Average Daily Gain Research Articles

Impact of Mating Methods and Semen Preservation on Reproductive and Growth Performances in Palestinian Assaf Sheep

As global demand for sheep products increases, improving reproductive efficiency and lamb growth performance has become a priority for sheep farmers. Artificial insemination (AI) offers several advantages over natural mating, including improved genetic selection and disease control. This study contributes to understanding the impact of different mating methods and semen preservation techniques on reproductive performance and growth traits in Palestinian Assaf sheep under local breeding conditions. The research included 123 adult Assaf ewes from two farms, which were hormonally synchronized and divided into three groups for different reproductive biotechnologies. Group 1 (G1) comprised 50 ewes inseminated with frozen semen straws, while Group 2 (G2) had 37 ewes inseminated with fresh semen from genetically superior rams. Both G1 and G2 used 0.5 mL straws containing 250 million sperm, with insemination occurring 48 h post sponge removal and eCG hormone injection. Group 3 (G3) consisted of 36 ewes that underwent natural mating at a ratio of 1 ram to 6 ewes. The study revealed that insemination methods significantly affected fertility rates (45.4, 61.1, and 71.9% for G1, G2, and G3, respectively; p < 0.05). Artificial insemination notably enhanced lamb performance indicators (p < 0.05), although it did not significantly influence prolific lambing (p > 0.05). Prolific lambing significantly impacted birth weight, weaning weight, and average daily gain at 60 days across all groups (p < 0.05), but not the average daily gain or final weight at 180 days (p > 0.05). The management system significantly affected birth and weaning weights at 60 days (p < 0.05), but not the final weight at 180 days or prolific lambing (p > 0.05). Lamb sex significantly influenced average daily gains at 60 and 180 days, as well as final weight at 180 days (p < 0.05). The findings suggest that, while artificial insemination with semen from elite rams may reduce fertility rates, it significantly improves lamb performance rates. In conclusion, our study demonstrates that, while natural mating offers higher fertility rates, AI with fresh semen can be a valuable tool for improving lamb growth performance in Palestinian Assaf sheep. These findings provide valuable insights for sheep farmers in the region to optimize reproductive strategies and enhance lamb production

Mare colostrum quality and relationship with foal serum immunoglobulin G concentrations and average daily weight gains

AbstractBackgroundFoals suffer from total failure to transfer passive immunity (TFTPI) when serum immunoglobulin (IgG) is <4 g/L, and partial failure to transfer passive immunity (PFTPI) when serum IgG is 4–8 g/L.ObjectivesTo explore risk factors for poor serum IgG concentration.Study designRetrospective observational study.MethodsData from 535 Thoroughbred foals born to 177 mares were analysed and included foal sex, birthweight, month and year of birth and colostrum Brix %. Associations between dam age and colostrum Brix (%); and between foal serum IgG and liveweight gains were also measured. Pre‐suckle colostrum samples and foal blood samples were collected (by jugular venipuncture within 12–24 h of birth). IgG was estimated in mare colostrum and foal serum using Brix refractometry and turbidimetric immunoassay, respectively. Foals were weighed within 20 h of birth; daily until 7 days of age and weekly until 130 days of age.ResultsMean foal serum IgG was 10.78 g/L (SD = 3.26) and mean mare colostrum Brix was 27.32% (SD = 5.96). A number of colostrum samples (20.9%, n = 112/535) measured <20% Brix and 20.4% of foals (n = 109/535) had serum IgG concentrations ≤8 g/L, 2.2% of foals (n = 12/535) had serum IgG less than or equal to 4 g/L and 18.1% (n = 97/535) had serum IgG between 4.1 g/L and 8 g/L. Foals had an average daily gain (ADG, kg) of 1.26 kg (SD = 0.14). Serum IgG (g/L) was associated with year of birth, birthweight (kg) and colostrum Brix (%). For every unit increase in foal birthweight (kg), there were small, significant increases in foal serum IgG (0.04 g/L, p = 0.04). Similarly, for every unit increased in mare colostrum Brix (%) there were small, significant increases in foal serum IgG (0.25 g/L, p < 0.001). Month of birth was significantly associated with colostrum Brix (%) and with average daily gains; with lower values for both outcome parameters with increasing calendar month. Increasing dam age at foaling was associated with lower colostrum Brix (%).Main limitationsRetrospective design with missing data, small convenience sample.ConclusionsSeveral risk factors were significantly associated with foal serum IgG and mare colostrum Brix (%) in the current work.

