Texel Cross Lambs Research Articles

224 Awardee Talk: Investigating Muscle Fiber Hypertrophy During pre- and Post-Natal Growth

Abstract Research has established that muscle fiber hyperplasia is complete during mid gestation; therefore, skeletal muscle fiber hypertrophy is responsible for the increase in muscle mass observed during late gestation and postnatal growth periods. Our research is investigating key times points during muscle fiber hypertrophy and the role of miRNA and mRNA transcriptome in this process. Two studies were conducted to examine changes in muscle mass, muscle fiber hypertrophy, and gene expression from gestational d (gd) 85 to market weight in Suffolk or Texel cross lambs. Longissimus muscle (LM) samples were taken for muscle fiber histology at the following time points: gd85, gd110, gd133, and market (d243) in study one and at postnatal d2, d14 and d203 in study two. microRNA (miRNA) and mRNA sequencing of the LM were conducted in study one and included biopsies at d 42 and 65. Type I and Type II muscle fiber area increased (P < 0.05) at each stage of growth evaluated. Type I muscle fiber area increased by 26.7-fold and Type II muscle fiber area increased by 37.4-fold from gd85 to market (d243). mRNA sequencing identified a total of 9360 unique genes differentially expressed (DEGs; P < 0.05) in LM during hypertrophic growth but the majority of DEGs were observed in the prenatal (51%) and early postnatal (54%) periods. There were 142 unique miRNAs differentially expressed (P < 0.05) during hypertrophic growth of LM but the majority (62%) were observed in the transition period from prenatal to postnatal growth. Overall, muscle fiber hypertrophy is dynamic from late gestation through postnatal growth, but transcriptomic changes indicate key time periods during development in which mechanisms underlying hypertrophic growth may be altered.

PSVI-23 Depot- specific patterns of mRNA and miRNA gene expression in adipose tissue from Texel-cross and Suffolk lambs

Abstract Excess fat deposition is costly to the producer in terms of input and final product; it also usually does not occur equally across all adipose depots. Further examination is necessary to determine a correlation between varying gene expression and fatty acid composition in different tissue depots, and further, across different breeds. Texel-Suffolk (n = 5) and Suffolk-Suffolk (n = 4) lambs were finished to 203 d of age and used to compare both mRNA and microRNA (miR) gene expression changes between breed and among tissue depots. Seven different depots were harvested and snap-frozen from all nine lambs. The liver, longissimus muscle of the rib, kidney fat, mesenteric fat, omental fat, subcutaneous fat, and intermuscular fat were all harvested. Texel-sired lambs had greater (P < 0.05) flank streaking, quality grade, and weight of fat depots compared to Suffolk. Texel-cross lambs had higher (P < 0.05) oleic-to-stearic fatty acid ratio than Suffolk lambs in this study, displaying a breed difference concerning this desaturation ratio. Tissue and breed interactions were observed for oleic-to-stearic and palmitoleic-to-palmitic ratio differences (P < 0.05) depending on tissue type. Tissue and breed interactions were trending in various tissues concerning the expression of the gene, stearoyl-CoA desaturase-1(SCD-1). SCD-1 seemed to be upregulated (P < 0.10) in a multitude of tissues while others do not appear to be differentially expressed, dependent upon breed. Data showed an association between SCD-1 and mi-199a-3p among different tissue variations. This may suggest that adipose tissue is more complex than what is currently known. Lipogenic gene expression differed between tissue and adipose depots, and could potentially broaden targets that could aid in maximizing animal efficiency.

Prediction of Myostatin on Carcass Composition in Crossbred Lambs

Abstract In order to maintain consumer acceptance of lamb meat, producers are aiming to produce leaner lambs through breeding for certain carcass characteristics. The Texel breed is known for its superior muscling phenotype due to a myostatin mutation. Because of this mutation, Texel and Texel cross lambs have been shown to have improved carcass lean with less fat in various locations throughout the carcass. The objective of this study was to observe the impacts of different sire and dam breeds on carcass composition. Lambs (n = 41) were produced by mating two dam breeds (Southdown or Suffolk) and two sire breeds (Southdown or Texel). Lambs were harvested and a hot carcass weight was obtained. At 24 h postmortem, a chilled carcass weight was taken, and each carcass was split in half. The left side of the carcass was cut into the four primal cuts and scanned using a DXA. The right half was used for standard carcass variables. After DXA scans, each primal was weighed and the major muscles were dissected from the primal cuts and weighed. Subsamples of muscles were used for total lipid analysis and Warner-Bratzler Shear Force testing. DXA scans showed a difference in the primal cut mass (P = 0.0207) with the Suffolk-Texel cross having the highest average primal cut mass at 12.52 kg. Southdown-Southdown lambs had the highest fat percentage (dam P = 0.0398; sire P = 0.0116). Dam breed had a more significant effect on muscle toughness (P < 0.0035). Southdown sired lambs had a higher SFA (P = 0.0046) and MUFA (P < .0001) but Texel sired lambs had a higher overall fatty acid ratio (P < .0001). On average, the Suffolk-Texel cross was shown to have heavier average weight for the primal cuts in the rack and leg, which are where some of the more profitable cuts of meat are located.

