Early-weaned Lambs Research Articles

A multi-omic assessment of the mechanisms of intestinal microbes used to treat diarrhea in early-weaned lambs.

Transplant of donor microbiota can significantly alter the structure of the host's intestinal microbiota and alleviate early weaning stress. Screening for alternative-resistant products by transplanting fecal bacteria from healthy lambs is a current research trend in the livestock industry. In the present study, fecal microbiota transplantation was performed in lambs with diarrhea during early weaning. The transplanted fecal microbiota greatly reduced the diarrhea and serum inflammatory factor levels caused by early weaning. Transcriptome sequencing revealed that fecal microbiota transplantation alleviated colonic inflammation and increased the expression of colonic ion transport proteins. In addition, the levels of Streptococcus, Enterococcus, and Escherichia Shigella decreased in the jejunum, cecum, and colon of the lambs; meanwhile, the levels of Bifidobacterium and multiple secondary bile acids, such as ursodeoxycholic acid, increased in the colon. Furthermore, the abundance of Bifidobacterium was significantly negatively correlated with the diarrhea index. The fecal microbiota transplantation reshaped the intestinal microbiota of early-weaned lambs, protected the intestinal physiology and immune barrier, and reduced weaning stress. In addition to making available bacteriological products for controlling intestinal inflammation in young lambs, this study offers a theoretical framework and technical system for the mechanisms by which microbiota transplantation regulates intestinal health in young lambs.IMPORTANCEBefore weaning, the digestive system of lambs is not well developed; hence, its resistance to infectious diseases is weak. Under intensive feeding systems, lambs can easily be stressed and the risk of bacterial infection is high, which causes diarrhea, which in turn may cause mortality and significant economic losses to the livestock industry. With the elimination of antibiotics in animal feed, the incidence of mortality due to intestinal illnesses in lambs has gradually increased. There are several types of probiotics routinely used in young animals, but the effects and processes of their usage have only been assessed in monogastric animals. The lack of data on ruminants, particularly sheep, has severely hampered the process of efficient and healthy sheep breeding. Therefore, there is an urgent need to identify effective and safe functional supplements for lambs.

Astragalus additive in feed improved serum immune function, rumen fermentation and the microbiota structure of early-weaned lambs.

The purpose of this study was to determine the mechanism of Astragalus activity on the immune function, rumen microbiota structure, and rumen fermentation of early-weaned lambs. Thirty healthy early-weaned lambs with similar body weights (17.42±2.02kg) were selected for the feeding experiment. The control group (KB) was fed a basal diet, and the Astragalus group (HQ) was fed 0.3% Astragalus additive on the basis of a basic diet. The formal trial period was 60 days. The results showed that the concentrations of blood immunoglobulin A (IgA) and immunoglobulin M (IgM) in the HQ group were significantly higher than those in the KB group (P<0.05). Compared with the KB group, the concentrations of acetic acid, butyric acid, and total volatile fatty acids (VFAs) in the HQ group were higher (P<0.01). The expression levels of the rumen epithelial-related genes MCT1, MCT4, NHE2, and ZO1 in the Astragalus group were significantly higher than those in the KB group (P<0.05). 16S rRNA analysis showed that at the phylum level, Bacteroidetes in the HQ group significantly increased (P<0.01); at the genus level, Prevotella (P<0.01) and Succiniclasticum (P<0.01) in the HQ group were found at significantly higher abundances than those in the KB group, and the results of microbiota gene and function prediction showed that "energy metabolism," "glycan biosynthesis and metabolic" pathways were significantly enriched in the HQ group (P<0.05). As a feed additive, Astragalus can improve the immunity of early-weaned lambs, the structure of the rumen microbiota of lambs, and the fermentation capacity of the rumen.

Yeast Peptides Improve the Intestinal Barrier Function and Alleviate Weaning Stress by Changing the Intestinal Microflora Structure of Weaned Lambs.

Early weaning stress in lambs leads to decreased feed intake, damage to intestinal morphology, changes in the microbial flora structure, and subsequent complications. Yeast peptides are antimicrobial peptides with anti-inflammatory, antioxidant, and bacteriostasis effects. To study the effects of yeast peptides on relieving weaning stress in lambs, 54 lambs were randomly divided into three groups: ewe-reared (ER), yeast-peptide-treated (AP), and early-weaned (EW) lambs. The body weight and dry matter intake did not significantly differ among all groups. After weaning, the daily gain and feed conversion rate decreased significantly (p < 0.01), but AP showed an upward trend. In the EW group, immunoglobulin (Ig) levels changed significantly post-weaning (IgG decreased; IgA and IgM increased); the villi shortened, the crypt depth increased, and the villi height/crypt depth decreased (p < 0.001). The abundance and diversity of microflora among all groups were not significantly different. A column coordinate analysis showed significant differences in the intestinal microbial structure between the AP and EW groups. Lactobacillus, Aeriscardovia, Ruminosaceae_UCG-014, and Catenisphaera may play key roles in alleviating weaning stress in lambs. Our study provides new clues for alleviating weaning stress in lambs by describing the influence of yeast peptides on the intestinal microflora during weaning.

