Physiological Auricular and Cornual Asymmetries of the Sanmartinero Creole Bovine.

Asymmetric studies can indicate disturbances in the developmental process. Fluctuating asymmetry (FA) is considered an indicator of stress. The Sanmartinero (SM) creole bovine is native to the department of Meta (Colombian Orinoquia) and its adaptation process has allowed it to live in extreme tropical environments. The aim of this cross-sectional and descriptive study was to present the current state of the knowledge of asymmetries in some cephalic characters of the SM creole bovine. A total of 94 animals were studied (18 uncastrated males and 76 females) from three different farms, with an age range of 0.5-10 years. For each animal, two measurements of the ear (width and length) and two measurements of the horn (perimeter and length) were obtained in vivo. The degree of asymmetry was calculated as (R - L)/(R + L). Bilateral differences pointed towards a fluctuating asymmetry (e.g., a random variation in the trait that is expected to be perfectly symmetrical) biased towards right for ear width and horn perimeter, and towards left for ear and horn length. Since the development of these structures-ears and horns-is under the control of the same set of genes, the fluctuating asymmetry could constitute a reflection of a normal condition.

Size Gynomimicry in the Sanmartinero Creole Bovine of the Colombian Orinoquia.

Variations in the size of animals of the same species but of different sex are called sexual size dimorphism. The aim of this study was to compare the biometrics between males and females of the Sanmartinero creole bovine, of Colombia, to establish if sexual dimorphism appears in the breed. A total of 94 animals (16 uncastrated males and 78 females, average age of 4.3 ± 1.4 and 4.2 ± 2.3 years, respectively) from three different farms were measured. A total of 21 linear variables were obtained using standard morphometric methods and live weight. A one-way NPMANOVA was used to evaluate between sexes, ages, and farms, a Principal Component Analysis was used to detect the most discriminating variables, and a multivariate regression used age as an independent value. Statistically significant differences were reflected between sexes (p = 0.033) and not by age and farms. The variables that differentiated the most between males and females were those related to size (thoracic circumference, body length, dorso-sternal diameter, height at the withers, height at the rump, and horn length), variables that were biased toward males, although only the height at the withers and the rump were the ones that presented statistically significant differences.

Index Development to Comprehensive Assess Liver Function during the Dairy Cows' Transition Period in Low-Tropic Conditions.

The aim of this work was to develop a liver tissue function index during the transition period of dairy cows managed in low-tropic conditions. In two farms, twenty crossbred and synthetic native cows during the peripartum period were selected, and blood samples were taken on days -30 and -15 prepartum, the calving day, and 7, 20, 35, 50, 65, 80 and 105 days postpartum for serum metabolic tests. On each measurement day, body condition scores (BCS) and parameters on nitrogen metabolism (total protein-TP, albumin-ALB, globulin-GLOB, urea), adipose tissue metabolism (cholesterol-COL, non-esterified fatty acids-NEFA) and two transaminases (alanine aminotransferase-ALT and aspartate aminotransferase-AST) were evaluated. Data analysis included the Spearman correlation, principal components, multiple linear regression and cluster analysis. Results showed that regarding the days after calving and BCS, a liver tissue function index can be constructed using the TP, urea, COL, ALT and NEFA. The estimated index generated three groupings, both by days after calving and BCS. In the former, the index discriminated the metabolic behavior in the prepartum, parturition and postpartum periods, while in the latter, the index discriminated between extreme (2.25, 2.50 and 4.25), slightly low (2.75 and 3.0) and slightly high (3.25 to 4) conditions. The results allow us to conclude that it is feasible to construct mathematical function indexes for liver function to monitor metabolic changes during highly demanding productive phases in dairy cows under tropical conditions.

Breed and non-genetic risk factors associated with the prevalence of subclinical mastitis in livestock systems of Arauca, Colombian orinoquia.

Subclinical Mastitis (SCM) is caused by several factors associated with the interaction of the individual cow, cow management, and the environment. The aim of this study was to assess the breed and non-genetic risk factors on the prevalence of SCM in cows from the dual-purpose livestock system on the floodplain of Arauca, Colombian Orinoquia. Milk samples were taken from the individual mammary quarters of 481 cows representing 28 different farms where the electrical conductivity (EC) test applied. To determine the factors associated with SCM, a multiple logistic regression analysis was used. The response variable was the SCM presence (1), or absence (0) obtained with the EC test. Breed was included as a genetic risk factor, and as non- genetic risk factors: number of cows in production, daily milk production, lactation month, cow age, climatic period, body condition, and calving number. The factors that were significantly associated with the SCM presence were body condition, climatic period, and breed (p < 0.05). Odds ratio (OR) analysis of significant effects indicates that for each unit increase in body condition, the OR of having animals with SCM is reduced by 71%. In the dry period the OR of animals with SCM increases by 150% compared to the rainy period. Composite breeds reduce the OR of SCM animals by 73%, compared with Indicus-predominance animals. In this study, the occurrence of SCM in extensive management systems in Arauca, Colombian Orinoquia, is determined by the risk factors of breed, climatic period, and body condition.