Effects of rumen exposure to anise oil on ruminal fermentation and biohydrogenation of N–3 polyunsaturated fatty acids

This study evaluated the effect of four weeks of microbial exposure to anise oil (ANO) on the fermentation activities of ruminal micro-organisms and the biohydrogenation of n -3 polyunsaturated fatty acids (PUFA). A total of six Hartline ´ Texel cross lambs were used. Three of the lambs were randomly assigned to the basal diet (basal diet group, BDG) and the remaining three lambs were offered basal diet with ANO (anise oil group, AOG) for four weeks. The rumen fluid donor lambs were offered water and hay ad libitum and supplemented with additional 400 g/sheep/day of concentrate plus 2.4 g/sheep/day of ANO (for the AOG). The ANO was thoroughly mixed with the concentrate prior to feeding. The total amount (400 g) of lamb finisher cubes offered per sheep/day was divided into two equal parts (200 g) and fed at 08.00 and 16.00 hours, respectively. After the four weeks’ exposure period, lambs were slaughtered and ruminal fluid (RF) was collected from each of the lambs on BDG and on AOG and used in a 48 h in vitro batch culture system to study the fermentation of a 70: 30 grass hay ( Lolium perenne) and concentrate (lamb finisher) diet. The study was a 2 (batches of rumen fluid: BDG and AOG) 2 (doses of ANO: 0 and 200 mg/L) factorial design experiment. Results showed that total volatile fatty acid (TVFA) in RF extracted from lambs on the BDG (242.0 mM) was similar to that in the AOG (242.2 mM). Concentrations of TVFA in in vitro digests were similar between groups on the BDG (68.6 mM) and on the AOG (66.4 mM), but differed between levels of anise oil (0 versus 200 mg/L). The levels of NH 3 -N were not different (P>0.05) between the RF collected from AOG and BDG. However, in vitro results showed that AOG 200 mg/L induced a 20% decrease on the concentration of NH 3- N in fermentation vessels, relative to BDG 0 mg/L. The in vitro digesta incubated in RF from the AOG (i.e. AOG 200 mg/L) maintained higher concentrations of PUFA (C18:2 n -6 and n -3 PUFA), trans vacceric acid and lower concentration of stearic acid. This suggests that there was no rumen adaptation within the period of trial. This study concludes that anise oil is potentially a useful feed additive to optimise the fatty acid composition of ruminant feedstuffs, if these effects are repeated in meat and milk.

Addressing sustainable sheep farming: Application of a targeted selective treatment approach for anthelmintic use on a commercial farm

Sustainable control of nematode parasites in small ruminant production is a worldwide ambition. Development of anthelmintic resistance can severely impair small ruminant production. A practical approach to reduce selection pressure for anthelmintic resistance is to treat only a proportion of the flock (Targeted Selective Treatment), leaving a proportion of the nematode population untreated. The aim of this study was to compare the sustainability and efficacy of a performance-based marker, the Happy Factor™, a monitor of nutrient utilisation efficiency, with a routine whole flock anthelmintic treatment. In a commercial flock in the South West of Scotland, 183 Texel cross lambs were split into two matched but co-grazing groups: one group managed as routinely for the farm (RT group) and the other subjected to targeted selective treatment (TST group). All lambs from the RT group were drenched every 6 weeks during the grazing season, while anthelmintic administration in the TST group was restricted to animals that failed to reach pre-determined weight gain targets, based on an estimate of their efficiency of gross energy utilisation. Animal performance and parasitological data were recorded every two weeks. In the 20 week period of the study, anthelmintic treatments were reduced by approximately 50% in the TST group compared to a routine anthelmintic administration that would have been applied, whilst epg counts were always <500 throughout the study in both groups. Finally, there was no discernible difference in the mean bodyweight gain between the two groups.

