Investigation of Toxoplasma gondii seroprevalence and associated risk factors in dairy cattle in the Eastern Anatolia region of Türkiye.

In conditions of intensive dairy farming, breeding and breeding work deserves special attention, which helps to create highly productive herds of animals with improved economic characteristics.
 To determine the state of the dairy industry in the research farms of the NAAS network and the possibilities of adjusting the direction of selection, the task was to study the productivity of herds of different breeds according to the Instructions for boning cattle of dairy and dairy-beef breeds.
 According to the results of the analysis, it has been established that in 25 breeding herds of experimental farms of the National Academy of Agrarian Sciences of Ukraine, the number of cattle of dairy production as of 01.01.2018 amounted to 15500, including 8060 cows. The Ukrainian Black-and-White Dairy breed was kept in 17 experimental farms, in three – Ukrainian Red-and-White Dairy breed, in two breeds – Ukrainian Brown breed, in one Ukrainian Red Dairy, Ayrshirе and Holstein breeds. The vast majority of zoonotic animals – 99.5%, belonged to pure-bred and IV-th generation. Elite-record and elite class account for 81% of the total livestock in experimental farms.
 The analysis of cows by age in calves shows that in experimental farms, the majority of cows with two or three calves (64.6%) are kept, although among the studied breeds this figure is slightly different. The evaluation of cows by the age of the first calving and age in the calving indicates that the herds are not evenly differed from the breed. It was found that the average age of cows in calving in herds of experimental farms was 3.1 out of the range of 1.3–4.7 beds. Average in the cows' cows at the first hotel was 27.7 months. The number of primates introduced into the herd, which depends on the presence of non-cells and the need for replacement of full-eyed cows, has high variability in herds of experimental farms, ranging from 13.8% to 77%, with an average herd score of 27.6%.
 The analysis of cows of investigated breeds in herds of experimental farms shows that the cows of the Ukrainian Red Dairy, Ukrainian Red-and-White Dairy and Ayrshirе breeds are superior to the breeds. At an average yield of the studied breeds – 6157 kg. For cows of all investigated breeds, there is a tendency to increase the supply with an increase in the number of lactation, and it is determined that cows with the highest tastes are selected to the breeding group.
 It was established that the breeds of cattle of experimental farms of the NAAS network did not differ significantly in their content of fat and protein in milk, both on average for herds and for lactation. At the same time, the fat content in milk of cows of investigated breeds on average was 3.8% for the variation of the characteristic within the limits of 3.6–4.1%. The highest fat content characterizes the milk of cows of Ukrainian brown breeds – 4.2% for the third lactation .The lowest fat content in milk was found in the Holstein breed – 3.6%. In cows of some breeds with an increase in supplements and serial numbers of calving, the fat content of milk increased, while in others the opposite – declined.
 The live weight of cows of the investigated breeds was 559 kg and ranged from 527 kg (Ayrshire) to 586 kg (Ukrainian Red Dairy). It should be noted that the cows of the investigated breeds most intensively increased live weight after the second lactation. The highest live weight is characteristic for full-age cows of Ukrainian Red Dairy and Ukrainian Brown Dairy breeds – 635 kg and 628 kg, respectively.
 The evaluation of cows by type of body structure showed that among the estimated 7602 cows in experimental farms, 39.5% had an excellent score, 30.1% – very good, 21.7% – good with a plus, 7.6% – good, 1.1% – satisfactory and 0.01% – not satisfactory.
 The proportion of fertilized females from the first insemination in experimental farms of the National Academy of Agrarian Sciences of Ukraine 50% for the variation in the indicator for breeds within 32–82%. From the available heifers in the herds of experimental farms artificially infected were almost 63% of the population for some variability of this indicator for the breeds. The average live weight of heifers at the first insemination in herds of experimental farms of the NAAS network was 385 kg and ranged from 360 kg in heifers of the Ayrshire breed to 405 kg in females of Ukrainian Black-and-White Dairy breed. The proportion of fertilized heifers from the first insemination among the animals of the investigated breeds was 73–84% on the average indicator of experimental farms – 78%.
 Analysis of the age of heifers at the first insemination shows that in experimental farms they are asymptomatic when they reach the age of 17.7 months. At the same time, the heifers of the Ukrainian Red Dairy and Ukrainian Brown Dairy breeds were earlier marketed by the 18-month old age, Ukrainian Black-and-White Dairy from 15 months to 23.2 months of age. At a rather late age – 23.2 months.
 The calves retention in the herds of the research farms of the NAAS network is rather high – on average 94.7% for changes in the trait from 91% to 100%.
 As the results of our research prove, the live weight of repair heifers of the investigated breeds at the age of 6 months varied from 154 kg (Ayrshire) to 185 kg (Ukrainian Brown Dairy) breed and on average in herds of experimental farms it was 173 kg. At 12 months of age, the average live weight of repair heifers in herds of experimental farms was 290 kg for the least live weight in this period in the hens of the Ayrshire breed – 251 kg, and the largest – 320 kg in the representatives of the Ukrainian Red breed. The number of heifers, which at live weight exceeded the requirements of the breed standard at 12 months of age, increased by 10% to the previous period and amounted to 59%. The live weight of heifers in this age period in breeding farms was 399 kg on average – 360 kg in the herd of the Ayrshire breed and the maximum – 452 kg in animals of Ukrainian Red Dairy breed.
 Monitoring of the state of dairy cattle breeding in breeding herds of the experimental farms of the NAAS network indicates that in the vast majority of them there are well-developed animals with high milk productivity and reproductive capacity.