Effect of Marine Red Yeast Rhodosporidium paludigenum on Diarrhea Rate, Serum Antioxidant Competence, Intestinal Immune Capacity, and Microflora Structure in Early-Weaned Lambs.

In this study, the influences of marine red yeast Rhodosporidium paludigenum (MRYP) on diarrhea rate, serum antioxidant capacity, intestinal immunity capacity, and microflora structure of early-weaned lamb were investigated in a 60-day feeding trial. A total of 96 early-weaned lambs were utilized in this study. The lambs were divided into four experimental groups based on the percentage of marine red yeast Rhodosporidium paludigenum (MRYP) as milk replacer supplement. The rates of milk replacer supplement for the four groups were 0, 0.1%, 0.3%, and 0.5% of marine red yeast Rhodosporidium paludigenum (MRYP), respectively. The study was continued for 30 days. The results showed that (1) compared with control group, 0.5% marine red yeast Rhodosporidium paludigenum (MRYP) supplementation caused significantly decreases in average fecal score and diarrhea frequency by 33.74% and 40.23% (P < 0.05). (2) No significant difference was found in all tested related antioxidant indexes in serum of four treatments (P > 0.05). (3) The concentrations of SIgA, IgG, and IL-10 of group IV was significantly increased by 17.78%, 18.27%, and 8.17%, but the IL-6 and TNF-α were significantly decreased by 21.20% and 31.80%, compared to group I in the colon (P < 0.05). (4) The number of Bifidobacterial and Lactobacilli of group IV was significantly increased by 14.87% and 15.09%, but Escherichia coli and Salmonella were significantly decreased by 20.19% and 10.15%, compared to group I in the colon (P < 0.05). (5) A portion of marine red yeast Rhodosporidium paludigenum (MRYP) survived in the intestine of early-weaned lamb, and the number of survival marine red yeast Rhodosporidium paludigenum (MRYP) increased as the addition of marine red yeast Rhodosporidium paludigenum (MRYP) increased from 0.1 to 0.5% in milk replacer. Therefore, marine red yeast Rhodosporidium paludigenum (MRYP) has a potential to be a replacer of antibiotics for prevention and treatment of diarrhea in early-weaned lambs.

English

This study was conducted to investigate the effects of Boulardiiyeast wall polysaccharide (BRYP) on the intestinal micro-ecosystem of early-weaned lambs. A total of 60 early-weaned lambs (35-days-old, Kazak♂*Altay♀*Suffolk♂) were randomly assigned into two treatments: a control group with a basal diet, an experimental group with a basal diet and added 0.05% BRYP. The HiSeq high-throughput sequencing analysis of 16SrRNA was used to investigate the differences in intestinal microbial flora composition, diversity, relative abundance, principle coordination analysis, and the correlation between intestinal microbial flora composition and immune indices. After feeding for 40days, the addition of 0.5% BRYP in milk replacer significantly enhanced the species richness in the cecum and colon, but decreased the diversity of species in the colon (P &lt;0.05); Compared with the control group, the relative abundance of Bacteroidetes in the experimental group was significantly enhanced, but the Proteobacteria was significantly decreased in all tested intestinal segments (P &lt;0.05).In the jejunum, the relative abundance of Lactobacillus, Prevotella, and Fibrobacter of the experimental group were significantly enhanced than that of the control group, but the Ruminobacter was significantly decreased (P &lt;0.05); In the cecum, the relative abundance of Bacteroides, Lactobacillus, Oscillospira and Bifidobacterium of the experimental group were significantly enhanced than that of the control group, but the Blautia were significantly decreased (P &lt;0.05); In the colon, the relative abundance of Akkermansia, Bifidobacterium, Lactobacillus and Faecalibacteriumof the experimental group were significantly enhanced than that of the control group, but the Prevotella, Streptococcus, and Escherichia were significantly decreased (P &lt;0.05). There were significant correlations between intestinal immune indices (IL-6, IL-10, TNF-α) and intestinal microbial composition in the colon (P &lt;0.05). These results indicated that BRYP may contribute to the promotion of the proportion of helpful microbial populations and enhancing the balance of intestinal; Besides, BRYP may indirectly improve the intestinal immune function by changes of intestinal microflora composition, but suppress the inflammatory response in the bottom of intestinal mucosa of early-weaned lambs.© 2021 Friends Science Publishers

Ultrasound-assisted extraction of boulardii yeast cell wall polysaccharides: Characterization and its biological functions on early-weaned lambs.