Ovine self assessment

LivestockVol. 18, No. 2 Self AssessmentOvine self assessmentPhil ScottPhil ScottSearch for more papers by this authorPhil ScottPublished Online:16 Aug 2013https://doi.org/10.12968/live.2013.18.2.36AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail View article FiguresReferencesRelatedDetails 1 March 2013Volume 18Issue 2ISSN (print): 2053-0862ISSN (online): 2053-0870 Metrics History Published online 16 August 2013 Published in print 1 March 2013 Information© MA Healthcare LimitedPDF download

Effects of genotype and plane of nutrition on growth and carcass characteristics of lambs from hill sheep systems

The objective of this study was to determine the effect of lamb genotype and plane of nutrition on post-weaning lamb growth, and carcass characteristics in hill sheep systems. The lamb genotypes compared were as follows: purebred Scottish Blackface, Swaledale × Scottish Blackface, Cheviot × Scottish Blackface, Lleyn × Scottish Blackface and Texel × Scottish Blackface lambs. During the finishing period, lambs were allocated to a (i) low plane of nutrition (LP), based on a fixed allowance of dried grass pellets representing a grass-based system; (ii) high plane of nutrition (HP-cereal), with a diet consisting proportionately of 0.20 dried grass pellets : 0.80 cereal-based concentrate offered ad libitum; (iii) high plane of nutrition (HP-cereal/oil), with a diet consisting proportionately of 0.20 dried grass pellets : 0.80 cereal-based concentrate containing oilseed rape offered ad libitum. There were significant genotype × diet interactions for dry matter (DM) intake (P < 0.001), live weight gain (P < 0.05) and carcass gain (P < 0.05). On the LP diet, carcass gains were higher for Texel cross compared to Blackface and Swaledale cross lambs (P < 0.05). On both HP diets, carcass gains were lower in Blackface and Swaledale crosses compared with the Cheviot, Lleyn and Texel cross lambs (P < 0.01). Feed conversion efficiency, expressed in terms of carcass gain per unit of DM, was highest for Texel cross and Cheviot cross, lowest in Swaledale cross and Blackface and intermediate for Lleyn cross lambs (P < 0.001). Conformation classification was lowest for Swaledale cross (P < 0.05) and highest for Texel cross lambs (P < 0.001), whilst those of Blackface, Cheviot and Lleyn cross lambs were similar. Carcasses from Blackface and Lleyn cross lambs had higher fat classifications than Texel and Cheviot cross lambs (P < 0.01). Feed conversion efficiency was lowest with the LP diet compared with the HP diets, resulting in a 5-week longer finishing period and lower carcass weights, fat scores, dressing proportions and subcutaneous fat depth measurements. These results indicate that crossbreeding can have a major effect on lamb performance in the hill sheep sector. Feeding a HP increased lamb growth rates, particularly for high growth-potential genotypes, improved feed efficiency, shortened the finishing period but increased carcass fatness. Including oilseed rape in concentrate-based diets did not affect performance.

Effect of Lactobacillus buchneri, Lactobacillus fermentum, Leuconostoc mesenteroides inoculants, or a Chemical Additive on the Fermentation, Aerobic Stability, and Nutritive Value of Crimped Wheat Grains

The preservation of crimped wheat grains by three bacterial inoculants or a chemical additive was compared. Crimped wheat grain [56.8g dry matter (DM)/kg] was conserved in 1.75-kg plastic bag, mini-silos without treatment, with 4L/tonne of Crimpstore (CS; an additive containing a mixture of ammonium formate, propionate, ethyl benzoate, and benzoate, SAS Kelvin Cave, Ltd., UK) or 1×105 cfu/g of each of three inoculant additives containing Lactobacillus fermentum (A), Leuconostoc mesenteroides (B), and Lactobacillus buchneri (C). Six replicates were conserved per treatment. Ensiling DM losses, chemical composition, fermentation characteristics, and aerobic stability were measured in the silages after 68 d of ensiling. All the silages were well fermented and remained stable for 84h after aeration. Subsequently, the rate of deterioration was slowest in crimped grains treated with CS treatment, followed by those treated with inoculant C, while those treated with inoculant A deteriorated most rapidly. Residual water-soluble carbohydrate concentration was higher in crimped grains treated with CS than those treated with the inoculants. Ammonia nitrogen concentrations were lowest in CS-treated crimped grains, followed by inoculants C and A. DM losses were greater in CS-treated crimped grains than in crimped grains treated with inoculants A and C. In vivo digestibility was also measured in Texel-cross lambs fed a grass silage basal diet supplemented with the additive-treated crimped grains or a conventional, lamb finisher concentrate. Dry matter intake and digestibility were unaffected by treatment. In conclusion, bacterial inoculants containing L. buchneri are promising preservatives for crimped wheat grains.

