Pre-weaned Lambs Research Articles

Relationship Between Growth Performance, Passive Immunity and Health In Preweaned Lambs

This study was designed to investigate associations between transfer of passive immunity, selected illness-es (diarrhoea, pneumonia, and fatigue anorexia syndrome-FAS) and growth performance [body weight (BW) and aver-age daily gain (ADG)] in preweaned lambs. A total of 347 lambs were blood sampled at 24±1 h of age after birth and the serum IgG concentration for each lamb was measured after colostrum intake using a commercial ELISA kit. Lambs were weighed on a scale immediately after birth (before colostrum intake) and reweighed on day 28 (end of neonatal period) and day 84 (age of weaning). Lambs ADG was calculated from 0 to 28 d of life, from 29 to 84d of life, and from 0 to 84 d of life. Growth performance (BW and ADG) of lambs with diarrhoea and FAS in the neonatal period and with pneumonia in the postneonatal period was significantly lower than that of healthy lambs of the same period (P<0.05). BW of lambs with serum IgG concentration at 24th hour after the birth (SIgGC-24)<600 mg/dL and <1000 mg/ml was significantly lower on days 28 and 84 than that of lambs with SIgGC-24 >600 mg/dL and >1000 mg/ml (P<0.001). Simi-larly, the ADG of lambs with SIgGC-24 <600 mg/dL and <1000 mg/ml was significantly lower on days from 0-28, 29-84 and 0-84 of age than those of lambs with SIgGC-24 >600 mg/dL and >1000 mg/ml (P<0.001). In conclusion, our find-ings show that low serum IgG concentration in lambs, as well as the presence of pneumonia, diarrhea and FAS, reduc-es growth performance in pre-weaning lambs.

A randomized control trial investigating the effectiveness of a commercial pneumonia vaccine (part I): Pre-weaned lambs

The objective of this controlled vaccine field trial was to determine the effectiveness of a commercial bacterin in increasing colostral immunity to reduce the risk of bacterial pneumonia in pre-weaned lambs in a commercial sheep operation. Pregnant ewes were randomly allocated to vaccination group (Ovipast™ Plus bacterin, n = 1807; unvaccinated, n = 1812). Ewe vaccination did not significantly (P > 0.05) improve lamb pneumonia treatment rates, crude or pneumonia specific mortality rates, or body weight gain. Interestingly, as birth weight increased in lambs from vaccinated ewes, they gained significantly more than lambs from unvaccinated ewes (P = 0.01). There was no difference in culture results from pneumonic lung samples for either Mannheimia haemolytica (P = 0.89) or Bibersteinia trehalosi (P = 1.00) between lambs from vaccinated and unvaccinated ewes. The results of this study suggest that there was no animal health and welfare benefit from vaccinating ewes with the Ovipast™ Plus bacterin prior to parturition to boost colostral immunity and improve health and growth in their lambs.

Effects of indigenous <i>Saccharomyces cerevisiae</i> on intake, growth, gut histology, and serum biomarkers in pre-weaned Lohi lambs

The purpose of this study was to determine the comparative efficacy of locally-produced yeastnto commercial yeast on growth nperformance, serum biomarkers, and gut histology. Thirty pre-weanednmale Lohi lambs were divided into; 1) C (Control; starter diet nwith no supplement), 2) CY (starter dietnwith ewe milk supplemented with 1 g/animal/day commercial yeast), and 3) LY (starter dietnsupplemented with 1 g/animal/day local yeast). Animals were housed individually and fed a starter dietnand orts were weighed ndaily. Dry matter intake (DMI) was determined daily while the body weights werendetermined on a weekly basis. At the end of the trial, nblood samples were collected and analysed fornblood urea nitrogen (BUN), glucose, β-Hydroxybutyrate (BHBA), and non-esterified fatty nacids (NEFA),nwhile ruminal fluid and tissues were collected for rumen fermentation parameters andnhistomorphometry. The results nrevealed that the DMI and average daily weight gain (ADWG) werenhigher in CY and LY compared to C. The feed efficiency was also nbetter in CY and LY lambs comparednto C lambs. The BHBA, BUN, total proteins (TP), cholesterol, creatinine, blood glucose, and tissuenhistomorphometry were similar in LY and CY supplementation. In conclusion, supplementation with LYnproduced comparable nresults to the CY.

Molecular evaluation of Cryptosporidium spp. in sheep in southern Xinjiang, China.

