Horn Size Research Articles

Frontal Horn of Lateral Ventricle of Brain and Its Relation with Age, Gender and Side: Morphometric Study by Computed Tomography among Bangladeshi Population

Background: Knowledge of the baseline reference value of frontal horn size is necessary for the initial and precise analysis of ventriculomegaly. The purpose of this study was to determine the size of frontal horn of lateral ventricle and its relation with age, gender and side among adult Bangladeshi population of Chattogram district. Materials and methods: This cross-sectional analytical study was conducted during the period from July 2022 to June 2023 in the Department of Anatomy, Chittagong Medical College, Chattogram, upon 150 respondents of 20-60 years who had normal Computed Tomography (CT) scans as reported by an expert radiologist. For statistical analysis, Mann-Whitney U test, Wilcoxon signed rank test and ANOVA test were done. p-value was considered significant if it was <0.05 at 95% level of confidence. Results: The mean right and left frontal horn length was 25.50 (±3.95) mm and 25.28 (±4.04) mm respectively. The length of the frontal horn of both right and left sided lateral ventricle were significantly higher in male than that of female (p<0.01). Spearman's correlation coefficient indicated positive linear correlation of length of frontal horn (Right and left side) with age, insignificant in right side (p=0.061) but significant in left side (p=0.046). Conclusion: Morphometric analysis of the frontal horn of the lateral ventricles among the Bangladeshi population produced a number of significant results that may help with the early diagnosis and treatment of neurological diseases that are particular to gender and age. These findings can be validated and expanded upon in future research using bigger sample sizes and cutting-edge imaging methods. IAHS Medical Journal Vol 7(1), June 2024; 54-59

Horns, hunters, and harvest: re‐examining management paradigms for pronghorn

AbstractThe sustainable use of wildlife is foundational to the success of the North American model of wildlife conservation. Harvest management often is shaped through both species biology and public desires. The long timespan it takes males of most ungulate species to reach peak weapon size has created a situation in harvest management in which harvest strategies cannot prioritize both generous hunter opportunity and opportunities to pursue large‐weaponed males; therefore, current harvest paradigms prioritize one at the expense of the other. In contrast to other species, pronghorn (Antilocapra americana) attain the majority of their peak horn size early in life. The rapid development of horns relative to their age may allow for liberal harvest without sacrificing the opportunity for hunters to harvest males with large horns. We evaluated the influence of sex ratios and average age of harvested males on the average horn size of harvested male pronghorn from 2019 to 2022 in 9 hunt areas in Wyoming, USA. Although mean age of harvested males was negatively affected by rate of harvest, increases in mean age at harvest led to only slight increases in mean horn size (i.e., a 1‐year increase in mean age increased mean horn size by 2.1 cm [~1 inch]). The proportion of the harvest composed of large‐horned males was not influenced by mean age of harvest or sex ratio of the population. Based on simulated populations, increasing harvest led to an increase in the number of large‐weaponed pronghorn in the harvest—a relationship that existed for bighorn sheep (Ovis canadensis) and elk (Cervus canadensis) but only at low to moderate rates of harvest. The comparatively young age that pronghorn attain near‐peak horn size alleviates what is otherwise a tradeoff between hunter opportunity and managing for large horn size that is evident in management of other ungulate species. Though rarely a reality in management for large ungulates, for pronghorn, liberal harvest may be possible while still providing opportunity to harvest males with large horns.

A sarcoptic mange outbreak drives long-term patterns of a fitness trait in an exotic ungulate

Species phenotypes are driven by persistent selective pressures that condition their adaptation to the environment. However, stochastic critical events, such as disease outbreaks, may also act as selective pressures because of drastic population decline. External structures like horns of ungulate species may reflect the consequences of these selective pressures on animal fitness. Using a generalized linear model approach, we analysed how a massive mortality event caused by a sarcoptic mange outbreak in 1992 affected the horn size of an Iberian aoudad population (dataset from 1980 to 2014) by comparing horn length before and after the outbreak. We found that this episodic, albeit massive, outbreak changed long-term trends in age-size horn relations. Both females and males presented shorter horns after the sarcoptic mange outbreak, although more marked in males. Even when animals reached mature ages, horn length did not increase with age to the same degree as before the outbreak. We consider that two processes may have acted on the population: a bottleneck favoured “shorter horns” phenotype and a post-mange enzootic period limited horn growth, as infected animals may invest more resources in the immune system. Overall, our results show a top-down regulation of a fitness trait for an ungulate population mediated by a parasite. This disease outbreak showed long-lasting effects on the ungulate population, with ecological and management implications.Graphical

Horn size is linked to Sertoli cell efficiency and sperm size homogeneity during sexual development in common eland (Taurotragus oryx).

