Fruitful Insemination Research Articles

Association of FSHR gene polymorphism with fertility of Holstein cows

Relevance. The view of the mechanisms of hormonal regulation of the ovarian cycle of cows has allowed the development of a large number of synchronization programs. An active search is underway for biomarkers related to the fertility of cows, as well as to identify animals with a high ovarian response to the injection of exogenous gonadotropins. The aim of the work is to study the polymorphism of the FSHR gene and its association with reproduction indicators in black-and-white Holstein dairy cows.Results. Based on the results of genotyping cows (n = 128) using the FSHR gene, the frequency of occurrence of the CC genotype was determined at the level of 0.601, the CG genotype — 0.360, GG — 0.031. It was found that for productive insemination, animals with the CG genotype require fewer inseminations. At the same age, the frequency of insemination of heifers with the CG genotype was 1.43, with the CC genotype — 1.60. After the first calving, the animals with the CG genotype responded more actively to hormonal stimulation in the postpartum period. The interval from the first to fruitful insemination in cows with the CG genotype was 34.7 days, in cows with the CC genotype — 57.2 days (p < 0.05). The number of pregnant cows with the CG genotype re-inseminated after natural hunting was 2.1 times higher than the number of cows with the CC genotype (66.7% and 31.2%). It is assumed that exogenous hormone injection has a stimulating effect on the hypothalamus-pituitary-gonad system in cows with the CG genotype.

Влияние возраста первого отела на молочную продуктивность и качество молока

Nowadays, in order to reduce the cost of replacement heifers raising, early insemination and, accordingly, earlier use of cows are practiced in many farms. The purpose of the research is to study the relationship between milk productivity and the age of the first insemination of Holstein heifers under the conditions of OOO Kaluzhskaya Niva (a limited liability company under the laws of Russian Federation) in the Peremyshl district. The experimental groups were formed from cows with completed fourth lactation, taking into account the age of the first fruitful insemination. As the result of the study, it was found out that the optimal insemination index is observed at heifers of the first and second groups upon reaching the age of 12-14 months with a live weight of 337.6-340.9 kg. The shortage of live weight of heifers by the age of 12 months lengthens the time of raising, and reduces the effectiveness of their insemination (group 4 – the multiplicity of insemination is 3.3). The maximum growth rate was observed at heifers of the first group and made 865-931 g/day, which is 6.1-32.1% higher than in heifers of the other groups. When analyzing the dairy productivity of cows, there is a tendency to decrease the level at the second and third lactations, and an increase in the fourth lactation in comparison with the first one. More balanced lactation activity in a number of lactations is observed in cows of the third group (II lactation decreased by 2%, III - decreased by 5%, IV – increased by 17.5%, compared with the first lactation). At the same time, the variation in milk yield in cows of the other groups ranges from -9.2% to +20.6%. The differences in the indicators of the mass fraction of fat and the mass fraction of protein in milk of cows of different groups are not significant. The tendency of decrease of the mass fraction of fat in milk in cows of all groups is noted by the 4th lactation, with increase in the mass fraction of protein. Thus, for the manifestation of high milk productivity and its preservation in a number of lactation, the optimal age for the first insemination of Holstein heifers is 15-16 months.

Идентификация гаплоблоков, потенциально ассоциированных с эмбриональной смертностью крупного рогатого скота черно-пестрого корня

