The Discovery of a Bone in the Anterior Fontanelle of the Skull of the Sheep (Ovis aries) / Descubrimiento de un Hueso en la Fontanela Anterior del Cráneo de la Oveja (Ovis aries)

SUMMARY: A comparative study of the skull morphology was conducted using 270 prenatal and 750 postnatal skull samples from three breeds of sheep in Nigeria namely, Balami, Uda and Yankasa. A unique bone peculiar to the Yankasa breeds of sheep was found consistently at the centre of the anterior fontanelle in the young (day-old to 1 year). At two years of age and above, the bone was fused and disappeared completely. This brings the total numbers of the neurocranium bones of the skull in the Yankasa breeds to 8, as against the 7 bones documented in the ovine species. Due to the fact that this bone has not been described in the literature, we venture to name it the anterio-fontanelle bone (of Atabo).

Se realizó un estudio comparativo de la morfología del cráneo utilizando 270 muestras de cráneos prenatales y 750 postnatales de tres razas de ovejas en Nigeria, Balami, Uda y Yankasa. Un hueso único peculiar de las razas de ovejas Yankasa se encontró consistentemente en el centro de la fontanela anterior en las crías (de un día a 1 año). A los dos años de edad o más, el hueso se fusionó y desapareció por completo. Esto eleva el número total de huesos del neurocráneo en el cráneo en las razas Yankasa a 8, frente a los 7 huesos documentados en la especie ovina. Debido a que este hueso no ha sido descrito en la literatura, nos aventuramos a denominarlo hueso antero-fontanela (de Atabo).

A morphometric study on skulls of Hasmer and Hasak sheep breeds / Un estudio morfométrico de cráneos de razas de ovejas Hasmer y Hasak

SUMMARY: The aim of the study was to investigate the head structures of two domestic sheep breeds (Hasak and Hasmer) in Turkey. Gender neutral eight adult Hasmer sheep of 45-66 kg and eight Hasak sheep breeds of 43-66 kg obtained from Bahri Dag˘das¸ International Agricultural Research Institute were used in this study. Measurements were made using digital caliper from 40 points on the skulls of both species. The skull of Hasmer sheep (265.56 ± 14.08) was longer than the skull of Hasak sheep (262.86 ± 9.65). However, the length of the arcus alveolaris maxillaris (77.01 ± 5.08), the length of the molar teeth (50.81 ± 1.22) and the length of the premolar teeth (26.16 ± 4.62) of Hasak sheep were compared to the Hasmer sheep (71.59, ± 5.25; 47.99 ± 3.64; 24.03 ± 3.76, respectively) was observed to be greater. According to these findings, although the skull length of Hasak sheep was shorter than that of Hasmer sheep and arcus alveolaris maxillaris in which molar and premolar teeth were placed was longer. In Hasmer sheep the values of greatest breadth of the foramen magnum, height of the foramen magnum (basion - opisthion), greatest neurocranium breadth-greatest breadth of the braincase (euryon - euryon) were higher than those of Hasak sheep. The difference between these values was also statistically significant (p <0.05). The lateral length of the premaxilla (nasointermaxillare- prosthion) parameter measured between these two species was statistically very important (p <0.01). In conclusion, in this study craniometric values depending on skull morphology of Hasmer and Hasak sheep which accepted as native breeds of Turkey were tried, to reveal similarities and differences with other sheep breeds in both amongst themselves.