Assessing the detection and interaction of Lawsonia intracellularis and porcine circovirus 2 in low and high-performance wean-to-finish pig groups in different porcine reproductive and respiratory syndrome virus detection scenarios

IntroductionEffective disease management strategies are essential for achieving optimal pig performance, ensuring high-quality animal health and welfare, and maintaining the economic viability of swine systems. Thus, understanding factors that lead to more or less severe disease are critically important. Porcine circovirus type 2 (PCV2) and Lawsonia intracellularis (L. intracellularis) are endemic pathogens in the U.S., affecting herds with varying degrees of subclinical and clinical disease and impact on performance. While these are common pathogens, their interaction with PRRSV and performance has seldom been investigated. This study investigated the detection dynamics of L. intracellularis, PRRSV, and PCV2, and their association with productivity impacts in wean-to-finish groups within a Midwest U.S. production system.MethodologyThis observational field study involved batches of growing pigs from PRRSV-stable or PRRSV-negative sow farms. Oral fluids were collected longitudinally from weaning until market age, and tested using quantitative PCR for each of the aforementioned pathogens. The study included 36 batches with a total of 46,446 growing pigs, resulting in 4,000 oral fluid samples. Then, batches were categorized based on key performance indicators (mortality and average daily gain), PRRSV detection timing and total genomic copies of each pathogen.ResultsNineteen groups were characterized as high-performance and seventeen as low-performance. Mortality ranged from 5 to 9% in high-performance groups and 10.3–20.9% in low-performance groups. Average daily gain ranged from 0.68–0.86 kg in high-performance groups and 0.63–0.81 kg in low-performance groups. L. intracellularis and PCV2 were detected in most groups, with significant differences in detection rates between high and low-performance groups. Groups with relatively high genomic copies of PCV2 and L. intracellularis that had PRRSV detection presented higher mortality rates (15.75%).DiscussionThis study expanded our understanding of PRRSV, PCV2, and L. intracellularis co-detections and their impact on swine populations.

16S rRNA and metabolomics reveal the key microbes and key metabolites that regulate diarrhea in Holstein male calves

IntroductionDiarrhea is a prevalent disease among calves, which significantly hinders their growth and development, thereby impacting farm productivity and revenue. This study aimed to investigate the impact of diarrhea on calf growth.MethodsHolstein male calves with similar birth weight (39.5 ± 4.2 kg) were included in this study, and key parameters such as fecal score, diarrhea incidence, and growth performance from birth to weaning were measured. Rectal fecal samples from both diarrheic (n = 24) and healthy calves (n = 24) aged 1–4 weeks were analyzed using 16S rRNA gene sequencing and untargeted metabolomics.ResultsOur findings indicated a high prevalence of diarrhea among calves between 1–4 weeks of age on pasture, which led to a marked decrease in growth performance, including average daily gain. At the genus level, the relative abundance of GCA-900066575 in one-week-old diarrheic calves was significantly higher; Escherichia-Shigella and Pseudoflavonifractor were more abundant in two-week-old calves; while Tyzzerella and Lachnospiraceae_UCG-004 increased significantly in four-week-old calves, and correlated negatively with average daily gain, suggesting that these bacteria may promote the occurrence of diarrhea. Correlation analysis revealed that fecal metabolites such as arachidonic acid, cis-vaccenic acid, oleic acid, choline, creatinine, and others were significantly negatively correlated with calf growth performance and were significantly increased in diarrheic calves. WGNCA identified that dark magenta module metabolites were significantly associated with diarrhea traits from 1–4 weeks. Thirteen metabolites, including glycerophospholipids (such as 1-stearoyl-2-hydroxy-sn-glycero-3-phosphoethanolamine), fatty acids (such as dodecanoic acid), and arachidonic acid, were positively correlated with GCA-900066575, Escherichia-shigella, Tyzzerella, and Clostridium_butyricum, but negatively correlated with UBA1819, Lachnoclostridium_sp_YL32, and Clostridium_scindens.DiscussionTherefore, GCA-900066575, Escherichia-shigella, Lachnospiraceae_UCG-004, and Tyzzerella are likely key bacterial genera causing diarrhea in calves, while arachidonic acid, glycerol phospholipids, and fatty acids are critical metabolites associated with this condition. These alterations in the fecal microbiota and metabolite composition were found to be the principal contributors to growth retardation in diarrheic calves.

Can the supplementation of autolyzed yeast (Saccharomyces cerevisiae) affect the diet digestibility, feeding behavior, levels of blood metabolites, and performance of Dorper × Santa Ines lambs finished in feedlot?

This study aimed to evaluate the effect of autolyzed yeast (obtained from culture of Saccharomyces cerevisiae in sugarcane derivatives) supplementation on diet digestibility, feeding behavior, levels of blood metabolites associated with protein and energy metabolism, and performance of Dorper × Santa Ines lambs finished in feedlot. Twenty-four non-castrated male lambs with an average age of 4months and a body weight (BW) of 19.49 ± 3.08kg were allocated to individual pens within a covered and elevated shed. The pens had a slatted floor without bedding suspended 1.8m above the ground, and an area of 1.5 m2. The trial was set out in a completely randomized design with two treatments and twelve replicates each. The treatments consisted of a basal diet without yeast products (Control) or with yeast culture (Yeast, RumenYeast® at 5g/animal/day). Lambs were fed ad libitum with a total mixed ration (TMR) composed of 400g/kg of dry matter (DM) of Tifton 85 hay (Cynodon spp.) and 600g/kg DM of concentrate feed, and contained 146g/kg DM of crude protein and 2.30 Mcal/kg DM of metabolizable energy. The experiment was conducted over 84days, with the first 14days serving as an adaptation period. The subsequent experimental period was divided into two phases to evaluate animal performance (Days 1-63) and DM digestibility (Days 64-70). The supplementation with autolyzed yeast did not affect rumen or fecal pH, the DM digestibility, as well as the feeding behavior of lambs (the time spent on feeding, rumination, water intake, and idleness activities). In addition, yeast supplementation did not alter the serum levels of albumin, creatinine, urea, or level of plasma glucose, resulting in similar animal performance compared to the Control group. The mean values for final BW, DM intake, average daily gain, and feed conversion ratio were 37.52kg, 1.051kg/day, 0.286kg/day, and 3.74kg DM/kg gain, respectively. In the conditions of this study, the supplementation of autolyzed yeast in TMR (5g/animal/day) does not affect diet digestibility, feeding behavior, blood metabolites, or performance of lambs finished in feedlot. Regarding that metabolic and performance lamb responses were not improved, the supplementation of autolyzed yeast at the tested dose is not recommended. However, it is important to note that markers related to immunity and inflammation were not evaluated in our work, and these should be considered in future studies.