Abstract. In modern realities, the problem of cattle reproduction is becoming one of the most important issues in managing a large herd. The long-term desire of breeders in all countries of the world to increase milk productivity in dairy cattle has led to the degradation of their reproductive capacity. The service period has increased by more than 40 days, the insemination index has increased almost 2 times, the intercalving period has become 3 months longer than a year. Due to intensive selection aimed at milk production and a decrease in reproductive capacity, a cow does not give birth to a calf every year, and the percentage of pregnant animals after the first insemination has sharply decreased to 30%. In terms of the degree of loss of reproductive function in cows, embryonic mortality ranks first, due to which up to 70% of pregnancy losses occur in the first 45 days after fruitful insemination. Accelerating the pace of breeding progress requires the use of genomic selection in animal husbandry, which will make it possible to conduct genome-wide association studies (GWAS) with indicators of productive longevity and fertility of cows and to identify genomic regions subject to the greatest selection pressure for indicators of productive longevity and reproductive function of dairy cattle. Purpose of the work: Identification of haplotypes responsible for reproductive function of cattle. Research methods. The studies were conducted on the Holstein breed of cattle. Identification of homozygous haplotypes was carried out using the GHap package in R software. The scientific novelty of the work lies in the identification of homozygous haplotypes responsible for early embryonic mortality and affecting fertility in a population of Holstein cows of the Ural type, Results. During the processing of the data obtained, chromosomes with haploblocks were identified, which may be responsible for early embryonic mortality and affecting the fertility of cattle.

ИЗУЧЕНИЕ БИОЛОГИЧЕСКОЙ ПОЛНОЦЕННОСТИ СПЕРМАТОЗОИДОВ В СПЕРМЕ С БАКТЕРИАЛЬНОЙ ОБСЕМЕНЕННОСТЬЮ

The aim of the study is to investigate the relationship between bacterial contamination of bull semen and the biological value of spermatozoa, as well as reproductive performance. The object of the study was Holstein bulls (n = 17). The material for the study was frozen-thawed semen of bulls in the amount of 61 samples. Microbiological studies of sperm doses were carried out using standard nutrient media in accordance with GOST 32222-2013. The total number of microorganisms was calculated by the number of grown colony-forming units (CFU/ml) in 1 cm3, with subsequent determination of their morphological pro-perties. Sperm motility and morphology were determined using the Argus CASA program. The state of DNA in spermatozoa was studied by the acridine orange test (AO test) using a fluorescence microscope. The study revealed a high positive correlation (r = +0.940**) between the number of microorganisms in sperm and pathology in individual sperm segments. Analysis of variance confirmed a statistically significant effect of the number of microorganisms on sperm morphology F = 123.2 (p=0.000). The correlation relationship between the fragmentation index and the content of microorganisms has a high value (r = +0.965**). Sperm motility negatively correlates (r = –0.768**) with the number of microorganisms (CFU/ml). In the presence of Mycoplasma spp in the samples, the number of cows with fruitful insemination was 35.5 % due to reduced motility, morphology and high fragmentation of sperm DNA (58 %). Sperm motility in samples containing Mycoplasma spp averages 24.5 %, while in samples without these microorganisms it is 48.9 %. Thus, it can be assumed that the presence of Mycoplasma spp in samples and high bacterial contamination rates lead to to lower reproductive performance in bulls.

Association of <i>FGF2</i> gene polymorphism with economically significant traits of Holstein cows of the Republic of Tatarstan

Improving the reproductive functions of dairy cows may be possible through the use of marker-associated breeding. The FGF2 gene is a candidate gene for bovine fertility, in early pregnancy and affects fetal embryonic development and embryonic mortality. The study of the interaction of the gene of the basic fibroblast growth factor 2 (FGF2 – SNP11646 [A → G]) and economic indicators was carried out on 270 full-aged cows of Holstein population of indigenous selection of Breeding Farm Integrated Agricultural Production Center of the Republic of Tatarstan. In the observed population, the G allele (0.591) and the AG genotype (42.6%) are the most common, and the genetic balance, according to the Hardy-Weinberg law, is preserved. Pearson's consensus criterion is 2χ=3.84, respectively, the expected distribution of FGF2 gene alleles in the study group coincides with the observed one. The maximum live weight at the first fruitful insemination was in full–aged cows carrying the homozygous allele A at the FGF2 gene locus – 435.5 kg, which is higher than in livestock with the GG genotype – by 17.7 kg (4.2 %; p < 0.01). The Doha fertility index for the studied population is average. It was revealed during the study that the level of fertility, with a high degree of reliability, is higher in individuals with the AG genotype – 6.2%, for the same group the earliest age of the first fruitful insemination was noted. A high level of maleness leads to milk losses in cows heterozygous for the FGF2 gene locus, exceeding milk losses observed for the AA genotype by 32.7 % (p < 0.001). There is an inverse correlation between high milk productivity and reproduction traits of cattle, which affects the economic efficiency of dairy production.