El objetivo del estudio fue investigar las estructuras de la cabeza de dos razas de ovejas domésticas (Hasak y Hasmer) de Turquía. En este estudio se utilizaron ocho ovejas Hasmer adultas de género neutral de 45-66 kg y ocho ovejas de raza Hasak de 43-66 kg, obtenidas del Instituto Internacional de Investigación Agrícola Bahri Dagdas. Las mediciones en los cráneos de ambas especies se realiza-ron con caliper digital de 40 puntos. El cráneo de la oveja Hasmer (265,56 ± 14,08 mm) era más largo que el cráneo que el de la oveja Hasak (262,86 ± 9,65 mm). En las ovejas Hasak la longitud del arcus alveolaris maxillaris fue 77,01 ± 5,08 mm, la longitud de los dientes molares fue 50,81 ± 1,22 mm y la longitud de los dientes premolares fue de 26,16 ± 4,62 mm, en cambio en las ovejas Hasmer fue de 71,59 ± 5,25 mm; 47,99 ± 3,64 mm; 24,03 ± 3,76 mm, respectivamente. Según estos hallazgos, la longitud del cráneo de la oveja Hasak era más corta que la de la oveja Hasmer y el arcus alveolaris maxillaris en el que se colocaron los dientes molares y premolares era más largo. En ovinos Hasmer los valores de mayor amplitud del foramen magnum, altura del foramen magnum (basion - opisthion), mayor amplitud del neurocráneo-mayor amplitud de la caja craneana (euryon - euryon) fueron superiores a los de las ovejas Hasak. La diferencia entre estos valores también fue estadísticamente significativa (p <0,05). El parámetro de longitud lateral del premaxilar (nasointermaxillare-prosthion) medido entre estas dos especies fu estadísticamente significativo (p <0.01). En conclusión, los valores craneométricos en relación a la morfología del cráneo de las ovejas Hasmer y Hasak que se definieron como razas autóctonas de Turquía revelaron similitudes y diferencias con otras razas de ovejas.

Diferencias morfométricas en el hueso palatino de la oveja (Ovis aries) y la cabra (Capra hircus) / Morphometric palatine differences between sheep (Ovis aries) and goat (Capra hircus)

RESUMEN: Un hueso craneal muy poco estudiado en anatomía veterinaria comparada es el palatino. En nuestro estudio, realizamos la comparación de este hueso entre la oveja (Ovis aries L., 1758) y la cabra (Capra hircus L., 1758), a partir de una muestra de 36 y 17 cráneos respectivamente, y utilizando métodos de morfometría geométrica. Se eligieron un total de 32 puntos (4 hitos y 28 semi-hitos) para analizar la lámina horizontal del hueso palatino. Se reflejaron diferencias estadísticamente significativas tanto para el tamaño como para la forma. En Capra se denota una clara expansión lateral del hueso y rostral y una contracción central, con un acercamiento relativo de los forámenes palatinos, mientras que en Ovis los forámenes están más lateralmente alejados. A nuestro parecer, esta mayor anchura y longitud de la lámina horizontal en Capra se explicaría por una mayor capacidad de frotación del alimento en relación a Ovis.

SUMMARY: Palatine is a cranial bone very less studied in comparative veterinary anatomy. In our study, we performed the comparison of this bone between sheep (Ovis aries L., 1758) and goat (Capra hircus L., 1758), from a sample of 36 and 17 skulls respectively, using methods of geometric morphology. A total of 32 points (4 landmarks and 28 semi-landmarks) were chosen to analyse the horizontal lamina of the palatine bone. Statistically significant differences were reflected for both size and shape. Capra denotes a clear lateral expansion of the bone and rostral and a central contraction, with a relative approach of palatine foramina, while in Ovis foramina are more laterally distant. In our view, this greater width of the horizontal lamina in Capra would be explained by a greater capacity to rub the food compared to Ovis.

Prediction of carcass composition through measurements in vivo and measurements of the carcass of growing Santa Inês sheep.

In vivo and carcass measurements were evaluated to predict carcass physical and chemical composition and to list the measurements that best fit the prediction of the composition of growing Santa Inês sheep carcasses. Thirty-three animals were used to measure the loin eye area by ultrasound in vivo (LEAu) and in the carcass. We used 39 animals for biometric measurement in vivo and 42 sheep for morphometric measurement in the carcass. For the physical and chemical compositions of carcasses, dissection of the half left carcass was carried out in 42 animals. The data were submitted to Pearson's correlation analysis and t test. Simple and multiple linear regressions were performed using a stepwise procedure. All correlations between in vivo measurements and the physical and chemical compositions of carcasses (in kg) were significant, except for LEAu. Biometric measurements and hot (HCW) and cold (CCW) carcass weights were considered as predictors of the carcasses' physical and chemical compositions. Slaughter body weight (SBW) was the variable that most influenced the equations in the assessment of in vivo measurements and HCW and CCW most influenced the equations for measurements on carcasses. Biometric measurements of Santa Inês sheep can be used together with the SBW to estimate the physical and chemical compositions of carcasses, with emphasis on body compactness index, breast width, wither height, and croup height. The morphometric measurements can be used together with carcass weight to estimate the physical and chemical compositions of carcasses, with emphasis on croup width, carcass compactness index, croup perimeter, external and internal carcass lengths, chest width, and leg length and perimeter. The HCW can be used to predict the physical and chemical composition of carcasses without affecting the accuracy of the prediction model.

