Cross-bred Sheep Research Articles

PC206 Transdifferentiation and Remodeling of a Tissue-Engineered Collagen Scaffold in the Ovine Carotid Model: An Experimental Pilot Study

Patch angioplasty is commonly performed after carotid endarterectomy. Although patch angioplasty is known for reduction in perioperative and long-term stroke rates as well as restenosis compared to primary closure, the ultimate patch in terms of performance and tissue remodeling is yet to be identified. This study evaluated the performance and remodeling potential of a novel tissue-engineered collagen scaffold (VascuCel) in an ovine carotid model. Cross-bred sheep (n = 6; body weight, 35-55 kg) were randomized into two groups (n = 3 animals per group). Implants were explanted at two different time points. In group 1, implants (n = 3) were explanted at 30 days and in group 2, implants (n = 3) explanted at 180 days. Computed tomography angiograms were performed at the end of each time point. Explants were assessed by means of macroscopic appearance, tensile characteristics, and histology (hematoxylin and eosin, trichrome, Von Kossa, and picrosirius red). All animals survived the entire study period without any vascular adverse events. Macroscopically, both early and late explants demonstrated smooth, intimal surfaces with well-incorporated native tissue on the edges of the scaffold (Fig 1). No signs of thromboembolic-related deposits were visible on the intimal surface (n = 12 grafts). Tensile strength of explants demonstrated acceptable vascular strength (full thickness = 8.14 ± 1.68 MPa; neointima = 2.9 ± 0.41 MPa). Histology in early explants showed a partially endothelialized neointima on the luminal side and presence of granulation tissue on the outside and the scaffold between these two layers. Computed tomography angiographic assessment of animals in the late follow-up group demonstrated normal blood flow in all implanted carotids without any signs of vessel wall thickening (stenosis). Histology of late explants demonstrated unique transdifferentiation of the scaffold into three distinctive layers, which consisted of a completely endothelialized neointima with smooth muscle cells, the scaffold saturated with host fibroblasts resembling the media, and an external layer consisting of loose collagen fibers resembling the adventitia (Fig 2). Normal flow dynamics, optimal tensile properties, and effective incorporation of the VascuCel patch by surrounding host tissue suggest ultimate function and reliability of the VascuCel patch in the carotid position. Superior transdifferentiation and remodeling demonstrated enhanced biocompatibility which resulted in site-specific transformation of the VascuCel patch into the ideal repaired vascular construct.Fig 2View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Variation in instrumental meat quality among 15 muscles from 14-month-old sheep and its relationship with fibre typing

The aims of the present study were to describe intermuscular differences in meat-quality traits in 15 young-sheep muscles, and to study the associations between meat quality and fibre typing across all (pooled) muscles as well as in previously selected homogeneous contractile–metabolic groups of muscles (slow-oxidative, intermediate and fast-glycolytic muscles). Meat-quality traits (pH, colour, expressed juice, cooking losses, tenderness and sarcomere length) and fibre typing were evaluated after 24 h of slaughter in 15 muscles from five cross-bred young sheep. Across all the studied muscles, intermuscular differences in some meat-quality traits (pH24, a* and expressed juice) seemed to be mainly explained by muscle oxidative activity, while intermuscular variation in other meat-quality traits (L*, b* and Warner–Bratzler shear force) were mainly explained by differences in fibre sizes. Within fast-glycolytic muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower ultimate pH, higher L* values, lower a* values and longer sarcomeres. Within intermediate muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower ultimate pH, higher L* values, shorter sarcomeres and reduced meat tenderness. Within slow-oxidative muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower amounts of expressed juice, lower a* values and reduced meat tenderness. The present study has contributed to a better understanding of the influence of muscle fibre types on intermuscular meat-quality variation, suggesting that although muscle fibre diversity may explain, at least in part, intermuscular differences in meat quality, these associations can also slightly vary among muscle contractile–metabolic groups.