Background: In polygynous species, the development of secondary sexual characters is usually decisive for male reproductive success. However, our understanding about the links between the growth of these traits and reproductive efficiency is still elusive. Most research efforts in this topic have been also focused on adult males, although the development of some secondary sexual characters, like bovid horns, typically starts after birth, continues during the puberty and in some species, such as the common eland, slows or even stops during adulthood. In this study, we investigated the relationships between horn size and testicular function during sexual development in common elands using a comprehensive approach that considers both spermatogenic and sperm parameters. Methods: Twenty-two non-sexually mature common elands were used for the present study. Horn size, body mass, testes mass, and gonadosomatic index were assessed. Spermatogenic activity was determined by cytological and histological analyses. Sperm concentration, morphology, morphometry, and intramale variation in sperm size were evaluated on epididymal sperm samples. Cluster analysis was performed to explore the influence of age on relationships between horn size and reproductive function. Results: We found that bigger horns are associated with increased Sertoli cell efficiency and reduced intramale variation in sperm size. Both parameters were not related to one another while they have shown to be associated with enhanced sperm quality in ungulates. Moreover, horn size was positively linked to the testis mass, sperm concentration, and testicular investment in the seminiferous epithelium. Spiral length and basal circumference were the horn traits most strongly correlated with spermatogenic and sperm parameters as well as those responsible for the sexual dimorphism in this species. Cluster analysis rendered two groups: the first one including males ≤30months old, while the second one those >30months old. Horn development and reproductive function were still correlated within age groups, with the strongest relationship found between horn size and sperm size homogeneity in males >30months old. Conclusion: Taken together, our results indicate that horn size can be regarded as a good index of male reproductive potential during sexual development and provide insights into the role of secondary sexual characters in sexual selection dynamics.

Cannot outrun the past: age, nutrition, and cohort influence horn size in pronghorn

AbstractIn North America, most ungulate species exhibit life‐history traits typical of long‐lived, iteroparous species wherein young males tend to prioritize essential life functions including body growth and maintenance that constrains allocation of resources to horn, antler, and pronghorn growth. As a result, males of most ungulate species require several years of growth before reaching asymptotic body size and thereafter, peak weapon size is attained. Unique among ungulate species in North America, pronghorn possess a suite of life‐history traits resulting in a precocious (i.e., unusually early development) pace of life relative to other North American ungulates. We tested the hypothesis that the fast pace of life of pronghorn extends to precocious development of large horns, and evaluated how horn size was affected by environmental conditions during the year they were grown and the potential for cohort effects associated with environmental signatures during the year of birth. We evaluated the influence of age and the environment on horn size of pronghorn using data collected from 1,789 male pronghorn harvested from 2019 to 2022 in Wyoming, USA. Pronghorn attained 95% of their peak horn size by 3.5 years old. Climatic conditions influenced horn growth through cohort effects and year of growth pathways. Snow depth during the year of birth positively influenced horn size, whereas the effects of environmental conditions during the year of horn growth were dependent on age. For young animals, snow depth and moderate drought positively influenced horn size during the year of horn growth, but the effect was negligible for prime aged and old animals. The precocious nature of pronghorn extended to their horn growth characteristics, resulting in early attainment of a large proportion of their peak horn size. The unique ecology of pronghorn and rapid attainment of size early in life can allow for greater flexibility to balance hunter opportunity and production of large‐horned males for pronghorn as compared with other ungulates.