Echocardiographic evaluation in Dorper ovine fetuses: Applications and limitations.

In this study we aim to show the application of ultrasound evaluation of the fetal heart in the ovine species, as well as its limitations in the field. Ten Dorper sheep, without any sedation, were evaluated starting from the second month of pregnancy through transabdominal ultrasound with an ultrasound device equipped with a convex transducer. Images of the fetal heart were obtained through maternal abdominal ultrasound by identifying the position of the fetus and conducting the following measurements: length and diameter of the heart, dimensions of the right and left ventricles and dimensions of the right and left atria. The measurements could only be conducted with acceptable precision starting from the third month of pregnancy. There was a significant difference only for left ventricle diameter, which was larger in the fifth month of pregnancy. The echocardiographic evaluation of the fetus enables monitoring the heart development identifying early fetal viability, assessing inadequate events that could put the pregnancy at risk, especially for production animals. For the experimental design of research employing production animals, it is important to consider, among other factors, the limitations of the evaluation on the field, such as restraining the animals, the stress caused by handling and environmental conditions, temperature, luminosity, facilities available and the qualifications of the team.

Vascular morphology and expression of angiogenic factors in sheep ovaries and their relation with the lambing rate.

The study aims to present the vascular anatomy of ovarian arterial system in sheep and to explore its relation with the angiogenic factors vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2), environmental factors and the lambing rate. Small-tailed Han sheep, Hu sheep, Aohan finewool sheep and Tibetan sheep who are from different habitats in China and with different lambing rates were investigated. The vascular corrosion casting technique and scanning electron microscopy were used to understand arterial architecture, and real-time quantitative PCR (qRT-PCR) and Western blotting were used for assessing VEGF and Ang-2 expression. Results showed that high-prolificity breeds had significantly larger vessel diameters in ovaries than low-prolificity ones. VEGF gene transcript and protein expression were related with the lambing rate, while Ang-2 gene transcript was negatively related with the lambing rate. Results indicated that high-prolificity breeds have more abundant arterial blood supply, which is associated with VEGF expression.

Breeding practices and trait preferences of smallholder farmers for indigenous sheep in the northwest highlands of Ethiopia: Inputs to design a breeding program.

The aim of this study was to identify breeding practices and trait preferences for indigenous sheep in three districts (Estie, Farta and Lay Gayient) located in the northwest highlands of Ethiopia. Questionnaire survey and choice experiment methods were used to collect data from 370 smallholder farmers. Respondents were selected randomly among smallholder farmers who own sheep in the aforementioned districts. A generalized multinomial logit model was employed to examine preferences for sheep attributes, while descriptive statistics and index values were computed to describe sheep breeding practices. Having the highest index value of 0.36, income generation was ranked as the primary reason for keeping sheep, followed by meat and manure sources. The average flock size per smallholder farmer was 10.21 sheep. The majority of the smallholder farmers (91%) have the experience of selecting breeding rams and ewes within their own flock using diverse criteria. Given the highest index value of 0.34, body size was ranked as a primary ram and ewe selection criteria, followed by coat color. Furthermore, choice modeling results revealed that tail type, body size, coat color, growth rate, horn and ear size have shown significant influences on smallholder farmers' preference for breeding rams (P<0.01). The part-worth utility coefficients were positive for all ram attributes except ear size. For breeding ewes, mothering ability, coat color, body size, lambing interval, growth rate, tail type and litter size have shown significant effects on choice preferences of smallholder farmers (P<0.05). Moreover, significant scale heterogeneity was observed among respondents for ewe attributes (P<0.001). Overall, the results implied that sheep breeding objectives suitable for the northwest highlands of the country can be derived from traits such as linear body measurement, weight and survival at different ages, and lambing intervals. However, selection decisions at the smallholder level should not only be based on estimated breeding values of traits included in the breeding objective but instead, incorporate ways to address farmers' preference for qualitative traits.

Ruminal and histological characteristics and nitrogen balance in lamb fed diets containing cactus as the only roughage.