Pedigree base of brown Swiss cattle breed in the Smolensk region

The current state by the end of 2020of the Brown Swiss breed of cattle in pedigree farms of the Smolensk region was studied. The average milk yield in herds for the last completed lactation is 4045 – 6626 kg of milk, the yield of milk fat and protein is 158 – 268 kg and 134 – 236 kg, respectively. In the best farm of the SPK “Druzhba”, the average milk yields of cows for the highest lactation exceed 7000 kg of milk, eight animals have record results of 10016 – 11720 kg. Cows are born from fathers of high breeding value. The average milk yield mothers of fathers in herds is 9767 – 12333 kg. The average age of cows according to the last completed lactation in the studied herds is 2.3 – 3.9 lactation. The age of the first fruitful insemination in the best farm is 16.5 months. From 87.8 to 98.3% of cows belong to lines of foreign origin.

Optimal calf insemination age as a reserve for increasing milk production

Increasing gross milk production is the main task of the dairy cattle industry. The level of milk productivity of a cow depends on the age and living mass of the calf at the first insemination. Under certain conditions, the technology of herd reproduction in the conditions of cattle breeding in a particular farm (maintenance technology, feeding conditions, etc.) it is necessary to determine the optimal period of the first fruitful insemination of heifers. The productivity of Holstein cows was studied due to the age of the first insemination. Among the first calves inseminated at the age of 11-18 months, cows turned out to be more productive with an age of insemination of 14 months. In order to increase productive longevity, it is recommended not to inseminate the calves earlier than this age.

The First Efficient Insemination of Holstein-Friesian Cows, Effect of Age and Body Weight

Age and live weight at the first fruitful insemination of replacement heifers is an important link in the breeding process. A study was made of the influence of several factors on the productive longevity of cows of the Holstein-Friesian breed. The relationship between lifelong milk yield and longevity with the age of the first fruitful insemination is higher (r = 0.10-0.23) than with the live weight at the first insemination (r = 0.04-0.13). The breed of animals does not affect the degree of relationship between age and body weight at the first fruitful insemination and their productive longevity. Increased indicators of productive longevity are characteristic of animals of Gilan Dairy Farms and ASA Animal Husbandry, inseminated at an earlier date of 14-16 months. with increased live weight. Analysis of the results obtained allows us to conclude that the factor ‘farming’ in the dispersion complex had a slight effect on the indicators of productive longevity of cows.

The direction of the breeding process in a herd of Ayrshire breed cows in the conditions of the Vologda region

The direction of the breeding process in herds and populations of dairy cattle breeds based on the actual indicators and variability of the trait is one of the main factors that allows to determine the effectiveness of breeding measures. As the initial material for the research there were taken the data of breeding records (n=681) of Ayrshire breed cows of the agricultural complex "Maysky" of the Vologda region. The number of cows was distributed by generations (195 cows with the first incomplete lactation, 177 cows with the first completed lactation, 130 cows for the second lactation, 179 cows for the third lactation and older). According to the research results, the superiority of the actual indicators for the live weight of heifers in animals of modern generation in early age periods was from 28 to 39 kg. Consequently, with each new generation, animals have better development indicators, as evidenced by the indicators of variation (variability) of the live weight of heifers in the early age periods of weak and moderate Cv = 5.3 to 10.6 %, depending on generation. The reduction of the age of the first insemination of heifers to 13.4 months (-2.2 months) and the first fruitful insemination to 14.0 months (-2.1 months) in animals from full-age to the first incomplete lactation was revealed. A targeted selection of cows was carried out in the herd according to the level of milk productivity of mothers after the first lactation - the selection efficiency was 977 kg of milk, according to the highest - 456 kg. The selection of breeding bulls was carried out according to the level of productivity of the breeding stock, however, it should be noted that the intensity of selection in cows for the incomplete first (10968 kg of milk) and first lactation (10635 kg of milk) is reduced compared to cows for the second lactation (11417 kg of milk). Consequently, in herds and populations of dairy cattle breeds, in order to achieve genetic progress in productivity in the next generation, it is necessary to determine the direction of the breeding process.

