight (AYW) and breeding soundness of bulls at two test stations in Virginia over a period of years. Materials and methods: The bulls were fed and housed similarly to compare their growth performance and breeding soundness. For T. orientalis Ikeda testing, DNA was extracted from whole blood for quantitative polymerase chain reaction. Results: The number of bulls infected with T. orientalis Ikeda at initial delivery to the stations increased significantly over the years studied. Multivariable linear regression models, using Angus bulls from Virginia test stations, indicated no significant effect on ADG or AYW in bulls that became test positive during the test or were positive for the duration, compared to Angus bulls that were negative for the duration. At LOC A, the odds of passing a breeding soundness exam (BSE) were not significantly different for bulls that turned positive during the test or were positive for the duration, compared to bulls that were negative for the duration of the test. At LOC B, bulls that became positive during the test were 2.4 times more likely (95% CI: 1.165-4.995, p = 0.016) to pass their BSE compared to bulls that remained negative throughout the test. Discussion: We do not suppose that an obscured infection of T. orientalis Ikeda is protective for bulls to pass a BSE. However, this study demonstrates an obscured infection of T. orientalis Ikeda does not negatively affect weight gain or achievement of a satisfactory BSE rating at the central bull test stations in Virginia.

Association of morbidity, mortality, and average daily gain with transfer of passive immunity in dairy-beef crossbred calves up to 60 days of life.

Adequate transfer of passive immunity (TPI) is a cornerstone for a proper health status of calves. In the literature, there is limited information on the prevalence of failure of TPI in dairy-beef crossbred calves and its effect on morbidity, mortality, and ADG during the preweaning period. Therefore, this study aimed to evaluate the association between TPI with morbidity, mortality, and ADG in preweaning dairy-beef crossbred calves. A total of 1,055 newborn dairy-beef crossbred calves were enrolled upon arrival at a calf-raising facility in California from January to August 2021. Farm of origin, genetic breed group, sex, and BW were recorded upon arrival. Blood was collected at 24 ± 1 h after arrival to evaluate serum IgG concentration, serum total protein (TP), and packed cell volume. Morbidity (diarrhea and respiratory treatment records) and mortality were recorded daily until 60 d of life. Calves were grouped into 2 genetic breed groups: Holstein × Beef (Ho × Be, 49.6%) and Jersey × Beef crossbred calves (Je × Be, 50.4%). Descriptive statistics and Cox proportional hazard models were created to evaluate the association of TPI categories for serum IgG (TPI-IgG: poor: <10.0 g/L, fair: 10.0-17.9 g/L, good: 18.0-24.9 g/L, and excellent: ≥25.0 g/L) and TP (TPI-TP: poor: <5.1 g/dL, fair: 5.1-5.7 g/dL, good: 5.8-6.1 g/dL, and excellent: ≥6.2 g/dL), sex, and genetic breed group with morbidity and mortality. Additionally, a mixed linear regression was performed to evaluate the association of sex, genetic breed group, and TPI categories with ADG. Overall morbidity and mortality were 84.8% (n = 895) and 2.5% (n = 26). Calves classified as TPI-IgG excellent were associated with the lowest (43.2% less) hazard of being treated compared with TPI-IgG poor calves. For mortality, dairy-beef crossbred calves with TPI-IgG excellent were associated with a reduction of 82.0% in the hazard of dying compared with TPI-IgG poor. The TPI-IgG poor and TPI-IgG fair calves were associated with a decreased ADG of 101.0 and 98.8 g/d, respectively, in comparison with TPI-IgG good calves. Average daily gain of TPI-IgG good and TPI-IgG excellent calves were not different. In our study, dairy-beef crossbred calves enrolled may have endured challenging conditions that increased morbidity. This reinforces the importance of high IgG levels to decrease morbidity and mortality and maximize ADG in dairy-beef crossbred calves raising systems. Further research should evaluate the long-term effects of TPI categories on the health and performance of dairy-beef crossbred calves.

