Genetic Diversity and Maternal Phylogenetic Relationships among Populations and Strains of Arabian Show Horses.

Genetic diversity and phylogenetic relationships within the Arabian show horse populations are of particular interest to breeders worldwide. Using the complete mitochondrial DNA D-loop sequence (916 pb), this study aimed (i) to understand the genetic relationship between three populations, the Desert-Bred (DB), a subset of the Kingdom of Saudi Arabia (KSA), United Arab Emirates (UAE) and Bahrain (BAH), the Straight Egyptian (EG) and the Polish bloodline (PL), and (ii) to assess the accuracy of the traditional strain classification system based on maternal lines, as stated by the Bedouin culture. To that end, we collected 211 hair samples from stud farms renowned for breeding Arabian show horses from Nejd KSA, Bahrain, Egypt, Qatar, Morocco, UAE, and Poland. The phylogenetic and network analyses of the whole mitochondrial DNA D-loop sequence highlighted a great genetic diversity among the Arabian horse populations, in which about 75% of variance was assigned to populations and 25% to strains. The discriminant analysis of principal components illustrated a relative distinction between those populations. A clear subdivision between traditional strains was found in PL, in contrast to the situation of DB and EG populations. However, several Polish horse individuals could not be traced back to the Bedouin tribes by historical documentation and were shown to differ genetically from other studied Bedouin strains, hence motivating extended investigations.

How have sheep breeds differentiated from each other in Morocco? Genetic structure and geographical distribution patterns.

BACKGROUND: Based on the relatively homogeneous origin of the sheep breeds in Morocco that originate mainly from Iberia, it is highly relevant to address the question of how these very diverse sheep populations differentiated from each other. The Mountains of the High Atlas and Middle Atlas are expected to constitute North-South and West-East geographical barriers, respectively, which could have shaped the history of the differentiation of sheep breeds. The aim of this study was to test this hypothesis by considering the genetic structure and the spatial distribution of five major breeds (Sardi, Timahdite, Beni Guil, Boujaad and D'man) and one minor breed (Blanche de Montagne), by analysing the mtDNA control region, using 30 individuals per breed. RESULTS: Phylogenetic and network analyses did not indicate any clear separation among the studied breeds and discriminant component principal analysis showed some overlap between them, which indicates a common genetic background. The calculated pairwise FST values and Nei's genetic distances revealed that most breeds showed a moderate genetic differentiation. The lowest and highest degrees of differentiation were retrieved in the Beni Guil and Boujaad breeds, respectively. Analysis of molecular variance (AMOVA) indicated that more than 95% of the genetic diversity occurs within individuals, while between- and within-population variabilities represent only 1.332% and 2.881%, respectively. Isolation-by-distance, spatial Principal Component Analysis (sPCA), and spatial AMOVA analyses evidenced clear examples of geographical structuration among the breeds, both between and within breeds. However, several enigmatic relationships remain, which suggest the occurrence of complex events leading to breed differentiation. CONCLUSIONS: The approaches used here resulted in a convergent view on the hypothetic events that could have led to the progressive differentiation between the Moroccan breeds. The major split seems to be linked to the West-East barrier of the Middle Atlas, whereas the influence of the High Atlas is less obvious and incompletely resolved. The study of additional breeds that have settled near the High Atlas should clarify the relationships between the breeds of the West part of the country, in spite of their small population size.

Non-genetic effects on daily milk yield and components of Holstein cows in Morocco.