Cryptosporidium spp. are diarrheagenic intestinal parasites with multiple hosts worldwide. A total of 1252 fresh fecal samples of sheep were collected from 10 large-scale farms in southern Xinjiang. Based on the small subunit ribosomal (SSU rRNA) gene of Cryptosporidium, 100 Cryptosporidium-positive samples (8.0%, 100/1252) were detected by PCR. Nine out of 10 farms were positive for Cryptosporidium, with the highest infection rate being 18.4% (23/125) on farm 9 in Qira. The infection rates of Cryptosporidium in pre-weaned lambs, weaned lambs, fattening sheep, and adult sheep were 20.3% (61/301), 10.3% (34/329), 0.9% (3/327), and 0.7% (2/295), respectively. Three Cryptosporidium species were identified, namely, C. xiaoi (n=61), C. parvum (n=22), and C. ubiquitum (n=17). Of them, C. xiaoi was detected on all positive farms and in different age groups of sheep. The subtypes of C. parvum and C. ubiquitum were identified by PCR at the 60 kDa glycoprotein (gp60) gene. Two C. parvum subtypes were identified: IIdA19G1 (n = 21) and IIdA15G1 (n = 1). One C. ubiquitum subtype was identified with XIIa (n = 17). These results indicated the common transmission and genetic diversity of Cryptosporidium in sheep in southern Xinjiang, and further investigations are needed on the zoonotic potential of C. parvum and C. ubiquitum in this region.

O-107 Investigating the efficacy of an ovine respiratory vaccine in reducing mortality and pneumonia-associated morbidity and mortality in pre-weaned and post-weaned lambs

O-107 Investigating the efficacy of an ovine respiratory vaccine in reducing mortality and pneumonia-associated morbidity and mortality in pre-weaned and post-weaned lambs

Effect of <i>Acacia albida</i> Leaf Supplementation on Reproductive Parameters and Pre-Weaning Growth of Arabian Lambs

A trial on Acacia albida leaf supplementation on reproductive parameters and pre-weaning growth of Arabian lambs was conducted from September 2020 to May 2021 at the small ruminant station of the Livestock Research Institute for Development (IRED) in N’Djamena, Chad. Forty-eight (48) Arabian sheep (45 non-pregnant females and 3 males for a sex ratio of 1 ram to 15 ewes) with an average weight of 20.3 ± 1.2 kg and aged approximately 2 years were divided into 3 groups of 15 ewes each. The supplemented group received in addition to the dominant forage of the pasture (300 g of Dactyloctenium aegyptium + 300 g of Cenchrus ciliaris + 600 g of Panicum maximum), 400 g and 600 g of Acacia albida leaves/animal/day while the control group received only 300 g of Dactyloctenium aegyptium + 300 g of Cenchrus ciliaris + 600 g of Panicum maximum. From the results of this study, it appears that the ewes that received 400 g of Acacia albida leaves had a significantly higher fertility rate and birth mortality rate (93.03% and 6.25% respectively). Animals in the control group had a significantly higher pre-weaning mortality rate than those receiving Acacia albida leaves as a supplement (16.66% versus 6.66% and 14.28% respectively). The highest weight of the lambs was observed in the ration supplemented with 600 g of Acacia albida leaves (12209.66 g). The total weight gain, as well as the average daily weight gain of the lambs receiving the 600 g Acacia albida leaf ration was significantly higher than those of the other rations. Supplementation with 400 g and 600 g of Acacia albida leaves can be recommended as a protein supplement for breeding ewes and pre-weaned lambs.

Increased Dietary Protein to Energy Ratio in Pre-Weaning Lambs Increases Average Daily Gain and Cortical Bone Thickness in the Tibia