This study examined rumen fermentation, histological, blood, and urinary characteristics as well as ammoniacal nitrogen concentration, pH, nitrogen balance, and microbial protein in lamb fed diets containing spineless cactus as the sole roughage source plus levels of wheat bran (WB) in comparison with a control diet based on spineless cactus and buffelgrass. Twenty-eight uncastrated, crossbreed lambs with an average initial weight of 22.6 ± 2.37 kg were used in the experiment. The treatments consisted of a standard diet (control) containing buffelgrass and spineless cactus and three diets containing cactus as the only roughage source plus varied concentrations of WB (30, 37, and 44%, on a dry matter basis). Results were evaluated by analysis of variance, and contrasts were applied at the 5% probability level for mean comparison. Rumen villus height and width were greater and musculature was lower in the lamb fed diets containing 37% and 44% WB compared with those fed control diet. In the intestine, the crypts were smaller in the animals which consumed the diets with 30, 44, and 37% WB. All WB levels resulted in lower nitrogen intake and retention. Microbial protein concentration, microbial protein efficiency, microbial nitrogen, urea, and glucose were not significantly affected. Feeding lamb with diets containing levels of wheat bran, with cactus as the only roughage source, does not negatively affect their ruminal-fermentation, blood, and urinary characteristics; ammoniacal nitrogen concentration; pH; or microbial protein. However, nitrogen balance and ruminal and intestinal morphometric characteristics are impaired.

Generic physiologically based kinetic modelling for farm animals: Part I. Data collection of physiological parameters in swine, cattle and sheep.

Physiologically based kinetic (PBK) models for farm animals are of growing interest in food and feed safety with key applications for regulated compounds including quantification of tissue concentrations, kinetic parameters and the setting of safe exposure levels on an internal dose basis. The development and application of these models requires data for physiological, anatomical and chemical specific parameters. Here, we present the results of a structured data collection of anatomical and physiological parameters in three key farm animal species (swine, cattle and sheep). We performed an extensive literature search and meta-analyses to quantify intra-species variability and associated uncertainty of the parameters. Parameters were collected for organ weights and blood flows in all available breeds from 110 scientific publications, of which 29, 48 and 33 for cattle, sheep, and swine, respectively. Organ weights were available in literature for all three species. Blood flow parameter values were available for all organs in sheep but were scarcer in swine and cattle. Furthermore, the parameter values showed a large intra-species variation. Overall, the parameter values and associated variability provide reference values which can be used as input for generic PBK models in these species.

Current challenges in sheep artificial insemination: A particular insight.

Ovine artificial insemination (OAI) is not commonly performed because of specific problems related to semen application techniques, leading to highly variable results. The ideal methodology (frozen-thawed semen/vaginal route) is unfeasible under field conditions due to the cervix morphology of the ewe, which prevents the process of intrauterine insemination necessary to obtain acceptable results. Currently, OAI commercial programmes use superficial cervical insemination, CAI (vaginal), with chilled semen (15°C) and intrauterine insemination, LAI (laparoscopic), with frozen-thawed semen. The ability to improve upon these contrasting techniques may be derived from examining certain poorly studied factors such as insemination time, productive state of females and alternatives of seminal preservation, some of which we reviewed in this work. This interim solution will remain in use until AI by the vaginal route with frozen-thawed semen is developed, but it poses new challenges in optimizing the freezing of the sperm and adapting the cervical (CAI) and/or transcervical intrauterine AI (TCAI). In this review, we address the current problems and evaluate their methodological (mechanical) and chemical (dilation) alternatives. Currently, TCAI is a methodologically complex technique with poor fertility results, so further studies are needed to improve the logistics of this procedure and the results of its application.

Two linked TBXT (brachyury) gene polymorphisms are associated with the tailless phenotype in fat-rumped sheep.