Effects of Different Molasses Levels and Slow-Release Urea Combinations on Growth Performance, Serum Biochemistry, Rumen Fermentation, and Microflora of Holstein Fattening Bulls

The aim of this study was to investigate the effects of different combinations of molasses levels and slow-release urea on Holstein fattening bulls. Sixty Holstein fattening bulls of a similar age, weight, and health status were randomly divided into four groups of fifteen Holstein fattening bulls each. All of the treatments were as follows: (1) basic diet group (CON); (2) 2% molasses slow-release urea group (LMU); (3) 4% molasses slow-release urea group (MMU); and (4) 6% molasses slow-release urea group (HMU). The results of the study showed that the MMU had an outstanding performance, with a 13.3% increase in average daily weight gain compared with the control group, a significant decrease in feed conversion ratio (p < 0.05), and a significant increase in apparent digestibility of crude protein (p < 0.05). In terms of serum biochemical indices, blood ammonia and alanine aminotransferase (ALT) concentrations were significantly higher in the MMU than in the CON (p < 0.05). The rumen pH of all treatment groups was lower than that of the CON (p < 0.05), whereas the concentrations of microbial crude protein (MCP), as well as acetic acid, propionic acid, and total volatile fatty acids (TVFA) were significantly higher in both the MMU and HMU (p < 0.05). The dominant phyla in each group were Bacteroidetes, Firmicutes, and Patescibacteria, and the relative abundance of Bacteroidetes in the MMU increased by 5.47% compared with that in the CON. In the MMU, Prevotellaceae, Lachnospiraceae, and Ruminococcaceae increased by 9.03%, 0.67%, and 3.43%, respectively, compared with the CON. The economic benefit analysis showed that the daily feeding cost of fattened cattle in the MMU was reduced by RMB 1.62 yuan, and the daily farming benefit of each cow was increased by RMB 7.19 yuan. In conclusion, the MMU was effective in improving the growth performance of fattening cows, optimizing rumen fermentation, reducing cost, and increasing profit, which is a nutritional strategy with great application value.

Dietary Fiber-Rich Spartina anglica Improves Intestinal Health and Antioxidant Capacity of Zhedong White Geese

Spartina anglica (SA), a plant rich in dietary fiber, has demonstrated considerable potential for enhancing gut health and antioxidant capacity in animals. This study investigates the integration of SA as a novel dietary ingredient for Zhedong white geese, with a specific focus on evaluating its effects on growth performance, nutrient digestibility, antioxidant capacity, intestinal health, and cecal microbiota composition. A total of 360 1-day-old Zhedong white geese with an average weight of 114.94 ± 0.81 g were randomly allocated to 4 dietary treatments, with 6 replicates per treatment and 15 geese per pen. The 4 dietary treatments included different SA supplement levels: a control group receiving a basal diet (CON), and three experimental groups supplemented with 3% SA (SA3), 6% SA (SA6), and 12% SA (SA12). Supplementation with 6% SA significantly enhanced the final body weight, average daily gain, and feed conversion ratio (FCR) compared to the CON group (p < 0.05). In contrast, the SA12 group exhibited reduced digestibility of crude protein and ether extract, relative to the SA3 and SA6 groups (p < 0.05). The highest antioxidant capacity was observed in the SA6 and SA12 groups, while the lowest was recorded in the CON group. SA supplementation did not significantly influence serum biochemical parameters or organ indices but increased cecum length (p < 0.05). Notably, SA supplementation markedly improved intestinal morphology, although excessive levels appeared to compromise these benefits. Additionally, SA supplementation significantly enhanced the richness and diversity of cecal microbiota and increased short-chain fatty acid concentrations. In conclusion, SA at an optimal supplementation level of 6% may be effectively utilized in Zhedong white geese diets to improve growth performance, gut health, and antioxidant capacity.