Firstly, this study was designed to determine the optimal ultrasound‐assisted extraction parameters of Saccharomyces boulardii yeast wall polysaccharides (BYWP). Besides, the molecular weight and the ratio of mannose to glucose in compositions of BYWP were determined. Also, the effects of BYWP on the gain feed ratio, diarrhea frequency, intestinal morphology, intestinal immunity, and intestinal microbial flora of early‐weaned lambs were investigated. Single‐factor tests and Response surface optimization analysis (RSA) were used to obtain the optimal ultrasound‐assisted extraction conditions. Sephadex G‐100 column chromatography and liquid chromatography were used to analyze the molecular weight and ratio of mannose to glucose. The feeding trial was used to observe the biological functions of BYWP on early‐weaned lambs. A total of 72 36‐day‐old crossbred early‐weaned lambs were randomly divided into 4 groups with 3 replicates per group and 6 lambs per replicate. Lambs in the four treatments were fed basal milk replacer without supplement (Group I), basal milk replacer+0.1% BYWP (Group II), basal milk replacer+0.3% BYWP (Group III), and basal milk replacer+0.5% BYWP (Group IV), respectively. The optimal ultrasound‐assisted extraction parameters were as follows: NaOH addition: 52.63%, ultrasonic power: 143.15 W, ultrasonic time: 86.20 min, and the optimized extraction yield reached 37.54%. The molecular weights of main components BLC‐1 and BLC‐2 were 164.68 KDa and 13.21 KDa, and their proportions in BYWP were 24.57% and 66.08%, respectively. The proportions of glucose, mannose in BLC‐1 and BLC‐2 were 47.68%, 39.18%, and 76.59%, 6.86%, respectively. The addition of 0.3% and 0.5% BYWP in basal milk replacer significantly increased the average daily gain and feed conversion rate, and decreased the average fecal index and diarrhea rate of early‐weaned lambs. The addition of 0.3% and 0.5% BYWP significantly enhanced the intestinal morphology (villus height, crypt depth, and V/C value) of jejunum, ileum (p < .05). The addition of 0.3% and 0.5% BYWP significantly improved the levels of SIgA and IL‐10, but significantly decreased the level of IL‐1 in the ileum (p < .05). The addition of 0.3% and 0.5% BYWP significantly increased the number of Lactobacillus, but significantly suppressed the growth of Salmonella and Clostridium perfringens (p < .05). The results of the present study suggest that the supplementation of BYWP in the diet of early‐weaned lambs could increase feed utilization rate, and enhance intestinal morphology, immunological competence, microbial flora balance, and decrease the rate of diarrhea occurrence.

Pre-Exposure of Early-Weaned Lambs to a Herb-Clover Mix Does Not Improve Their Subsequent Growth.

Simple SummaryExposure of lambs to herbage-based diets prior to weaning may facilitate the development of the rumen which may subsequently increase animal performance after early weaning. The aim of this study was to estimate the effects of varying durations of exposure of lambs to a herb–clover mix containing chicory, plantain, red clover, and white clover prior to early weaning (at ~45 days of age) on their subsequent growth and rumen development at conventional weaning age. Prolonged exposure of lambs to the herb–clover mix prior to early weaning had no impact on lamb growth or rumen development, suggesting that using this management option will not improve performance of lambs after early weaning.Twin sets of lambs were randomly allocated to one of six treatments: (1) lambs born and managed on ryegrass–clover-based pasture until conventional weaning approximately at 99 days of age (Grass–GrassCW); (2) lambs born on ryegrass–clover-based pasture and early weaned onto a herb–clover mix at ~45 days of age (Grass–HerbEW); (3) lambs born on ryegrass–clover-based pasture, transferred with their dam onto a herb–clover mix at ~45 days of age until conventional weaning (Grass–HerbCW); (4) lambs born on ryegrass–clover-based pasture, transferred with their dam onto a herb–clover mix at ~15 days of age and early weaned onto a herb–clover mix at ~45 days of age (Grass–HerbD15EW); (5) lambs born and managed on herb–clover mix until conventional weaning (Herb–HerbCW); (6) lambs born on herb–clover mix and weaned early onto a herb–clover mix at ~45 days of age (Herb–HerbEW). In both years, Herb–HerbCW lambs had greater (p < 0.05) growth rates than lambs in other treatments. The liveweight gains and rumen papillae development of Herb–HerbEW, Grass–HerbD15EW and Grass–HerbEW lambs did not differ (p > 0.05). The weight of the empty digestive tract components at either early weaning or conventional weaning did not differ (p > 0.05) between treatments. Exposing early-weaned lambs to the herb mix for a prolonged period, prior to early weaning, does not improve their subsequent growth.