Identification of polymorphisms in the myostatin and leptin genes of santa inês breed and crossbreed sheep and association with carcass traits

The objective of this study was to identify polymorphisms in the myostatin and leptin genes in Santa Ines (SI) and crossbreed (SI x Dorper) sheep, to verify the effect of these polymorphisms on carcass traits. We evaluated seventy sheep of 8-month-old at the Federal Institute of Espirito Santo, Brazil. Data collected were slaughter weight (SW), hot carcass weight (HCW), cold carcass weight (CCW), loin weight, tenderloin weight and fat thickness (FT). The hot carcass yield (HCY) was calculated by the formula (HCW/SW) x 100. We collected hairs from each animal for DNA extraction by the alkaline protocol. The animals were genotyped for the G>A mutation in nucleotide 9827 of the myostatin gene and for three polymorphisms in exon 3 of the leptin gene, by the PCR-RFLP technique. The amplicons the myostatin and leptin gene were cleaved with restriction enzyme for allelic discrimination. The alleles were recorded for each animal and analysis of variance was performed to check the influence of the mutations on the carcass traits. The mutant allele of the myostatin gene showed association with increased measures of CCW, FT and with reduced HCY. Among the three alleles of the leptin gene, only one showed an effect (increased CCW). The other alleles were not associated with any traits.

Nutritional evaluation of corn silage with different levels of inclusion of wet corn gluten feed in sheep

The objective of this study was to evaluate the intake and apparent digestibility of nutrients, as well as the feeding behavior of sheep fed an exclusively corn silage diet (0%); this diet incorporated wet corn gluten feed (WCGF) in increments of 30%, 50%, 60%, and 90%, together with the profile of the particles of these silages. Five cross-breed sheep were used with an average weight of 40 kg; they were housed in metabolic cages and were arranged in a Latin square 5×5 experimental design. There was a quadratic effect on dry matter (DM) intake, with a maximum consumption of 1.75 kg/day –1 to an inclusion of 39.09% of WCGF. The crude protein (CP) consumption exhibited an ascending linear effect with the inclusion of the co-product, and fiber consumption in neutral detergent fiber (NDF) and acid detergent fiber decreased linearly with the inclusion of WCGF. The apparent digestibility of DM, CP, and NDF increased linearly with the increasing inclusion of co-product in corn silage. Rumination time, total chewing, and idleness were influenced by increases in the inclusion of WCGF in corn silage, and there was a decreasing linear effect on the amount of time spent ruminating and total chewing, as well as an increasing linear effect for idleness duration. The chewing time for bolus, the number of chews for bolus, and the number of chews per day were influenced by the inclusion of WCGF. Through the obtained results, especially the equation of DM intake, which estimated a maximum point of 39.09%, as well as the presence of diarrhea at levels up to 50%, it was concluded that the addition of up to 40% of WCGF in corn silage can be recommended as it improves nutrient intake and features good digestibility without negatively altering the normal behavior of sheep.

Comparative pharmacokinetics of enrofloxacin, danofloxacin and marbofloxacin following intramuscular administration in sheep

The aim of this study was to determine and compare the pharmacokinetic profiles of enrofloxacin (ENF), danofloxacin (DNF) and marbofloxacin (MBF) after intramuscular administration in sheep. A total of 18 cross-bred healthy sheep were used in the study. The animals were allocated into three groups of six such that the mean weight of animals in each group was similar. In Group I (ENF) was given intramuscularly at a dose rate of 2.5mg/kg, in Group II (DNF) was given intramuscularly at a dose rate of 1.25mg/kg and in Group III (MBF) was given intramuscularly at a dose rate of 2mg/kg. Heparinized blood samples were collected between 0.5 and 48h after treatment.The results indicated that MBF produced a significantly higher maximum plasma concentration (Cmax:1.43±0.50μg/ml) with quicker absorption (tmax: 1.00±0.00) and larger area under the concentration vs. time curve (AUC: 8.36±2.58μgh/ml) as compared with ENF (Cmax: 0.88±0.13μg/ml, tmax: 1.66±0.47, AUC: 5.64±2.52μgh/ml) and DNF (Cmax: 0.70±0.08μg/ml, tmax: 1.33±0.23, AUC: 3.00±0.65μgh/ml) following intramuscular administration of drugs. Similarly, the mean residence time (MRT: 6.37±0.59) and the half-life (t1/2λz: 9.50±1.86) was significantly longer MBF group than ENF (MRT: 4.54±0.79, t1/2λz: 3.06±0.39) and DNF (MRT: 4.04±0.17, t1/2λz: 3.52±0.22) groups.In this study, regarding ENF, DNF and MBF, three of fluoroquinolones antibacterial agents with common usages in sheep at recommended doses, with intramuscular administration were compared in pharmacokinetic parameters and as a result, marbofloxacin was found significantly the highest in rate to reach the maximum concentration in plasma.