A Framework for Comprehensive Dairy Calf Health Investigations

The objective of this narrative review is to provide a systematic framework for veterinarians to investigate dairy calf health, focusing on critical control points and key performance indicators (KPIs) to address morbidity and mortality challenges in preweaned calves. Recommendations target prenatal maternal nutrition, heat stress abatement, and optimal calving management to minimize risks associated with perinatal mortality and preweaning morbidity. Further, comprehensive colostrum management is discussed to ensure excellent transfer of passive immunity, which includes prompt collection and feeding within two hours of birth at a volume of 8.5–10% of calf body weight. Nutritional guidance emphasizes the importance of transition milk and feeding higher planes of nutrition to support immunity, with recommendations that milk total solids exceed 10% to meet energy needs. Environmental management recommendations include a minimum of 3.3 m2 of space per calf, the use of low-dust bedding, and air quality controls to reduce respiratory disease. Lastly, regular health data collection and KPI monitoring, such as average daily gain and morbidity rates, are essential for data-driven improvements. By implementing these evidence-based recommendations, veterinarians can support dairy farmers in reducing calf morbidity and mortality, ultimately enhancing calf welfare and lifetime productivity.

Dietary inclusion of <i>Bacillus</i>-based probiotic complex improved average daily weight gain and gain-to-feed ratio and reduced faecal noxious gas emission in weaned pigs

Dietary inclusion of <i>Bacillus</i>-based probiotic complex improved average daily weight gain and gain-to-feed ratio and reduced faecal noxious gas emission in weaned pigs

Early Weaning Impairs the Growth Performance of Hu Lambs Through Damaging Intestinal Morphology and Disrupting Serum Metabolite Homeostasis.

This study aimed to evaluate the effect of early weaning (EW) on the growth performance, gastrointestinal development, serum parameters, and metabolomics of Hu sheep lambs. Twenty-four male Hu lambs were initially ewe-reared. A total of 12 lambs were weaned at 30 d of age (D30) as the EW group, and the remaining 12 lambs were weaned at 45 d of age (D45) as the control (CON) group. Serum samples were collected from six lambs per treatment on D30, D33, D36, and D45, and the lambs were slaughtered on D45 to collect the rumen and small intestine. The results showed that, compared with the CON group, the average daily gain (ADG), final body weight (p < 0.001), as well as average daily feed intake (ADFI) of lambs in the EW group significantly decreased in the first (p = 0.004) and second (p = 0.013) 5 days of treatment. Additionally, EW increased the ruminal weight and papillae length but reduced the duodenal villus height on D45 (p < 0.05). As for the serum parameters, the concentrations of glucose on D33, D36, and D45 (p < 0.001), and the IL-6 content on D45 (p = 0.018) were observed to be lower, while the levels of immunoglobulin A (IgA) (p = 0.027), IgG (p = 0.035), and IgM (p = 0.002) on the four ages were all higher in the EW group than those in CON group. Additionally, both treatment and age interactively affected the levels of GLU (p = 0.001), TP (p = 0.041), and IL-6 (p = 0.016). Additionally, the serum metabolomics analysis on D45 showed that the contents of 5-HT and arachidonic acid were increased, while L-phenylalanine, L-tyrosine, and L-glutamic acid were reduced in the EW group (p < 0.05). These differential metabolites were enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including inflammatory mediator regulation, protein digestion and absorption, and phenylalanine and tyrosine biosynthesis. The current results identify that EW at D30 decreased the growth performance (ADG and ADFI) of Hu lambs within two weeks post-weaning, which might be associated with impaired duodenal morphology and glucose metabolism. The serum metabolomics analysis revealed that EW altered the concentrations of 5-HT, phenylalanine, tyrosine, and arachidonic acid, which could serve as potential regulatory targets for modulating the health of EW Hu lambs.

Effect of multispecies fungal extract supplementation on growth performance, nutrient digestibility, ruminal fermentation, and the rumen microbiome composition of beef cattle fed forage-based diets.

Our objective was to evaluate the effect of a multispecies fungal extract (MFE) on growth performance, apparent total tract digestibility (ATTD), fermentation characteristics, and rumen microbiome composition of beef cattle fed forage-based diets. For experiment 1, ruminally cannulated Angus × SimAngus cows (n = 4; body weight [BW] = 569 ± 21kg) were used in a randomized crossover design with two 21-d study periods and a 23-d washout period to evaluate the effect of dietary inclusion of an MFE on in situ digestion, ruminal fermentation, and the composition of the rumen microbiome. Treatments consisted of a forage-based diet with or without the inclusion of a MFE. Rumen samples were collected on days 5, 10, and 20. Experiment 2 evaluated different inclusion rates of the MFE in a randomized complete block design using Angus × SimAngus-crossbred steers (n = 80; BW = 370 ± 44kg). Steers were blocked by BW and randomly assigned to one of four treatments (2 pens/treatment): diet with no MFE, 0.02%, 0.04%, and 0.08% of the MFE (dry matter [DM] basis). Steers were fed a forage-based diet for 122 d. Subsets of 10 steers/treatment were randomly selected for the determination of ATTD on d 20, 40, and 60. All data were analyzed using the MIXED procedure of SAS. In exp 1, adding the MFE to the diet tended to increase the ruminal disappearance rate of the DM on day 10 (P = 0.06). No interactions or treatment effects were observed for the short-chain fatty acid profile of the rumen fluid (P ≥ 0.13). Metagenomic analysis of the rumen microbiome showed an MFE × d interaction for the Fibrobacter genus (P = 0.01), which on day 20 was less abundant in the rumen of cows fed the MFE. In exp 2, steers supplemented with 0.04% of MFE had a lower average daily gain and were lighter at the end of the experiment (cubic, P ≤ 0.04) compared to steers supplemented with 0.02% MFE. Steers fed the diet with 0.02% of MFE had the greatest gain-to-feed ratio among the MFE-supplemented groups (cubic, P < 0.01). Dietary inclusion of the MFE increased neutral detergent fiber digestibility (linear, P = 0.05). Steers supplemented with 0.04% of MFE had the greatest acid detergent fiber digestibility among treatments (quadratic, P = 0.03). Collectively, results showed that ruminal disappearance rate and digestibility of forage-based diets increased due to MFE supplementation, but did not translate into growth performance improvements or beneficially alter rumen fermentation.