The objective of this study was to examine if diets differing in crude protein (CP) to metabolizable energy (ME) ratio (CP:ME) pre-weaning altered peripheral quantitative computed tomography (pQCT) measures of bone mass and strength in lambs. The left hind leg of lambs were available at the completion of a trial designed to examine the effect that altering the CP:ME ratio in milk replacer had on growth and body composition of pre-weaned lambs reared artificially. Treatments consisted of either normal commercial milk replacer (CMR, n = 10) containing 240 g/kg CP and 21.89 MJ/kg ME, high protein milk replacer (HPM, n = 9) containing CMR with additional milk protein concentrate to reach 478.7 g/kg CP and 19.15 MJ/kg ME or a mix of normal milk replacer and milk protein concentrate adjusted twice-weekly to match optimal CP:ME requirements (MB, n = 8) based on maintenance plus 300 g/d liveweight gain. At 22 kg live weight, lambs were euthanized and the tibia including the surrounding muscle was collected and scanned using pQCT at the mid-diaphysis. Lambs on the HPM and MB diets had a greater average daily gain (p < 0.01). There were limited differences in bone morphology and muscle mass, though notably the higher protein diets (MB and HPM) were associated with greater cortical thickness (p < 0.05) and, therefore, potentially greater peak bone mass at maturity This finding demonstrates that pre-weaning diets, and the protein content in particular, may influence the developmental potential of long bones and attainment of peak bone mass at maturity.

Growth dynamics and altitude effect on growth performance of Ouled Djellal lambs during the pre-weaning period

Abstract. This study evaluates the growth dynamics and the effect of altitude on different growth phases of pre-weaned Ouled Djellal lambs in northeastern Algeria. Forty-nine lambs born in the spring to multiparous ewes were weighed, and their average daily gain was calculated at different ages (at birth, D 30, 60, 90 and 120). The results show that maximum growth occurs during the lamb’s first month of life at 200 g/day. Highly positive and significant correlations were recorded between D 90 and D 120 (0.94), D 60 and D 120 (0.88), D 60 and D 90 (0.87) and D 30 and D 90 (0.77). Concerning the altitude effect, lambs born in low altitude regions show a better growth performance than lambs born in high altitude regions, with a significant difference (P0.05) noticed for D 90 and D 120, which confirms that the Ouled Djellal breed is a typical breed of the steppe and the high plains.

Validation of a mechanistic dynamic pre-weaned lamb growth and body composition simulation model

Lamb growth and body composition simulation models can provide valuable insights into the assessment of feeding regimens and rearing systems, allowing optimisation of farm profitability without the need for in-vivo trials. The objective of the present study was to evaluate the performance of a published mechanistic dynamic model on the growth and body composition of pre-weaned lambs using independently published data sets. Data generated from eight treatments, representing three artificial lamb rearing experiments (n = 77 lambs) were used. Initial body composition data were obtained from four lambs at approximately two days of age, with the remaining lambs being provided with defined nutritional treatments until the trial end-point. The body composition of lambs at slaughter was determined in six treatments across two experiments. Feed intake and live weight (LW) of lambs were recorded in all treatments. The LW, average daily gain (ADG) and ash deposition rates of lambs were accurately simulated by the model (paired t-test, P > 0.05). The overall empty body weight (EBW), gutfill, protein and fat deposition rates were overestimated, and water deposition rate was underestimated by the model (paired t-test, P < 0.05). Collectively, these results suggest that the model can be used at the farm level with acceptable accuracy to determine lamb growth. Further improvements in the model are required for protein, fat and water deposition rates, gutfill and EBW to make it more applicable for wider usage.

Predicting the Feed Intake of Artificially Reared Pre-Weaned Lambs from Faecal and Dietary Chemical Composition

Predicting feed intake in suckling lambs consuming both milk and pasture can be challenging, and thus intake values are often derived from solely milk or solid feed consumption. The present study investigated if dry matter (DM), organic matter (OM), and metabolisable energy (ME) intakes of lambs given a combination of milk and pellets under controlled conditions could be predicted with enough precision using dietary and faecal chemical composition. A total of 34 pre-weaned lambs bottle-fed milk replacer with or without access to pellets and kept in metabolic cages for four days were used. To develop the prediction equations, 54 faecal samples with detailed information on their chemical compositions, and the feed consumed by the lambs, were used. Pellet DMI was predicted from neutral detergent fibre concentration in faeces and pellets, pellets %DM, and live weight (LW) of lambs. Milk DMI was predicted from faecal Nitrogen concentration and LW. Milk and pellet DMI and their ME content were combined to predict DMI/d and ME intake/d. The equations developed were validated against 40 spot faecal samples randomly selected from the lambs. DM, OM, and ME intakes were predicted with high accuracy and precision. The results showed that the developed equations can be used with enough accuracy to predict ME, OM, and DM intakes in pre-weaned lambs ingesting milk and pellets concurrently, thus the results revealed that the established equations may be used to predict ME, OM, and DM intakes in pre-weaned lambs drinking milk and pellets at the same time, allowing feeding regimens for young lambs to be developed.

