Post-weaning Phase Research Articles

257 Effects of Prebiotic Galactooligosaccharide (GOS) on Hindgut Microbial Composition of Pigs During the Peri-Weaning Period

Abstract Galactooligosaccharide (GOS) is a prebiotic containing beta-linked galactose oligomers of 2 to 8 units. Previously, GOS positively impacted post-weaning growth performance and altered jejunal morphology. In this study, GOS-enriched whey permeate (Milk Specialties Global, Eden Prairie MN) was supplemented to piglets in farrowing and nursery phases. To maximize pre-weaning GOS intake, novel gruel creep feeders were used. Piglets from 24 litters received either no creep feed (NC), creep without GOS (CG-) or creep with 5.0% GOS (CG+) followed by a phase 1 nursery diet without (NG-) or with 3.8% GOS (NG+). At d 22 (pre-weaning) and d 31 (post-weaning), 6 pigs per treatment were euthanized for sample collection. DNA was extracted from cecal and rectal swabs for downstream 16S rRNA sequencing via Illumina MiSeq (Zymo Research Corp, Irvine CA). An amplicon sequence variant (ASV) table was created using the DADA2 pipeline in R and taxonomy assignment was performed using the SILVA database. Average sequencing depth after filtering was 138,323 and low sequencing counts were discarded based on 20% prevalence. Data were analyzed using the lmer and adonis procedures in RStudio ver. 4.2.2. Analysis of 16S rRNA genes did not detect pre- or post-weaning GOS effects on Chao1, Simpson, or Shannon alpha diversity measures (P > 0.1). Similarly, no pre-weaning GOS effects were detected in Principal Coordinates Analysis (PCoA) beta diversity plots (P > 0.1); however, pigs fed GOS post-weaning segregated from controls (P < 0.01). The relative abundance of several genera including Fusicatenbacter and Collinsella increased by 2.0 and 1.3-fold, respectively, in the cecum of NG+ pigs, whereas, Bacteroides decreased by 3.8-fold (FDR, P < 0.05). In the rectum, relative abundance of Corprococcus decreased by 2.0-fold and Fusicatenbacter increased by 1.5-fold in NG+ pigs compared with NG- pigs (FDR, P < 0.05). Collectively, these genera in the cecum and rectum comprise of less than 3% of the total community. In contrast, lactobacillus in the cecum (33%) and rectum (21%) had a large relative abundance but was unaffected by treatment. We conclude that supplementation of GOS in the post-weaning phase 1 nursery diet alters the hindgut microbial community and may contribute to improvements in growth performance.

439 Identifying Forage Efficient 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 and where > 74% of the total feed energy required to produce beef is consumed. Considerable evidence indicates the existence of a genetic by environment interaction for feed efficiency. Therefore, more rapid progress in forage utilization efficiency and reduction in greenhouse gas emissions in the cow herd could be made by studying feed efficiency when cattle consume moderate quality, unprocessed forage diets. 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, little is known about the repeatability of forage utilization efficiency between growing heifers and beef cows. An update of recent advancements to identify forage-efficient cows will be provided during the presentation.

206 Development and Validation of an Indigestible Protein Index to Investigate the Effects of Protein Content in Weaned Pigs: A Multivariate Approach

Abstract Increased proteolytic fermentation may lead to negative effects on gastrointestinal health and function, which ultimately impact on performance. The objective was to develop and validate, by investigating performance and gut structure outcomes, an index of indigestible protein content (IDP) in weaned pigs. Ninety-four studies reporting growth performance [average daily gain (ADG), average daily feed intake (ADFI), gain: feed (GF), initial (IBW) and final body weight (FBW)] and duodenal histomorphometries [villus height (VH), crypt depth([CD), and villus height: crypt depth ratio (VCR)] variables of pigs fed different protein content (CP) and sources in the diet were included. Diets were recalculated using a common database to generate the IDP from each study. Studies were grouped by similarity in performance in two clusters (C1 and C2) by hierarchical clustering on principal components (HCPC). The effects of cluster were investigated. Quadratic response plateau (QRP) models were fitted to assess the interrelationships between ADG, ADFI, GF, VH, CD, and VCR with the dietary CP or calculated IDP content within cluster. Pigs from C2 had greater IBW (6.3 vs. 8.8 ± 0.2kg), FBW (10.2 vs. 17.2 ± 0.7kg), ADG (0.2 vs. 0.4 ± 0.0kg/d), and ADFI (0.3 vs. 0.6 ± 0.1kg/d) compared with C1 (P < 0.05). There was no effect of cluster (P > 0.05) on VH (405.5 vs. 405.5 ± 15.8μm), CD (232.5 vs. 220.7 ± 10.1μm), or VCR (1.9 vs. 2.0 ± 0.3μm). Pigs from C1 achieved break point (BP) and plateau (Pl) for VH (BP = 24.25%, Pl = 96.32μm; P < 0.05) when fed increasing CP content and for ADG (BP = 2.32%, Pl = 0.28kg/d; P < 0.05) and GF (BP = 2.18%, Pl = 0.83kg/kg; P < 0.05) when fed increasing calculated IDP content. Pigs from C2 fed increasing content of calculated IDP achieved BP and Pl for ADG (BP = 3.04%, Pl = 0.54kg/d; P < 0.05). Our findings suggest that calculated IDP might be a reliable index to investigate the effects of proteolytic fermentation on pig performance, particularly in the immediate post-weaning phase.