Ejaculate traits of ram lambs with different rectal temperatures under heat stress conditions. Impacts of heat stress on semen traits in rams with different rectal temperature

Background: heat stress diminishes semen quality in rams. Objective: to evaluate productive and reproductive responses of rams and ram lambs with different rectal temperatures under heat stress conditions. Methods: the animals (n=12, Dorper × Katadhin × Pelibuey crossbreed, 235 to 730 days old ) were assigned to one of three experimental groups: ram lambs with low rectal temperature (RLLRT), ram lambs with high rectal temperature (RLHRT) and Rams. Results: afternoon rectal temperatures were higher (p≤0.05) in the RLHRT group, and there was no difference (p&gt;0.05) between the Rams and RLHRT groups. The ejaculated volume and sperm concentration were higher (p≤0.05) in the group of Rams than in RLLRT and RLHRT. Mass motility and sperm concentration were lower (p≤0.05) in the RLLRT group than in the RLHRT and Rams groups. Average daily weight gain was not different (p&gt;0.05) between the RLLRT and RLHRT groups. Conclusion: the selection of ram lambs with low rectal temperature under heat stress conditions showed no benefit in terms of average daily weight gain and ejaculate traits.

Efeito da adição de Megathyrsus maximus em ração total mista sobre desempenho, metabolismo e qualidade de carcaças de cordeiros

ABSTRACT: This study assessed the impact of total mixed ration silage of Megathyrsus maximus harvested with 70 cm composed of Megathyrsus maximus harvested at 70 cm in height and concentrate at the time of silage or total mixed ration of grass cut at 70 cm composed of Megathyrsus maximus harvested with 70 cm in height (in Exp. I and III) and total mixed ration silage cut at 130 cm composed of Megathyrsus maximus harvested 130 cm height and concentrate at the time of silage or total mixed ration of Megathyrsus maximus harvested with 130 cm composed of Megathyrsus maximus harvested at 130 cm height (in Exp. II and IV), on rumen metabolism, nutrient digestibility, and the performance and carcass characteristics of feedlot lambs. The results showed that TMRS70 increased ruminal pH in Exp. I and TMRS130 exhibited higher ether extract digestibility, propionic concentration, and lower acetic to propionic ratio and ruminal pH compared to TMR130 in Exp. II. In Exp. III and IV, there was no significant effect on the performance and quality of the carcass. However, in Exp. IV, TMRS130 led to decreased dry matter intake and average daily gain, while lambs fed with TMR130 showed a higher rib-eye area. Total ration ensilage could be used as a conservation method for young grasses (70 cm) without impairing performance, metabolism, carcasses, and meat quality. However, further research is recommended to evaluate the economic analysis of feeding total ration ensilage (70 cm) instead of total mixed ration as a forage conservation method.

Genetic relationships between male and female reproductive traits in Retinta beef cattle

Scrotal circumference (SC) is an indirect measure used to predict the reproductive fitness of beef cattle raised in an extensive regime with limited seasonal breeding. It stands out for having a moderate to high heritability and favorable correlations, with seminal and reproductive quality traits in both the bull and its daughters. In the present study, we analyzed 2,634 SC records of young bulls evaluated in testing stations for future bulls of the Retinta cattle Breed. The data was collected from 828 young bulls which produced 3,616 daughters. Monthly measurements of live weight, average daily gain, feed consumption, and SC were also performed in the bulls during testing. In addition, reproductive controls were performed in the daughters to estimate age at first calving (AFC) and reproductive efficiency (RE). We also estimated genetic parameters for the traits using a classical REML repeatability animal model. Average SC was 34.04 ± 2.43 cm. at 12 months, showing a heritability of 0.282 ± 0.052. Phenotypic (-0.05, 0.11, 0.42) and genetic (0.12, 0.15, -0.09) correlations were obtained between AFC and Reproductive Efficiency (RE) at 3, 6, and last calving and SC. These results suggest a strong environmental influence on the reproductive variables of daughters, probably motivated by the breeding model and the farmer's decision on the date of reproduction of the heifers. However, it can be seen that the AFC, RE3 and RE6 are more favorable for individuals with SC >37 cm, and more unfavorable for SC ≤32 in relation to SC >32 and ≤37. Finally, 85 of the bulls underwent sperm analysis using computer-assisted sperm analysis (C.A.S.A.) technology, using frozen semen samples belonging to the Retinta Breeding Program. Residual phenotypes for SC showed positive correlations with progressivity (0.11 in STR and LIN) and longevity (0.2 in L40 and 0.1 in L50). The highest r2 was obtained using a canonical correlation, suggesting that a higher SC may improve sperm quality in bulls. It can therefore be confirmed that the use of this selection criterion (SC) in the breeding program of this breed will determine a response to positive selection, both for the fertility of the bull and its daughters.