Proteomic identification of ruminal epithelial protein expression profiles in response to starter feed supplementation in pre-weaned lambs.

The present study aimed to comparatively characterize the ruminal epithelial protein expression profiles in lambs fed ewe milk or milk plus starter diet using proteome analysis. Twenty new-born lambs were randomly divided into a group receiving ewe milk (M, n = 10) and a group receiving milk plus starter diet (M + S, n = 10). From 10 d old, M group lambs remained with the ewe and suckled ewe milk without receiving the starter diet. The lambs in the M + S group were separated from the ewe and received starter feed. All lambs were slaughtered at 56 d old. Eight rumen epithelia samples (4 per group) were collected to characterize their protein expression profiles using proteomic technology. Proteome analysis showed that 31 upregulated proteins and 40 downregulated proteins were identified in the rumen epithelium of lambs in response to starter diet supplementation. The results showed that starter feeding regulates a variety of biological processes in the epithelium, especially blood vessel development and extracellular matrix protein expression. Meanwhile, the expression of proteins associated with synthesis and degradation of ketone bodies, butanoate metabolism, and citrate cycle signaling transduction pathway were upregulated in the group with starter diet supplementation, including 3-hydroxy-3-methylglutaryl coenzyme A synthase (HMGCS2, fold change [FC] = 1.93), 3-hydroxybutyrate dehydrogenase 1 (BDH1, FC = 1.91), and isocitrate dehydrogenase 1 (IDH1, FC = 8.12). The metabolic processes associated with ammonia detoxification and antioxidant stress were also affected by starter diet supplementation, with proteins, microsomal glutathione S-transferase 3 (MGST3, FC = 2.37) and IDH1, linked to the biosynthesis of glutamate and glutathione metabolism pathway being upregulated in the group with starter diet supplementation. In addition, starter feeding decreased the expression of Ras-related protein rap-1A (RAP1A, FC = 0.48) enriched in Rap1 signaling pathway, Ras signaling pathway, cyclic adenosine monophosphate (cAMP) signaling pathway, and mitogen-activated protein kinase (MAPK) signaling pathway. In summary, starter feed supplementation changed the expression of proteins related to energy production, ammonia detoxification, antioxidant stress, and signaling pathways related to proliferation and apoptosis, which facilitates the rumen epithelia development in lambs. The results provide new insights into the molecular adaptation of rumen epithelia in response to starter diet supplementation at the protein level in lambs.

Effect of Palpable Udder Defects on Milk Yield, Somatic Cell Count, and Milk Composition in Non-Dairy Ewes.

Simple SummaryThe occurrence of udder defects in ewes impacts the productive lifespan of the affected ewe and reduces their lamb production. This study investigated the effects of palpable udder defects on milk yield and milk composition in Romney ewes. The findings showed that the effect of udder-half defects on udder-half milk yield was substantial; however, there was no difference in individual (whole udder) ewe milk production between ewes with one udder-half defective and both normal udder-halves. This was due to a compensatory increase in milk production of the normal udder half when the other udder half was defective, with the exception being ewes that retained the defects for several weeks. No notable difference in milk composition was observed between defective and normal udder halves, except for solids non-fat (SNF). This study shows that udder defects affect milk production in non-dairy ewes, highlighting the potential effects on lamb production.In non-dairy ewes, udder defects hinder the survival and weight gain of their pre-weaned lambs. The objectives of this study were to determine the effects of palpable udder defects on milk yield, somatic cell count (SCC), and milk composition in non-dairy Romney ewes. Ewes with a history of udder defects or normal udders were selected for the study. Of a total of 48 ewes that lambed, 30 ewes reared at least one lamb, and were milked six times, once weekly, for the first six weeks of lactation. Udder halves were palpated and scored at each milking event. Multivariate linear mixed models examined the impacts of udder defects on udder-half and whole-udder milk yield, SCC, and milk composition (fat, protein, lactose, total solids, and solids non-fat (SNF)). Across the six examinations, 24.7% of the total 352 udder-half examinations were observed to be defective. Udder halves that were defective at least once produced on average 57.9% less (p < 0.05) milk than normal udder halves, while normal udder halves with a contralateral defective half yielded 33.5% more (p < 0.05) milk than normal udder halves. Successive occurrence of both hard and lump udder defect categories in an udder-half, udder defect detection early in lactation, and a high frequency of udder defect detection were all associated with udder-half milk yield loss (p < 0.05). At the whole-udder level, no differences in milk yield (p > 0.05) were observed between those with one udder-half defective and both normal udder-halves. However, udders in which one udder half was categorised as hard but progressed to lump and remained as lump until 42 days of lactation produced less (p < 0.05) milk compared with normal udders. With the exception of SNF, there were no significant associations (p > 0.05) between milk composition parameters and udder defect. Overall, these findings emphasise the importance of udder health in non-dairy ewes and the potential effect of udder defects on their lambs.