PSIII-4 Effect of Two Torula Yeast Sources on Growth Performance, Intestinal Health, and Immune Function of Weanling Pigs

Abstract An experiment was conducted to test the hypothesis that dietary inclusion of either a conventional or a novel source of torula yeast in diets for weanling pigs improves growth performance and intestinal health. The novel torula yeast was produced using forestry byproducts (i.e., wood hydrolysate) as the carbon source, whereas the conventional torula yeast was produced using wheat dextrose as the carbon source. A total of 120 weanling pigs (6.53 ± 0.78 kg) were allotted to three treatments with four pigs per pen and ten replicate pens per diet. Pigs were fed one of three diets from d 1 to 14 post-weaning (phase 1), whereas all pigs were fed a common diet in phase 2 (d 15 to 28). The three dietary treatments included a control diet that contained 5% fishmeal, 3.5% plasma protein, and no torula yeast. The second diet contained 1.5% fishmeal, 14% of the novel torula yeast, and no plasma protein, whereas the third diet contained 1.5% fishmeal, 14% of the conventional torula yeast, and no plasma protein. Pig weights were recorded on d 1, d 14, and d 28. Feed allotments were recorded daily, and feed left in the feeders was recorded on d 14 and 28 to calculate average daily gain, average daily feed intake, and average gain to feed ratio. Fecal scores were visually assessed every other day. On d 7, one pig per pen was euthanized to collect ileal tissue for assessment of morphology. At the end of phases 1 and 2, blood samples were collected, and cytokines, plasma urea nitrogen, peptide YY, immunoglobulin G, total protein, and albumin were analyzed. Data were analyzed using an ANOVA in the Mixed Procedure of SAS with pen as the experimental unit. Diet was the fixed effect, whereas weaning weight was the random effect. Results indicated that both sources of torula yeast could replace fish meal and plasma protein without negatively affecting overall growth performance, intestinal morphology, or blood characteristics of pigs (Table 1). Pigs fed one of the diets containing torula yeast had reduced (P < 0.05) fecal scores during phase 1 compared with pigs fed the control diet. On d 14, pigs fed the conventional torula yeast diet had greater (P < 0.05) concentration of interleukin-2 in plasma compared with pigs fed the control diet. Greater (P < 0.05) concentrations of interleukin-4 and interleukin-10 were observed in plasma from pigs fed one of the diets containing torula yeast compared with pigs fed the control diet on d 14. In conclusion, inclusion of either a conventional or a novel source of torula yeast at the expense of animal proteins in diets for weanling pigs may improve intestinal health without influencing growth performance of weanling pigs.

Comparing forecasting models for predicting nursery mortality under field conditions using regression and machine learning algorithms