T-box transcription factor T (TBXT), encoding the brachyury protein, is an embryonic nuclear transcription factor involved in mesoderm formation and differentiation. Previous studies indicate that TBXT mutations are responsible for the tailless or short-tailed phenotype of many vertebrates. To verify whether the tailless phenotype in fat-rumped sheep is associated with TBXT mutations, exon 2 of the TBXT gene for 301 individuals belonging to 13 Chinese and Iranian sheep breeds was directly sequenced. Meanwhile, 380 samples were used to detect the genotypes of the candidate variations by mapping to their reads databases in the Sequence Read Archive repository of GenBank. The results showed that one missense mutation, c.334G>T (GGG>TGG) with a completely linked synonymous variant c.333G>C (CCG>CCC) was found to be associated with the 'tailless' characteristic in typical fat-rumped sheep breeds. The c.334G>T transversion led to the conversion of glycine to tryptophan at the 112th amino acid in the T-box domain of the brachyury protein. In addition, crossbreeding experiments for long-tailed and tailless sheep showed that CT/CT allele of nucleotides (nt) 333 and 334, a recessive mutation, would cause sheep tails to be shorter, suggesting that these two linked variants at nucleotides 333 and 334 in TBXT are probably causative mutations responsible for the tailless phenotype in sheep.

The effects of birth rank (single or twin) and dam age on the lifetime productive performance of female dual purpose sheep (Ovis aries) offspring in New Zealand.

Greater rates of genetic gain can be achieved by selecting animals born to younger parents. However, little is known about the lifetime performance of dual purpose ewes (Ovis aries) that are born to primiparous ewe lambs (8 to 9 months old at breeding). This experiment investigated the effect of being born from either a ewe lamb or mixed age dam as either a single or twin on the lifetime performance of ewe progeny. Lifetime performance was measured in terms of the life time live weights of the ewes, the weight and number of lambs born and weaned, the efficiency of production (kilograms of lamb weaned / predicted pasture intake (kgDM) of the ewes), and ewe survival. The study followed the lifetime production of 17 single and 41 twin female lambs born to mature ewes (M1 and M2, respectively), and 28 single and 29 twin lambs born to ewe lambs (L1 and L2, respectively). Over their lifetime L2 ewes were lighter (P<0.05) but had similar body condition scores to the other three ewe groups. There was no difference in average progeny weaning weight or total progeny litter weaning weights between groups. The M1 ewes had the greatest longevity (P<0.05) of the four groups. Even though L2 ewes were lighter than the other three groups, this was insufficient to increase their lifetime efficiency of production (kg lamb weaned/predicted pasture consumption), relative to the other groups. These results suggest farmers could select replacements born to ewe lambs without sacrificing animal production.

Influence of laterality on testis anatomy and histology in Ghezel rams.

Whether paired organs are equivalent has to be analyzed by assessing both structural and functional aspects. The present study compared the paired left and right testis from Ghezel sheep originating from Northwestern Iran (Azerbaijan) and Northeastern Turkey. Twenty-five pairs of testes were collected from mature Ghezel rams from Tabriz slaughterhouse. The two glands were compared for their size, weight and activity rate. Weight, length, width and thickness were measured. Then, paraffinized blocks were prepared by routine histological techniques and sections were stained by the haematoxylin-eosin method. Five 6 µm sections were prepared from each paraffinized block and 50 seminiferous tubules (STs) were analysed in each section for tubular differential index (TDI) and spermiogenesis index (SPI). TDI and SPI were compared between the paired left and right testes. Weight, length and thickness of left testes were significantly higher than in right testes (P < 0.05). Moreover, TDI and SPI were found to be higher in left testes than the right (P < 0.05).

Genotypic and allelic effects of the myostatin gene (MSTN) on carcass, meat quality, and biometric traits in Colored Polish Merino sheep.

The aim of this study was to identify polymorphisms in the first intron and c.*1232G>A position of the MSTN gene and analyze associations between the detected alleles/genotypes and carcass, meat quality, and biometric traits in Colored Polish Merino sheep. We analyzed 44 traits using the MIXED procedure of the SAS software. Five alleles (MSTN-A, MSTN-B, MSTN-C, MSTN-E and MSTN-E1) were detected. Significant genotypic effects were detected with regard to chest depth (live lamb) and fat depth over ribs, drip loss, subjective meat flavor and color, whereas significant allelic effects were found for chest depth (live lamb), pre-slaughter weight, hot carcass weight, cold carcass dressing out, leg depth (carcass), eye of loin width and area, intramuscular fat (IMF) content, water-holding capacity, and subjective meat tenderness, flavor and color. The results suggest MSTN gene polymorphisms may be considered a genetic marker of carcass quality, meat quality, and biometric traits in sheep.