Evaluation of treatment methods for cows with subclinical endometritis

The article presents the results of the spread of various forms of endometritis in cows. At the same time, the subclinical form of endometritis was most often recorded (22.48%). Intrauterine administration of Metricef allows achieving fruitful insemination of cows (82.35%). Positive results in restoring fertility in cows with subclinical endometritis can also be obtained after treatment with the anti-mastitis preparation dienomast. Fertilization of animals after its application was 76.47%.

Association of coenzyme Q9 (COQ9) gene polymorphism with traits of reproductive qualities of holstein cows

The paper presents the results in 2019-2022 of studying the associations of polymorphism of the coenzyme Q9 (COQ9) gene, which a ects the energy and metabolic processes in the body, with traits of the reproductive qualities of Holstein heifers. The experimental population was selected from animal analogues (251 heads).DNA testing of allelic polymorphism G → A (guanine → adenine) of the COQ9 gene, which results in changes in oxidative phosphorylation, that a ects the respiratory function of mitochondria, was carried out by PCR-RFLP. Two alleles (A - 0.604; G - 0.396) and three genotypes (AA - 36.6 %; AG - 48.2 %; GG - 15.5 %) have been identi ed, in the COQ9 - BstMB I gene locus, that indicates genetic biodiversity populations. The chi-square takes on a value well below the critical value (0.05). The population is in genetic equilibrium according to the Hardy- Weinberg law. The traits of the reproductive ability of cows (251 animals) of di erent genetic groups of the COQ9 gene have been studied. An analysis of the relationship between fertility rates and genotypes of the COQ9 gene showed that individuals with the COQ9AA genotype were characterized by increased live weight during insemination and at calving. Animals with the COQ9AG genotype were characterized by a later age of the rst fruitful insemination, while the number of sperm doses spent on them was minimal. The same group of heifers had the shortest calving interval, open day and service period and, as a result, a greater yield of live calves, a high fertility index of Dohi and a reproductive ability coe cient. The data presented in our research prove the in uence of genetic factors on the reproductive qualities of cattle, which makes it possible to develop systems for managing the productivity of farm animals based on the use of molecular genetics methods

Plant raw materials for correction of reproductive function of cows

The article presents data on the study of the effect of the supplement Lamarin Saldonum on the reproductive ability of highly productive cows. The experiment was conducted in the APC collective farm "Iskra" (Kotelnichsky district, Kirov region). The experiment involved cows of a black-and-white Holstein breed aged 2-5 lactation, with a milk yield of 7,500 kg for 305 days of the previous completed lactation, divided according to the principle of analogues into experimental groups O1, O2, O3 and control K4 (n=5). The additive was introduced into the ration of cows in groups O1, O2 and O3 30 days before the expected date of calving for 2 months (60 days) daily in doses of 0.3, 0.4 and 0.5 g/kg live weight per day respectively. It was found that the use of dietary supplements in these doses does not affect the duration of pregnancy of females and the timing of their arrival in the hunt after calving. However, it reduces the number of spermodoses spent per fruitful insemination by 7,69; 46,15 (p?0,01) and 23,08 % (p?0,05), the number of days from calving to fruitful insemination by 19, 65 (p?0,01), 38,24 (p?0,001) and 27,27 % (p?0,001), and period of infertility by 32,81 (p?0,01), 63,84 (p?0,001) and 45,54 % (p?0,001) respectively relative to group K4 (intact animals). According to the conducted studies, the most optimal dose for correcting the reproductive function of cows is an additive dose of 0,4 g per 1 kg of live weight.