Swine nursery mortality is one of the most important key performance indicators (KPIs) for commercial swine production systems and, for the purpose of this study, refers to the number of pigs that died during the first 60 days during the post-weaning phase (approximately 170-day period). Likewise, nursery mortality accounts for almost 50% of the mortality that occurs throughout the post-weaning phase. Despite being a metric concerning the post-weaning phase of production, previous studies have demonstrated that nursery mortality is highly correlated with the previous performance of the piglets in the pre-weaning phase and to stocking conditions at placement in nursery sites. However, there is no evidence of that predictive models are currently routinely utilized in the swine industry to predict the nursery performance of individual groups of pigs based on their previous performance in the pre-weaning phase. One obstacle to building such predictive models is that health and management data as well as production data for the pre and post-weaning phases are collected with separate record-keeping programs and stored in unconnected databases.Thus, the objective of this study was to measure and compare the performance of 5 forecasting models for predicting nursery mortality using a master table containing data collected from a single swine production system for 1,831 groups of pigs. An automated model was built to integrate information for 48 variables included in the master table that was previously disconnected within the production system. After the model and parameter tuning process, the model with the best overall prediction performance was the Support Vector Machine (SVM) in terms of Root Mean Squared Error (RMSE=0.3929), Mean Absolute Error (MAE=0.2956), and coefficient of determination (R2=0.7761). This study demonstrated the ability to use an integrated master table containing whole-herd information until the placement event of nursery groups to predict their downstream nursery mortality through the initial 60 days of the post-weaning phase.

Temporal progression of anaerobic fungal communities in dairy calves from birth to maturity.

Establishment of microbial communities in neonatal calves is vital for their growth and overall health. While this process has received considerable attention for bacteria, our knowledge on temporal progression of anaerobic gut fungi (AGF) in calves is lacking. Here, we examined AGF communities in faecal samples from six dairy cattle collected at 24 different time points during the pre-weaning (days 1-48), weaning (days 48-60), and post-weaning (days 60-360) phases. Quantitative polymerase chain reaction indicated that AGF colonisation occurs within 24 h after birth, with loads slowly increasing during pre-weaning and weaning, then drastically increasing post-weaning. Culture-independent amplicon surveys identified higher alpha diversity during pre-weaning/weaning, compared to post-weaning. AGF community structure underwent a drastic shift post-weaning, from a community enriched in genera commonly encountered in hindgut fermenters to one enriched in genera commonly encountered in adult ruminants. Comparison of AGF community between calves day 1 post-birth and their mothers suggest a major role for maternal transmission, with additional input from cohabitating subjects. This distinct pattern of AGF progression could best be understood in-light of their narrower niche preferences, metabolic specialisation, and physiological optima compared to bacteria, hence eliciting a unique response to changes in feeding pattern and associated structural GIT development during maturation.

144 Assessment of Backgrounding Management on Growth Performance and Health in Southeastern Beef Calves

Abstract The backgrounding period is a post-weaning management strategy to add weight and build the health status in beef calves. This phase is used to prepare beef calves to enter the next phase of the production supply chain. Weaning and backgrounding management methods can be strategies to reduce calf morbidity and mortality in the feedlot. The objective of this study was to assess beef calf growth performance based on weaning management strategy and subsequent backgrounding using commonly used forage-based diets by Alabama beef producers. A two-year study was conducted using 427 steers (n = 216, year 1, average BW 306kg; n = 213, year 2, average BW 294kg). Steer calves from three Auburn University research farms were randomly assigned based on weaning weights to one of three different weaning method groups: fenceline weaning, nose-flap weaning, or abrupt weaning. After the weaning period calves were brought to a centralized farm and began a 60-d backgrounding period where they were randomized according to previous weaning management, farm of origin and body weight to one of three nutritional management strategies in a 3×3 factorial design: cool-season baleage (oats, ryegrass and crimson clover) and 1% BW dried distillers’ grains (DDGS), bermudagrass hay and 1% BW DDGS, or grazing mixed warm-season annuals and 1% BW DDGS. Body weights were collected on d 0, 30 and 60 of the backgrounding phase. In both years, fenceline weaned calves had the greatest average daily gain (year 1, 0.76 kg/d; year 2, 1.03 kg/d; P = 0.0225) in the first 30 days of the backgrounding period regardless of backgrounding diet type. Calves fed the bermudagrass hay-based diet also had a greater average daily (year 1, 0.78 kg/d; year 2, 1.24 kg/d; P < 0.0001) than both the grazing and baleage diet groups in the first 30 days of backgrounding. From d 30 to 60 of backgrounding in each year, calves on the hay-based diet had the least average daily gain (year 1, 0.19 kg/d; year 2, 0.42 kg/d; P < 0.0001). Steers on both the warm-season annual grazing and cool-season baleage diets supported greater average daily gains (P =0.0041) during the last 30 days of the backgrounding period (0.74 kg/d and 0.75 kg/d, respectively). Steers in year 2 had a greater total gain (year 1, 45.55kg; year 2, 51.56 kg; P = 0.0042) than steers in year 1. However, results in both years indicate that weaning and backgrounding management strategies may influence calf performance during the transition period into the post-weaning phase.