The objectives of this study were to determine milk yield and constituents' levels of Holstein cows under Moroccan conditions and to assess the effects of environmental factors influencing them. Data including 93,815 test day records of 6343 Holstein cows in 162 herds were analyzed for milk yield, contents of fat, protein, lactose and solids-not-fat (SNF), milk urea nitrogen (MUN), and somatic cell score (SCS). Averages were 25.1 ± 7.33 kg/day, 3.54 ± 0.76%, 3.02 ± 0.34%, 4.89 ± 0.24%, 8.72 ± 0.36%, 17.6 ± 8.17 mg/dl, and 4.12 ± 2.06 units, respectively. The effects of herd and calving year were found to be significant on all the studied traits. Parity was determined to have significant effects on all analyzed traits, with the exception of MUN concentration. Milk yield, fat content, protein content, and SCS increased with parity, whereas lactose percentage decreased in later parities. Except fat and lactose contents, all the other studied variables were significantly influenced by calving season. Milk yield and MUN were highest for cows calving during humid season, whereas protein content, SNF content, and SCS tended to be higher in dry season. All the studied traits changed significantly according to stage of lactation. The peaks of milk yield and lactose content occurred between 35 and 65 days, whereas that of MUN between 95 and 125 days after parturition. Protein and SNF contents and SCS attained their lowest values between days 35 and 65, while fat content between days 65 and 95. It was concluded that these environmental factors should be taken into consideration if the milk yield and quality in Morocco is to be optimized.

Morphologic characterization of the Blanche de Montagne, an endemic sheep of the Atlas Mountains.

The present study aims to investigate the morphological characteristics of the Blanche de Montagne sheep breed, mainly known by its long white fleece. The morphological characterization was performed on a total of 70 unrelated individuals of both sexes, having between 2 and 8 teeth and belonging to 13 farms located in the Ouarzazate region. The body measurements studied were body weight, body length, chest circumference, height at withers, rump height, chest depth, chest width, hip width, head length, head width, ear length, ear width, horn length, cannon circumference, wool length, and tail length. These measurements averaged 28.2±8.10 kg, 65.8±6.25 cm, 73.5±6.71 cm, 59.5±4.39 cm, 59.5±4.72 cm, 27.4±2.90 cm, 19.8±2.70 cm, 21.0±2.14 cm, 19.2±1.57 cm, 11.0±1.01 cm, 9.71±1.02 cm, 5.47±0.53 cm, 43.2±13.8 cm, 7.44±0.77 cm, 10.9±3.56 cm, and 31.8±4.36 cm, respectively. Descriptive statistics presented an overall coefficient of variation less than 15%, showing a homogeneous morphostructure of the breed. Most characters were small in relation with the low productivity of pastures. Moreover, 77.5% of correlation coefficients among the different body measurements were positive and significant, reflecting the strong morphological harmony of the breed, suggesting a long period of adaptation to its environment. The variance analysis showed that sex influenced the measurements, with males having the highest values. Similarly, individuals with 6 or 8 teeth showed higher values than those with 2 or 4 teeth. Through the comparison with other Moroccan breeds, the variation of some morphological traits was found in relation to some climatic parameters (mainly winter temperatures) and feeding supplementation.

Review of milk let-down in camels and proposition of a milk recording method.

The aim of this article was to review the milk let-down in camels and to propose a simple milk recording method. Milking of camels generally starts between 1 and 3 months postpartum. The udder is stimulated for 0.5 to 2 min by either calf suckling or hand massaging to induce the milk let-down. About 40% of daily milk yield is consumed by the calf before and after milking. The best interval between milking is 8-12 h. Lactation length is in the range 8-18 months, and the mean total milk yield is 1000-4000 kg. Peak yield of 4 to 10 kg is attained between 2 and 7 months post calving, and persistency is greater than 85%. The proposed milk recording method for camels has been adapted from ICAR's procedures. The milking (manual or machine) starts after a suckling period of 1 month. Before each milking, the udder is stimulated for 1 min, either by calf suckling or by hand massaging. The milk recording interval is 36 days. The first test recording must take place within 75 days following the end of the suckling period. Milk yield recorded is the milk off-take or milked only. The lactation period corresponds to the milking length. Records are standardized to the reference lactation of 335 days. At each recording day, milk yields are recorded and milk samples are collected alternatively at either morning or evening milking. It was concluded that using this method, a sound milk recording database will be built for camels.