Analysis of reproduction indicators of brown Swiss cattle of the Smolensk region

In dairy cattle breeding, the breeding work is carried out mainly to increase the milk productivity of cows, which often leads to a decrease in the reproductive qualities of the breeding stock. Therefore, practicing breeders are faced with the task of studying and improving the qualities of animals associated with the reproduction of the herd. At the same time, in the conditions of a decrease in the number of livestock, the issue of preserving and improving the reproductive properties of animals is also put forward in the first position. For design breeding problems, it is necessary to have information about the genesis of reproduction. The conducted studies covering the period 2011-2020 reveal the dynamics of significant reproductive indicators – the age of the first fruitful insemination, the number of inseminations per fruitful one, as well as the open days in the first lactation of the breeding stock of the Swiss breed. In the process of its improvement, the age of the first fruitful insemination of animals decreased. The multiplicity of insemination and the associated open days in the first lactation do not have a stable nature of changes. To obtain more informative data on the level of organization of the biological system under study, the entropy – information analysis was used in the study. The age of the first fruitful insemination at the initial stages was poorly controlled, with an absolute organization (O) having values from 0.168 bits (H=3.292 bits) it was found however, during the selection process, the controllability of this system increases (O=0.873 bits; H=2.586 bits). The most controlled feature throughout all stages is the multiplicity of insemination (O = 0.401...1.147 bits; H=1.921 ...1.175 bits). The least controlled is the open days (O=0.136...0.604 bits; H=3.449...2.981 bits). The obtained results of the study contribute to the conduct of purposeful breeding of Brown Swiss cattle, taking into account the reproductive ability.

Качественные характеристики замороженно-оттаянного семени (обычное и разделенное по полу ) у быков-производителей голштинской черно-пестрой породы и возраст полового созревания полученных от них телочек

A study was carried out to assess the quality of frozen-thawed semen using the sex separation method and the traditional method in a comparative aspect, and the authors believe that the work will be of some interest to specialists in zootechnical and biological fields, as well as to veterinary specialists. The work was carried out at the Federal Research Center for Animal Husbandry named after Academy Member L.K. Ernst and on the basis of LLC “Agrofirma Zarya”, Bogorodsky district, Nizhny Novgorod region in the period from 2017 to 2022. usng the semen of eight sires. To assess the quality of the semen, the index of nuclear DNA fragmentation (nDNA) in chromatin was determined, and the activity of spermatozoa was assessed visually and using the Biola AFS‑500 sperm analyser (ZAO Biola, Moscow). On the basis of the studies conducted, it was found that the morphology of the spermatozoa depends on the individual characteristics of the sires; the content of abnormal spermatozoa varies from 2 to 8% when collected by the traditional method and from 4.10 to 15% when collected by the sexing method. A significant difference between the sires is observed in the iDNA fragmentation index – this indicator varies from 2.66 to 8.62% and from 8.50 to 28.57%, respectively. The division of spermatozoa by sex has a direct effect on the quality indicators, leading to a decrease in their activity. This indicator is 11.2% higher in semen obtained by the traditional method than by the alternative technique. The number of abnormal cells in the semen divided by sex is 2.2% higher than in the semen collected by the traditional method, and the proportion of spermatozoa with fragmented iDNA is 7% higher. The velocity of spermatozoa in the studied doses of semen collected using the technique of sex separation was 96–113 μm/s immediately after thawing, and five hours after incubation at +38°C in a thermostat this indicator decreased to the level of 20–34 μm/s. The age of puberty of their calves obtained from the sexed semen from birth to fruitful insemination is 490 days, which is 16 days more than in group I, where heifers were obtained from the semen frozen in the traditional way (TS). The term of fruiting in heifers born from the use of the sexed semen (SS) was 273 days, while that of heifers born from the use of traditionally frozen semen (TS) was 275 days (2 days more). The age of heifers from birth to first calving in the SS group was 762 days and was 14.4 days more than in the TS group, which was 748 days.