Protein Content in the Diet Influences Growth and Diarrhea in Weaning Piglets.

The aim of this research has been to assess the effect of the dietary protein level on piglet growth and post-weaning diarrhea (PWD) incidence. Piglet fecal microbiota and feces composition were also assessed. The experiment was carried out on 144 weaned piglets (Duroc × Large White; 72 piglets per treatment) and lasted from weaning (at 25 days of age) until the end of the post-weaning phase (at 95 days). Two dietary protein levels were compared: high (HP; 17.5% crude protein on average, during the experiment) and low (LP; 15.5% on average). Lower (p < 0.01) average daily gain and feed conversion ratio were observed in LP piglets in the first growth phase. However, at the end of the post-weaning period, the growth parameters were not significantly different in the two diets. Diarrhea scores were lower in piglets fed LP diets than in piglets fed HP diets (28.6% of the total vs. 71.4% in the HP piglets). Fibrobacteres, Proteobacteria, and Spirochaetes were more abundant in the feces of the piglets fed LP diets. Feces nitrogen content was lower in piglets fed LP diets. In conclusion, low protein levels in the diet can reduce the incidence of PWD while only marginally affecting growth parameters.

Growth rate and efficiency-related traits in Kermani lambs: estimations of (co)variance components and genetic parameters.

Using Kermani sheep, the current study estimated (co)variance components and genetic parameters for average daily gain, Kleiber's ratio, growth efficiency, and relative growth rate. Data were analyzed by the average information restricted maximum likelihood (AI-REML) method using six animal models with different combinations of direct and maternal effects. The best-fitting model was determined after testing for improvement in log-likelihood values. The estimates of h2 for average daily gain (ADG), Klieber's ratio (KR), growth efficiency (GE), and relative growth rate (RGR) in pre- and post-weaning phases were 0.13 ± 0.6 and 0.17 ± 0.02, 0.12 ± 0.04, and 0.16 ± 0.03; 0.05 ± 0.05 and 0.07 ± 0.03 and 0.06 ± 0.02 and 0.07 ± 0.01, respectively. Maternal heritabilities (m2) ranged from 0.03 ± 0.01 for relative growth rate in pre-weaning phase to 0.11 ± 0.04 for average daily gain in post-weaning period. The maternal permanent environmental component (Pe2) accounted for 3 to 13% to the phenotypic variance for all the studied traits. Estimated values of additive coefficient of variations (CVA) ranged from 2.79% for relative growth rate at 6 months of age to 23.74% for growth efficiency at yearling age. Genetic and phenotypic correlations among traits were ranged from -0.687 to 0.946 and -0.648 to 0.918, respectively. The result indicated that selection for growth rate and efficiency-related traits would also be less effective in achieving genetic change, because there was little additive genetic variation among Kermani lambs.

Torula yeast may improve intestinal health and immune function of weanling pigs.

An experiment was conducted to test the hypothesis that inclusion of a conventional torula yeast or a torula yeast produced from forestry byproducts (i.e., woody torula yeast) in diets for weanling pigs instead of fish meal and plasma protein improves growth performance and intestinal health of pigs. A total of 120 weanling pigs (6.53 ± 0.78 kg) were allotted to three treatments with ten replicate pens per diet. Pigs were fed one of three diets from days 1 to 14 post-weaning (phase 1), whereas all pigs were fed a common diet in phase 2 (days 15 to 28). The three treatments in phase 1 included a control diet with 5% fish meal, 3.5% plasma protein, and no torula yeast. The second diet contained 1.5% fish meal, 14% woody torula yeast, and no plasma protein, whereas the third diet contained 1.5% fish meal, 14% conventional torula yeast, and no plasma protein. Fecal scores were assessed every other day. On day 7, one pig per pen was euthanized to collect ileal tissue and mucosa for determination of morphology and for ribonucleic acid (RNA) sequencing analysis. At the end of phases 1 and 2, blood samples were collected and concentrations of cytokines, plasma urea nitrogen (PUN), peptide YY, immunoglobulin G, total protein, and albumin were analyzed. Results indicated that both torula yeast sources could replace fish meal and plasma protein without affecting growth performance, intestinal morphology, or blood characteristics of pigs. Pigs fed a diet containing torula yeast had improved (P < 0.05) fecal scores during phase 1. Pigs fed the conventional torula yeast diet had greater (P < 0.05) concentration of interleukin-2 compared with pigs fed the control diet. On day 14, greater (P < 0.05) concentrations of interleukin-4 and interleukin-10 were observed in pigs fed the diet containing the woody torula yeast or conventional torula yeast compared with pigs fed the control diet. Results from the RNA sequencing indicated that 19 of 24 analyzed genes involved in digestion and absorption of protein and vitamins were downregulated in pigs fed the diet containing woody torula yeast compared with pigs fed the control diet. However, only two genes (i.e., ANKS4B and FAM54A) were downregulated in pigs fed the woody torula yeast diet compared with the conventional torula yeast diet. In conclusion, using woody or conventional torula yeast instead of fish meal and plasma protein in the phase 1 diet for weanling pigs may improve intestinal health without influencing growth performance of pigs.