Correlating male white‐tailed deer antler size with female body mass across multiple spatial scales

AbstractManagers use morphometric data collected from harvested animals as indicators of nutritional condition. Antler or horn size often are considered in ungulates, but there are problems associated with biased and limited harvest data available from male animals in many populations. Adult female body mass also may be collected, but little information exists on how male antler size scales with female body mass. We evaluated the relationship between property‐specific mature male white‐tailed deer (Odocoileus virginianus) antler size and adult female body mass from harvest data collected at 2 spatial scales. Regression predicted a 4.4‐cm increase in average mature male antler size for every 1‐kg increase in female body mass from 31 properties across the eastern United States, 2015–2023. Adult female mass explained 64% of the variation in mature antler size, and including latitude as a covariate did not improve model fit. When we considered data from 174 properties in Mississippi, USA, 1991–1994, we predicted a 4.7‐cm increase in average mature male antler size for every 1‐kg increase in adult female body mass. Including soil resource region in the Mississippi model explained 48% of the variation in mature male antler size by accounting for differences in average sizes across regions. Our results indicate average female body mass correlates with mature male antler size at multiple spatial scales. We recommend managers collect body mass and age from harvested female deer, as female mass represents a useful metric to track management progress and predict changes in antler size.

Analysis of genetic variants for different horn phenotypes and their inheritance in Icelandic sheep

Abstract. Icelandic sheep are characterized by a great diversity in horn phenotypes. Within their breed, they show a variability in terms of this trait to an extent rarely observed elsewhere. Previously, several genetic variants were published as markers for horn status (in terms of absence or presence of horns, including scurs) and horn traits (e.g., oval horns, horn length and polyceraty). The aim of this study was to genotype, for the first time, five of these genetic variants in Icelandic sheep with different horn phenotypes, as well as to analyze their inheritance. Phenotypic and pedigree data, as well as DNA samples from two Icelandic sheep farms, were used. Genetic variants were genotyped by published PCR-based methods in all samples (n=94) or in subsets. As in other sheep breeds with variable horn status, the inheritance of the presence or absence of horns was shown to be complex in Icelandic sheep, especially when sheep carry anything other than regularly formed horns. The 1.78 kb sized RXFP2 insertion on ovine chromosome 10 previously described to be associated with polledness in several sheep breeds was also found to be present in Icelandic sheep and showed some association but not a perfect segregation with the individuals' horn statuses. Missing associations were especially seen in sheep with scurs and oval horns. Regarding horn shape, there was no agreement with the studied variants described in Chinese breeds having comparable horn traits. However, matching tendencies were seen for the horn size variant that was found in the same study. All sheep with four or more horns carried the already published 4 bp deletion in HOXD1, as previously described for three other sheep breeds. Interestingly, for the first time, the deletion was also detected in phenotypically polled animals originating from multi-horned families. According to the results from animals genotyped simultaneously for the RXFP2 and the HOXD1 variants, polledness in sheep with a genetic disposition for polyceraty seems not to be controlled by the RXFP2 insertion. However, this and all other findings in Icelandic sheep need to be confirmed by analyzing a higher number of well-phenotyped animals.

Eye development influences horn size but not patterning in horned beetles.

Understanding the origin of novel morphological traits is a long-standing objective in evolutionary developmental biology. We explored the developmental genetic mechanisms that underpin the formation of a textbook example of evolutionary novelties, the cephalic horns of beetles. Previous work has implicated the gene regulatory networks associated with compound eye and ocellar development in horn formation and suggested that horns and compound eyes may influence each other's sizes. Therefore, we investigated the functional significance of genes central to visual system formation in the initiation, patterning, and size determination of head horns across three horned beetle species. We find that while the downregulation of canonical eye patterning genes reliably reduces or eliminates compound eye formation, it does not alter the position or shape of head horns yet does result in an increase in relative horn length. We discuss the implications of our results for our understanding of the genesis of cephalic horns in particular and evolutionary novelties in general.

Risky conclusions regarding shrinking rhino horns

Abstract Image‐based analyses from an online repository on rhino horns asserted that declines in size over time could be the consequence of poaching and hunting. We provide reflections on whether the sample was representative enough to make generalizations, the study adequately accounted for the main sources of horn‐size variation and the statistical methods were adequate to be confident in the results. The sample had a limited representation, most coming from zoo animals. We highlight several sources of variance in horn size that such a sample could not evaluate robustly using linear regressions, both for establishing a proxy for horn size corrected for size of a rhino and assessing trends over time. Nevertheless, horn poaching continues to be the key threat to rhinos. Addressing the underlying drivers of poaching and trafficking are key priorities for responsible public debate, policy making and interventions. Read the free Plain Language Summary for this article on the Journal blog.

Expression, Polymorphism, and Potential Functional Sites of the BMPR1A Gene in the Sheep Horn.