Genetic Diversity and Population Structure of Arabian Horse Populations Using Microsatellite Markers.

Understanding the genetic diversity and the relationships among the show Arabian horse populations is a current issue for breeders and professionals. This study aimed to define the relationship among the Desert breed, the Straight Egyptian, and the Polish Arabian populations by considering the historical background of their origin and to verify their genetic diversity. All selected samples were related to Arabian show activities. One hundred forty four hair samples were collected from horses at stud farms having notoriety in the breeding of Arabians from different geographic regions. A set of 17 microsatellites markers for parentage control were used for genotyping. Genetic diversity among and between these populations were evaluated using several statistical methods. All the microsatellites were informative and the marker set analyzed provided 145 alleles. The average number of alleles per locus was 6.52, 6.35, and 7 for the Desert breed, Straight Egyptian, and Polish Arabian, respectively. The high genetic diversity observed within the three populations (0.63-0.71) was associated with a high number of effective alleles. Desert breed and Polish Arabian populations appeared the closest, whereas the Egyptian population was more distant. The significant positive inbreeding coefficient FIS found in Desert breed, Straight Egyptian, and Polish Arabian horses (0.09, 0.14, and 0.11, respectively) confirmed the deficit of heterozygosity observed in these populations. These results suggested that the three populations have high levels of gene flow or share the same origin and have a recent divergence. This study may highlight the risk of the loss of gene diversity in these populations and help to implement appropriate breeding programs to preserve genetic diversity.

The origin of sheep settlement in Western Mediterranean.

The arrival of Neolithic culture in North Africa, especially domestic animals has been essentially documented from archaeological records. As the data relative to sheep are scarce, we studied the genetic relationship between Moroccan sheep breeds and Mediterranean ones using the sequencing of 628 bp of the mitochondrial DNA control region in 193 Moroccan individuals, belonging to six breeds, and 652 sequences from other breeds in Europe and Middle East. Through Network analysis and an original phylogenetically derived method, the connection proportions of each Moroccan breed to foreign ones were estimated, highlighting the strong links between Moroccan and Iberian breeds. The first founders of Moroccan sheep population were issued at 79% from Iberia and 21% from a territory between Middle East and Africa. Their calculated expansion times were respectively 7,100 and 8,600 years B.P. This suggests that Neolithization was introduced by a double influence, from Iberia and from another route, maybe Oriental or Sub-Saharan. The consequence of the environmental changes encountered by founders from Iberia was tested using different neutrality tests. There are significant selection signatures at the level of Moroccan and European breeds settled in elevated altitudes, and an erosion of nucleotide diversity in Moroccan breeds living in arid areas.

Morphological diversity of female camel (Camelus dromedarius) populations in Morocco.

Fourteen body measurements of 132 adult female camels belonging to three populations Guerzni (60), Khouari (28), and Marmouri (44) reared in 38 herds of 8 provinces of Southern Morocco were studied to identify homogeneous groups according to their conformation. The measurements were chest girth (CG), hump girth (HG), height at withers (HW), body length (BL), fore limb length (FLL), chest width (CW), chest depth (CD), fore hoof circumference (FHC), head length (HL), distance between eyes (DE), ear length (EL), neck length (NL), neck circumference (NC), and tail length (TL). The three populations were compared according to their mean body measurements and through multivariate analyses. The results revealed that only HG, HW, BL, and FLL were significantly influenced by the population. Moreover, the MANOVA showed that Guerzni and Marmouri populations were significantly different, whereas Khouari was not significantly different either from Guerzni or Marmouri populations. Discriminant analysis showed that out of 14 variables, BL and FLL were the most discriminant and resulted into two significant canonical variables (CAN1 and CNA2). Khouari population could be best discriminated from Guerzni and Marmouri by CAN1, and Guerzni could be best distinguished from Marmouri by CAN2. The discriminant analysis revealed that 46.7%, 60.7%, and 40.9% of Guerzni, Khouari, and Marmouri animals, respectively, were correctly classified in their original population. The clustering of the three populations highlighted two Moroccan camel groups: Guerzni and Marmouri in the first group and Khouari in the second one.