BackgroundQ fever is a zoonotic disease, caused by Gram negative bacterium C. burnetii, which imparts significant socio-economic burden due to production and reproductive loss (abortion, stillbirth, and infertility) in ruminants and debilitating clinical disease in human populations. While sheep and goats are considered the primary reservoirs of infection to humans, infection can also result from exposure to cattle. Recent studies indicate that in Ethiopia Q fever is a disease of growing public health interest. The top cattle producing region in Ethiopia is the Oromia region and Jimma is the zone that ranks first in the population of cattle within Oromia. While in Jimma zone livestock production plays an important role in people’s livelihoods and nutrition, to date, there is no available report on seroprevalence of Q fever in cattle. This is particularly important due to the low dairy farm biosecurity in Jimma town. This study aimed to evaluate the potential risk for public health from cattle production; a specific objective of this study included the estimation of the seroprevalence of C. burnetii infection and its potential risk factors in dairy cattle and cattle for slaughter in Jimma Town.ResultsThe seroprevalence of C. burnetii in cattle present at dairy farms was significantly lower compared to cattle presented at slaughterhouse [6.17% (95% CI: 3.41–10.13) and 11.79% (95% CI: 7.63–17.17), respectively; (P = 0.04)]. As the age of dairy cattle increase by 1 year, they were 1.51 more likely to be positive of C. burnetii [OR = 1.51 (95%CI: 1.30–1.75; (P = 0.000)]. Cattle managed in semi-intensive production systems were 8.08 more likely to be C. burnetii seropositive compared to intensively managed dairy cattle [OR = 8.08 (95%CI: 1.03–63.68); P = 0.047]. Dairy cattle with access to nuisance animals like dogs, cats and mice were 5.65 more likely to be C. burnetii seropositive compared to dairy cattle without access to these animals. On the other hand, dairy cattle that have no tick infestation are 93% less likely to be seropositive for C. burnetii [OR = 0.07 (95%CI: 0.01–0.74); P = 0.027]. Concerning farm-level data, farms of larger herd sizes were 1.03 more likely to be C. burnetii seropositive than small herd farms [OR = 1.03 (95%CI: 0.99–1.06)]. The result from slaughterhouse indicates that as the age of cattle increase by 1 year their chance of being C. burnetii seropositive increases by 2.27 [OR = 2.27 (95%CI: 1.93–2.68); p = 0.000].ConclusionConsidering its zoonotic and economic burden the seroprevalence of Q fever recorded in this study is of eminent public health concern with a farm-level and slaughterhouse seroprevalence of 6.17 and 11.79% respectively. Based on modifiable risk factors identified in this study, Q fever management plans better be focused on health education and awareness campaigns for abattoir workers and dairy farm workers. Dairy farm Q fever management plans should contemplate improved dairy herd biosecurity with regards to cattle tick infestation, keeping different livestock species segregated and avoiding mixing of herd with others with unknown health status.