Prevalence of Cryptosporidium parvum in sheep in Abeokuta, Ogun State, Nigeria

The prevalence of Cryptosporidium parvum infection in sheep was determined in Abeokuta, Ogun state, Nigeria. Faeces from randomly selected sheep were analyzed using the Enzymelinked Immunosorbent assay (ELISA) technique. Cryptosporidium parvum antigens were detected in stools of 174 sheep by the use of a commercial ELISA kit. A total of 28.7% of the stools were positive for the antigens. The infection rates decreased with age, the pre-weaned lambs (51.1%) having a significantly higher (p&lt;0.05) in males (42.9%) and sheep with diarrhoeic stools (41.8%) than in females (17.5%) and sheep with formed stools (17.9%) respectively. This study therefore reveals that the prevalence of Cryptosporidium parvum infection is high in sheep reared in Abeokuta and may serve as a reservoir for human infections.

Occurrence and molecular characterization of Giardia duodenalis in lambs in Djelfa, the central steppe of Algeria

Little is known of the prevalence and genetic identity of Giardia duodenalis in sheep in Algeria. The present study aimed at characterizing G. duodenalis in lambs up to 6months of age in Djelfa, Algeria. A total of 346 fecal specimens were collected from 28 farms and screened for G. duodenalis cysts by zinc sulfate flotation microscopy, and positive specimens were confirmed using a direct immunofluorescence assay. Microscopy-positive specimens were analyzed by PCR and sequence analysis of the triosephosphate isomerase and glutamate dehydrogenase genes to determine G. duodenalis assemblages. Coprological examination indicated that the overall infection rate was 7.0% (24/346). Lambs under 3months of age had higher infection rate (18/197, 9.0%) than older (6/149, 4.0%) animals, and animals with diarrhea (7/44, 16.0%) had higher infection rate than animals without diarrhea (17/302, 5.6%). PCR sequence analyses of the 15 G. duodenalis isolates revealed the presence of assemblages A in 6 isolates, assemblage E in 7 isolates, and both in 2 isolates. Assemblage A was only found in pre-weaned lambs with diarrhea, while assemblage E was mostly found in post-weaned lambs without diarrhea. The assemblage E isolates from sheep were genetically related to those from cattle in Algeria, while assemblage A isolates were from a well-known subtype prevalent in humans. Data generated from the study improve our understanding of the transmission of G. duodenalis in Algeria.

Effect of dietary protein to energy ratio of milk replacer on growth and body composition of pre-weaned lambs reared artificially

This study aimed to determine the effect of changing the dietary crude protein to metabolisable energy ratio (CP:ME) of milk replacer on growth and body composition of pre-weaned lambs. Thirty-two Romney twin-born ram lambs were selected with four lambs being slaughtered at 24 h post-partum to estimate initial body composition. The remaining twenty-eight lambs were assigned to one of three nutritional treatments. Treatments consisted of either (i) a commercial milk replacer (CMR, n = 10); (ii) a high protein milk replacer (HPM, n = 9) or (iii) a mix of normal milk replacer and milk protein concentrate (MB, n = 9). All lambs were fed at 2.1 times their maintenance requirement. The CP:ME ratio of MB was adjusted twice-weekly to match the lambs CP and ME requirements for growth and maintenance over time. All lambs were slaughtered at 22 kg live weight (LW). The LW and chemical composition of carcass and viscera plus blood were determined. The combined CP:ME ratio of milk and pellets was greater for the HPM lambs than MB lambs, which was greater (P < 0.0001) than CMR lambs. Daily ME intake was greater (P < 0.05) in MB compared to HPM and CMR, which did not differ (P > 0.05). Average daily LW gain was higher (P < 0.05) in both HPM and MB lambs than CMR lambs. The ME and CP intakes per kilogram LW gain were greater (P < 0.05) for CMR and HPM lambs, respectively than MB lambs. Omental fat content at slaughter was lowest (P < 0.05) and gut fill was greatest (P < 0.05) in HPM, while CMR and MB did not differ (P > 0.05) for either parameters. Fat content of the carcass and viscera plus blood was lowest (P < 0.05) in HPM whilst, there was no difference (P > 0.05) between CMR and MB. Lambs fed HPM had lower (P < 0.05) daily fat deposition than CMR, which was highest (P < 0.05) in MB. Daily dry matter deposition was greater (P < 0.05) in MB than both CMR and MB, which did not differ (P > 0.05). In conclusion, adjusting the CP:ME ratio of milk replacer to match the lambs’ theoretical requirement improves growth performance of artificially reared lambs. Further studies are required to determine the optimal CP:ME ratio effect of milk replacer, its cost effectiveness and to examine post-weaning growth effects.