225 Effects of Supplementing a Live Yeast Supplement in pre-Weaning and Finishing Diets of Holstein Bull Calves on Meat Production and Quality

Abstract A study was conducted to evaluate the effects of a live yeast supplement in the preweaning and finishing diets of Holstein bull calves on growth performance, carcass quality attributes and physiochemical traits. Holstein bulls (n = 39) at 5 days of age were randomly allocated to one of two treatment groups with 20 receiving no yeast supplement and 19 calves receiving the yeast supplement. The inclusion level of the yeast supplement in the pre-weaning diet was 54 mg/calf/day added to the milk replacer. During the post-weaning phase, the calves in the yeast treatment group received a pelleted feed with the yeast supplement already incorporated at 150g/tonne. The bull calves were slaughtered at 156 ± 15 days and the m. longissimus thoracis et lumborum was sampled for meat quality measurements. The live yeast supplement had no significant effect (P &amp;gt; 0.05) on average daily gain and final body weight of Holstein bull calves. Furthermore, carcass attributes and meat physiochemical traits were not influenced (P &amp;gt; 0.05) by diet. It was concluded that addition of yeast to preweaning and finishing diets of dairy bull calves has no effect on meat production and quality

Impacts of Reducing Protein Content in Milk Replacer on Growth Performance and Health of Young Calves.

Simple SummaryThe appropriate protein percentages in calf milk replacer (MR) is a key factor in determining the optimal growth of young calves. We hypothesized that elevated MR feeding with a lower protein content may not negatively affect the performance, metabolic traits, and health of the calves. The question on is: how much protein is required by calves in order to achieve an intended growth rate? In the present study, the average daily gain was similar between both groups fed MR of 19% and 22% protein, although crude protein intake was reduced in the group fed MR of 19% protein. Even though the mean dry matter content in the feces of group fed MR of 19% protein was partly lower, the incidence of diarrhea was not greater in this group. Both groups fed MR of 19% and 22% protein had very great serum insulin-like growth factor 1 (IGF-1) concentrations. This confirms that both groups, i.e., also the animals fed with a crude protein-reduced MR, were adequately supplied with nutrients. Furthermore, the lower serum urea concentration in the 22% protein in MR calves indicates that they probably had a greater body protein accretion and the proportion of amino acids for energy supply was lower than in the 19% protein in MR calves. Thus, the urea content in the blood serum indicated that a higher protein intake during the pre-transition period is feasible with a higher protein content in the MR.In the present study, a drinking amount of 10 L of milk replacer (MR) was allowed to dairy calves in order to approach the natural drinking behavior. The question is: how much protein is required by calves in order to achieve an intended growth rate? For this reason, sixty-eight pre-weaned Holstein calves were divided into two groups and fed with 10 L/d of MR containing either 22% protein (MR22) or 19% protein (MR19) at an almost comparable energy intake. Effects on performance, metabolic status, and health were compared. Feed intake, growth performance, and health status were monitored during the pre-transition, transition, and postweaning phase (until 157 d of age). Total feed intake, and intake of MR, body weight (BW), and average daily gain (ADG) were not significantly different between MR22 and MR19 during the entire experimental period (p > 0.05). At d 42, calves in MR19 group showed greater serum levels of growth hormone (16.2 vs. 22.2 ng/mL; p = 0.02), insulin-like growth factor 1 (262 vs. 291 ng/mL; p = 0.03), and urea (2.86 vs. 3.04 mmol/L; p < 0.01). The results of the present study suggested that when high amounts of MR are provided, the protein content in MR can be reduced to 19% without any adverse effects on growth performance as well as on health status of dairy calves.