Essential oil blend and monensin for feedlot steers consuming backgrounding and finishing diets: growth performance, methane emissions using the GreenFeed system, and feeding behavior.

A study was conducted to assess growth performance, methane (CH4) emissions, and feeding behavior of feedlot steers consuming backgrounding and finishing diets with an essential oil blend (EO), monensin (Mon), and their combination (EO + Mon). The study was structured as a 2 × 2 factorial, with two feed additive treatments (Control, EO) and two monensin treatments (no Monensin, Monensin). One hundred Angus × steers were evenly distributed across each treatment into four pens, and each dietary phase consisted of four, 28-d periods. Using the GreenFeed system to estimate CH4 yield (g CH4/kg dry matter intake [DMI]), the mean CV (coefficient of variation) within the same steer across measurement periods was 14.0% and 15.2% for the backgrounding and finishing phases, respectively. The mean CV of CH4 production for steer within period and time-of-day block was up to 83.4% and 102.9% for the backgrounding and finishing phases, respectively. There was no difference in overall average daily gain (P ≥ 0.22) or gain:feed ratio (P ≥ 0.26) with EO or Monensin during the backgrounding or finishing phases. There were variable period effects on CH4 emissions, but overall control had lower (EO × Mon; P ≤ 0.01) CH4 production, yield, and CH4 energy as a percentage of gross energy intake (GEI) (Ym, Mcal CH4 % GEI), during the backgrounding phase. During the finishing phase, CH4 yield (EO × Mon; P = 0.02) and Ym (EO × Mon; P ≤ 0.01) were greatest in the EO + Mon treatment. Monensin, irrespective of EO, decreased DMI (P < 0.01) and eating rate (P = 0.01), and increased intermeal interval (P < 0.01) for the backgrounding phase. In the finishing phase, Monensin decreased (P < 0.01) DMI, variation of DMI (EO × Mon), meal size, and eating rate. Number of GreenFeed visits was negatively (P < 0.01) correlated with all feeding behavior metrics in the finishing phase. In conclusion, supplementation of EO or Monensin and their combination into backgrounding and finishing diets of feedlot steers had no effect on overall feedlot performance or CH4 emissions. Additionally, the high variability in CV of CH4 production and yield suggests a need to improve the accuracy and precision of the GreenFeed system for estimating enteric CH4 emissions from cattle.

Hesperidin enhances broiler growth performance by augmenting gastric acid secretion via the proton pump pathway.

Hesperidin exhibits promising potential as a feed additive for augmenting gastric acid secretion in animals. Gastrointestinal function is essential for animal growth and the efficient digestion of dietary nutrients, with gastric acid secretion serving as one of its critical components. The secretion of gastric acid, together with other digestive fluids and substances, significantly influences the digestion and absorption of animal feed, which in turn affects growth performance. However, there is limited research regarding the application of hesperidin as a feed additive to enhance gastric acid secretion. The present study aims to evaluate the efficacy of hesperidin as a feed additive in enhancing gastric acid secretion and to elucidate its underlying mechanisms. A total of 200 newly hatched (1-day-old) broilers with similar body weight were randomly allocated into four groups as follows: the control group receiving only the basal diet, and the other three groups supplemented with 50, 100, and 150 mg of hesperidin per kg of the basal diet, respectively. Each group consisted of five replicates with ten broilers per replicate, and the feeding trial lasted for a duration of 21 days. The growth performance was evaluated by monitoring feed intake and body weight throughout the trial. A four-day nutrient utilization trial was conducted prior to the conclusion of the feeding experiment. Adoption of the total collection method, the collected droppings were weighed and dried at 65 °C. Fifteen broilers from each group were euthanized and immediately dissected to obtain gizzard, proventriculus, gizzard chyme, and jugular blood samples, The proventriculus and gizzard weight were weighed and the pH of gizzard chyme was measured at the same time. The collected jugular venous blood was used to assess gastrin levels, whereas chicken gizzard chyme was utilized for the analysis of lactate, hydrochloric acid, and pepsin activity. Proventriculus and gizzard tissues were used to evaluate pepsinogen levels, perform hematoxylin-eosin (H&E) staining, conduct enzyme-linked immunosorbent assays (ELISAs) for key proton pump components, and assess proton pump activity. The results demonstrated that, in comparison to the control group, both the 100mg/Kg and 150 mg/Kg groups exhibited a significant increase in final body weight (FBW) and average daily gain (ADG) (P < 0.05). Additionally, the feed to gain ratio (F/G) was significantly reduced in the 150mg/Kg group (P < 0.05). The results of the nutrient utilization trial indicate that all treatment groups had significantly higher levels of dry matter (DM) and ether extract (EE) compared to the control group (P < 0.05). Furthermore, crude protein (CP) and gross energy (ME) were significantly higher in the 100mg/Kg and 150mg/Kg groups than in both the control group and the 50mg/Kg group (P < 0.05). The inclusion of hesperidin in broiler diets leads to significant improvements in stomach development and lactic acid content, while pH and hydrochloric acid content exhibit opposite trends (P < 0.05). Supplementation of broiler diets with hesperidin at doses of 100 mg/Kg and 150 mg/Kg significantly up-regulates pepsin activity and pepsinogen levels (P < 0.05). Incorporation of hesperidin into the broilers' diet significantly enhances parietal cell numbers (P < 0.05). Dietary supplementation of hesperidin in broilers effectively up-regulates key signaling pathways and intracellular signal substances involved in proton pump activation (P < 0.05). The proton pump activity also exhibited a significant increase compared to the control group of 100mg/Kg and 150mg/Kg (P < 0.05) in our findings. In conclusion, hesperidin exhibits promising potential as a feed additive for broilers, and it can improve the growth performance of broilers by increasing gastric acid secretion and promoting nutrient utilization through activation of proton pump. Notably, basal diet supplemented with 150mg/Kg hesperidin demonstrates superior efficacy.