How lamb production systems can affect the characteristics and sward structure of Tifton 85 pasture?

Abstract Aimed at understanding how lamb production systems can affect sward structure in tropical grass pastures, the productive, structural and morphological characteristics of Tifton 85 (Cynodon spp.) pasture were evaluated in four systems: non-weaned and non-supplemented lambs (NW); non-weaned lambs receiving concentrate supplementation in creep feeding (CF); early-weaned lambs not supplemented (W); and early-weaned lambs supplemented with concentrate (WS). The trial lasted 105 days and was set out in a randomized block design with four treatments (systems), three replications (paddocks) and five lambs per replication. In the systems with weaning, lambs were weaned at 46 ± 6 days of age and immediately allocated to the paddocks; in the systems with supplementation, lambs received daily a protein–energy concentrate at 2% body weight (BW) on a dry matter (DM) basis. Continuous stocking management was used and the forage allowance was kept at 12% BW in DM/day in all systems. Changes in the structural and morphological characteristics of pasture were more intense up to 63 days of grazing. Sward height and forage mass were higher in WS compared to NW and CF systems, and forage accumulation rate was also higher in WS compared to the other systems. The mass of leaves and stems were higher in the WS system than in NW. Higher heterogeneity of pasture morphological characteristics was observed when weaning was performed. Forage mass was concentrated up to 20 cm sward height in the systems without weaning, with stem mass concentrated in the 0–10 cm stratum and leaf mass highly exposed to grazing in the 10–20 cm stratum. The systems with weaning presented the greatest dispersion of leaves and stems in all sward strata, which increased when the concentrate supplementation was provided to the lambs. Independent of concentrate supplementation to the lambs, the systems without weaning resulted in a better sward structure, with higher leaf/stem ratio for the animals on Tifton 85 pasture. In addition, supplementation of weaned lambs had a deleterious effect on sward structure.

Lambs Weaned Early onto a Herb-Clover Mix Have the Potential to Grow at a Similar Rate to Unweaned Lambs on a Grass-Predominant Pasture.

Simple SummaryEarly weaning of lambs may be a useful management tool when either herbage quality or quantity limits lamb growth. Herb-clover mixes containing chicory, plantain, red clover, and white clover have been shown to improve the growth of suckling lambs and those weaned at a traditional age compared to grass-predominant pastures in New Zealand. In this study, lambs were weaned at a minimum live weight of 14 kg and their liveweight gains at a conventional weaning age (~99 days of age) were compared with lambs unweaned on a grass-predominant pasture. We found that lambs weaned early onto a herb-clover mix have the potential to achieve live weights similar to lambs unweaned on grass-predominant pasture.Liveweight gain of lambs weaned early at a minimum live weight of 14 kg, at ~50 days of age, onto a herb-clover mix was compared with lambs that remained unweaned on a grass-predominant pasture or a herb-clover mix until conventional weaning (at ~99 days of age). Over two years, twin sets of lambs that had a minimum live weight of 14 kg were randomly allocated to one of three treatments: (1) Early weaning of lambs onto a herb-clover mix (HerbEW); (2) ewes and lambs grazing a herb-clover mix until conventional weaning (HerbCW); and (3) ewes and lambs grazing a grass-predominant pasture until conventional weaning (GrassCW). HerbEW lambs had slower (p < 0.05) growth rates than GrassCW lambs between early weaning and conventional weaning in 2016 and were 800 g lighter (p < 0.05) at conventional weaning. In 2017, however, both HerbEW and GrassCW had similar (p > 0.05) growth rates and did not differ (p > 0.05) in live weight at conventional weaning. HerbCW lambs had a greater (p < 0.05) growth rates than both HerbEW and GrassCW lambs in both years. Lambs weaned early onto a herb-clover mix have the potential to achieve live weights similar to lambs unweaned on grass-predominant pasture. Further research, however, is required to understand conditions under which early-weaned lambs can achieve similar live weights.

Impact of early weaning on small intestine, metabolic, immune and endocrine system development, growth and body composition in artificially reared lambs.