The Impact of Abrupt and Fenceline-Weaning Methods on Cattle Stress Response, Live Weight Gain, and Behaviour.

The impact of abrupt (AB) and fenceline (FL) weaning methods on cattle stress response, live weight gain, and behaviour were determined across 14 days. Thirty-two cow-calf pairs were fitted with ear tag sensors (to continuously record behaviour) and allocated to two weaning treatments. After separation, FL calves were maintained in a pen adjacent to the FL cow paddock. The AB calves were transported to a pen removing all contact with the cows. After 7 d, FL cows were transported away from all calf pens. Body weights and salivary samples were collected for all animals on experimental days 0, 7, and 14. Fenceline-weaned calves had a greater duration of rest and rumination with reduced high activity across the first 3 days after separation as compared to abruptly weaned calves in line with the greater occurrences of pacing observed for AB calves. Fenceline-separated cows had greater levels of rest across the first 7 days but similar levels of rumination compared to abruptly separated cows. Fenceline-separated cow activity levels tended to be greater and eating levels were similar across the first three days. Body weight (BW) and cortisol concentrations were similar for AB and FL cattle, but FL cows had lower overall weight gain than the abrupt cows likely due to reduced eating time on days four to seven. Together, these results suggest that calves be fenceline-weaned for three days followed by total separation.

Effect of High Molybdenum Diet on Copper Status, Growth Performance, Blood Metabolites, Select Liver and Kidney Minerals, and Immune Responses of Boer Crosses.

This study examined the effects of elevated molybdenum (Mo) in goat diets on the growth, blood parameters, and immune responses in goats. Eighteen Boer crosses goats (BW = 25.6 ± 1.03 kg) were randomly assigned to three treatment groups: (1) control (no additional Mo), (2) 5 ppm Mo, and (3) 10 ppm Mo as ammonium molybdate was added to the grain mix. Animals were fed a 50:50 hay:grain diet ad libitum twice daily. Daily feed refusals were monitored, and intake was adjusted weekly. Body weights were recorded every 14 days and blood samples were collected on the second week of every month to determine Cu, Mo, Fe, Zn, and other blood metabolites. After 85 days, animals were humanely euthanized and carcass traits were measured. Liver, longissimus muscle area, and kidney samples were collected postmortem. Liver Cu (p < 0.003), blood triacylglycerides (p < 0.03), and serum total protein (p < 0.03) levels were reduced; the liver (p = 0.07) and kidney (p < 0.001) Mo concentrations were increased; and the immune response was decreased linearly (p < 0.01) with additional Mo. Low levels of Cu with increasing Mo levels in the diet did not negatively impact animal performance or blood metabolites, in the duration of this study (85 days); however, it lowered the liver Cu, Fe, and immune responses in goats.

Calcium Requirement of Yunnan Semi-fine Wool Rams (Ovis aries) Based on Growth Performance, Calcium Utilization, and Selected Serum Biochemical Indexes.

Calcium (Ca) is required for the growth and development of sheep, but the requirement of Yunnan semi-fine wool (YSW) rams remains uncovered. The current study aims to estimate the Ca requirement of growing YSW rams based on their growth performance, Ca utilization, and serum biochemical indexes. Forty-five YSW rams (10-month-olds) were randomly allocated to five dietary treatments with varying Ca levels of 0.50% (D1), 0.68% (D2), 0.73% (D3), 0.89% (D4), and 0.98% (D5). A higher value for average daily gain and a lower value for the feed conversion ratio were observed in the D3 group compared to the D5 group (p < 0.05). The dry matter intake amount changed quadratically with the increased Ca levels (p < 0.05). The levels of Ca intake, fecal Ca, and excreted Ca were significantly higher in the D5 group than those in the D1 group (p < 0.05). The apparent Ca digestibility rate and the Ca retention rate were significantly higher in the D4 group than in the D1 group (p < 0.05). The serum Ca concentration increased linearly with the incremental levels of dietary Ca (p < 0.05). The activity of alkaline phosphatase was significantly higher in the D1 group than in the D2 group (p < 0.05). The serum levels of hydroxyproline, osteocalcin, and calcitonin decreased from the D1 group to the D2 group, and then significantly ascended (p < 0.05) with the dietary Ca levels from the D3 group to the D5 group. The serum parathyroid hormone content was elevated from the D1 group to the D3 group and then decreased from the D4 group to the D5 group. After calculation, the daily net Ca requirement for the maintenance of YSW rams was 0.073 g/kg of BW0.75, and the daily total Ca requirement was 0.676 g/kg of BW0.75. To optimize the growth performance and the Ca utilization of YSW rams, the recommended dietary Ca level ranges from 0.73% to 0.89% based on this study.