Идентификация популяций клеток крови рыб на основе сверточной нейронной сети для составления лейкограммы

A study was carried out to assess the quality of frozen-thawed semen using the sex separation method and the traditional method in a comparative aspect, and the authors believe that the work will be of some interest to specialists in zootechnical and biological fields, as well as to veterinary specialists. The work was carried out at the Federal Research Center for Animal Husbandry named after Academy Member L.K. Ernst and on the basis of LLC “Agrofirma Zarya”, Bogorodsky district, Nizhny Novgorod region in the period from 2017 to 2022. usng the semen of eight sires. To assess the quality of the semen, the index of nuclear DNA fragmentation (nDNA) in chromatin was determined, and the activity of spermatozoa was assessed visually and using the Biola AFS‑500 sperm analyser (ZAO Biola, Moscow). On the basis of the studies conducted, it was found that the morphology of the spermatozoa depends on the individual characteristics of the sires; the content of abnormal spermatozoa varies from 2 to 8% when collected by the traditional method and from 4.10 to 15% when collected by the sexing method. A significant difference between the sires is observed in the iDNA fragmentation index – this indicator varies from 2.66 to 8.62% and from 8.50 to 28.57%, respectively. The division of spermatozoa by sex has a direct effect on the quality indicators, leading to a decrease in their activity. This indicator is 11.2% higher in semen obtained by the traditional method than by the alternative technique. The number of abnormal cells in the semen divided by sex is 2.2% higher than in the semen collected by the traditional method, and the proportion of spermatozoa with fragmented iDNA is 7% higher. The velocity of spermatozoa in the studied doses of semen collected using the technique of sex separation was 96–113 μm/s immediately after thawing, and five hours after incubation at +38°C in a thermostat this indicator decreased to the level of 20–34 μm/s. The age of puberty of their calves obtained from the sexed semen from birth to fruitful insemination is 490 days, which is 16 days more than in group I, where heifers were obtained from the semen frozen in the traditional way (TS). The term of fruiting in heifers born from the use of the sexed semen (SS) was 273 days, while that of heifers born from the use of traditionally frozen semen (TS) was 275 days (2 days more). The age of heifers from birth to first calving in the SS group was 762 days and was 14.4 days more than in the TS group, which was 748 days.

The influence of Holstein crossbreeding on the reproductive qualities of Black-and-White cows

The purpose of the research was to study the main indicators of the reproductive ability of Black-and-White cows, depending on the proportion of Holstein genes. As the material for the research there were taken the data of breeding and zootechnical records of cows of Black-and-White breed of CJSC Semenovsky Breeding Plant of the Mari El Republic. The results of the research showed that with an increase in the proportion of thorough-bredness on the Holstein breed the reproductive ability of cows improved. Thus, the first-calf heifers with a low proportion of Holstein genes (up to 12.5 %) had the latest age of the first fruitful insemination and the first calving (21.9 months and 32.3 months). With an increase in thorough-bredness up to 87.6 % and more, the age for the first insemination decreased by 7.7 months (31.8 %), the age of the first calving - by 7.4 month (21.8 %), fertility index increased by 5.8 (14.6 %). At the same time, the duration of the service period in high-blooded animals increased by 18.8-26.4 days (15.8-23.8 %). The duration of the calving interval in all genetic groups exceeded the optimal time and changed in accordance with the change in the service period. The longest calving interval was in cows with the thorough-bredness degree of 87.6 % (13.8 months), which was 0.1-0.7 months longer than in animals of other genetic groups. There was a low coefficient of reproductive ability of the studied animals of all genetic groups ‒ 0.91-0.93. The significant influence of Holstein genes on the age for the first fruitful insemination (ɳ2 = 9.57 %), the first calving (ɳ2 = 8.80 %) and the fertility of cows (ɳ2 = 1.98 %) (P≤0.05) was established. The effect of the genotype on the duration of the service period and calving interval was weak (ɳ2 = 0.09 % and ɳ2 = 0.26 %) and unreliable.