Impact of housing environment and management on pre-/post-weaning piglet productivity.

The complex environment surrounding young pigs reared in intensive housing systems directly influences their productivity and livelihood. Much of the seminal literature utilized housing and husbandry practices that have since drastically evolved through advances in genetic potential, nutrition, health, and technology. This review focuses on the environmental interaction and responses of pigs during the first 8 wk of life, separated into pre-weaning (creep areas) and post-weaning (nursery or wean-finish) phases. Further, a perspective on instrumentation and precision technologies for animal-based (physiological and behavioral) and environmental measures documents current approaches and future possibilities. A warm microclimate for piglets during the early days of life, especially the first 12 h, is critical. While caretaker interventions can mitigate the extent of hypothermia, low birth weight remains a dominant risk factor for mortality. Post-weaning, the thermoregulation capabilities have improved, but subsequent transportation, nutritional, and social stressors enhance the requisite need for a warm, low draft environment with the proper flooring. A better understanding of the individual environmental factors that affect young pigs as well as the creation of comprehensive environment indices or improved, non-contact sensing technology is needed to better evaluate and manage piglet environments. Such enhanced understanding and evaluation of pig–environment interaction could lead to innovative environmental control and husbandry interventions to foster healthy and productive pigs.

Effects of nature identical essential oils (carvacrol, thymol and cinnamaldehyde) on growth performance of piglets and non-invasive markers of antioxidant status and calprotectin release

The post-weaning phase is one of the most critical periods in pig production due to many stress factors that may negatively affect the response of the immune system and lead to intestinal gut dysfunction in pigs. The use of products of natural or synthetic origin could support the animals’ health in this stressful situation. The aim of this study was to evaluate the effects of nature identical essential oils (SEOs; carvacrol, thymol and cinnamaldehyde) added to post-weaning piglets’ diet on growth performance, fecal antioxidant status and calprotectin (CALP) release. At weaning, a total of 72 crossbred piglets were randomly assigned to three dietary treatments: a control group fed with the basal diet (CTR) and treatment groups fed with the basal diet with either a low dosage of SEOs (T1, 50 ppm) or a high dosage of the product SEOs (T2, 100 ppm). The body weight (BW) was measured at 0, 14 and 42 days, and the average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency (FE) were calculated at the end. From fecal samples, we measured the total antioxidant capacity (TAC), by FRAP and ABTS assays, and the CALP release. The ADG was higher in the treated groups (p < 0.05), although there was no significant effect of a treatment x time interaction. No significant differences were detected between the groups for BW, ADFI and FE. As for the antioxidant activity, the FRAP after SEOs administration showed a significant (p < 0.05) reduction at the end of the trial, probably due to an accumulation of a complex mixture of antioxidant compounds and a consequent underestimation of the antioxidant capacity. Calprotectin, a marker of gut inflammation, decreased in the SEOs-treated groups with a significant (p < 0.05) time effect after 42 days. The results of this study demonstrate that the use of a natural extract can improve some parameters of growth performance and gut health.

A 3-week post-weaning restricted feeding as alternative to an ad libitum antibiotic-medicated feed: Effects on growth, carcass and meat of rabbits differing in genotype and slaughter age