Prediction of lamb body composition using in vivo bioimpedance analysis.

The objective of this study was to evaluate the potential of in vivo bioimpedance analysis (BIA) as a method to estimate body composition in lambs. Thirty-one Texel x Ile de France crossbreed ram lambs were slaughtered at pre-determined intervals of average weights of 20, 26, 32, and 38 kg. Before the slaughter of the animals, their body weight (BW) and body length (BL) were measured. The values for resistance (Rs) and reactance (Xc) were collected using a single-frequency BIA equipment (Model RJL Quantum II Bioelectrical Body Composition Analyzer). The BIA main variables such as body bioelectrical volume (V), phase angle (PA), resistive density (RsD), and reactive density (XcD) were then calculated. The soft tissue mass of the right-half cold carcass was analyzed in order to determine its chemical composition. Multiple regression analyses were performed using the lamb body composition as dependent variables and the measurements related to bioimpedance as independent variables. The best regression models were evaluated by cross-validation. The predictive model of moisture mass, which was developed by using XcD and V, accounted for 84% of its variation. Resulting models of percentage moisture (R2 = 0.79), percentage lean mass (R2 = 0.79), percentage fat (R2 = 0.79), and fat mass (R2 = 0.87) were obtained using RsD and V. Furthermore, the values of RsD regarding V, and PA in the prediction models accounted for 91% and 89% of variation in protein mass and lean mass, respectively. Bioimpedance analysis proved to be an efficient method to estimate the body composition of lambs slaughtered at different body mass stages.

The effect of consecutive pregnancies on the ovine pelvic soft tissues: Link between biomechanical and histological components.

BACKGROUND: Pelvic organ prolapse, various types of incontinence (urinary incontinence, defecatory dysfunction), chronic cystourethritis, and sexual dysfunctions remain between the most common disorders in urogynecology. Currently, it is believed that the nature and number of births plays a major role in their development. Moreover, after these events, pelvic floor tissues may not recover to their original statuses. The close anatomical relationship among the vaginal wall, bladder and rectum often contribute to the emergence of anatomical-functional failure of adjacent organs and systems. BASIC PROCEDURES: The aim of this study was to investigate the effect of consecutive pregnancies on pelvic floor soft tissues, conducting biomechanical and histological analysis. Fifteen Swifter ewes: virgins, parous and pregnant were used. Samples, for uniaxial tension tests and histological analysis, were cut out from fresh tissue. A description of the mechanical properties of native tissue was obtained from the stress-strain curve. Histological samples were stained with Miller's Elastica staining and analyzed using ImageJ software. Collagen, elastin, and smooth muscle contents (%) were analyzed along the full wall thickness of the selected organs. The links between mechanical properties of the soft tissues and histological parameters were analyzed. MAIN FINDINGS: Mechanically, vaginal wall tissue and cervix of pregnant sheep were more compliant. In contrast, bladder and rectum became stiffer and had the highest total collagen content. Parous sheep rectum and bladder were stiffer, compared to virgin sheep. PRINCIPAL CONCLUSIONS: Tensile strength appears to be linked to total collagen content. Elastin and smooth muscle show a direct influence on tissue compliance.

Development of an in situ procedure to evaluate the reticulo-rumen morphology of sheep selected for divergent methane emissions.

Published studies have shown that methane yield (g CH4/kg dry matter) from sheep is positively correlated with the size (volume and surface area) of the reticulo-rumen (RR) and the weight of its contents. However, the relationship between CH4 yield and RR shape has not been investigated. In this work, shape analysis has been performed on a data set of computerised tomography (CT) scans of the RR from sheep having high and low CH4 yields (n=20 and n=17, respectively). The three-dimensional geometries of the RRs were reconstructed from segmented scan data and split into three anatomical regions. An iterative fitting technique combining radial basis functions and principal component (PC) fitting was used to create a set of consistent landmarks which were then used as variables in a PC analysis to identify shape variation within the data. Significant size differences were detected for regions corresponding to the dorsal and ventral compartments between sheep with high and low CH4 yields. When the analysis was repeated after scaling the geometries to remove the effect of size, there was no significant shape variation correlating with CH4 yield. The results have demonstrated the feasibility of CT-based computational shape determination for studying the morphological characteristics of the RR and indicate that size, but not shape correlates with CH4 yield in sheep.