Vitamin D3 requirements and relative bioavailability for starter male White Pekin ducks fed either cholecalciferol or 25-hydroxycholecalciferol

The objectives were to investigate effects of various concentrations of dietary vitamin D3 (VD3) or 25-hydroxycholecalciferol (25-OH-D3) on growth performance, VD3 status, calcium (Ca) metabolism, and tibia mineralization of starter male White Pekin ducks, and dietary requirements and relative bioavailability of these two compounds. One-day-old male White Pekin ducks (n = 624) were assigned to 13 dietary treatments, including 6 added VD3 concentrations (100, 200, 400, 800, 1200, and 2000 IU/kg), and 2 vitamin D3 sources (VD3 and 25-OH-D3), plus a negative control (no vitamin D3 supplementation) for 21 days. Each group had 6 replicate pens of 8 birds per pen. At 21 days of age, growth performance, carcass traits, plasma 25-OH-D3 and Ca content, and tibia mineralization were examined. There was a high incidence of leg disease and mortality in ducks fed the control diet; however, those negative effects were avoided by adequate VD3 or 25-OH-D3 supplementation. Ducks in the negative control group had the lowest body weight, average daily weight gain (ADG), average daily feed intake (ADFI), breast muscle percentage, plasma 25-OH-D3, plasma Ca, and tibia indices (weight, diameter, ash, density, tibia mineral, strength) (P < 0.05), with all these end points enhanced linearly or quadratically as dietary VD3 or 25-OH-D3 increased (P < 0.05). Furthermore, at 100 or 200 IU/kg, ducks fed 25-OH-D3 had greater body weight, ADG, ADFI, plasma Ca, plasma 25-OH-D3, tibia weight, tibia diameter, tibia ash than those fed VD3 (P < 0.05), indicating 25-OH-D3 was more effective in stimulating growth, Ca absorption, and tibia mineralization. For growth performance, breast muscle percentage, plasma Ca, and tibial indices of starter male Pekin ducks, the VD3 requirements were 281 to 633 IU/kg, whereas 25-OH-D3 requirements were 119 to 395 IU/kg. Based on slope ratio comparisons from multiple linear regressions of plasma 25-OH-D3, bioavailability of 25-OH-D3 was 186% relative to cholecalciferol.

Oral-Delivery Lactococcus lactis Expressing mCherry Fusion Lactoferrin Peptides against Infection of Avian Pathogenic Escherichia coli in Chickens

Avian pathogenic Escherichia coli (APEC) infections result in significant economic losses and reduced animal welfare. Historically, antibiotics and vaccinations currently control APEC infections in poultry, however, antibiotic-resistant strains and heterologous serotypes limit their effectiveness. Meanwhile, antibiotic-resistant strains can be transmitted to humans via contact with animals, food or their environment. Probiotics and antimicrobial peptides (AMPs) are potential alternatives to antibiotics and represent promising strategies to combat APEC. Bovine lactoferricin and lactoferrampin possess anti-bacterial, anti-inflammatory, and anti-oxidant properties. Lactococcus lactis (L. lactis) is an excellent vector for delivering recombinant proteins. In this research, we generated a recombinant L. lactis strain MG1363 expressing lactoferrin peptides, which was labeled with a fluorescent marker mCherry and lacked an antibiotic resistance gene (LL-EFLmC). Our investigation focused on the impact of LL-EFLmC strain on the gut microbiota composition and avian pathogenic E. coli O78 challenge. Our findings indicate that LL-EFLmC exhibits inhibitory effects against APEC-O78 and Staphylococcus aureus CVCC26003 (S. aureus CVCC26003) in vitro. Furthermore, the inclusion of LL-EFLmC in chicken feed significantly improved the average daily intake and gain to feed ratio. Additionally, LL-EFLmC treatment resulted in a significant increase in serum IgG and intestinal mucus SIgA levels. Administration of LL-EFLmC was found to effectively suppress APEC-O78 infection and mitigate the expression of pro-inflammatory cytokines, including IL-1β, IL-12, IFN-γ, and TNF-α. Additionally, 16S rDNA sequencing data revealed that LL-EFLmC was able to restore the intestinal flora that had been disrupted by APEC-O78. These findings suggest that LL-EFLmC may serve as a promising feed additive and antibiotic alternative in chicken production, due to its potential to enhance immune regulation, promote growth, and confer resistance against APEC-O78 infection.