AbstractThis study evaluated the effect of early weaning (EW) of artificially reared lambs using a restricted milk replacer (MR) feeding and step-down weaning system on the short- and long-term effects on growth, feed intake, selected blood metabolites and hormones, body composition, and small intestine development. Mixed-sex twin-born 2 to 5 d old lambs were randomly allocated to individual pens and fed MR at 20% of initial individual BW in week 1 and 15% in week 2 followed by weaning off MR by the end of week 4 (EW; n = 16) or week 6 (Control; Ctrl, n = 16) using a step-down procedure. Concentrate starter and fiber diets were offered ad libitum to week 9, then gradually removed over a 10-d period. All lambs were managed as a single group on pasture from weeks 6 to 16 of the trial. Feed intake was recorded daily in the first 6 wk, and BWs recorded weekly. At weeks 2, 4, 6, and 8, and pre- and postclostridial vaccination at week 8, blood samples were collected for analysis of selected blood metabolites, IGF-1, and immune function. Body composition was evaluated in eight animals per group at weeks 4 and 16 after euthanasia, and duodenal samples collected for histomorphometric evaluation. Early weaned lambs had lower DM, ME, CP, and NDF intake than Ctrl lambs at 21, 15, 21, and 36 d of rearing, respectively (P < 0.001), driven by lower intakes of MR from day 15 (P < 0.001) as per the experimental design, and lower total DMI of fiber (P = 0.001) from 21 to 42 d of rearing. Lamb BW tended (P = 0.097) to be lower in EW than Ctrl lambs from 5 to 10 wk of rearing, with lower ADG in EW lambs from weeks 3 to 6 (P = 0.041). Early weaning had negligible effects on duodenal morphology, organ, and carcass weights at weeks 4 and 16. Plasma metabolites (urea nitrogen, triglycerides, NEFA, glucose, and total protein) were similar between groups, while β-hydroxybutyrate was greater in EW than Ctrl lambs at weeks 4 and 6 (P = 0.018) but not week 8 indicative of early rumen development. Serum IGF-1 tended to be lower in EW than Ctrl lambs from weeks 2 to 6 only (P = 0.065). All lambs developed antibody responses postvaccination and there was no effect of treatment (P = 0.528). The results of this study illustrate that artificially reared lambs can be weaned off MR by 4 or 6 wk of rearing without compromising growth, small intestine morphology, major organ development, and body composition, nor immune function at either 4 (preweaning) or 16 (postweaning) wk of age.

Analysis of Factors Affecting the Rearing of Early-Weaned Lambs of Dairy Breeds for the Meat Market

Sheep farming makes an important socio-economic contribution to Spain’s rural areas by sustaining farming and employment in less favored regions, but it is a low-profit sector because of high operating and regulatory costs. One possible solution would be to raise for slaughter lambs from dairy sheep that are not required as replacements. However, the early weaning of these lambs and their artificial rearing generally lead to reduced growth rates and high mortalities. In the work presented herein, three housing systems (slat + heating plate, slat + infrared lamp, and deep-litter + infrared lamp) were tested on 763 lambs over an eight-month period in a farm located in Ejea de los Caballeros (Zaragoza, Spain), with a view to reducing mortality during the period of artificial lactation. The effect of the environmental parameters of the lamb housing on the development of the lambs was evaluated by monitoring environmental (temperature, relative humidity, CO2 and NH3) and productive parameters (weight, average daily gain, and deaths). The results suggested that the combination of deep litter with straw bedding and infrared lamp heating would be the most favorable option, as it led to the highest average daily gain and the lowest percentage of deaths. From the study of the relationship of the initial weight with deaths, a prediction curve was obtained, defining the maximum prices to be paid per lamb as a function of their initial weight to guarantee the profitability of the raising process. This may be regarded as a valuable guidance for Spanish sheep farmers, as it can reduce their economic uncertainty.

Can herb-clover mixes compensate for the lack of milk in the diet of early-weaned lambs?

ABSTRACTThis experiment investigated the feasibility of using herb-clover mixes to enable early weaning of lambs at ∼60 days of age. Over two years, twin lambs weighing more than 16 kg were allocated to three treatments: ryegrass pastures until 90 days-of-age, herb-clover mix until 90 days-of-age or weaned at ∼60 days of age onto herb-clover mix. In 2014, lambs offered the herb-clover mix, weaned at 60 or 90 days, were heavier at 90 days than lambs grazing on pasture with their dams. In 2015, lambs that weaned early onto the herb-clover mix were lighter at the same age as lambs that remained with their dam, but they still achieved a commercial weight. Ewes weaned early were heavier at weaning than ewes suckling lambs on ryegrass pasture in both years. Under some conditions, early weaning of lambs onto a herb-clover mix can be an effective alternative to conventional weaning on ryegrass pasture.