In-vivo evaluation of the adverse effects of ochratoxin A on broiler chicken health and adsorption efficacy of indigenous and commercial clay of Balochistan, Pakistan.

Mycotoxins in animal feed pose health risks and economic losses, but using various adsorbent types could potentially protect animals from mycotoxicosis. The study aimed to assess the effect of OTA on the health of broiler chickens and to envisage the ameliorative potential of clay adsorbents. The objectives of this in vivo study were to investigate the effects of OTA on productivity, biochemical parameters, fecal residues, and the preventive effects of indigenous and commercial clay of Balochistan as adsorbents to alleviate the adverse effects of exposure. Male broiler chickens (n = 160) were treated with 400 µg/kg OTA and 0.5 g/kg clay adsorbent for 42 days, with feed and water available in an ad libitum manner. The amount of OTA in diet and fecal residues was assessed through HPLC. The administration of OTA in the diet, resulted in a significant (p < 0.05) decrease in the average daily gain (ADG) and average daily feed intake (ADFI) while increasing the feed conversion ratio (FCR) as compared to the control group. Furthermore, no significant (p > 0.05) differences were found between the weight gain of broiler chickens fed without OTA (positive control) and that of chickens fed adsorbent. The group given a diet containing OTA without adsorbents as compared to the control and adsorbent-supplemented group has shown a significant (p < 0.05) increase in the relative weight of the liver, kidney, gizzard, and proventriculus while decreasing the relative weight of the spleen and bursa of Fabricius. Alterations in the levels of serum total protein (TP), cholesterol (CHL), serum urea (SU), enzymatic activity (aspartate aminotransferase (AST) and alanine transaminase (ALT)), and creatinine were observed in the OTA-intoxicated and adsorbent-supplemented groups as compared to the control group. Adsorbent supplementation resulted in a significantly (p < 0.05) higher OTA content in the faeces. It can be concluded from the results of this study, that OTA intoxication negatively affects the health of broiler chickens, and the clay of Balochistan has shown effective adsorption potential against OTA.

Connectedness rating among commercial pig breeding herds in Korea.

This study aims to estimate the connectedness rating (CR) of Korean swine breeding herds. Using 104,380 performance and 83,200 reproduction records from three swine breeds (Yorkshire, Landrace and Duroc), the CR was estimated for two traits: average daily gain (ADG) and number born alive (NBA) in eight breeding herds in the Republic of Korea (hereafter, Korea). The average CR for ADG in the Yorkshire breed ranges from 1.32% to 28.5% depending on the farm. The average CR for NBA in the Yorkshire herd ranges from 0% to 12.79%. A total of 60% of Yorkshire and Duroc herds satisfied the preconditions suggested for genetic evaluation among the herds. The precondition for the genetic evaluation of CR for ADG, as a productive trait, was higher than 3% and that of NBA, as a reproductive trait, was higher than 1.5%. The ADG in the Yorkshire herds showed the highest average CR. However, the average CR of ADG in the Landrace herds was lower than the criterion of the precondition. The prediction error variance of the difference (PEVD) was employed to assess the validation of the CR, as PEVDs exhibit fluctuations that are coupled with the CR across the herds. A certain degree of connectedness is essential to estimate breeding value comparisons between pig herds. This study suggests that it is possible to evaluate the genetic performance together for ADG and NBA in the Yorkshire herds since the preconditions were satisfied for these four herds. It is also possible to perform a joint genetic analysis of the ADG records of all Duroc herds since the preconditions were also satisfied. This study provides new insight into understanding the genetic connectedness of Korean pig breeding herds. CR could be utilized to accelerate the genetic progress of Korean pig breeding herds.