Effects of Bacillus subtilis addition to milk replacer on growth performance, nutrient digestibility, intestinal microbiota, and short-chain fatty acid concentration of Hu lambs

We aimed to investigate the effects of adding Bacillus subtilis to milk replacers on the incidence of diarrhea, growth performance, intestinal microbiota composition, and short-chain fatty acid (SCFA) production in newborn Hu lambs. Thirty newborn lambs with similar genetic backgrounds and initial body weights were selected and nursed by their dams for 4 days before transitioning to a milk replacer. At age 7 days, the lambs were randomly assigned to two experimental groups of 15 lambs each: CON (basic milk replacer feeding) and BS (basic milk replacer feeding supplemented with 0.2% B. subtilis). At age 28 days, eight lambs in each group were randomly euthanized, and their colonic and cecal contents were collected for microbiological and SCFA analyses. The lambs were monitored daily to determine the incidence of diarrhea. The BS group showed significantly increased average daily feed intake and gain and significantly reduced incidence of diarrhea. Furthermore, dry matter digestibility and crude protein and ether extract content increased in the BS group compared with those in the CON group. Increased acetate and total SCFA concentrations were noted in the colon and cecum, with elevated propionate levels specifically in the cecum. Microbiota analysis revealed that B. subtilis supplementation enhanced microbial diversity and beneficially modulated bacterial communities. Potentially harmful bacteria showed significantly decreased abundance in the colon (Campylobacterota by 11.09% and Fusobacteriota by 2.98%), whereas beneficial bacteria exhibited increased abundance (Firmicutes by 8.9%, Actinobacteriota by 3.59%, Lactobacillus by 5.92%, and Bifidobacterium by 3.18%). Similar trends were observed in the cecum, with decreases in Campylobacterota (4.82%) and Fusobacteriota (3.12%) and increases in Bacteroidota (4.11%), Lactobacillus (3.75%), and Prevotella (3.59%). These findings indicate that adding 0.2% B. subtilis to the milk replacer is an effective approach for enhancing lamb growth performance, maintaining intestinal health, and improving the intestinal microbiota.

Beneficial effects of ε-polylysine on growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in broilers fed a lysine-deficient diet.

This study was conducted to investigate the effects of dietary ε-polylysine supplementation on growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in broilers fed a lysine-deficient diet. A total of 960 one-day-old yellow-feathered broilers were randomly allocated into six groups with eight replicates and 20 birds per replicate. Birds in the six groups were fed a lysine-deficient basal diet (-0.20 % lysine, NC) or basal diets supplemented with 0.20 % L-lysine hydrochloride (normal lysine level, PC) or varying levels (0.10 %, 0.20 %, 0.30 %, or 0.40 %) of ε-polylysine hydrochloride for 10 weeks. Results showed that compared with the NC group, dietary supplementation with 0.10 % and 0.20 % of ε-polylysine improved growth performance, meat quality and intestinal morphology, evidenced by increased average daily gain, decreased feed-to-gain ratio, increased water holding capacity of breast muscle, and increased jejunal and ileal villus height in ε-polylysine-treated broilers (P < 0.05). In addition, 0.10 % and 0.20 % of ε-polylysine supplementation improved serum nitrogen metabolism, immune and antioxidant capacity to varying degrees. No significant diffrences in growth performance, meat quality, or intestinal morphology were observed among PC and ε-polylysine-supplemented groups (P > 0.05). Interestingly, compared with the PC group, dietary 0.10 % of ε-polylysine positively altered the microbiota composition of broilers, evidenced by the increased the relative abundance of beneficial bacteria (e.g., Faecalibacterium and Phascolarctobacterium) and decreased the abundance of harmful bacteria (e.g., Lachnoclostridium and Peptococcus). In conclusion, diets supplemented with ε-polylysine have beneficial effects on growth performance, meat quality, and gut health of broilers via replenishing lysine or favorably altering immune and antioxidant capacity and gut microbiota. The recommended supplemental amount of ε-polylysine in lysine-deficient diets (L-lysine content in the starter and growing diet is 0.95 % and 0.80 % of the basal diet, respectively) is 0.10 %-0.20 %.