The pay-off of hypsodonty - timing and dynamics of crown growth and wear in molars of Soay sheep.

BACKGROUND: Several lineages of herbivorous mammals have evolved hypsodont cheek teeth to increase the functional lifespan of their dentition. While the selective drivers of this trend and the developmental processes involved have been studied in greater detail, thus far no quantitative information is available on the relationship between additional investment into tooth growth and the resulting extension of the functional period of these teeth. To achieve this, we performed a detailed analysis of molar crown growth in known-age Soay sheep repeatedly injected with different fluorochromes. RESULTS: Our study revealed that in sheep molars especially the formation of the crown base portion is prolonged in comparison with other herbivorous artiodactyl species. Our results demonstrate that growth of the crown base accounted for more than half of the total crown formation time (CFT) of the anterior lobes of the first (approx. 220 days of total CFT of 300 days), second (approx. 260 of 460 days) and third (approx. 300 of at least 520 days) molars, and that the formation of this crown portion occurred largely after the teeth had already reached functional occlusion. By combining data on wear-related changes in crown morphology from the literature with the reconstructed additional investment into the crown base portion, it was possible to relate this additional investment to a prolongation of the functional periods of the molars ranging from 4 years in the M1 to 6 years in the M3. CONCLUSIONS: Our results allow to establish a quantitative link between an additional investment into molar crown growth of sheep and the extension of the functional period of these teeth. The reported findings enable an assessment of the adaptive value, in terms of increased longevity, of an additional investment into crown elongation in a mammalian herbivore.

Genetic variants in fat- and short-tailed sheep from high-throughput RNA-sequencing data.

The identification of genetic variations underlying desired phenotypes is one of the main challenges of current livestock genetic research. High-throughput transcriptome sequencing has been recognized as an efficient way to unravel the rich genetic variants across various species. The Lanzhou Fat-Tail sheep is an endangered sheep breed in China with a notable feature of an exaggerated fat tail that also independently occurs in other sheep breeds. However, the genetic mechanism underlying this particular trait has not been fully elucidated yet. In this study, we used RNA-seq on tissue samples (longissimus dorsi muscle, perinephric fat and tail fat) from three sheep breeds with either fat or thin tails and characterized the genetic variation in Lanzhou Fat-Tail sheep with the ultimate goal of identifying the causal genes and genetic networks responsible for the fat tail in this rare sheep breed. In total, 7 122 920 SNPs and 901 518 indels were detected in the nine individual sheep investigated, of which 606 952 SNPs (8.5%) and 77 633 indels (8.6%) overlapped with QTL associated with fat traits in sheep. Furthermore, we detected 26 613 specific SNPs in Lanzhou Fat-Tail sheep and 44 SNPs located in the same genomic position reported in another sheep breed with fat tails. Interestingly, 33 SNPs are selectively distributed on a chromosome 3 region (39.58-40.91 Mb) that was reported as a strong candidate genomic region for fat deposition in tails of sheep. Our research has also suggested that three genes (CREB1, WDR92 and ETAA1) may be associated with fat tail development. In summary, the resultant genetic variants data in this study provide a valuable resource for marker-assisted selection of the trait in Lanzhou Fat-Tail sheep populations.

Do carcasses of lambs finished on commercial production systems meet market standards?

This study aimed to characterize a commercial lamb finishing system using animals of undefined breed from production to slaughter by analyzing performance, carcass traits, yield of commercial cuts, and the quality and meat acceptance of different slaughter groups, as to evaluate whether this system provides the market with a standardized product. The lots were not homogeneous for yield of commercial cuts and performance and morphometric traits evaluated in vivo. The groups were heterogeneous to 75% of the 13 carcass traits evaluated, among them, hot and cold carcass weights, hot and cold carcass yields, carcass grade finishing and biological yield. There was also no uniformity for the proportion of non-carcass components, morphometry of carcass, visual appraisals, and loin traits. On the other hand, homogeneity was achieved in physico-chemical and sensory traits, except for hardness and proportion of saturated, monounsaturated and polyunsaturated fatty acids. We conclude that the commercial finishing system with the use of undefined crossbred lambs does not produce carcass and cuts standardized to the market.