Early Cannon Development in Females of the "Sanmartinero" Creole Bovine Breed.

The variation in the dimensions of the body of living beings in relation to their size, function, or shape is known as allometry. Allometry studies allow the analysis of the function of body structures and their relationship with the performance and survival of breeds and species. The aim of this study was to describe the ontogenetic characteristics of the weight of certain bone elements of the Sanmartinero creole bovine breed, from an early age (6 months) until maturity. A total of 79 females of the Sanmartinero creole bovine breed with an age range of 0.5 to 10 years were studied. Body measurements were obtained individually using standard procedures: cannon perimeter, thoracic perimeter, body length, withers height, and body weight. Functional and production indices were obtained for animals aged more than 3 years (n = 53): corporal index, anamorphosis index, dactylo thoracic index, and the relative thickness of the cannon. The correlation between body weight and the cannon perimeter showed no trend towards a plateau. In the Sanmartinero creole bovine, therefore, a very early development of the cannon perimeter is detected, which could lead to bone fragility in heavier animals. Therefore, data suggest little harmony with appendicular bone development, i.e., with less robust cannons which are those necessary to support body mass. It is suggested that in genetic improvement programs of the Sanmartinero creole bovine, the measurement of the cannon perimeter, the withers height, and the thoracic perimeter should be considered.

Environmental and Breed Risk Factors Associated with the Prevalence of Subclinical Mastitis in Dual-Purpose Livestock Systems in the Arauca Floodplain Savannah, Colombian Orinoquia.

The aim of this study was to assess the environmental and breed risk factors associated with the prevalence of subclinical mastitis (SCM) in cows in the dual-purpose livestock system of Arauca, Colombian Orinoquia. Milk samples were taken from 1924 mammary quarters, corresponding to 481 cows on 28 different farms, and the California Mastitis Test (CMT) was applied. Risk factors associated with SCM were determined using multiple logistic regression analysis. The response variable was the presence (1) or absence (0) of SCM. Breed was included as a genetic risk factor, and daily milk production, number of cows in production, lactation month, calving number, cow age, climatic period, and body condition were included as environmental risk factors. The analysis of the odds ratio (OR) of significant effects indicated that the factors significantly associated with the presence of SCM were the number of cows (OR = 2.29; p = 0.005), milk production (OR = 0.88; p = 0.045), and the Taurus-Indicus breeds (OR = 1.79; p = 0.009) and composite breed (OR = 3.95; p = 0.005). In this study, the occurrence of SCM was determined by the following risk factors: number of cows, milk production, and breed. Likewise, the highest prevalence seemed to occur on farms with less technological development and sanitary management of producers from the lowest socioeconomic stratum.

Chemical Composition and In Vitro Ruminal Fermentation Characteristics of Native Grasses from the Floodplain Lowlands Ecosystem in the Colombian Orinoquia.

Grasses from lowland ecosystems in flooded savannahs are useful to feed extensive grazing animals; however, scarce information about its agronomic and fermentation characteristics exists. This study aims to determine the chemical composition and fermentation parameters of native grasses from the floodplain lowlands ecosystem in the Colombian Orinoquia. Three native grasses (Leersia hexandra, Acroceras zizanioides and Hymenachne amplexicaulis) and a "control" grass (introduced Urochloa arrecta-Tanner grass) were sown and sampled at 30, 40 and 50 days of age. On each sampling date, biomass production in a 1 m2 frame was estimated, and the chemical composition and fermentation parameters were analyzed using near-infrared spectroscopy and the in vitro gas production technique, respectively. Data were analyzed using a mixed model for repeated measures and the least significant difference (LSD) was used for mean differentiation (p < 0.05). The grasses' nutritional characteristics varied as follows: dry matter (DM, 0.7-2.0 ton/ha), crude protein (CP, 6.1-12.2%), neutral detergent fiber (NDF, 56.6-69.6%), ash (5.8-15.8%) and dry matter digestibility (DMD) between 20.8 and 60.6% from 12 to 48 h of fermentation. Native plants such as L. hexandra and A. zizanioides presented higher biomass production, CP, ash, cellulose, and Ca levels than the control plant. During the experimental period (30 to 50 days), the grasses did not present significant nutrient availability changes. In terms of fermentation characteristics, L. hexandra increased ammonia concentrations and total volatile fatty acids (TVFA) and butyric acid. This latter effect was also observed in A. zizanioides grass. L. hexandra and A. zizanioides grasses constitute a valuable alternative forage resource during the flooding times of the studied ecosystem.