In vitro gas production, in vivo nutrient digestibilities, and metabolisable energy concentrations for sheep of fresh and conserved pangola grass

In vitro gas production, nutrient digestibilities and metabolisable energy (ME) values of fresh and conserved pangola grass (Digitaria eriantha Steud., synonym D. decumbens) were studied in 16 cross-bred (Thai native×Merino) sheep. The study was designed as a completely randomized design with Napier grass (Pennisetum purpureum) as a control and pangola grass in fresh, hay and silage forms with the same cutting age (45 days growth) as treatments. Chemical composition of forages and faeces was determined and used to estimate nutrient digestibility. In vitro gas production was recorded at 3, 6, 8, 12, 24, 48, 72, 84 and 96h of incubation and used to estimate the kinetics of gas production. Chemical composition was relatively constant across treatments. Likely due to the addition of 5% sugarcane molasses before ensiling, pangola grass silage had higher (P<0.05) nutrient digestibilities and ME concentrations than the other forages when estimated from in vivo digestibility and in vitro gas production. Cumulative gas production at 12, 24, 48 and 96h of incubation was highest (P<0.05) in pangola silage followed by fresh pangola, pangola hay and Napier grass, in that order. In conclusion, pangola grass in fresh or conserved forms has a high potential to deliver energy and protein through forage and can be recommended as a nutrient source for small ruminants.

Non-Genetic Factors Affecting Growth and Production Traits in Dorper Crossbred Sheep

Data on growth traits of 401 animals used in the present study were collected from history sheet of crossbred sheep maintained at Government Sheep Breeding Farm Panthal, Reasi, J&K, India. Traits included in the study were birth weight (BWT), weaning weight (WWT), 6-month body weight (6-BW), 12-month body weight (12-BW), mature body weight (MBW) and annual wool production (AWP). The statistical analysis was carried out using LSMLMW computer programme. The overall least-squares means were 2.857 ± 0.058 kg, 15.269 ± 0.296 kg, 17.034 ± 0.258 kg, 22.315 ± 0.298 kg, 29.375 ± 0.237 kg and 0.651 ± 0.012 kg, respectively for BWT, WWT, 6-BW, 12-BW, MBW and AWP. The co-efficient of variations for different traits were low to moderate. Period of lambing had significant effect on all the traits except for BWT. Moreover, there was no definite trend for different traits over different periods except for 12-BW, where increasing trend was obtained. Season of lambing had significant effect only on WWT and MBW. Genetic group had non-significant effect on all the traits under study although, 50% genetic groups were superior for most of the traits. Sex had significant effect on all the traits except for 6-BW and 12-BW. It can be concluded from the study that growth traits and production traits are influenced by different non-genetic factors like period, season and sex.

Comparative immunogenicity of two peste des petitis ruminants (PPR) vaccines in South Indian sheep and goats under field conditions

Peste des petitis ruminants (PPR) is an economically important endemic viral disease of sheep and goats in India, where several different homologous PPR vaccine candidates have been developed. We evaluated the serological response to two vaccine strains, Arasur/87 and Sungri/96, in South Indian cross-bred and native sheep and goats reared under organized and unorganized settings. Animals seronegative (percent inhibition or PI <40) by competitive enzyme-linked immunosorbent assay (c-ELISA) were immunized with either of the vaccine strains or placebo. Sera collected on 21, 60 and 90days post-vaccination were subjected to c-ELISA and serum neutralization test (SNT). Seropositivity (PI >40), seroconversion (fourfold increase in SNT titres) and seroprotection (SNT titre of ≥8 deemed to be protective) ranged from 66.7 to 84.0%, 56.0 to 69.2%, and 60.0 to 76.0%, respectively. However, no significant difference was observed between responses to the two vaccine strains. These results support the premise that the two vaccine strains are equally efficacious.