Strategies to alleviate heat stress on performance and physiological parameters in feedlot-finished cattle under heat stress conditions. A systematic review-meta-analysis.

Strategies to alleviate heat stress on live performance - dry matter intake (DMI), average daily gain (ADG), and feed conversion efficiency (FCE) - and on physiological parameters - respiratory rate (RR) and panting score (PS) - of feedlot-finished cattle were evaluated by systematic review-meta-analysis. Using the PICO framework were identified 3813 records, with 31 publications and 6729 cattle being considered in the meta-analysis (MA). The comparison most reported was sun vs. shade (n = 24 publications), followed by shade vs. shade (area per animal and effectivity in reduce solar load) (n = 7 publications) and sun vs. sprinkling (n = 4 publications). Cattle with access to shade with total reduction in solar load improved ADG (p = 0.008) and FCE (p = 0.024), and reduced RR (p < 0.001) compared to unshaded animals. Cattle with access to shade with a height between 3 and 4 m increased ADG (p < 0.001), tended to improve FCE (p = 0.054), and reduced RR (p < 0.001) compared to unshaded animals. An area of shade from 2 to 4 m2/animal increased ADG (p = 0.002), and higher than 4 m2/animal reduced RR (p < 0.001) compared to unshaded animals. Animals that received sprinkling volume below 1 L/animal/min improved ADG (p = 0.008) compared to unshaded animals. Cattle with access to shade with a high area per animal improved DMI (p = 0.023) and ADG (p < 0.001) compared to animals with a low area. In univariate meta-regression, it was observed that the variables significantly (P < 0.05) influencing DMI were THI category; influencing ADG were cattle gender, THI category, and coat color; influencing FCE were cattle age and hemisphere; and influencing RR were country, THI category and climate. Performance and physiological parameters of feedlot-finished cattle under heat stress depend on animal and environmental characteristics.

Long-read sequencing-based transcriptomic landscape in longissimus dorsi and transcriptome-wide association studies for growth traits of meat rabbits.

Rabbits are an attractive meat livestock species that can efficiently convert human-indigestible plant biomass, and have been commonly used in biological and medical researches. Yet, transcriptomic landscape in muscle tissue and association between gene expression level and growth traits have not been specially studied in meat rabbits. In this study Oxford Nanopore Technologies (ONT) long-read sequencing technology was used for comprehensively exploring transcriptomic landscape in Longissimus dorsi for 115 rabbits at 84 days of age, and transcriptome-wide association studies (TWAS) were performed for growth traits, including body weight at 84 days of age and average daily gain during three growth periods. The statistical analysis of TWAS was performed using a mixed linear model, in which polygenic effect was fitted as a random effect according to gene expression level-based relationships. A total of 18,842 genes and 42,010 transcripts were detected, among which 35% of genes and 47% of transcripts were novel in comparison with the reference genome annotation. Furthermore, 45% of genes were widely expressed among more than 90% of individuals. The proportions (±SE) of phenotype variance explained by genome-wide gene expression level ranged from 0.501 ± 0.216 to 0.956 ± 0.209, and the similar results were obtained when explained by transcript expression level. In contrast, neither gene nor transcript was detected by TWAS to be statistically significantly associated with these growth traits. In conclusion, these novel genes and transcripts that have been extensively profiled in a single muscle tissue using long-read sequencing technology will greatly improve our understanding on transcriptional diversity in rabbits. Our results with a relatively small sample size further revealed the important contribution of global gene expression to phenotypic variation on growth performance, but it seemed that no single gene has an outstanding effect; this knowledge is helpful to include intermediate omics data for implementing genetic evaluation of growth traits in meat rabbits.