Chondrodysplasia of Texel sheep — a new disease of suspected genetic aetiology

Extract A chondrodysplasia characterised by dwarfism and varus deformity of the forelimbs has been recognised over four seasons in Texel and Texel-cross lambs on three related properties. Affected lambs appear normal at birth, but by 2 weeks of age have reduced growth rate, shortened neck and legs, varus forelimb deformities and a progressive reluctance to walk. Most die within the first 4 months of life. Some affected lambs have had normal co-twins.

The effect of breed of sire on the accumulation of copper in lambs, with particular reference to copper toxicity

ABSTRACTLambs, 9 weeks of age, the offspring of sires of the Scottish Blackface, East Friesland, Finnish Landrace, Suffolk and Texel breeds mated to Scottish Blackface females, as a common maternal breed, were given diets containing 12 or 20 mg copper per kg dry matter for 13 weeks. Concentrations of liver copper and of copper and aspartate amino-transferase in the plasma were measured regularly, and the concentrations of copper in the kidney, mandible and cheek muscle were also measured terminally. Livers were examined for histological symptoms of copper toxicity.Wide breed variation was apparent in liver copper concentration after 6 weeks and in plasma aspartate aminotransferase concentration after 9 weeks. At slaughter, total liver copper and kidney copper concentration showed significant breed variation. For all traits, the Texel-cross lambs had the highest concentrations, followed by the Suffolk crosses, and the Blackface had the lowest. The proportion of ingested copper retained in the liver of the Texel-cross lambs was twice that of the Blackface lambs (0·137 v. 0·056), with the other breed crosses intermediate.There was a significant difference between diets for liver, kidney and mandible copper concentrations, plasma aspartate amino-transferase concentration, and for total liver copper but not for cheek muscle. Both diets produced elevated plasma aspartate amino-transferase concentration and histological symptoms of copper toxicity in the livers of some lambs.The results show large breed differences in the susceptibility to copper poisoning, some breeds being at risk when given diets containing 12mg copper per kg dry matter for long periods. There was no suggestion that breeds differed in resistance to poisoning other than through different retentions of copper consumed

Growth and carcass composition in the crossbred progeny of six terminal sire breeds of sheep

ABSTRACTRecords were available for the progeny of Dorset Down, Oxford, Suffolk, Ile-de-France, Oldenburg and Texel sires out of Border Leicester × Blackface and Animal Breeding Research Organisation Dam Line × Blackface ewes. The data analysed were: (a) growth traits to 12 weeks for 2585 lambs, the progeny of 102 sires; (b) growth traits for slaughter at fixed weights of 35kg and 40kg for 1884 lambs (79 sires); and (c) half carcass dissection traits for 956 lambs (65 sires).Oxford and Suffolk cross lambs were heaviest at all ages and thus youngest at slaughter. Texel cross lambs grew slowly to 12 weeks but were not significantly older than Dorset Down, Ile-de-France and Oldenburg cross lambs at slaughter. The Texel cross produced the leanest carcass with a high lean/bone ratio and eye-muscle area. Dorset Down and Ile-de-France cross lambs were fattest at slaughter but had high values for lean/bone ratio and eye-muscle area. Interactions between breed of sire and slaughter weight were non-significant for all traits (P&gt;0·05).Breed differences in carcass composition were also compared statistically as if at a constant percentage of subcutaneous fat. The differences were not so great as at constant live weight but the Texel cross would have had the leanest carcass. Side weights would be heaviest in the Texel and lowest in the Dorset Down and Ile-de-France. Oxford, Suffolk and Dorset Down cross lambs would be youngest at slaughter and Texel and Oldenburg crosses oldest.

The effect of sustained lactation on intake of solid food and growth rate of lambs

SummaryAn experiment was designed to investigate the effect of a sustained lactation pattern on the intake of milk or solid food by lambs and on their consequent growth rate. Normal lactation pattern was compared with sustained lactation, achieved by fostering lambs at 24 days of age on to newly-lambed nurse ewes. Two genotypes of lamb were used; these were pure-bred Scottish Blackface and Textel × Blackface. Lambs were offered one of two qualities of pelleted concentrate food from 4 weeks of age.Maximum daily intakes of milk were 2·16 and 1·87 kg/day, respectively, for fostered and non-fostered lambs. This differential was maintained until the 10th week. Pattern of lactation had no significant effect on total energy intake from milk and solid food combined or on live-weight gain up to 10 weeks of age. Texel cross lambs consumed more food than did pure Blackface lambs and showed correspondingly higher rates of live-weight gain. Lambs ate slightly more of the higher quality pellets than the lower but there was no effect of solid food quality on milk intake. Within breed of lamb there was a negative relationship between intake of milk and of solid food.