Occurrence and molecular characterization of Cryptosporidium spp. and Enterocytozoon bieneusi in dairy cattle, beef cattle and water buffaloes in China

Toxoplasmosis, caused by Toxoplasma gondii, is one of the most common parasitic infections of humans and other warm-blooded animals in most parts of the world. The disease is common among sheep and goats and it is recognized as one of the major causes of reproductive failure in these animals. Cattle, on the other hand, can be infected, but abortion or perinatal mortality has not been recorded. This survey was carried out to study the prevalence of this disease in cattle in Khartoum and Gazira States (Sudan). 181 sera samples collected from dairy cattle with reproductive problems were assayed for antibodies to T. gondii by ELISA. The prevalence rate of T. gondii antibodies in cattle at herd level was 44.8% (13/29). Herd level infection rates were 50% and 33.3% in Khartoum and Gazira States, respectively. The overall prevalence of T. gondii at individual level in both states was 13.3% (24/181). The prevalence was 12.7% (17/134), was 14.9% (7/47) in Khartoum and Gazira State, respectively. There was significantly higher (P < 0.05) prevalence of T. gondii antibodies in the age group less than one year old (36.4%) than in other age groups and in males (30.8%) than in females (11.9%) while no significant relationship was discerned regarding breed, location, season, or signs of reproductive disease.

The study was conducted on the materials of primary breeding records in the herd of Ukrainian Red-and-White dairy breed of the State Enterprise of the State Enterprise experienced farm “Khristinovske” of the Institute of animal breeding and genetics nd. a. M.V.Zubets of National Academy of Agrarian Science. The calculations were performed by the methods of mathematical statistics by means of software package "STATISTICA-12,0" on the PC. Observed matrix of observations in the format “*.sta”, which contains data on 448 variables of 1540 cows&#x0D; Breeding work has provided a gradual increase in dairy productivity of the herd. The average hope for the 305 days of lactation of the firstborn herds in the last 18 years ranged from 2571 kg in 1999 calving to 7106 kg in 2015 year. The fat content of milk ranged from 3.34% (2000 year) to 4.02% (2013 year). In general, the curvilinear increase in milk yields of the firstborn in the analyzed years reaches more than 4500 kg or almost 2.8 times. The biological regularity of increase of dairy productivity of cows with age is realized. The experimental animals that were calved during the control period are the daughters of 31 boogies, belonging mainly to 12 lines and related groups and related to two (Ukrainian Red-and-White dairy and Holstein) breeds. The deterioration of the firstborn's yield in the studied herd was the Holstein breed Ingibitor EТ Red 402151, Jupy Red TV TL 114386090 and the sire of the Ukrainian Red-and-White dairy breed May 5573.&#x0D; Firstborns demonstrate the realization of the genetic potential of the breed, however, with age, the influence of environmental factors leads to the elimination of intergenerational differences in productivity. In mature age cows, this advantage is offset. No qualitative milk indicators of probable unidirectional patterns of intergroup differentiation of cows of different breeds and conditional blood were found.&#x0D; Belonging to a lineage or kinship group has a relatively low but significant effect on the phenotypic variability of milk yield and protein content of firstborn milk. By protein content, the influence of the specified genetic factor prolongs (even doubles) to the second lactation. The effect of linear affiliation on the live weight of heifers and cows after the first two calves, the age of the first calving and the length of time between the first two calves were statistically significant.&#x0D; A statistically significant influence of linear affiliation (on average 8.3%) and paternal ancestry (13.1%) on the variability of individual signs of live weight, dairy productivity and reproductive capacity of cows was established. The influence of the father in the herd under study is 1.58 times more significant than the linear membership of the animals. Revealed a significant level of differentiation of cow groups of different lines, related groups, and half-sisters by paternal father for the first lactation.&#x0D; For the firstborn, there was a tendency for curvilinear productivity increase with an increase in the conditional share of heredity in the Holstein breed. In the interspecific comparison, a statistically significant excess of the Holstein milk yields over such cows of the Ukrainian Red-and-White dairy breed (404 ± 158.0 kg, td = 2.57, P &lt; 0.02) was established, which is leveled by the third lactation.&#x0D; A significant level of differentiation of groups of cows of different lines, related groups and half-sisters by father for milk yield for the first lactation was revealed. Combining estimates of enhancing effect and phenotypic consolidation, the most desirable for further use in the herd are the prepotent enhancers Tumpy EТ Red Tl 112367468 and Michel Red 402213, and the most undesirable are the pretentious tadpill Inhibitor EТ Red 403860 and Jupy Red TV TL 114386090.