Sheep horns are composed of bone and sheaths, and the BMPR1A gene is required for cartilage and osteogenic differentiation. Therefore, the BMPR1A gene may have a function related to the sheep horn, but its relationship with the sheep horn remains unclear. In this study, we first utilized RNA sequencing (RNA-seq) data to investigate the expression of the BMPR1A gene in different tissues and breeds of sheep. Second, whole-genome sequencing (WGS) data were used to explore the functional sites of the BMPR1A gene. Lastly, the allele-specific expression of the BMPR1A gene was explored. Our results indicate that BMPR1A gene expression is significantly higher in the normal horn groups than in the scurred groups. Importantly, this trend is consistent across several sheep breeds. Therefore, this finding suggests that the BMPR1A gene may be related to horn type. A total of 43 Single-Nucleotide Polymorphisms (SNPs) (F-statistics > 0.15) and 10 allele-specific expressions (ASEs) exhibited difference between the large and small horn populations. It is probable that these sites significantly impact the size of sheep horns. Compared to other polled species, we discovered ten amino acid sites that could influence horn presence. By combining RNA-seq and WGS functional loci results, we identified a functional site at position 40574836 on chromosome 25 that is both an SNP and exhibits allele-specific expression. In conclusion, we demonstrated that the BMPR1A gene is associated with horn type and identified some important functional sites which can be used as molecular markers in the breeding of sheep horns.

Allometry, asymmetry and sexual dimorphism in blue wildebeest (Connochaetes taurinus)

AbstractHyper‐allometry, whereby an anatomical unit increases in size at a faster rate than other structures of the same organism, is considered to be an important feature of many sexually selected structures, with large ‘high‐quality’ animals carrying a feature that is proportionally larger than smaller, ‘low‐quality’ animals. When these structures are bilaterally symmetrical, it has been suggested that the degree of fluctuating asymmetry (deviation from perfect symmetry) acts as an indicator of the quality of the bearer. Bovids are useful models for testing sexual selection hypotheses due to their large horns and variety of reproductive systems. Here we use male and female specimens of the southern African blue wildebeest (Connochaetes taurinus) to assess the levels of allometry and fluctuating asymmetry in morphological features of the horns and skull. Males were found to be significantly larger than females for overall horn size, horn length and horn circumference and the horns were found to be isometric in both sexes. Directional asymmetry was found for horn length and horn circumference with the right being longer than the left side. These findings suggest that in C. taurinus the horns follow predicted patterns of variation for sexually selected traits, but that here fluctuating asymmetry may not be as important in sexual selection as previously suggested. Additionally, females did not differ greatly from males in variation and asymmetry and allometry, indicating their horns could be under sexual selection as a result of male choice, or that like males, they also engage in intraspecific combat as well.

Dall's sheep horn growth and harvest management in the Mackenzie Mountains, Northwest Territories, Canada

AbstractAcross most of their native North American range, the horns of mountain sheep (Ovis spp.) males are getting smaller, a pattern attributed to selective hunting pressure. We measured the horns of 755 Dall's sheep males (Ovis dalli dalli) in the southern Mackenzie Mountains, Northwest Territories, between 2002 and 2017. For each male, we measured the circumference and length of each annulus for the right horn and calculated horn volume for each year. We examined changes in horn size in 4 different outfitter areas, using age at harvest as a covariate. Hunting pressure across years in the study area was consistently low, and this population did not experience the decline in horn size observed in several other mountain sheep populations in Canada. Over the 16‐year period, the average horn volume of harvested males was stable and even increased in 1 outfitter area. Local management of Dall's sheep delivered independently by the guide outfitters in the Mackenzie Mountains appears to contribute to maintaining a population of males that has not been adversely affected by strong selective hunting pressure. The resilience of this management strategy may be challenged by environmental changes associated with rapid warming in northern mountain environments.

The genomes of Hercules beetles reveal putative adaptive loci and distinct demographic histories in pristine North American forests.