Environmental Factors That Affect the Sanitary and Nutritional Variability of Raw Milk in Dual Purpose Livestock Systems of Colombian Orinoquia.

Milk is the natural food with the highest biological quality for the human population and its production can be affected by several sanitary factors and management conditions. With the objective of identifying influence factors on milk compositional and sanitary quality in a region with wide productive potential in the Colombian Orinoquia, an experiment was carried out in two contrasting climatic seasons. For the milk compositional analysis, samples of daily production from 30 dual-purpose systems were analyzed. Similarly, the udder sanitary status of 300 cows was studied using the California Mastitis Test (CMT). Data analysis included mixed models, Pearson correlations, frequency tables, and the Kruskal-Wallis test. The results showed that the total daily milk production of the farm and the season influenced the milk compositional quality. The farms with milk productions lower than 100 kg/day presented the highest levels of protein, lactose, solid non-fat (SNF), and density, while in the rainy season, the milk quality was higher compared to the dry season. The CMT test indicated that only 7.6% of the evaluated mammary quarters presented two or more degrees of positivity. There is an opportunity to improve the milk compositional quality by improving the nutritional offer for animals during the year. The low CMT positivity indicates that, in the calf-at-foot milking system, the presence of subclinical mastitis is not a determining variable in milk production.

Basicranial Modular Organization. A Study in the Araucanian Horse of Colombia.

The skull is divided into neurocranium and splanchnocranium, and its variation allows ecomorphological studies to learn about possible evolutionary and adaptive characteristics. The basicranial organization of the neurocranium and splanchnocranium modules was studied in a sample of 31 skulls from adult Araucanian horses by means of 2D geometric morphometric techniques. The neurocranium and splanchnocranium modules on the ventral aspect were analyzed separately using a set of 31 landmarks. The RV coefficient (the multivariate analog of a correlation) was estimated to analyze the independence of these two parts, as well as their morphological integration, using a two-block analysis of least squares. The study results confirm the modular development of the neurocranium and the splanchnocranium, the former being more stable than the latter as well as low morphological integration between the two. The development between both parties is structured in a modular way but allows relative independence. Now it would be interesting for future studies to add muscles (those that connect the cranial parts, but also the cervical), the hyoid apparatus, and the ossicles of the internal ear and the jaw and analyze if they behave as integrated modules between them. Since this research has been conducted at the subspecific breed level, it could be plausible that in other breeds, this integrative development was different.

Would the Cephalic Development in the Purebred Arabian Horse and Its Crosses Indicate a Paedomorphic Process?

This study examined paedomorphosis in PAH and F1 crossbreds. A sample of 99 horses was selected from 40 different breeders and consisted of three groups: stallions (n = 16), mares (n = 53), and geldings (n = 30), ranging from 10 months to 27 years in age. All horses presented a concave celloid lateral left head profile in the acquired photographic images. The hypothesis proposed in this study suggested the lateral profile of the head in juveniles was representational in the adult form due to the neonate's facial bones (part of the splanchnocranium) developing at a different rate to those of the skull. The methodology utilized geometric morphometrics to identify 23 landmarks so as to identify profile curvature indicative between the three groups (stallions, mares, and geldings). Principal component analysis reduced the number of variables to 14 examinable landmarks. Using a two-NPMANOVA and multivariate regression test, it was demonstrated that an isometric relationship between the concave celloid profile in the juvenile and its adult counterpart existed. This result supported the hypothesis that PAH and F1 crossbreds expressed a paedomorphic trait due to the adult form retaining the concave celloid profile identified in the juvenile.

No Morphological Integration of Dorsal Profiles in the Araucanian Horse (Colombia).

The aim of this research was to determine if the division between the cervical, dorsal, and croup profiles (three regions commonly assessed for descriptive profile purposes) has a modular basis as well as a morphological integration. For this, a total of 135 digital photographs were obtained, in a lateral view, of adult horses (14 females and 121 geldings; age range: 2-20 years), of the Araucanian breed, an equine population typical of the flooded savannah of Arauca, NE Colombia. From each image, 25 reference points (semi-landmarks) were obtained at the dorsal level of the neck, back, and croup. The hypothesis of the modularity of different body profiles based on differentiated regions was tested using the RV coefficient, and an analysis of two blocks of partial least-squares allowed the evaluation of the level of morphological integration. The results showed that each alloidic group reflected high integration but low modularity. The covariation between the modules was centered mainly on the withers, the loin, and the croup. For the studied profile blocks, no module can be considered. The absence of the fragmentation of the alloidic sets would promote the adaptive capacity of the breed by linking coordinated functional responses to similar selection pressures, e.g., field work. Although the integration between the neck, back, and croup profiles was proven, their modular covariation was low.