Heat stress effects on the genetics of growth traits in Thai native chickens (Pradu Hang dum).

OBJECTIVE: The objective of this study was to investigate the effect of heat stress on the growth traits and genetic parameters of Thai native chickens. METHODS: A total of 16,487 records for growth traits of Thai native chickens between 2017 and 2022 were used in this study. Data included the body weight at birth, body weight at 4, 8, and 12 weeks of age (BW0, BW4, BW8, BW12), average daily gain during 0 to 4, 4 to 8, and 8 to 12 weeks of age (ADG0-4, ADG4-8, ADG8-12), absolute growth rate at birth, at 4, 8, and 12 weeks of age (AGR0, AGR4, AGR8, AGR12). The repeatability test day model used the reaction-norm procedure to analyze the threshold point of heat stress, rate of decline of growth traits, and genetic parameters. RESULTS: At temperature and humidity index (THI) of 76, Thai native chickens began to lose their growth traits, which was the onset of heat stress in this study. The estimated heritability, genetic correlation between animal and heat stress effect, and correlations between the intercept and slope of the permanent environmental effects were 0.27, -0.85, and -0.83 for BW, 0.17, -0.81, and -0.95 for ADG, 0.25, -0.61, and -0.83 for AGR, respectively. Male chickens are more affected by heat stress than female chickens with a greater reduction of BW, ADG, and AGR, values equal to -9.30, -0.23, -15.21 (in males) and -6.04, -0.21, -10.10 (in females) gram per 1 level increase of THI from the THI of 76. CONCLUSION: The influence of thermal stress had a strong effect on the decline in growth traits and genetic parameters in Thai native chickens. This study indicated that genetic models used in conjunction with THI data are an effective method for the analysis and assessment of the effects of heat stress on the growth traits and genetics of native chickens.

Preweaning period is a critical window for rumen microbial regulation of average daily gain in Holstein heifer calves.

BACKGROUND: Rumen bacterial groups can affect growth performance, such as average daily gain (ADG), feed intake, and efficiency. The study aimed to investigate the inter-relationship of rumen bacterial composition, rumen fermentation indicators, serum indicators, and growth performance of Holstein heifer calves with different ADG. Twelve calves were chosen from a trail with 60 calves and divided into higher ADG (HADG, high pre- and post-weaning ADG, n = 6) and lower ADG (LADG, low pre- and post-weaning ADG, n = 6) groups to investigate differences in bacterial composition and functions and host phenotype. RESULTS: During the preweaning period, the relative abundances of propionate producers, including g_norank_f_Butyricicoccaceae, g_Pyramidobacter, and g_norank_f_norank_o_Clostridia_vadinBB60_group, were higher in HADG calves (LDA > 2, P < 0.05). Enrichment of these bacteria resulted in increased levels of propionate, a gluconeogenic precursor, in preweaning HADG calves (adjusted P < 0.05), which consequently raised serum glucose concentrations (adjusted P < 0.05). In contrast, the relative abundances of rumen bacteria in post-weaning HADG calves did not exert this effect. Moreover, no significant differences were observed in rumen fermentation parameters and serum indices between the two groups. CONCLUSIONS: The findings of this study revealed that the preweaning period is the window of opportunity for rumen bacteria to regulate the ADG of calves.

Effects of Antimicrobial Administration Route on Growth and Antimicrobial Resistance in Weaned Piglets.