A Comparative Performance Study between Afec-Awassi Crossbred , Improved Awassi and Local Awassi Sheep Reared Intensively in Jordan

A total of 246 performance and 257 prolificacy records belong to Afec-Awassi crossbred, improved and local Awassi sheep were collected through the years from 2007 to 2010. The sheep were kept under intensive production system at Al-Khanasry Research Station in the North of Jordan. The studied traits were: milk production, lactation, period, milk composition, birth weight and prolificacy of ewes of the three lines. The following environmental effects, parity of ewe, type of birth, sex of lambs and body weight of ewe at lambing were studied. The results showed that sex of lamb’s effect was significant in which males were heavier (P≤0.05) than females. Single born lambs were heavier (P ≤ 0.05) than other types of birth. Effect of ewe body weight at lambing on prolificacy was negatively significant (P≤ 0.01). Birth weight of Afec-Awassi crossbred lambs and the ewes' prolificacy were significantly higher than the lambs of other two lines. Year and ewe parity had significant effect on total milk production and lactation period. Total milk production was the highest (P < 0.05) in Improved Awassi ewes (134.1 ±15. 5 kg) with average lactation period of 106.2 ± 8 days, while the lowest lactation period was obtained by Afec Awassi ewes (83.3 ± 7 d). Fat and protein contents did not significantly differ between the studied lines. In conclusion, the fecundity gene that introduced into the Awassi sheep might have a remarkable positive effect on prolificacy, while it may contribute negatively in milk production.

A Novel Technique of Multi-point Pacing in Substrate Evaluation Using Conduction Velocity with Non-contact Mapping

Introduction: Complex electrophysiological mapping is based on the principles of activation, voltage-substrate, pace, and entrainment mapping. The pathology underlying many arrhythmias is related to functional conduction changes, which is not seen directly with any of the current techniques. Non-contact mapping, and the dynamic substrate mapping system, could be extended to examine for changes in conduction velocity. Method: Under general anaesthetic, a geometric construct was acquired with a roving mapping catheter in the right atrium of eight cross-bred sheep. Non-contact virtual electrograms were collected prior to, and post creation of a cavo-tricuspid line of ablation, during pacing from multiple sites within the right atrium. Post-processing included: (1) Reference beat selection by user. (2) Automated detection of location activation by maximum negative dv/dt. (3) Calculation of local speed by comparing the distance and activation timing of surrounding points. (4) Consolidation of multiple local speeds for a single point from various pacing sequences. Results: Bidirectional block was successful in all eight animals. There were no significant changes in global measures pre and post ablation, such as global velocity (11.7 ± 1.1 mm/s vs 10.7 ± 1.3 mm/s, p = NS). Locally, the area underlying the ablations changed velocity significantly (10.8 ± 2.4 mm/s, pre-ablation vs 0.75 ± 1.25 mm/s post-ablation, p < 0.001). Conclusion: Multi-point pacing with this semi-automated conduction velocity substrate mapping technique can identify areas of slowed or blocked conduction. This can lead to further comprehensive evaluation of substrate in complex electrophysiological mapping which is of particular significance in macro-reentry circuits such as ischaemic ventricular tachycardia.

Disruption of egg formation by Fasciola hepatica following treatment in vivo with triclabendazole in the sheep host

Eight indoor-reared cross-bred sheep with no prior exposure to Fasciola hepatica were infected by oral gavage with 200 metacercarial cysts of the triclabendazole (TCBZ)-susceptible Cullompton isolate of F. hepatica. Twelve weeks after infection, sheep were treated with 10mg/kg triclabendazole. Two sheep were euthanised per time period; at 48h, 72h and 96h post-treatment (pt). Two untreated control sheep were euthanised at 96h pt. Flukes were recovered from the liver and, if present, from the gall bladder of the sheep. They were processed for whole mount analysis, histology and transmission electron microscopy of the female reproductive system; specifically, the uterus, vitelline follicles, Mehlis’ gland and ovary.Over the 4-day post-treatment period, there was a progressive reduction in the number of oogonia and oocytes in the ovary and evidence of apoptosis. Vacuolation and a decrease in the number of Mehlis’ gland cells were observed from 48h pt onwards and disruption of the normal role of the gland in egg formation was evident. The vitelline follicles showed a gradual decrease in size and became vacuolated; the population structure in each follicle changed to be one consisting mainly of mature cells and the production of shell protein material declined. The follicle became disorganised as the cells broke down and released their contents into the lumen of the follicle. While the uterus appeared to contain eggs at 48h pt in whole-mount specimens, no properly-formed eggs were observed in histological sections. By 96h pt, the uterus was completely devoid of eggs. Overall, egg production was seen to be severely affected by TCBZ treatment and flukes were incapable of producing normal eggs within 2 days of treatment. The implications of this in terms of the epidemiology of the disease are discussed.