In this investigation, the impact of a 3-week post-weaning restricted feeding (RF) using an antibiotic-free feed, applied to rabbits from 36 to 56 days of age to preserve their health status as alternative to an ad libitum medicated feed with antibiotics (AMF), was verify in relation to rabbit genotype and slaughter age (SA). The RF and AMF treatments were compared evaluating their effects on feed intake, growth, mortality, carcass and meat quality of rabbits of two genotypes, Italian White purebred (IWP) and hybrid Hycole×IWP crossbred (HIWC), slaughtered at 78 or 92 days of age to obtain light or heavy carcasses. At 36 days of age, 256 weaned rabbits of both sexes were divided into 4 homogeneous groups based on feeding treatment (FT) and genotype: RF-IWP, RF-HIWC, AMF-IWP and AMF-HIWC. The RF treatment was performed offering to each rabbit 70, 80 and 90 g/day of feed in the 1st, 2nd and 3rd week. After the 3-week RF and AMF treatments, all rabbits received the same ad libitum antibiotic-free feeds until their slaughter. For each group, 24 rabbits were slaughtered, 12 at 78 days and 12 at 92 days. On the whole feed intake with RF was equal to 63% of that with AMF. Regardless of genotype, RF was associated with a lower feed intake until 78 days and a compensatory growth from 58 to 78 day, whereas from 79 to 92 days intake was not affected by FT and genotype. Despite the compensatory growth, the lower intake of restricted rabbits resulted in lower live weight at 78 and 92 days, but in more favourable feed conversion than with AMF. The growth potential allowed the crossbred rabbits to reach higher body and carcass weights with more efficient feed utilization. Mortality for enteropathies occurred mainly during the post-weaning phase from 36 to 56 days of age, with no difference due to FT, whereas HIWC rabbits showed a lower resistance to enteropathies. Heavier and fatter carcasses were obtained from AMF rabbits, at both SA, whereas the heavier HIWC carcasses showed a lower fat content than IWP ones. Carcass yield was influenced by FT and SA, being lower in RF rabbits and at earlier age. The restriction affected some colour indexes of meat and induced lower adiposity. Collagen was higher in meat of 92-day rabbits and in males, with no relationship to shear force. No particular effect of genotype emerged for meat quality. On the whole a 3-week post-weaning RF with antibiotic-free feed is confirmed to be a suitable method to replace an ad libitum feed containing antibiotics. In addition, RF appeared more suitable for rabbits of high-growth genotype slaughtered at 92 days which were more effective to recover the growth slowing due to the post-weaning feed restriction.

PSIII-14 Early Introduction of Structural Fiber Improves Growth Performance and Gut Health of Nursery Pigs

Abstract Structural fiber inclusion in post-weaning piglet feeds has been previously demonstrated to improve growth performance and gut health. The objective of this study was to determine whether a pre-weaning inclusion of structural fiber (STR) would bring added value to piglet performance and gut health and if the potential benefits could be maintained at a later stage. A total of 26 litters, were creep fed either a control or high STR diet (HSTR; 4% oat hulls) for 10 d before weaning. Upon weaning, a total of 240 pigs (body weight: 6.7 ± 0.5 kg, 5 pigs/pen, 12 pens/treatment) of mixed sex, blocked by body weight, were randomly allocated to either a control or HSTR diet for 2 weeks. The experimental treatments were as follows, depending on pre- and post-weaning dietary intervention: control/control; control/HSTR; HSTR/control; and HSTR/HSTR. Oat hulls were added to expense of corn starch to produce the HSTR treatment diet. Diets were adjusted with wheat and soy oil to achieve equal amount crude protein and SID Lysine but had up to 40 kcal net energy difference. Pigs were fed a common diet for the rest of nursery phase. Data were analyzed by general linear model in R. Results indicated pig performance was not different at weaning. Addition of STR in the pre-weaning phase increased average daily gain in the last post-weaning phase (P &amp;lt; 0.05), regardless of the post-weaning diets (Table 1). When HSTR was fed both in the pre and early post-weaning phase, greater fermentation (indicated by numerically greater butyrate and caproate concentration in colon digesta) was observed at 21 d post-weaning. In conclusion, providing HSTR during pre-weaning phase improves performance during later nursery phase and if STR is used both pre- and post-weaning, gut fermentation is affected.

39 Cow-calf Management Strategies and Their Influence on Environmental Sustainability

Abstract Forage and supplemental feed costs remain the overriding factors driving profitability in U.S. cow/calf operations. The cow/calf sector uses 74% of the total feed energy required to produce one pound of carcass weight. Methane is the second most abundant anthropogenic greenhouse gas after carbon dioxide. The cow/calf sector of beef production accounts for 77 to 81% of enteric methane emissions per unit of carcass weight produced. Reducing feed energy required and methane emissions by the cow/calf segment of the beef production system will improve economic, environmental, and social sustainability. Most of the beef production cycle occurs on land not suitable for raising crops. Of the 2.3 billion acres available in the United States, about 655 million acres (29%) are classified as grassland pasture and rangeland, and 316 million acres (14%) are identified as parks and wildlife areas, some of which are grazed. Therefore, improving forage utilization efficiency would have a wide-reaching impact on U.S. food security and profitability of cow/calf enterprises. Beef production is a critical component in U.S. and global food security because cattle upcycle poorly digestible plant components and food waste products into high-quality human edible protein. In recent years, substantial progress has been made in understanding 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 forage utilization efficiency for beef cows consuming moderate to low-quality forage diets common to most cow/calf production systems. Considerable evidence indicates the existence of an environment by genetic interaction for feed efficiency. More rapid progress in forage utilization efficiency and reduction in greenhouse gas emissions could be made by studying forage utilization efficiency directly.