Early weaning and concentrate supplementation strategies for lamb production on Tifton-85 pasture

The influence of early weaning and concentrate supplementation strategies on sward characteristics, forage chemical composition and lamb productivity were evaluated in four production systems on Tifton-85 pasture: suckling lambs not supplemented until slaughter; suckling lambs supplemented with concentrate in creep feeding until slaughter; early-weaned lambs not supplemented until slaughter; and early-weaned lambs supplemented with concentrate until slaughter. Structural, morphological and productive characteristics of pasture were measured. The forage was chemically analyzed to estimate its composition. Lambs average daily gain and productivity were calculated. Sward height, forage and morphological components mass were lower in systems without weaning. Forage production was higher in systems with supplementation. Higher levels of neutral and acid detergent fiber were observed in forage ingested by lambs in creep feeding and by weaned and unsupplemented lambs. Average daily gain was higher for lambs in creep feeding (275 g/d) and lower for the weaned and unsupplemented animals (57 g/d). Productivity was higher for weaned and supplemented lambs (21 kg lamb body weight, BW gain/ha/d). Lower productivity was observed in systems without supplementation (5 kg lamb BW gain/ha/d on average). Ewes modify the sward conditions improving the pasture characteristics and the quality of forage produced. Changes in sward conditions affect the chemical composition of forage ingested by lambs. Early weaning may be an alternative to maximize pasture utilization in small areas. Concentrate supplementation may increase lamb performance and productivity in grazing systems. If the objective is to improve lamb individual performance, creep feeding should be used.

Growth performance and carcass traits of early-weaned lambs as affected by the nutritional regimen of lactating ewes

Three isonitrogenous diets with different levels of metabolizable energy (ME; 10.3, 10.9, and 11.5MJ/kg) were fed to lactating ewes to study the relationships among milk yield and feed intake, growth rate, and carcass traits of early-weaned lambs. Eighteen multiparous Texel×Ile de France ewes (55.7±1.3kg of initial body weight; BW) supporting single male lambs were penned individually at 24h after lambing and evaluated for 42 days. Lambs had free access to a creep feeding system before weaning (42 days of age), and after that they were individually penned and fed a common diet until reaching the slaughter weight (32kg of BW). Carcasses were then evaluated after 24h of refrigeration. Dry matter and ME intake of ewes presented a quadratic relationship with energy level of the diet (P<0.05), and it directly affected milk yield (P<0.01). Milk yield was correlated with DM intake (r=−0.75; P<0.01) and growth rate (r=0.74; P<0.01) of lambs from birth to weaning. On the other hand, in this period there was no relationship between solid feed intake and ADG of lambs (r=−0.05; P>0.05). Therefore, creep feed supplementation was not enough to support a similar growth rate among lambs ingesting different amounts of milk. From weaning to slaughter, DM intake of lambs was greater (P<0.05) for the lambs raised by ewes in the low-energy group, resulting in a worse feed efficiency (P<0.05). No remarkable changes were observed in carcass traits. We concluded that improving ewe nutrition and consequently the early life nutrition of lambs can really increase profitability of lamb meat production.

The fatty acid composition of longissimus &amp;lt;i&amp;gt;lumborum&amp;lt;/i&amp;gt; muscle of suckling and earlyweaned dual-purpose wool/meat lambs

Abstract. Twenty-four dual purpose (wool/meat) suckling and early weaned ram lambs were used to study the fatty acid profile in intramuscular fat of longissimus lumborum muscle and lipid oxidation in blood serum. At 60 days of age 12 rams were slaughtered as suckling lambs. The other 12 early weaned and fed according to standards by grass hay and concentrate, and slaughtered at 90 days of age. Suckling lambs had more polyunsaturated fatty acids (P≤0.01) than early-weaned lambs. Younger lambs obtained also higher values of n-3 fatty acids (P≤0.01) and lower n-6/n-3 ratio (P≤0.01) appropriate in relation to their contribution to human health. Muscle tissue of early-weaned lambs compared to suckling group was characterised by significantly higher c9,t11C18:2 content (P≤0.01), which is desirable in human diet with regard to its peculiarities. The higher amount (P≤0.01) of vaccenic acid, which is the substrate for rumenic acid formation, has been observed in early-weaned lambs also.