Time-dependent changes to the tegumental system and gastrodermis of adult Fasciola hepatica following treatment in vivo with triclabendazole in the sheep host

Eight indoor-reared cross-bred sheep with no pre-exposure to Fasciola hepatica were infected by oral gavage with 200 metacercarial cysts of the triclabendazole (TCBZ)-susceptible Cullompton isolate of F. hepatica. At 12 weeks post-infection, sheep were dosed with 10mg/kg triclabendazole. Two sheep per time period were euthanized at 48h, 72h and 96h post-treatment (pt). Two control sheep were euthanized alongside the 96h triclabendazole-treated sheep. Flukes were recovered from each of the sheeps liver and, if present, from the gall bladder and they were processed for transmission electron microscopy (TEM). Disruption to the ultrastructure of the tegument became increasingly severe over time pt. Flukes recovered at 48h pt showed widespread blebbing of the apical plasma membrane and swelling of the mucopolysaccharide masses surrounding the basal infolds. There was evidence of reduced secretory activity in the tegumental cells and spacing between the cells. Sloughing of the tegumental syncytium was observed at 72h pt. The subtegumental musculature, parenchyma and tegumental cells were severely disrupted. At 96h pt, all of the flukes were totally devoid of tegument. Disruption to the subtegumental tissue and somatic musculature was severe, and was so extreme in some specimens that the tegumental cells were barely discernible. Disruption to the gastrodermis was also progressive, though not as severe as disruption to the tegument. There was a general decline of secretory activity with time pt. Autophagic activity was apparent from 48h pt and became more widespread with increasing time, culminating in breakdown of the gastrodermal cell cytoplasm. The mitochondria were swollen and electron-lucent and the cisternae of the granular endoplasmic reticulum were dilated and fragmented from 72h pt.

Prion protein (PrP) gene polymorphism in Red Maasai and Black Head Persian sheep breeds in Tanzania: Consistent profile regardless of locations

The status of scrapie in Africa is largely unknown. The susceptibility to scrapie and its pathology is determined by amino acid polymorphisms at positions 136 (A/V), 154 (R/H) and 171 (Q/R/H) of the ovine PrP gene (PrP genotype) of the animals. Despite the widely studied PrP gene polymorphisms worldwide, limited data is available on PrP genotypes of sheep from the African continent. Previously, we have reported six PrP genotypes derived from four different alleles in Red Maasai and Black Herd Persian (BHP), the ARQ/ARQ genotype being more frequent in the Red Maasai than in the BHP sheep. The highly susceptible VRQ allele was not found in any of the sheep breeds; the ARR allele was absent in the Red Maasai or occurred at a low frequency in the BHP. The lack of the highly susceptible VRQ alleles among Tanzanian sheep examined, necessitated further examinations on genetic susceptibility in sheep of the same breeds, but originating from an entirely different part of Tanzania. Consistently, ARQ/ARQ genotype was observed in 88% of Red Maasai and 64% of BHP sheep, ARQ/AHQ genotype was present in 12% in Red Maasai and 36% in BHP. Neither the highly resistant (ARR/ARR), nor the highly susceptible (VRQ/VRQ) genotypes were found. The ARQ and AHQ were the only alleles observed. The ARQ allele constituted 94%, 82% and 67% in the Red Maasai, BHP and cross-bred sheep, respectively. The AHQ constituted 6%, 18% and 33%, respectively. Data reported here, provide additional information on genetic susceptibility of the Red Maasai, BHP and their crosses; they may be helpful in policy formulation for future prevention of scrapie.

IL‐10 and TGF‐β1 are associated with variations in fluke burdens following experimental fasciolosis in sheep

Infection with Fasciola hepatica causes an economically important disease in ruminants. Variability in parasite load may indicate innate differences in the host immune system. This study aimed to investigate the immunological mechanisms that are associated with variability in parasite burden following experimental F. hepatica infection in cross-bred sheep. Of a total of 16 animals, four were randomly chosen as uninfected controls, and the remainder infected with 100 viable metacercariae. Uninfected animals were used as the control group for evaluation of cytokine gene expression levels. For comparative analysis, specific animals were selected on the basis of extremes of fluke burdens, and were categorised into light (n = 4) and heavy burdened (n = 3) cohorts. Serum antibody levels, haematological parameters, and expression of IL-4 and IFN-gamma genes in hepatic lymph nodes were equivalent in both groups. However, significant differences in mitogen-specific lymphocyte proliferation in vitro and in expression of TGF-beta1 and IL-10 genes in hepatic lymph nodes were observed at acute and chronic phases of infection, respectively. These results provide useful information in developing further understanding of natural resistance to fasciolosis in sheep.