Neospora caninum is a major cause of reproductive loss in cattle worldwide as it leads to abortion and animal repositioning. Although Toxoplasma gondii does not cause a reproductive problem in cattle, consuming raw or uncooked beef poses the risk of transmission. This study aimed to evaluate the occurrence of anti-N. caninum and anti-T. gondii antibodies in dairy cattle in the West and Northwest regions of São Paulo State, Brazil. A total of 653 serum samples from dairy cows were analyzed using an indirect immunofluorescence assay (IFA). Epidemiological data from the farms were associated with the serological results of the animals by logistic regression based on the presence of antibodies. The frequencies of the antibodies against N. caninum and T. gondii were 41.6% (272/653) and 11.5% (75/653), respectively. A statistically significant association was observed between: the serum anti-N. caninum antibodies and breed, history of food supplementation for calves, introduction of outside animals that later presented reproductive problems, and history of reproductive problems by the trimester of gestation. The present study highlights the importance of neosporosis in dairy cattle in the study regions and that the inclusion of this parasite in the investigation of animals with reproductive disorders is important.

The aim of the research was too investigate the peculiarity of the phenotypic manifestation of economically useful traits of cows of the Ukrainian Red-and-White dairy breed during the period of its genesis and different genotypes under the conditions of using absorptive crossing methods. Material and methods of research. The research was on 116.4 thousand of cows of the Ukrainian Red-and-White dairy breed in 199 farms and on 1142 cows of Holstein breed in 5 farms carried out. The dynamic of the main productive and reproductive traits of cows of the Ukrainian Red-and-White dairy breed for the period of its genesis and comparative assessment of the phenotypic manifestation of economically useful traits of cows of different genotypes of the Ukrainian Red-and-White dairy breed under the conditions of using different crossbreeding methods was carried out. The results of research. In process of the implement of the first selection program of the Ukrainian Red-and-White dairy breed (2003–2013), the negative influence of yield of milk on the reproduction ability and fat content in milk of cows has been established. Too decide this problem, new methods of selection and artificial insemination of cows by semen of proven bulls for the complex of traits native selection was introduced. The liquidation of the state value of bulls in the Ukraine make the selection of the Ukrainian Red-and-White dairy breed bulls, what has absorptive crossing of the Ukrainian Red-and-White dairy breed by Holstein bulls (genotype - 96.87% and higher for the Holstein breed) promouted. Statistically not significant relationships between the increase the conditional part of Holstein blood in cows over 93.75% and the level of milk productivity were established. Cows with an increased conditional part of Holstein blood of 96.87% and above, obtained by absorption crossbreeding and assigned to the Holstein "native selection", in terms of 305 days of the last completed lactation, lagged behind their analogues of the Ukrainian Red-and-White dairy breed on average by 26.0 kg of milk and outweighed them by 2.0 kg of milk fat. The level of milk productivity of cows of both breeds, in three breeding farms was practically the same. According to the indicators of the reproductive ability of the Holstein breed cows of "domestic" selection (genotype - 96.87% and higher for the Holstein breed), they were significantly inferior to the analogues of the Ukrainian Red- and-White dairy breed. The duration of the service period for the group of cows of the Holstein breed of "domestic" selection was 140.4 ± 15.30 days, which is 16.4 days longer compared to this indicator for cows of the Ukrainian Red-and-White dairy breed. The yield of calves per 100 cows of the Ukrainian Red-and-White dairy breed was 85.2 ± 1.98% and exceeded this indicator of Holstein cows of "domestic" selection by 4.6 calves. The direction of further improvement of animals of the Ukrainian Red-and-White dairy breed was determined. Conclusions. The genetic potential of dairy productivity of cows of the Ukrainian Red-and-White dairy breed (genotype 62.5–93.75% of Holstein blood) is 10.0–11.0 thousand kg of milk, high reproductive ability (116 days off and 88–90 calf per 100 cows). The absorptive crossing the cows of the Ukrainian Red-and-White dairy breed by Holstein bulls, on the level of feeding, which is in most dairy plants of the Ukraine, das not ensure of the increasing of economically useful traits of cows.