Shape Directional Asymmetry in Hindlimb Pairs among Calves (Bos Taurus).

The aim of this study was to determine paired asymmetries (right-left) in the autopods of bovine hindlimbs using geometric morphometry (GM). A total of 28 hindlimb right-left matched autopods belonging to healthy Brown Pyrenean calves were assessed. Dorsoplantar radiographs were obtained for each autopod. The bone shape was compared on right and left pairs by means of GM techniques, using a set of 15 landmarks. The results suggest that right and left distal limbs are, despite a perceived resemblance of symmetry, differently directionally developed in shape, with right hindlimbs tending to supinate (rotate outwards) and left hindlimbs tending to pronate (rotate inwards). This unevenness is probably related to the mediolateral forces' contribution of each limb in carrying out the tasks of propulsion and control during walking, and/or a consequence of a laterality associated with a lateralized grazing posture. Our findings prompt a new reassessment of the function of each bovine hindlimb during standing and locomotion.

Sexual Allometric Monomorphism in Araucan Pig from Colombia: Preliminary Results.

This study aimed to evaluate the allometric growth of the Araucan pig breed, a creole breed from Arauca, East Colombia, locally known as "Sabaneros", in relation to different quantitative traits and considering genders separately. To do this, a total of 31 male and 27 female Araucan pigs, ranging from 4 to 48 months of age, were studied in order to evaluate their growth patterns, using a multivariate approach. Animals belonged to different farms ("fincas") of the Department of Arauca, Colombia. From each individual, 10 quantitative traits were obtained: face width, croup height, croup length, croup width, tail base height, hock height, loin height, cannon length, and length and width of ear. Our results, which must be interpreted as preliminary, showed that the Araucan pig is allometrically monomorphic as sexual differences do not increase with body size. We suggest that although males and females have evidently different reproductive roles, during growth they shift the allocation of energy to structures linked to environmental adaptation rather than those linked to reproduction.

Lineal Discrimination of Horses and Mules. A Sympatric Case from Arauca, Colombia.

This is the first morphological comparative study between local horses and mules from Arauca, Colombia. It was realized to compare morphological traits between both species by analysing 15 adult mules (7 males and 8 females) and 150 adult horses (137 males and 13 females), with an age interval from 2 to 22 years. Data consisted of 24 different body quantitative traits which can explain the body conformation: thoracic circumference, body length (BL), thoracic depth and width, withers height (WH), sternum height, shoulders width, chest width, forelimb cannon perimeter and length, head length and width, skull length and width, face length and width, ear length and width, loin height, croup height (CrH), width and length, dock height (DoH), and hock height. Heart girth circumference, body length, withers height, croup height, and dock height were the most discriminative traits, showing statistical differences between species. The formula is X = (BL × 0.402) + (WH × 0.323) + (CrH × 0.352) + (DoH × 0.384). A value of X > 184.5 assigns with total certainty that a skeleton belongs to a horse, and if X < 174.0, it is a mule. The proposed formula has a 100% specificity but a 71.4% sensibility for mules and an 84.4% for horses into the rank of 174.0-184.5. Therefore, results demonstrate that some postcranial anatomical elements of Equus could give enough information for a bone differentiation between horses and mules, at least in animals from the Araucan region, but the main interest is that it reflects the possibility to differentiate morphometrically both species from bone remains when horses and mules were sympatric.

A Comparison of Traditional and Geometric Morphometric Techniques for the Study of Basicranial Morphology in Horses: A Case Study of the Araucanian Horse from Colombia.

Skull size and shape have been widely used to study domestic animal populations and breeds. Although several techniques have been proposed to quantify cranial form, few attempts have been made to compare the results obtained by different techniques. While linear morphometrics has traditionally been used in breed characterization, recent advances in geometric morphometrics have created new techniques for specifically quantifying shape and size. The objective of this study was to compare two morphometric methods for their ability to describe external morphology. For this purpose, 20 skull specimens of adult male Araucanian horses were examined. Two age categories were established (the "mature group", M3 not fully erupted to moderately worn, n = 7; and the "senile group", M3 totally erupted and highly worn, n = 13). Both methods showed that there were statistical differences between generations, but discrimination rates were different between methods with the geometric morphometric analysis obtaining a rate of 97.5%. Although linear morphometrics was found to be compatible with geometric morphometrics, the latter was better able to discriminate the two groups and it also provides more information on shape.