Effects of feeding transgenic canola on apparent digestibility, growth performance and carcass characteristics of lambs

This study evaluated the effects of including meal from glyphosate-tolerant (Roundup-Ready®) canola (RRC) in barley-based diets for lambs on apparent digestibility of the diets, growth performance of the lambs, and carcass quality and composition. Four isonitrogenous diets were prepared that included canola meal [6.5%, dry matter (DM) basis] from four different sources (two commercially available canola blends, COM1 and COM2; a transgenic line, RRC and the parental non-transgenic line from which RRC was derived, PAR). Apparent digestibilities of the four diets were determined using eight mature wethers (67.8 ± 2.3 kg) in a replicated Latin square with four 21-d periods. No aspect of digestibility (DM, fibre, or nitrogen balance) was influenced by canola source. The growth trial involved 60 early-weaned Arcott lambs (30 ewes; 30 wethers; initial age approximately 2 mo; initial weight 21.5 ± 1.0 kg). The lambs were blocked by weight and gender for assignment to treatments, and fed the diets until reaching or exceeding 45 kg body weight. Intake of DM was similar among lambs fed COM1, COM2 and PAR diets, and between PAR and RRC (COM1, COM2 &gt; RRC, P &lt; 0.05). Diet did not affect (P &gt; 0.05) average daily gain or feed efficiency. Carcass yield grade was higher (P &lt; 0.05) for COM1 and COM2 diets than for PAR or RRC, although carcass composition did not differ (P &gt; 0.05) between PAR and RRC. Canola source did not affect (P &gt; 0.05) meat tenderness, as determined by shear force, drip loss or intramuscular fat content. Meat colour o f RRC-fed lambs did not differ from that of all other treatment groups. In this study, including canola meal prepared from glyphosate-tolerant canola did not alter diet digestibility, feed efficiency, growth performance, carcass characteristics or meat quality of lambs. Key words: Growth, lambs, meat quality, ruminant, transgenic canola

Hand-feeding and gentling influence early-weaned lambs' attachment responses to their stockperson.

Artificially reared herbivores are highly dependent on the stockperson at an early age in order to learn to drink from an artificial milk provider. This period of training may be a determinant for the animals' subsequent responses toward humans. However, long-term responses may also depend on the human contact (e.g., visual, physical interactions, gentling, and handling) provided to the young lambs after this training period. We examined whether different levels of subsequent contact (no visual and physical contact, stroking, and feeding reward) affect long-term attachment responses of lambs to the caretaker that provided the subsequent contact, after a common initial training period for artificial feeding provided by another person. Ewe lambs (n = 45) were artificially reared from multinippled buckets in groups of three. All the lambs were trained by a stockperson (S1) to suck from the bucket (4.4 +/- .3 sessions of 3 min per animal for the first 2 d of life). Subsequently, 15 lambs received no further human contact (T0). Fifteen other lambs received only stroking from a second stockperson (S2) for 6 min three times a day during the first 4 wk (T1). The remaining 15 lambs (T2) were stroked and bottle-fed by S2 during the same posttraining period as for T1. Tests were performed at 4, 6 (just before weaning), 9, and 13 wk of age in an unfamiliar arena marked in a grid pattern. The test procedure included three successive parts: 1) isolation for 1 min; 2) S2 presence for 2 min; and 3) isolation for 1 min. The T0 lambs spent a similar amount of time in the grid square close to S2 regardless of whether he was present. The T1 and T2 lambs spent more time close to S2 than T0 (P < .01), and T2 spent more time close than T1 (P < .05). In the presence of S2, T2 vocalized less (P < .01) than T0, and T1 did not differ from either T2 or T0. The T2 lambs also crossed fewer squares than T0. When S2 left the arena, T2 vocalized more (P < .01) than T0 and more (P < .05) than T1, and T1 had a tendency to vocalize more (P = .08) than T0. Differences persisted with increasing age. Human contact, especially stroking and feeding, during the 4 wk following initial training strongly and durably influenced the lambs' response not only to the appearance but also to the disappearance of a familiar stockperson. This last result supports the idea that lambs could form a social bond with their stockperson.

Effects of grain or pasture finishing systems on carcass composition and tissue accretion rates of lambs.

The effects of finishing system on growth performance and carcass composition were determined in an experiment using 40 crossbred, early-weaned lambs (28 kg BW). Finishing systems were 1) grazed alfalfa, 2) 100% concentrate diet fed in drylot, and 3) grazed ryegrass for 42 d followed by a 100% concentrate diet fed in drylot. All lambs were fed to similar final weights (48 kg). Average daily gain was greater for lambs placed directly in the feedlot than for lambs on the other two finishing protocols. The quantity of separable lean tissue and bone were not affected by finishing system. However, quantity of total fat and each of the three major fat depot sites (subcutaneous, seam, and mesenteric) were reduced (P < .05) in alfalfa-finished lambs compared with fat in lambs fed concentrate at some time during finishing. Daily accretion rates of lean and fat tissue were greater (P < .05) for lambs placed directly in drylot than for lambs that consumed forage at some time. In addition, daily fat accretion rates were greater in lambs placed directly in drylot than in lambs that initially grazed ryegrass. Composition of individual primal cuts revealed reductions (P < .05) in total separable fat with alfalfa finishing compared with the other two systems. However, chemical composition of the lean tissue within the primal cuts was not affected by finishing system, with the exception of the loin and breast. Finishing systems based on grazed forage can lead to the production of leaner carcasses, but major differences in the composition of consumable product were not observed.