Neospora caninum and Toxoplasma gondii are closely related obligate intracellular protozoan parasites. They are considered to be the major causes of infectious abortions and congenital abnormalities in livestock worldwide resulting in huge economic losses. Currently, there are no reports on the prevalence of neosporosis or toxoplasmosis in cattle in Beheira, Egypt's most important region for cattle industry. The current study investigated the presence of anti-N. caninum and anti-T. gondii antibodies in apparent healthy cattle from eight localities representing the whole area of Beheira. A total of 358 plasma samples were randomly collected from 6 dairy and 10 beef farms and analyzed by commercially available ELISAs. Production type (dairy versus beef), sex (female vs male), age (< 3 years, 3-5, and > 5 years old), breed (mixed vs Holstein vs Colombian Zebu), and location (various locations) were assessed as risk factors for N. caninum and T. gondii infections. Of the samples, 88 (24.6%) and 19 (5.3%) were positive for anti-N. caninum and anti-T. gondii antibodies, respectively, and mixed infection was detected in 7. Of the 16 herds, 6 dairy and 7 beef herds were positive for antibodies to N. caninum. Antibodies to T. gondii were detected in 4, and 5 of dairy and beef herds, respectively. Production type (dairy) and, therewith, sex (female), age (aged over 5 years), and location were considered as risk factors for N. caninum infection. No factors statistically associated with T. gondii infection were identified. Overall, this study provided the first serological detection of N. caninum and T. gondii infections in cattle from Beheira, demonstrating the endemicity of both parasites in the main cattle rearing region of Egypt. This study also confirmed earlier reports of N. caninum being more present in dairy cattle than in beef cattle. Routine monitoring of N. caninum and T. gondii infections and the implementation of control strategies are urgently needed.

PECULIARITIES OF FORMATION OF GENEALOGICAL STRUCTURE OF UKRAINIAN BLACK-AND-WHITE DAIRY BREED IN SUMY REGION AND RESEARCH OF ITS INFLUENCE ON THE GENOTYPE OF COWS BY CAPA-CASEIN

Toxoplasma gondii is a worldwide zoonotic protozoan. Donkeys are often susceptible to many pathological agents, acting as carriers of pathogens for other animal species and humans. However, data on the prevalence of T. gondii in donkeys during lactation and on the status of antibodies against T. gondii in donkey milk are lacking. A cross-sectional study evaluated the variation of the anti-T. gondii antibodies in the blood and milk of domestic donkeys during lactation. A total of 418 domestic donkeys were randomly selected from the Shandong province, eastern China from January 2019 to March 2020. The anti-T. gondii antibodies were found in 11.72% (49/418) serum and 9.81% (41/418) milk samples using a commercial ELISA kit, respectively. There was a very high consistency between the serum and milk (Spearman’s coefficient = 0.858, p-value < 0.0001 and Kendall’s tau = 0.688, p-value < 0.0001), particularly at the 45th to 60th day of lactation. The present results of the statistical analysis showed that the history of abortion (p = 0.026; adjusted OR = 2.20; 95% CI: 1.15–4.20) and cat in the house (p = 0.008; adjusted OR = 2.36; 95% CI: 1.26–4.44) were significantly associated with T. gondii infection in the domestic donkeys. This is the first report to detect antibodies against T. gondii in donkey milk in China. These results indicate a potential risk of humans contracting the infection through the consumption of raw milk from the naturally infected donkeys.

Epidemiological data for Toxoplasma gondii regarding malignancy have gained increasing attention; however, the information about T. gondii infection among children with malignant lymphoma (ML) in China is unclear. Therefore, 314 children with lymphoma and 314 healthy children, age- and gender-matched, were recruited to estimate the seroprevalence of T. gondii in the participants and identify the risk factors of infection. Blood samples from all participants were collected and examined for T. gondii IgG and IgM antibodies using ELISA. The results showed that the overall seroprevalence of T. gondii antibodies (including IgG and/or IgM) in ML patients and healthy controls was 19.8% and 9.9%, respectively. Contact with the cats, consumption of oysters and history of chemotherapy were estimated to be the risk factors for T. gondii infection in children with lymphoma by multivariable logistic regression analysis, whereas in healthy children, contact with cats and consumption of oysters were the risk factors. Moreover, among various histological types of lymphoma, individuals with NK/T-cell lymphoma, B-small lymphocytic lymphoma, marginal zone B-lymphoma and Hodgkin's lymphoma had a higher seroprevalence than healthy controls (P < 0.05). These findings indicated the high prevalence of T. gondii infection in children with lymphoma, and hence, efforts should be performed to evaluate the effect of the infection further in lymphoma patients.