This study aimed to determine how the route of antimicrobial administration affected the growth performance of weaned piglets. Additionally, we aimed to investigate potential differences between antimicrobial resistance developed by antimicrobials administered orally through drinking water, and those administered through feed, in weaned piglets. The research was undertaken on a farm housing 500 sows and involved 150 weaned piglets at 21 days of age. These piglets were evenly distributed into three groups of equal size: water, feed, and control. Antimicrobials were administered through drinking water and feed in the water and feed groups, respectively, while the control group received no antimicrobial treatment. The observation of piglets continued until they reached 70 days of age. The feed conversion ratio in the water group (1.7 ± 0.78) was significantly higher than in the control (2.4 ± 1.77) and feed (2.7 ± 1.68) groups. Additionally, the route of administration did not affect antimicrobial resistance rates. Based on these results, it can be inferred that administering antimicrobials through drinking water is advantageous for pig farming.

Increased Yearling Weight Gain Is Associated with a Distinct Faecal Microbial Profile.

Microbial communities inhabiting the gut have the ability to influence physiological processes contributing to livestock production and performance. Livestock enterprises rely on animal production traits such as growth performance for profit. Previous studies have shown that gut microbiota are correlated to growth performance and could even influence it. The aim of this study was to characterise the faecal microbial profiles of Angus steers with high and low ADG at both weaning and yearling stages by profiling 16S rRNA gene sequences from rectal faecal samples. When microbial profiles were compared in terms of relative abundances, LEfSe analysis, alpha diversity metrics, and beta diversity, at the weaning stage, few significant differences were found between the high and low ADG groups. However, at yearling stage, microbial profiles significantly differed between the high and low ADG groups. The relative abundances of eight phyla and six genera significantly differed between the two groups. Alpha diversity metrics showed a significant decrease (p = 0.001) in species richness in the high ADG group. Similarly, beta diversity analysis showed that samples clustered clearly according to high and low ADG groups at yearling stage, indicating that phylogenetic similarity between the two ADG groups was significantly reduced (p = 0.005).

Effect of Diet Supplementation with Oat Hay and Whole Carrot on Rabbit Growth and Productive Efficiency.

Is it possible to reduce feeding costs in rabbit meat production without compromising rabbit health and productive yield? The study tested four feeding strategies: Control group (CC) fed exclusively with concentrate feed; group CT supplemented with whole carrot; group OH supplemented with oat hay; and Group CO supplemented with oat hay and whole carrot. Each feeding strategy was tested in 20 rabbits, randomly allocated in five cages with four rabbits each. The average daily weight gain (ADG), feed conversion ratio (FCR), and the amount of concentrated feed consumed daily were estimated in all experimental groups. Group CC displayed the best ADG (37.1 g/rabbit/day), carrot had no significant influence on ADG (34.2 g/rabbit/day), but oat hay had a negative impact (p < 0.05), either used alone or in combination with carrot (33.0 and 32.6 g/rabbit/day, respectively). Supplementation with carrot, oat hay, or both increased the FCR (p < 0.001). Nevertheless, there were no significant differences in final live weight or carcass weight between the rabbits in the different experimental groups. In conclusion, supplementation with oat hay, carrot, or both can be a valid approach to reducing production costs by decreasing concentrate feed without affecting rabbit's health and meat yield. The combined supplementation with oat hay and carrot proved to be the best option in reducing the amount of concentrate feed ingested by rabbits (less than 1107 g/animal), but at current market values, supplementation exclusively with oat hay was the less expensive feeding strategy (less 14% than fed exclusively with concentrate feeding).

Coccidiosis infection and growth performance of broilers in experimental trials: insights from a meta-analysis including modulating factors.