Management of highly fecund ewe types and their lambs for 8-monthly lambing. 2. Effect of weaning age and sex on lamb growth and carcass traits

The effect of weaning at ages ranging from 6 to 13 weeks on growth of lambs from Booroola Merino x Poll Dorset (BD), Trangie Fertility Merino x Poll Dorset (TD), and Border Leicester x Merino (BLM) ewes was examined over 2 years as a component of management in an 8-monthly lambing system. Skin weight and carcass traits were also analysed. In the first year, there was a significant (P&lt;0.01) difference between growth rates to 3 months of age of lambs weaned at 12, 9, and 6 weeks (222.5 � 4.4, 204.8 � 4.4, and 180.0 � 4.6 g/day, respectively). In the second year, lambs were weaned at weekly intervals from 6 to 13 weeks of age, and growth rates were higher because of better seasonal conditions. Using regression coefficients, lambs weaned at 12 and 9 weeks were estimated to have higher (P&lt;0.01) growth rates by 17 and 8%, respectively, than lambs weaned at 6 weeks. There was no difference between lambs weaned at 6 and 9 weeks for liveweight at 5 months, but those weaned at 12 weeks were 5% heavier (P&lt;0.01). Postweaning mortality was higher amongst early-weaned lambs. Progeny from TD and BLM ewes had 7% higher growth rates and liveweights than those from BD ewes (P&lt;0.01). Male lambs (rams and wethers) grew faster (P&lt;0.01) than ewes, and in the second year there was a 5% liveweight advantage of rams over wethers (P&lt;0.01). Weaning age had no effect on any carcass trait. Carcass weight accounted for most variation in carcass traits, and its inclusion in the model removed the effect of type of rearing. There was a significant (P&lt;0.01) crossbred type x carcass weight interaction for fat depth at the C site, due to progeny of BLM ewes being fatter than the other crossbred types at heavier carcass weights. The regression coefficients for fat depth at the C site on carcass weight were 0.39 � 0.05, 0.31 � 0.04, and 0.60 � 0.05 mm/kg for BD, TD, and BLM progeny. Carcasses of rams were leaner than those of wethers, which were leaner than those of ewes (P&lt;0.01). There was no advantage from early weaning in management for an monthly lamb production system because lamb growth and survival were depressed.

Effect of grain processing on the performance of early-weaned lambs and kids

ABSTRACTThe effect of grain processing and form of the concentrate mixture were studied on early-weaned Chios lambs (42 days of age) and Damascus kids (56 days of age). Forty-five, 36, 33 and 33 animals were used in trials 1 (lambs), 2 (lambs), 3 (kids) and 4 (kids), respectively. Within trials animals were divided on the basis of live weight and age into three groups. Treatments (three forms of concentrate mixture) were randomly allocated to one of the three groups. The treatments were: whole cereal (WGP) grains mixed with pellets made from the other ingredients of the concentrate mixture; pelleted (P), where all ingredients were ground and pelleted in 5-mm cubes; rolled cereal grains (RGP), where cereal grains were rolled and then mixed with pellets (5-mm cubes) made from the other ingredients of the concentrate mixture. Cereal grains comprised 774 g/kg concentrate mixture. Fattening diets were based on ad libitum feeding of concentrates and a daily allowance of 01 kg per animal of long lucerne hay. Digestion coefficients, outflow rate of small particles from the rumen and rumen metabolites were measured using five animals per species per treatment.There were no significant differences between diets for live-weight gain in lambs. On the other hand, kids on the P diet gained more weight and had better food to gain ratio than the other two diets. Feeding the P diet resulted in a significant decrease of acetate and butyrate molar proportion ( P &lt; 0·001) and an increase (P &lt; 0·001) of propionate molar proportion. Similarly, feeding the P diet resulted in a significant reduction in ruminal pH (P &lt; 0·01) and NH,-N (P &lt; 0·05) concentration. Outflow rate (% per h) of small particles from the rumen was lower from lambs and kids on the P diet (P &lt; 0·001). There were no significant differences between species and/or among diets for apparent digestion coefficients and nitrogen balance.