Ukrainian Red- and Black-and-White dairy breeds, which are the most common in the region, as well as each biological system, are in constant variability and need constant scientifically-based support and improvement not only in general milk productivity, but also in such specific features as duration of economic use and reproducibility. A systematic approach in the optimization of breeding programs and the search for optimal crossbreeding options in populations of domestic dairy breeds is a little-studied and relevant area of research.&#x0D; The aim of the research is to study the peculiarities of the formation of the exterior of the first-born cows obtained from bulls of the Montbeliard, Norwegian Red and Holstein breeds.&#x0D; Materials and methods of research. The research was conducted in 2019–2020 on the basis of 4 breeding farms of Cherkasy region. 120 heads of first-born cows of Ukrainian Black-and-White dairy breeds, 201 heads of Ukrainian Red-and-White dairy breeds, 80 heads of first-generation Ukrainian Red-and-White dairy breeds and Montbeliards, 96 heads of first-generation Ukrainian Black-and-White dairy breeds and Norwegian Black-and-White cows were taken into account. Comparative evaluation of animals on productive traits, exterior type was carried out within breeding herds, taking into account the structure of the genotype of animals. The study of morphological and physiological features of the udder of cows was carried out by determining the shape and size by taking measurements at 2–3 months of lactation for 1 hour. 30 min before milking.&#x0D; The functional properties of the udder were studied by the intensity of milk production (kg/min.) during the control milking. The milk yield was determined by the formula proposed by N. P. Pogribna and others. The growth intensity of repair heifers and the index of decline in growth energy were determined by the methods of Yu. K. Svechin, L. I. Dunaev, V. P. Kovalenko. Biometric processing of experimental data – statistical, correlation and analysis of variance were performed according to the methods of N. A. Plokhinsky and E. K. Mercury on a computer type IBM PC/AT.&#x0D; Research results. At the age of six months among local heifers obtained from breeders of the Montbeliard Breed received a live weight of more than 200 kg (when using Holstein Breeders for reproduction, the weight of heifers at 6 months was 174.4–182.1 kg), at the age of over 380 kg (383.5–384.8 kg), in 15 months over 440 kg (442.9–449.9 kg). From birth to 6 months of age, heifers of the Ukrainian Black-and-White dairy breed obtained from Holstein Breeders had a higher live weight compared to crossbreeds obtained from bulls of the Norwegian Breed. After 6 months of age, local heifers outnumbered their peers in terms of live weight with an unlikely difference.&#x0D; The first-born cows of the Ukrainian Red-and-White dairy breed had high growth rates with well-developed breasts in depth, width and girth: height at withers and buttocks, respectively 133.7 ± 0.96 cm and 136.1 ± 1.05 cm with well-developed chest depth (72.9 ± 1.17 cm), width 42.6 ± 2.18 cm) and girth 193.0 ± 1.54 cm), with a wide back in the macula 51.6 ± 3.77 sm and in the buttocks 35.2 ± 1.09 sm.&#x0D; Body measurements of local first-borns of genotype 1/2URW1/2M – only 80 heads: height at withers 124.7 ± 3.71 cm (below first-borns obtained from Holstein bulls by 9.0 sm (P &gt; 0.95) URW); in the buttocks 127.9 ± 2.19 sm (8.2 sm below the firstborn URW breed) (P &gt; 0.99), oblique body length 158.3 ± 13.82 cm (4.6 cm below the firstborn URW breed)). However, they outnumbered the first-borns obtained from Holstein bulls by measuring the depth of the breast 75.3 ± 3.11 cm (2.4 cm), breast width from 47.7 ± 2.40 cm (5.1 sm), chest circumference 205.0 ± 4 10 sm (12 sm (P &gt; 0.99)), width of the buttocks in the macula and buttocks (6.1–3.1 sm (P &gt; 0.95)).&#x0D; The first-born cows of the Ukrainian Black- and-White dairy breed obtained from Holstein breeders had a height at the withers and buttocks of 130.9 ± 1.22 cm and 137.2 ± 0.86 cm, respectively, with well-developed breasts in depth and girth. Local first-borns obtained from the selection of Ukrainian Black-and-White dairy cows of Norwegian Black-and-White breeders had no significant difference in basic body measurements with those of the same age as those obtained from Holstein breeders.&#x0D; Regardless of genotype and breed, the udder of first-born cows is large in volume (in girth – 128.6 ± 3.14 and 148.7 ± 2.66 sm, length – 35.1 ± 1.23 and 40.3 ± 1.55 sm and a width of 29.5 ± 3.26 and 33.8 ± 4.36 sm.) With proportionally developed parts of the udder, bath- or cup-shaped, firmly attached to the abdominal wall with cylindrical teats. Duration of milking 10.1 ± 0.167 – 12.2 ± 0.157 minutes, milk production rate 1.90 ± 0.01 – 2.50 ± 0.07 kg/min. It was found that with increasing daily milk yield, the intensity of milk production also increased: correlation coefficients (r = 0.439–0.577) have a high reliability (td = 3.97–7.58). The value of the udder index among the studied breeds and genotypes was different and ranged from 43.4 ± 0.06% to 45.2 ± 0.02%.&#x0D; Conclusions. The crossing of Ukrainian Black-and-White dairy cows with Norwegian Black-and-White breeders did not have a significant effect on the exterior type of repair heifers under 12 months of age. Crossbreeding with the Montbeliard breed made it possible to obtain heifers that were inferior in growth, but had a developed, three-dimensional body, chest and pelvis. The use of genetic material of the Montbeliard and Norwegian Black-and-White breeds has contributed to the formation of cows of the desired exterior type with good udder characteristics that meet modern requirements of machine mil.