34 Extended Effects of Sequential Weaning and Backgrounding Management in Beef Calves

Abstract Alternate weaning methods and backgrounding periods are strategies to reduce calf morbidity and mortality at feedlot arrival. The objective of this study was to assess the collective effects of weaning and post-weaning management practices on potential carryover effects on calf health and performance through the backgrounding phase. A total of 216 steer calves (average BW, 298 kg) from three Auburn University research farms were randomly assigned to one of three different weaning method groups: Fenceline weaning, nose-flap weaning, or abrupt weaning. Calves were weighed on d 0 and d 14 post weaning, and then began a 60-d preconditioning period. Calves were randomized according to previous weaning management, farm of origin, and body weight to one of three nutritional management strategies in a 3 ×3 factorial design: cool-season baleage (oats, ryegrass and crimson clover) and 1% BW dried distillers grains (DDGS), bermudagrass hay and 1% BW DDGS, or grazing mixed warm-season annuals and 1% BW DDGS. Calf body weights were collected on d 0, d 30 and d 60 of the backgrounding phase. Weights did not differ during the weaning phase but calves in the fenceline group had the greatest average daily gain (1.13 kg/d; P &amp;lt; 0.0001) during this phase. There was a weaning × backgrounding treatment interaction (P = 0.0097) for average daily gain during the first 30 d of the backgrounding phase. Calves that were fenceline weaned and on the cool season baleage diet had the highest average gain at 1.02 kg/d, whereas abruptly weaned calves on the grazing diet only gained 0.29 kg/d in the first 30 d. Steers on the cool season baleage diet had the greatest total gain (P &amp;lt; 0.0001) at 45.8 kg over the course of the 60-d period. These results indicate that backgrounding diet, coupled with weaning management strategies, may influence calf performance during the transition period for calves into the post-weaning phase.

Weaning differentially affects the maturation of piglet peripheral blood and jejunal Peyer\u2019s patches

The study aimed to assess how the post-weaning condition changes piglet peripheral blood (PB) and jejunal Peyer’s patches (JPPs) as compared to the suckling period, and how these changes are associated with intestinal microbiota evolution. Sixteen pigs were slaughtered and sampled for PB, JPPs and jejunal content (JC) at weaning (26 days) or at 12 days fed on a pre-starter diet. The PB and JPP transcriptomes were analysed using mRNA-seq. The Gene Set Enrichment Analysis was used to demonstrate enriched gene clusters, depending on sampling time. Jejunal microbiota was profiled using 16S rRNA gene sequencing. Post-weaning JPPs were enriched for processes related to the activation of IFN-γ and major histocompatibility complex (MHC) class I antigen processing which clustered with the reduced abundance of the Weisella genus and Faecalibacterium prausnitzii in JC. The post-weaning microbiome differed from that seen in just-weaned pigs. For just-weaned PB, the enrichment of genes related to hemoglobin and the iron metabolism indicated the greater presence of reticulocytes and immature erythrocytes. The JPP genes involved in the I MHC and IFN-γ activations were markers of the post-weaning phase. Several genes attributable to reticulocyte and erythrocyte maturation could be interesting for testing the iron nutrition of piglets.

Antibacterial potential of essential oils against planktonic and sessile cells of Escherichia coli isolated from diarrhea cases in swine

Escherichia coli is a pathogen associated with infections in piglets in the post-weaning phase, its pathogenicity is related to the animal's susceptibility to bacterial enterotoxins. The objective of the present study was to determine the EOs activity against E. coli strain, in the form planktonic and sessile. Although the Disc-Diffusion tests to determine the Minimum Inhibitory Concentration, do not fully corroborate with the other analyzes of this study, it was noticed bacteria inhibition. The EOs were prepared at 0.4%, 0.8% and 1.0% for tests. The tested EOs were effective against E. coli planktonic cells (p&lt;0.05). As for the sessile cells, the most significant result was inhibition and 100% sessile cells at the concentration of 1.0% of Cymbopogon citratus EO. Although there was resistance in some treatments, the tested EOs demonstrated inhibition capacity, constituting promising alternatives for the control of E. coli, especially of planktonic cells.