A Mechanistic dynamic simulation model of nutrient utilization, growth and body composition in pre-weaned lambs reared artificially

A mechanistic dynamic model was developed to simulate the growth and body composition of pre-weaned lambs reared artificially. The results of the simulated model were evaluated using data from the three experiments involving 79 twin-born male lambs randomly allocated to different combinations of milk replacer and pellet feeds resulting in ten treatment groups. The accuracy of simulation of the output traits was evaluated by mean bias, concordance correlation coefficient (CCC), relative predictive error (RPE) and the coefficient of determination (R2). The model accurately simulated daily protein deposition (mean bias = 0.07 g /d ± 1.5; R2 = 0.93; RPE = 4.21 %; CCC = 0.96), water deposition (mean bias = -2.34 ± 6.75 g /d ± 1.5; R2 = 0.97; RPE = 6.23 %; CCC = 0.94) and ash deposition (mean bias = 0.22 ± 0.43 g /d ± 1.5; R2 = 0.83; RPE = 9.00 %; CCC = 0.87) rates. Fat deposition in lambs was underestimated (paired t-test, P < 0.05; mean bias = 3.75 ± 4.99 g /d) due to an over-estimation of maintenance energy requirement for lambs given restricted access to pellet feeds and, therefore, resulting in an overall poor prediction of fat deposition rate (R2 = 0.37 RPE = 29.78%; CCC = 0.34). Empty body weight at slaughter of the lambs was accurately simulated (R2 = 0.95 RPE = 1.66%; CCC = 0.97). Although live weights (LW) and average daily gains (ADG) of the lambs were underestimated (paired t-test, P < 0.05), the accuracies of the overall simulated means for LW and ADG were substantial (R2 = 0.90 and 0.99; RPE = 3.73 % and 6.11; CCC = 0.89 and 0.95 for LW and ADG, respectively). The model was re-run after adjusting for the maintenance energy function. The R2 and CCC values for daily fat deposition increased from 0.37 to 0.46 and from 0.34 to 0.67 respectively, while the RPE decreased from 29.78% to 10.68% and overall actual and simulated mean fat deposited were not different (paired-t-test, P > 0.05). The evaluations presented indicated that the lamb growth model developed in this study can be used to simulate, with acceptable accuracy, pre-weaned lamb growth and body composition under different artificial rearing conditions where milk replacer, pellet intake and composition varies.

A metagenomic survey of lamb's pre- and post-weaning fecal microbiomes

ABSTRACT Weaning is known to be the most stressful and critical transition experienced by lambs, it affects the structure of the gastrointestinal tract microbiomes, which significantly influences the lamb’s health and performance. The present study identified the structure of lambs' pre- and post-weaning fecal microbiomes to define the implications of the weaning transition. Illumina MiSeq yielded a total of 5169 sequence reads per fecal sample ranging from 106 to 2028. Before weaning, the taxonomic analysis indicated that the phylum Firmicutes dominated other bacterial phyla at a rate of (≤52.47%), followed by Proteobacteria at a rate of (≤52.00%). On the contrary, the phylum Firmicutes (≤93.01%) tended to increase, while the phylum Proteobacteria tended to decrease (≤26.83 %) after weaning. At the genus level, twenty-eight genera assigned to three phyla were detected in pre-weaned lambs; meanwhile, thirty-three genera assigned to four phyla were identified in post-weaned lambs. These findings suggested that weaning significantly influenced the diversity and the abundance of lambs' fecal microbiota.