Mastitis, the most frequent disease in dairy cattle. Resistance to mastitis is a complex, polygenic trait controlled by several genes, each with small effects. Genome-wide association studies have been widely used to identify genomic variants associated with complex traits, including resistance to mastitis, to elucidate the underlying genetic architecture of the trait. However, no systematic review and gene prioritization analysis have been conducted to date on GWAS results for resistance to mastitis in dairy cattle. Hence, the objective was to perform a systematic review and gene prioritization analysis of GWAS studies to identify potential functional candidate genes associated with resistance to mastitis-related traits in dairy cattle. Four electronic databases were searched from inception to December 2020, supplemented with multiple sources of gray literature, to identify eligible articles. Annotation for genes and quantitative trait loci (QTL), and QTL enrichment analysis were conducted using GALLO. Gene prioritization analysis was performed by a guilty-by-association approach using GUILDify and ToppGene. From 52 articles included within this systematic review, 30 articles were used for further functional analyses. Gene and QTL annotation resulted in 9,125 and 43,646 unique genes and QTL, respectively, from 39 studies. In general, overlapping of genes across studies was very low (mean ± SD = 0.02% ± 0.07%). Most annotated genes were associated with somatic cell count-related traits and the Holstein breed. Within all annotated genes, 74 genes were shared among Holstein, Jersey, and Ayrshire breeds. Approximately 7.5% of annotated QTL were related to QTL class "health." Within the health QTL class, 2.6 and 2.2% of QTL were associated with clinical mastitis and somatic cell count-related traits. Enrichment analysis of QTL demonstrated that many enriched QTL were associated with somatic cell score located in Bos taurus autosomes 5, 6, 16, and 20. The prioritization analysis resulted in 427 significant genes after multiple test correction (false discovery rate of 5%) from 26 studies. Most prioritized genes were located in Bos taurus autosomes 19 and 7, and most top-ranked genes were from the cytokine superfamily (e.g., chemokines, interleukins, transforming growth factors, and tumor necrosis factor genes). Although most prioritized genes (397) were associated with somatic cell count-related traits, only 54 genes were associated with clinical mastitis-related traits. Twenty-four genes (ABCC9, ACHE, ADCYAP1, ARC, BCL2L1, CDKN1A, EPO, GABBR2, GDNF, GNRHR, IKBKE, JAG1, KCNJ8, KCNQ1, LIFR, MC3R, MYOZ3, NFKB1, OSMR, PPP3CA, PRLR, SHARPIN, SLC1A3, and TNFRSF25) were reported for both somatic cell count and clinical mastitis-related traits. Prioritized genes were mainly associated with immune response, regulation of secretion, locomotion, cell proliferation, and development. In conclusion, this study provided a fine-mapping of previously identified genomic regions associated with resistance to mastitis and identified key functional candidate genes for resistance to mastitis, which can be used to develop enhanced genomic strategies to combat mastitis by increasing mastitis resistance through genetic selection.

GROWTH, REPRODUCTIVE CAPACITY AND PRODUCTIVITY OF COWS OF DIFFERENT BREEDS, METHODS OF SELECTION AND PATERNAL ORIGIN

DAIRY PRODUCTIVITY OF UKRAINIAN BLACK-AND-WHITE DAIRY BREED COWS DEPENDING ON THE GENOTYPE