Sequence polymorphism of PrP exon 3 gene in Istrian and crossbred sheep

Polymorphisms in sheep PrP (prion protein) gene are known for scrapie susceptibility. We sequenced part of PrP exon 3 gene in 92 autochthonous Istrian (IS) and 38 crossbred sheep (CBS). ARQ, ARR and AHQ alleles were predominant with frequency of 0.674 (0.526), 0.228 (0.132) and 0.082 (0.263) in IS (CBS), respectively, while VRQ (0.011 in IS) and ARH (0.005 in IS and 0.079 in CBS) alleles were rare. We also found non-synonymous mutations at codons 112 (M→T), 127 (G→S) and 143 (H→R), and synonymous mutations at codons 231 (R) and 237 (L). Additional mutations were associated only with AHQ, ARH and ARQ alleles. The polymorphism of PrP gene in IS was not critical with respect to scrapie susceptibility and with some efforts number of “favourable” genotypes can be increased.

Phenotype Characterization of Pelibuey Native Lambs Resistant to Haemonchus contortus

Specific phenotypic traits of the blood-feeder nematode Haemonchus contortus were characterized on Pelibuey native, cross-breed sheep in a tropical region of Mexico with background of anthelmintic problems. Data were collected on 4-month-old lambs (n= 63) and analyzed weekly in three stages: stage 1 (S1, not infected (0-3 weeks)); S2, first infection with 350 H. contortus infective larvae (L(3)) per kg of body weight by oral route (3-10 weeks); and S3, second infection with 175 H. contortus L(3) per kg of body weight by oral route (10-18 weeks). Once infection took place, sheep grazed in a free-nematode experimental paddock, and hemoncosis-related traits, such as the number of eggs per gram of feces (epg), packed cell volume (%pvc), and eosinophils (%eo), were measured each week. Results were analyzed on specific traits and stages using SAS statistics. Statistical differences of the main phenotypic traits (P < 0.05) were observed throughout S2 on Pelibuey high (hr) and low (lr) responders, respectively: epg mean, 475 +/- 340.5 and 1439 +/- 243.6; %pvc mean, 31 +/- 0.3 and 27 +/- 0.2; and %eo mean, 2.5 +/- 0.3 and 1.99 +/- 0.2. In addition, lr and hr sheep grazed for 3 months on an area infected with Haemonchus, Cooperia, and Strongyloides, and the hr sheep showed a low number of epg after being exposed to multiple infections, so that no further treatment was required. These results showed that the selection of animals resistant to nematodes can be an alternative method of control against anthelmintic resistance problems in order to improve animal health and avoid a negative environmental impact.

Grazing on mountain pastures-does it affect meat quality in lambs?

Meat from lambs raised on mountain pastures without any supplementary feeding or treatment is often considered to be of superior quality. Hence, the objective of this study was to compare the quality of meat from lambs grazing on unimproved mountain range (1000 m above sea level) with meat from lambs grazing on cultivated lowland pastures. The experiment was undertaken in Hardanger on the Western Coast of Norway with 150 Norwegian Crossbred Sheep (Norsk Kvitsau) randomly allocated to “Lowland” and “Mountain” groups. Twenty lambs from each group were selected for final evaluation. Slaughtering and grading were performed at a commercial slaughterhouse. Thereafter, loin samples of M. longissimus dorsi were analyzed for sensory traits and other meat quality. For further comparisons, loin samples were also taken from lambs slaughtered at two other locations in Norway. Significant differences between the groups were found in grading, fat content and fatty acid composition, meat colour, and meat flavour. Differences in sensory traits were in general small and most likely not noticed by the consumer. Still the results suggest that meat from lambs raised in extensive systems on mountain range has certain qualities that might be used in promotion of local and regional products.