Beetles, despite their remarkable biodiversity and a long history of research, remain lacking in reference genomes annotated with structural variations in loci of adaptive significance. We sequenced and assembled high-quality chromosome-level genomes of four Hercules beetles which exhibit divergence in male horn size and shape and body colouration. The four Hercules beetle genomes were assembled to 11 pseudo-chromosomes, where the three genomes assembled using Nanopore data (Dynastes grantii, D. hyllus and D. tityus) were mapped to the genome assembled using PacBio + Hi-C data (D. maya). We demonstrated a striking similarity in genome structure among the four species. This conservative genome structure may be attributed to our use of the D. maya assembly as the reference; however, it is worth noting that such a conservative genome structure is a recurring phenomenon among scarab beetles. We further identified homologues of nine and three candidate-gene families that may be associated with the evolution of horn structure and body colouration respectively. Structural variations in Scr and Ebony2 were detected and discussed for their putative impacts on generating morphological diversity in beetles. We also reconstructed the demographic histories of the four Hercules beetles using heterozygosity information from the diploid genomes. We found that the demographic histories of the beetles closely recapitulated historical changes in suitable forest habitats driven by climate shifts.

Utilizing geometric morphometrics to investigate gene function during organ growth: Insights through the study of beetle horn shape allometry.

Static allometry is a major component of morphological variation. Much of the literature on the development of allometry investigates how functional perturbations of diverse pathways affect the relationship between trait size and body size. Often, this is done with the explicit objective to identify developmental mechanisms that enable the sensing of organ size and the regulation of relative growth. However, changes in relative trait size can also be brought about by a range of other distinctly different developmental processes, such as changes in patterning or tissue folding, yet standard univariate biometric approaches are usually unable to distinguish among alternative explanations. Here, we utilize geometric morphometrics to investigate the degree to which functional genetic manipulations known to affect the size of dung beetle horns also recapitulate the effect of horn shape allometry. We reasoned that the knockdown phenotypes of pathways governing relative growth should closely resemble shape variation induced by natural allometric variation. In contrast, we predicted that if genes primarily affect alternative developmental processes, knockdown effects should align poorly with shape allometry. We find that the knockdown effects of several genes (e.g., doublesex, Foxo) indeed closely aligned with shape allometry, indicating that their corresponding pathways may indeed function primarily in the regulation of relative trait growth. In contrast, other knockdown effects (e.g., Distal-less, dachs) failed to align with allometry, implicating these pathways in potentially scaling-independent processes. Our findings moderate the interpretation of studies focusing on trait length and highlight the usefulness of multivariate approaches to study allometry and phenotypic plasticity.

Do honest signals or piercing weapons determine rank in a polygynous ungulate?

Abstract In polygynous ungulates, males are often larger than females and bear more elaborate/larger weapons. Quantifying sexual dimorphism in different traits could provide insights into species-specific evolutionary pathways of sexual selection. Concerning the combination of secondary sexual traits, we found that Himalayan tahr (Hemitragus jemlahicus) is unique among the ~20 species in the tribe Caprini, as its body mass dimorphism is ~2-fold greater than the dimorphism in horn size, whereas horn shape appears to be near-monomorphic. Whilst horns show the same growth rate in both sexes, body mass increases faster in males. Considering age variation, dominant, golden-ruffed males are also heavier than brown-ruffed, lower-ranking males. Unlike most bovids, male–male competition in tahr does not seem to have influenced weapon development, suggesting a lower importance of horns in male–male competition compared to body mass, as their unritualized combat style also suggests. Our study highlights alternative evolutionary pathways occurring in the Caprinae, where intraspecific signals involve different traits, from weapons to pelage features. Accordingly, male tahr use their ruff colour as an ‘honest’ signal of rank.

Genetic diversity, tissue-specific expression, and functional analysis of the ATP7A gene in sheep.

In humans, variation of the ATP7A gene may cause cranial exostosis, which is similar to "human horn," but the function of the ATP7A gene in sheep is still unknown. Tissue expression patterns and potential functional loci analysis of the ATP7A gene could help understand its function in sheep horn. In this study, we first identified tissue, sex, breed, and species-specific expression of the ATP7A gene in sheep based on the RNA-sequencing (RNA-seq) data. Second, the potential functional sites of the ATP7A gene were analyzed by using the whole genome sequencing (WGS) data of 99 sheep from 10 breeds. Last, the allele-specific expression of the ATP7A gene was explored. Our result showed the ATP7A gene has significantly higher expression in the big horn than in the small horn, and the ATP7A gene has high expression in the horn and skin, suggesting that this gene may be related to the horn. The PCA results show that the region around the ATP7A can distinguish horned and hornless groups to some extent, further indicating that the ATP7A may be related to horns. When compared with other species, we find seven ruminate specific amino acid sites of the ATP7A protein, which can be important to the ruminate horn. By analyzing WGS, we found 6 SNP sites with significant differences in frequency in horned and hornless populations, and most of these variants are present in the intron. But we still find some potential functional sites, including three missenses, three synonymous mutations, and four Indels. Finally, by combining the RNA-seq and WGS functional loci results, we find three mutations that showed allele-specific expression between big and small horns. This study shows that the ATP7A gene in sheep may be related to horn size, and several potential functional sites we identified here can be useful molecular markers for sheep horn breeding.