An infection by protozoa Eimeria spp. can cause coccidiosis, which negatively affects broiler chicken performance and causes economic and production losses. To understand the effect of coccidiosis on broilers' performance, we evaluated the independent variables and their interactions on the severity of coccidiosis in broilers that cause variation (Δ) of average daily feed intake (ADFI), average daily gain (ADG), and gain per feed (G:F) of broiler chicks using a meta-analysis approach. A database of 55 papers describing 63 experiments was gathered; broilers were challenged by Eimeria species (E. acervulina, E. maxima, E. tenella, and mixed) and at least 2 variables among ADFI, ADG, and feed conversion ratio (FCR) were studied. The variation induced by the challenge was calculated relative to the control group of each experiment. The indirect factors evaluated were days postinfection (DPI), Eimeria type and dose, infection age (IA), bird's mean age in the analyzed period, genetic line, sex, and whether they were raised in a cage or a pen. Graphical, correlation, and variance analyses were performed to evaluate the form of the responses. Then, a linear plateau model was adjusted for each response variable as a function of DPI to determine the consequences of the disease on the variation of performance over time after infection. The impact of the infection challenge on the variation of performance vs. nonchallenge broilers was only impacted by DPI (P < 0.05). The adjustment of the data with the linear plateau model allows us to determine the host response to the coccidiosis disease at different stages. At 5 DPI (acute phase), ΔADFI, ΔADG, ΔG:F were of -19.0; -39.8, and -25.5, respectively. After almost 13 DPI birds achieved the recovery phase for all variables with Δ varying from -19 to -3.75% for ADFI, from -39.8 to -10.5% for ADG, and from -25.5 to -7.24% for G:F. The Eimeria impact was higher in ADG than ADFI in all periods due to Eimeria aggressive action form causing lesions in gut epithelial reducing the use of nutrients and energy. The results can be used as a quantitative approach to determine the consequences of Eimeria spp. on broiler performance.

Oral meloxicam given as an ancillary treatment at respiratory disease diagnosis was not associated with growth, clinical scores, or ultrasound scores in preweaned dairy calves.

Objective: To assess the efficacy of a single dose of oral meloxicam as an ancillary therapy to an antibiotic given at the time of respiratory disease identification on average daily gain (ADG), behavioral attitude, clinical respiratory, and lung ultrasound scores in preweaned dairy calves. Animals: 215 male and female Holstein, Jersey, and crossbred preweaned calves enrolled between 1 and 14 days of age at study enrollment on a single commercial dairy in the western US. Methods: The study took place from March 4, 2021, to November 21, 2021. In this double-blind placebo-controlled study, calves were given an antibiotic (1.1 mL of tulathromycin/kg, SC, once) and either a placebo (1 mg of lactose monohydrate/kg, in a gelatin capsule) or oral meloxicam (1 mg/kg) at the time of respiratory disease identification. Behavioral attitude, clinical respiratory, and lung ultrasound scores and ADG were assessed in preweaned dairy calves at different time points including the next health examination, 1 week later, or at weaning. Results: There was no association between treatment (placebo vs meloxicam) on ADG or respiratory disease status at weaning (P > .05). There was no effect of treatment on behavioral attitude, clinical respiratory, or lung ultrasound scores at the next health examination or 1 week later (P > .05). Clinical Relevance: The present study did not provide evidence that oral meloxicam given once is beneficial for growth, behavioral attitude, or clinical or lung ultrasound scores.

Dynamic distribution of gut microbiota in posthatching chicks and its relationship with average daily gain.

The colonization and development of gut microbiota are essential for the health and growth of chicks after hatching. However, the colonization and prevalence of gut microbiota have not been well characterized, and knowledge of which microbes and their relationship with average daily gain in chicks is still limited. This study characterized the dynamic succession of microbiota in the intestinal tract of chicks and investigated its relationship with daily weight gain. A total of 121 fecal samples across 7 time points from d 0 to 10 posthatching were collected from 19 chicks randomly selected from 1,950 chicks. Using 16S rRNA gene sequencing examined microbial composition of fecal samples. The observed species index of alpha diversity increased with age, gradually achieving stability at 3 d of age. The microbiota of chicks after hatching was primarily Clostridium_sensu_stricto_1 (34.49%), and its relative abundance diminishes with age. In contrast, Lactobacillus had a low relative abundance in the first 2 d after hatching and gradually increased with age. Predicted functional capacities found that the microbiota of early-stage posthatching (d 0 and 1 after hatching) was involved in metabolism, including amino acid metabolism, metabolism of cofactors and vitamins, and nitrogen metabolism. However, at the later stage posthatching (from d 3-10 after hatching), the intestinal microbial function was involved in carbohydrate metabolism, amino acid metabolism, cell growth and death, and methane metabolism. It was identified that 47 operational taxonomic units were associated with average daily gain of chicks, 12 of which were annotated with Lactobacillus and significantly positive associated with average daily gain. In addition, Clostridium_sensu_stricto_1 was significantly negatively associated with average daily gain. Taken together, we characterized the dynamic successions of intestinal microbiota in hatching chicks. The intestinal microbiota of chicks has an impact on the host average daily gain. Our findings should be instrumental in improving local chick production.