Aspartame supplementation in starter accelerates small intestinal epithelial cell cycle and stimulates secretion of glucagon-like peptide-2 in pre-weaned lambs.

The objective of this study was to test the hypothesis that aspartame supplementation in starter diet accelerates small intestinal cell cycle by stimulating secretion and expression of glucagon-like peptide -2 (GLP-2) in pre-weaned lambs using animal and cell culture experiments. In vivo, twelve 14-day-old lambs were selected and allocated randomly to two groups; one was treated with plain starter diet (Con, n=6) and the other was treated with starter supplemented with 200mg of aspartame/kg starter (APM, n=6). Results showed that the lambs received APM treatment for 35 d had higher (p<.05) GLP-2 concentration in the plasma and greater jejunum weight/live body weight (BW) and jejunal crypt depth. Furthermore, APM treatment significantly upregulated (p<.05) the mRNA expression of cyclin D1 in duodenum; and cyclin A2, cyclin D1, cyclin-dependent kinases 6 (CDK6) in jejunum; and cyclin A2, cyclin D1, CDK4 in ileum. Moreover, APM treatment increased (p<.05) the mRNA expression of glucagon (GCG), insulin-like growth factor 1 (IGF-1) in the jejunum and ileum and mRNA expression of GLP-2 receptor (GLP-2R) in the jejunum. In vitro, when jejunal cells were treated with GLP-2 for 2hr, the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) OD, IGF-1 concentration, and the mRNA expression of IGF-1, cyclin D1 and CDK6 were increased (p<.05). Furthermore, IGF-1 receptor (IGF-1R) inhibitor decreased (p<.05) the mRNA expression of IGF-1, cyclin A2, cyclin D1 and CDK6 in GLP-2 treatment jejunal cells. These results suggest that aspartame supplementation in starter accelerates small intestinal cell cycle that may, in part, be related to stimulate secretion and expression of GLP-2 in pre-weaning lambs. Furthermore, GLP-2 can indirectly promote the proliferation of jejunal cells mainly through the IGF-1 pathway. These findings provide new insights into nutritional interventions that promote the development of small intestines in young ruminants.

Effects of starter feeding on caecal mucosal bacterial composition and expression of genes involved in immune and tight junctions in pre-weaned twin lambs

The objective of this study was to explore the effects of starter feeding on caecal mucosal bacterial composition and the expression of genes involved in immune and tight junctions in pre-weaned lambs. Six pairs of new-born twin lambs were selected. From 10 days of age, one lamb of each pair received ewe's milk only (M group, n = 6), while the other one was fed ewe's milk plus starter feed (M + S group, n = 6). At 56 days of age, the lambs were sacrificed, and then cecum digesta was collected to measure pH values and concentrations of volatile fatty acid (VFA), and caecal mucosa were collected to determine the changes in bacterial communities and the mRNA expression of cytokines, toll-like receptors (TLRs) and tight junction proteins. The results showed the body weight and average daily gain were not significantly different between both groups. Starter feeding significantly (P < 0.05) increased the concentrations of propionate and butyrate; the proportions of acetate, propionate and butyrate to total concentrations of VFA; and decreased the ratio of acetate to propionate in caecal contents. Principal coordinate analysis showed that samples from the M + S group could be distinguished from those from the M group; starter feeding also increased the diversity of caecal mucosal bacteria. At the genus level, starter feeding significantly (FDR < 0.05) increased the relative abundance of Alistipes, Parabacteroides, Parasutterella and Butyricimonas, and caused a decreasing trend (FDR < 0.10) in the relative abundance of Campylobacter and Helicobacter. The real-time PCR results showed that starter feeding significantly (FDR < 0.05) decreased the relative mRNA expression level of IL-12, TNF-α and TLR4 and increased the relative mRNA expression level of claudin-4. These results indicate that starter feeding altered caecal mucosal bacterial communities and decreased the expression of inflammatory factors, which may be beneficial in alleviating the weaning stress of lambs.

Novel Picornavirus in Lambs with Severe Encephalomyelitis.

Using metagenomic analysis, we identified a novel picornavirus in young preweaned lambs with neurologic signs associated with severe nonsuppurative encephalitis and sensory ganglionitis in 2016 and 2017 in the United Kingdom. In situ hybridization demonstrated intralesional neuronotropism of this virus, which was also detected in archived samples of similarly affected lambs (1998–2014).