Abstract 4236: Obesity-associated endometrial cancer: Identifying the contributions of TMEM205 expression to the pathogenesis of disease

Abstract Background & Objective: Endometrial cancer (EC) is the most common gynecologic malignancy in the US. EC is more strongly associated with obesity than any other cancer type, with 57% of cases linked to obesity. As rates of obesity increase, the incidence of EC is also rising with worsening prognosis. The objective of this study is to identify the molecular mechanisms of TMEM205 expression that regulate exosome secretion, and the oncogenic proteins that underlie this transformation. Our findings are critical to understanding the pathways of obesity mediated EC and essential for developing novel strategies for preventing and treating EC. Methods: The exosomes were then quantified using nanoparticle tracking analyzer (NTA) and their size measured by Transmission electron microscopy (TEM). TMEM205, STAT5, FAS and PIAS3 expression was confirmed by IHC, WB and RT-PCR in patient and high fat diet treated mouse tissue. Endometrial hyperplasia was developed in immunocompetent mice using high fat diet (HFD; 45 kcal% fat diet) for 16 weeks. Results: To examine the effect of a continuous HFD (45 kcal% fat diet) on adipose, uterine and endometrial tissue, we first investigated body weight and uterine morphology in mice after 24 weeks of treatment. As expected, mice fed a HFD had a significantly higher body weight and increased adipose tissue when compared to control. In addition, mice in the HFD group showed marked enlargement in uterine horn size (hyperplasia) and inflammation with increased cell proliferation in the endometrial layer. The HFD treated mice were associated with increased exosome secretion and expression of the oncogenic proteins TMEM205 and STAT5. Expression of the tumor suppressor gene PIAS3 wasdownregulated in adipose and uterine tissues. L-2265 is a small molecule inhibitor that selectively inhibits TMEM205 and exosome secretion in EC cancer cells. To examine the effect of L-2263 in the context of obesity, we fed mice a HFD and treatment with L-2263 (2mg/kg/) weekly for 3 doses. L-2263 treatment resulted in significantly decreased body weight (BW) and decreased accumulation of adipose tissue relative to control HFD treated mice. Mice in the HFD group showed marked enlargement in uterine horn size (hyperplasia), whereas mice that received L-2263 treatment had normal uterine morphology of mouse age. L-2263 treated mice also demonstrated a significant decrease in the expression of proteins involved in exosome secretion (e.g., TMEM205 and STAT5) and those found in exosomes. Conclusion: This study provides fundamental insight into the mechanism of obesity-mediated TMEM205 expression and exosome secretion and their contribution to the pathogenesis of EC. This study is also provides pre-clinical evidence for the development of the first in-human studies of exosome-targeted therapies to prevent obesity-mediated EC. Citation Format: Takahiko Sakaue, Roman Zingarelli, Wafa Khadraoui, Uksha Saini, John Wallbillich, Muralidharan Anbazhakan, Ross Warner, Kalpana Deepa Priya Dorayappan, Deepika Kalaiyarasan, Molly Morton, Casey Cosgrove, Adrian Suarez, Larry J. Maxwell, David O'Malley, David E. Cohn, Karuppaiyah Selvendiran. Obesity-associated endometrial cancer: Identifying the contributions of TMEM205 expression to the pathogenesis of disease. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4236.

Novel metrics to characterize temporal lobe of very preterm infants on term-equivalent brain MRI.