Effect of ultrasonographic lung consolidation on health and growth in dairy calves: A longitudinal study.

Bovine respiratory disease (BRD) is a common and complex disease process in calves. Subclinical disease exists and early detection can be challenging due to inconsistent or nonexistent clinical signs. Thoracic ultrasonography (TUS) is often used and has the potential to improve the identification of respiratory diseases. Combining systematic TUS with clinical examination allows distinguishing BRD, including upper respiratory tract disease (clinical signs of respiratory disease, but no significant lung consolidation), clinical pneumonia (clinical signs of respiratory disease along with lung consolidations), and subclinical pneumonia (no clinical signs, but lung consolidations). Data on subclinical pneumonia are scarce, particularly outside of the North American or European contexts similar to Iran in west Asia with a dry and semi-arid climate and intensive breeding systems similar to North America which breeding calves begin in individual boxes, then moving to group pens, and finally to free stall or open shed housing systems. The first objective of this longitudinal study was to use weekly ultrasonography to monitor calves from birth until weaning in an Iranian dairy herd. The second objective was to look for any association between individual lung consolidation episode or cumulative consolidation episodes on preweaning growth. Thoracic ultrasonography was performed on calves (n = 221) weekly from birth to weaning (8 wk), and scanning occasions for each calf were equally distributed with 1-wk intervals (using consolidation threshold ≥3 cm as a specific lung consolidation definition, and ≥1 cm as a more sensitive threshold). Calf body weights were recorded using a weight tape. Other information recorded were transfer of passive immunity (TPI) using serum Brix (%) ≥8.4% as adequate TPI within the first week after birth and the treatment history of the calves. The main strategy for modeling was to determine how long-term lung consolidation affects average daily gain (ADG) during the preweaning period. A linear model was used to determine the effect of the number of weeks with consolidation on ADG. Using consolidation threshold of ≥3 cm, the mean (±SD) of total ADG for calves with no consolidation episode, 1 consolidation episode, and 2 or more consolidation episodes were 0.45 (±0.10), 0.39 (±0.10), and 0.38 (±0.11) kg/d, respectively. In the final multivariable regression analysis model and based on consolidation threshold of ≥3 cm, calves with 1 and 2 or more consolidation episodes had significantly lower ADG ± standard error (SE) of 0.04 ± 0.02 kg/d, and 0.06 ± 0.02 kg/d, respectively compared with animals with no consolidation episode. A total of 20% of calves (46/229 calves that entered the study) were treated for respiratory disease based on clinical signs (based on farmer examination). The final model also included specific confounders related to ADG and their interactions with lung consolidation (TPI and BRD treatment). An overall of 86% of adequate TPI was obtained. Bovine respiratory disease treatment based on farmer diagnosis had a larger negative effect on preweaning ADG than ultrasonography-diagnosed consolidation episodes (lower ADG ± SE of 0.10 ± 0.03 kg/d). When using a more sensitive consolidation threshold (≥1 cm as consolidation), the number of weeks with consolidation was also negatively associated with the ADG in the multivariable linear regression model with significant difference of 0.05 ± 0.02 kg/d for nonconsolidated calves versus calves consolidated for 2 or more weeks and insignificant difference of 0.01 ± 0.02 kg/d for nonconsolidated calves versus calves with 1 consolidation episode.