Comparison of body weight estimation equations for camels (Camelus dromedarius).

The objective of the present study was to evaluate the accuracy of six different equations for weight estimation of camels using body measurements as chest girth, height at withers, and hump girth in order to identify the most reliable equation for use in the field. The prediction equations that were compared were those of Boué Revue d'Élevage et de Médecine vétérinaire des Pays tropicaux 3 (1), 13-16, 1949; Graber Revue d'Élevage et de Médecine vétérinaire des Pays tropicaux, 19, 527-543, 1966; Wilson Tropical Animal Health and Production, 10, 19-25, 1978; Field Proceedings of the Khartoum workshop on camels V1, 209-230, 1979; Bucci et al. Indian Veterinary Journal, 61, 26-30, 1984; and Yagil A Handbook for Camel Breeding, 1994 noticed as BW1, BW2, BW3, BW4, BW5, and BW6, respectively. The dataset used for this evaluation is the one published by Boué Revue d'Élevage et de Médecine vétérinaire des Pays tropicaux 3 (1), 13-16, 1949. Range observed in predicted weight, mean prediction error (MPE), residual mean square (MSE), mean square prediction error (MSPE), coefficient of determination (CD), and concordance correlation coefficient (CCC) were used to assess the different body weight prediction equations. Moreover, paired t tests were applied to compare the true weight and each of the six predicted weights. From the six prediction equations, range observed in predicted weights varied from 193 to 237 kg, MSE from 335.5 to 806.1, MPE from - 129.8 to 24.7 kg, MSPE from 329.4 to 17,617.1, CD from 0.753 to 0.867, and CCC from 0.162 to 0.928. BW4 presented the best prediction results, showing a low MSE, high CD and CCC, whereas BW3 yielded the least accurate estimate of body weight and had weak statistics. The study concluded that BW4 is the most reliable of all equations to estimate camel's body weight, whereas BW3 is less reliable and its use must be discontinued.

A genomic map of climate adaptation in Mediterranean cattle breeds.

Domestic species such as cattle (Bos taurus taurus and B. t. indicus) represent attractive biological models to characterize the genetic basis of short-term evolutionary response to climate pressure induced by their post-domestication history. Here, using newly generated dense SNP genotyping data, we assessed the structuring of genetic diversity of 21 autochtonous cattle breeds from the whole Mediterranean basin and performed genome-wide association analyses with covariables discriminating the different Mediterranean climate subtypes. This provided insights into both the demographic and adaptive histories of Mediterranean cattle. In particular, a detailed functional annotation of genes surrounding variants associated with climate variations highlighted several biological functions involved in Mediterranean climate adaptation such as thermotolerance, UV protection, pathogen resistance or metabolism with strong candidate genes identified (e.g., NDUFB3, FBN1, METTL3, LEF1, ANTXR2 and TCF7). Accordingly, our results suggest that main selective pressures affecting cattle in Mediterranean area may have been related to variation in heat and UV exposure, in food resources availability and in exposure to pathogens, such as anthrax bacteria (Bacillus anthracis). Furthermore, the observed contribution of the three main bovine ancestries (indicine, European and African taurine) in these different populations suggested that adaptation to local climate conditions may have either relied on standing genomic variation of taurine origin, or adaptive introgression from indicine origin, depending on the local breed origins. Taken together, our results highlight the genetic uniqueness of local Mediterranean cattle breeds and strongly support conservation of these populations.

Growth at fattening and carcass characteristics of D'man, Sardi and meat-sire crossbred lambs slaughtered at two stages of maturity.