Preterm birth adversely impacts brain development and contributes to neurodevelopmental impairment; the temporal lobe may be particularly vulnerable to the impact of very preterm (VP) birth. Yet, no prior magnetic resonance imaging (MRI) scoring system incorporated a method to quantify temporal lobe size in VP infants. We developed and applied three metrics (temporal lobe length, extra-axial space, and temporal horn width) to quantify temporal lobe structure on term-equivalent brain MRIs obtained from 74 VP and 16 term infants. We compared metrics between VP and term infants and explored associations of each metric with perinatal risk factors. All metrics had excellent reliability (intra-class correlation coefficient 0.62-0.98). VP infants had lower mean temporal lobe length (76.8 mm versus 79.2 mm, p = 0.02); however, the difference attenuated after correction for postmenstrual age. VP infants had larger temporal horn widths compared with term infants (2.6 mm versus 1.8 mm, p < 0.001). Temporal lobe length was positively associated with gestational age, birth weight, and male sex, and negatively associated with the duration of parenteral nutrition. The proposed metrics are reliable and sensitive in distinguishing differences in temporal lobe development between VP and full-term infants. We developed a novel method for quantifying temporal lobe size among very preterm infants at term equivalent using simple metrics performed on brain MRI. Temporal lobe metrics were reliable, correlated with brain volume from volumetric analysis, and were sensitive in identifying differences in temporal lobe development among preterm compared with term infants, specifically larger temporal horn size in preterm infants. This temporal lobe metric system will enable future work to delineate the perinatal and postnatal factors that impact temporal lobe growth, and better understand the relationship between temporal lobe disturbance and neurodevelopment in very preterm infants.

Effect of rams’ social hierarchy upon scrotal circumference, semen quality, and copulation performance under arid land conditions

Social hierarchies among animal species are based on the animal ́s dominance-aggressiveness level aligned with the subordination oftheir mates. Social order is mostly defined by animal size, live weight, or age. This study aimed to evaluate the association betweenodor score (OS), horn presence (HP), horn size (HS), and body temperature on social rank hierarchy, scrotal circumference (SC), semenquality (SQ), and sexual drive (SD). Adult Dorper rams (n=24) with similar live weight (LW), body condition score (BCS), and age (AG)were subjected to a behavioral test to define a success index (SI) based on male-to-male interactions. OS was highest (P&lt;0.05) for ramswith high social rank (HSR; 2.5±0.4) and lowest for rams with low social status (LSR; 0.75±0.01). Scrotal circumference was highest(P&lt;0.05) for HSR rams (40.0±3.5) and lowest for rams with medium social rank (MSR; 29.3±1.20). Sperm cell concentration/mL washighest (P&lt;0.05) for HSR rams (3848±187) and lowest for LSR (2660±463). 80% of the HSR rams had horns, while 33.3 of the LSRrams were hornless. The percentage of rejection to mount an estrous ewe was 77.7 for LSR and 20% for HSR and MSR rams (P &lt;0.05).To conclude, the HSR rams presented the highest successful copulation, scrotal circumference, and sperm cell concentration comparedto rams with lesser social rank scores

PSVI-14 Effect of Morphometric Traits Upon Social Hierarchy of Dorper Rams from Northern Mexico

Abstract Usually, social order is defined by the animal size, live weight, or age. This study aimed to evaluate the association among horn presence (HP), and horn size (HS) on social rank hierarchy. Adult Dorper rams (n=24) with similar live weight (LW), body condition score (BCS), and age (AG) were subjected to a behavioral test to define the success index (SI, ranked form 0 to 1) based on male-to-male interactions, determining three social ranks: low hierarchy rams (LHR; SI = 0-0.33; n=9), medium hierarchy rams (MHR; SI=0.34-0.66; n=10) and high hierarchy rams (HHR; SI= 0.67-1; n=5). Afterward, skull, horn (HP and HS), and body morphometrics were measured. The GLM procedure of SAS (SAS Institute, Cary, NC) was used to analyze LW, AG, BCS, HS and HP with three social ranks and five to ten replicates per group. Rams within social rank were the experimental units. Differences were considered as significant at P &amp;lt; 0.05. Regarding HP, 80% of the HHR rams had horns, while 77.7% of the LHR rams were hornless, with intermediate values for MHR (50%), but no differences were found regarding HS between low, medium and high hierarchy rams (85.1±2.6, 84.3±3.3, and 90.7±4.7, respectively). In conclusion, while presence of horns have an important role for establishing social hierarchy, it is a complex trait influenced by factors other than horn presence or size so, we recommend more research in relation to other factors that could influence the position of rams in the hierarchy rank levels of the herds.