Genetic and Environment Factors Influencing Birth Weight in Yankasa and Yankasa * West African Dwardf Crossbred Sheep in Humid Southwest Nigeria

Genetic and Environment Factors Influencing Birth Weight in Yankasa and Yankasa * West African Dwardf Crossbred Sheep in Humid Southwest Nigeria

Evaluation of primary rumen epithelial cell incubation techniques in sheep

Objectives of this study were to determine if the number of cells incubated in primary rumen epithelial cell cultures affects production rates of metabolites and to establish an ideal mode of data expression in order to standardize the reporting criteria for primary cell incubation. Epithelial tissue was excised from five Suffolk×Dorset cross-bred sheep and subjected to serial tryptic digestion to isolate cells. Isolated cells were incubated for 90 min in 25 mM propionate and 10 mM butyrate at concentrations of 0.5, 1, 5, 10, 20 and 40 million cells per flask (total volume=3 ml). Production of acetoacetate (ACAC), β-hydroxybutyrate (BHBA), lactate (LAC) and pyruvate (PYR) were measured. Data were expressed as either cell number, cell dry matter (DM) or cell crude protein (CP) alone or per epithelial wet tissue weight, body weight (BW) or metabolic BW to generate 12 different forms of data expression. Coefficients of variation (CVs) were calculated for all 12 modes of expression. Expressing data per cell number resulted in the lowest variation ( P<0.01) and data adjusted for metabolic BW had less variation than BW. ACAC concentrations were largest at 0.5 million cells per flask ( P<0.05) and there were no differences between 1, 5, 10 and 20, and only 40 differed from 0.5 and 5 million cells per flask. Concentrations of BHBA were largest at 1 and 5 million cells per flask, but were different ( P<0.05) only from 20 and 40 million cells per flask. LAC and PYR concentrations were largest at 1 million cells per flask, but no significant differences were found. Ratios of BHBA:ACAC were below one for the 0.5 million cells per flask indicating low mitochondrial redox potentials ( P<0.05). A suggested range of rumen epithelial cells to include in incubations is 5–20 million cells per flask. This range will minimize the potential for altered metabolite production caused by incubating large cell quantities as well as the experimental error associated with using low cell numbers. When rumen tissue is taken from animals of the same species, size and stage of development, data adjusted by cell number is preferred. However, it is recommended that metabolic BW, cell CP and cell DM be included to facilitate future comparison between laboratories and species.

Seasonal changes in body weight and condition, and pregnancy and lambing rates of sheep on endophyte-infected tall fescue in the south-eastern United States

The objective of these studies was to evaluate the seasonal maintenance of body weight (BW) and condition, signs of fescue toxicosis, and reproductive performance of straightbred and cross-bred hair sheep grazing tall fescue or bermudagrass forage. Breeds examined were St. Croix (SC), Romanov (ROM) and cross-bred ewes. BW was measured in the summer (1998–2000) and the fall (1999) on ewes grazing bermudagrass overseeded with ryegrass (BER) or tall fescue (FES) forage. Body condition score (BCS) and serum prolactin concentrations were determined in the summer (1999, 2000) and fall (1999). Pregnancy and lambing rates of a summer and fall (1999) breeding season and pregnancy rates of the spring (2000) breeding season were recorded. BW and BCS reflected seasonal differences related to the forage availability of BER and FES, seasonal variations in toxins of FES forage and breed differences. At all times, serum prolactin concentrations were reduced in ewes grazing FES pastures ( P<0.01), with the exception of the summer of 1999, where cross-bred yearling ewes maintained on FES exhibited an increase in prolactin level compared to those grazing on BER forage (forage×breed; P<0.05). Pregnancy and lambing rates were similar for forage treatments, with the exception of a reduction in reproductive rate in yearling cross-bred ewes maintained on FES in summer (1999; P<0.05). Birth and weaning weights of lambs were similar for suckling ewes maintained on BER and FES forage. These experiments demonstrated that, in contrast to cattle, BCS of SC, ROM and cross-bred ewes can be maintained in an acceptable range with either BER or FES forage. Pregnancy rate may be reduced in yearling, but not the older ewes maintained on FES forage. Birth weights and growth of lambs of mature ewes were similar for the forage treatments. It is recommended that breeding of yearling ewes occur on pastures free of endophyte-infected tall fescue.