The objective of this study was to evaluate growth at fattening, carcass characteristics and carcass measurements of 19 Sardi, 19 D'man and 52 meat-sire crossbred lambs of both sexes slaughtered at 50 and 70 % of mature weight. Crossbred lambs were born from Sardi, D'man and F1 Sardi × D'man ewes mated to meat-breed rams (Ile de France and Mérinos Précoce). Lambs of each group (breed type by sex) were chosen at random and slaughtered either at 50 or 70 % of mature weight. Sardi and D'man purebred lambs had significantly lower growth at fattening, pre-slaughter live weight, empty body weight, hot carcass weight, carcass conformation, carcass fatness, red offal, white offal, sub-products and non-carcass fat than meat-sire crossbred lambs. Differences were 42.2 g/day, 5.03 kg, 4.46 kg, 2.57 kg, 0.96, 0.59, 0.18 kg, 0.39 kg, 0.63 kg and 0.12 kg, respectively. B and Wr measurements of meat-sire crossbred lambs were higher than those of Sardi and D'man purebred lambs, whereas the F measurement was in favour of purebreds. Likewise, CC, G/F and Wr/Th indices of meat-sire crossbreds were higher than those of purebreds; however, the opposite was observed for L/G and Th/G indices. Maternal heterosis was positive and not significant for most traits, negative and not significant for few traits (P > 0.05), but negative and significant for the proportion of sub-products (P < 0.05). It was concluded that growth and carcass characteristics of local sheep can be significantly improved by terminal crossbreeding.

Effect of some non-genetic factors on milk yield and composition of Draa indigenous goats under an intensive system of three kiddings in 2 years.

With 5 millions heads, goats occupy the second place after sheep in Morocco. The indigenous populations are generally raised for meat, except Draa goat that is raised as a dual purpose doe. The objective of this study was to assess milk yield and composition of Draa indigenous goat breed under an intensive system of three kiddings in 2 years and to evaluate the effects of non-genetic factors. Data were collected on 381 lactations between 2006 and 2012 and on 174 samples for milk composition between 2008 and 2010. The highest milk yield was recorded in does of 36-48 months old (84.3 ± 4.78), those suckling more than one kid (80.0 ± 3.39) and those kidding in spring (80.4 ± 3.60) and summer (79.9 ± 3.67). Except protein content, milk composition was not affected by age of does. Dry matter and fat content increased significantly with the lactation stage, protein content decreased from early to middle/late lactation, and lactose content was high in middle lactation. The highest dry matter and fat and lactose contents were obtained for summer kiddings, while the highest percent of protein was recorded for autumnal kiddings. It was concluded that under the three kiddings in 2-year system, Draa does produce enough milk with an interesting milk composition, indicating that this system may be used with success to improve farmers' income.

Effects of clinical mastitis on reproductive and milk performance of Holstein cows in Morocco.

The aim of this study was to determine the influence of clinical mastitis and time of first mastitis occurrence on reproductive and milk performance of Holstein cows. Data were collected in a dairy farm from 2008 to 2012 on 1725 cows, among which 464 cows with mastitis. To determine the influence of clinical mastitis on reproductive and milk performance, models included fixed effects of parity, calving season, calving year, and group (cows with and with no mastitis). To determine the effect of time of 1st mastitis occurrence on reproductive performance, the mastitic cows group was further reclassified into three groups: prior to 60 days, between 60 and 90 days and greater than 90 days postpartum. For milk performance, the mastitic cows group was divided into two groups: before and after peak milk yield. Clinical mastitis had significant effects on calving to first AI interval, milk yield, and fat yield, but a non-significant effect on days open, number of inseminations per conception, and milk fat percentage. Mastitic cows had a calving to first AI interval 6.1 days longer and 549.6 kg milk and 20.4 kg fat per 305 days of lactation lower than those with no mastitis. Time of 1st mastitis occurrence did not have any significant effect on reproductive performance. Further, milk and fat yields of cows diseased before peak milk yield were 506 kg and 23.9 kg, respectively, lower than those of cows affected after peak milk yield. Extra attention needs to be paid to mastitis during the early postpartum period.

Genetic and environmental factors affecting perinatal and preweaning survival of D'man lambs.

This study examined the viability of 4,554 D'man lambs born alive at Errachidia research station in south-eastern Morocco between 1988 and 2009. Lamb survival to 1, 10, 30 and 90 days old was 0.95, 0.93, 0.93 and 0.92, respectively. The majority of deaths (85.7%) occurred before 10 days of age. Type and period of birth both had a significant effect on lamb survival traits, whereas age of dam and sex of lamb did not. The study revealed a curvilinear relationship between lamb's birth weight and survival traits from birth to 90 days, with optimal birth weights for maximal perinatal and preweaning survival varying according to type of birth from 2.6 to 3.5 kg. Estimation of variance components, using an animal model including direct and maternal genetic effects, the permanent maternal environment as well as fixed effects, showed that direct and maternal heritability estimates for survival traits between birth and 90 days were mostly low and varied from 0.01 to 0.10; however, direct heritability for survival at 1 day from birth was estimated at 0.63. Genetic correlations between survival traits and birth weight were positive and low to moderate. It was concluded that survival traits of D'man lambs between birth and 90 days could be improved through selection, but genetic progress would be low. However, the high proportion of the residual variance to total variance reinforces the need to improve management and lambing conditions.

Genetic and nongenetic effects for milk yield and growth traits in Saudi camels.

The study was based on a set of 256 records for milk yield at 305 days, 1,899 records of test day yield, and 466 growth records collected at Al Jouf center from 1987 to 2009. Except season of calving, milk yield at 305 days was affected by parity and calving year, whereas test day yield was influenced by parity, calving year, stage of lactation, and test milk day. Only birth year had a significant effect on all growth traits, whereas dam's parity influenced weights at birth and 3 months, and birth season affected birth weight, weight at 6 months and average daily gain (ADG) 3-6 months. Variance components estimated using an animal model showed that heritability and repeatability estimates for milk yield at 305 days were 0.24 and 0.28, respectively. The corresponding estimates for test day yield were 0.22 and 0.66, respectively. Direct heritabilities were 0.37, 0.50, 0.60, and 0.85 for body weights at birth, 3, 6, and 12 months of age, respectively, and 0.25, 0.37, 0.49, and 0.29 for ADG 0-3, 3-6, 6-12, and 0-12 months, respectively. The annual genetic progress was 0.05 kg for milk yield at 305 days and 0.0003 kg for test day yield. Annual genetic gains during 23 years were 0.050, -0.185, 0.079, and 0.331 kg for body weights, respectively, and -9, -5, -4, and -13 g, for ADG, respectively. It was concluded that it is necessary to set up a field milk and growth recording system in order to collect a large number of records to check these estimates.

Non-genetic factors influencing reproductive traits and calving weight in Saudi camels.

Reproductive traits and calving weight were assessed in Saudi camels, and non-genetic factors influencing them were studied using data collected at Al Jouf centre from 1987 to 2009. Age at first conception, age at first calving, open period, calving interval, gestation length and weight at calving of camels averaged 42.3 months, 54.8 months, 10.6 months, 22.6 months, 377.5 days and 591.9 kg, respectively. A mixed model including the camel as a random effect was used to assess the effect of environmental effects on the traits studied. Age at first conception and age at first calving were affected by camel's birth year. Open period and calving interval were not affected by parity or year of calving. However, camels that calved from October to February had a calving interval of 2.5 months higher than those that calved from March to September. Gestation length was affected by season and year of calving but not by parity or sex of calf. Camels calving from March to September had a gestation length 6.6 days shorter than those calving from October to February. Weight at calving was affected by parity and year of calving but not by season of calving. It was concluded that an improvement in camel reproductive traits is possible both through improving management systems and utilisation of controlled breeding techniques.