Effect of introducing Lamarine Saldonum into the diets of cows during dry period and period of lactation on their productivity and reproductive ability

The article presents the data on the effect of the Lamarin Saldonum additive on reproductive function and milk productivity of cows when used in different periods: 30 days and 60 days before calving (groups S1 and S2), beginning from the day of calving (group S3) compared with the control (group C4). Highly productive black and white Holstein breed cows were used in the experiment. The additive was fed at a dose of 0.4 g per 1 kg of live weight during 60 days. It was found that S2 group had significantly shorter duration of pregnancy than S1 and C4 groups by 6.2 and 8.2 days, respectively, remaining within the limits of the physiological norm. The shortest indifference-period compared to C4 was observed in groups S1 and S3, the significant difference being 15.25 % and 18.39 %, respectively. The least number of days from calving to fruitful insemination was recorded in group S1, compared to control the statistically significant differences were 37.16 %, compared to groups S2 and S3 – 28.82 % and 27.67 %, which reliably reduced the period of infertility by 57.33 % relative to the values of group C4, as well by 47.90 % and 46.49 % relative to the indicators of groups S2 and S3. The highest average daily milk yields were recorded in group S1: in the first month of lactation, the difference with groups S2, S3 and C4 was 5.74 %, 14.01 % and 17.06 % (psecond (at p0.05), 14.53 %, 16.52 %, 15.19 %, in the third 9.57 % (p0.05), 13.06 %, 10.94 % (p0.05), in the first 100 days of lactation 11.90 %, 16.86 % (p0.05) and 13.28 % (p0.01), respectively. Thus, the most optimal scheme of application of Lamarin Saldonum for stimulation of reproductive function and milk productivity of cows is 30 days before the expected calving.

Association of leptin (LEP) gene polymorphism with reproduction traits of domestic and imported Holstein cattle in different milking technologies and housing conditions

The article presents results of traits of reproductive ability of Holstein cows of domestic (379 animals) and imported (228 animals) breeding with different genotypes of the leptin gene (LEP) with different milking technologies and housing conditions. Frequency of occurrence of genotypes of LEP gene in imported herd range: CC – 32.5; TC – 49.1 и TT – 18.4 %. In herd of domestic animals frequency of CC, TC and TT genotypes of LEP gene was – 23.5; 54.3 and 22.2 %. In our research it has been shown that animals with the TT genotype of the LEP gene are distinguished by the best traits of live weight at the first fruitful insemination, reproductive capacity coefficient, Dohi index, yield of calves per 100 cows, duration of the calving interval and open days, compared with animals with CC and TC genotypes. Among the cows of domestic breeding, superiority was established for animals with the TC genotype in traits of live weight, service period and Dohi index. For others traits of reproductive ability stand out favorably animals with the CC genotype of the LEP gene. In the context of two farms in the course of the experiment, it is noted that Holstein cows of imported selection with yard housing technology have the best indicators of reproductive qualities, compared with the population of domestic selection of stall barn housing technology. It follows from this that genetic and paratypic factors, along with such herd management principles as milking technology and housing conditions, equally affect the reproductive qualities of Holstein cattle. This research was supported by FASO Russia project number 122011800138-7.

The effect of ultra-dispersive humate-sapropel suspension on the digestibility of nutrients in the diet

The article presents the results of the effectiveness of the use of ultra dispersionhumate-sapropel suspension (UDGSS ) in the diets of heifers selected for insemination. The use of UDGSS allowed one to increase the absorption of nutrients from the diet, to increase the digestibility coefficients in the experimental groups. Thus, the value of the dry matter digestibility coefficient in the first experimental group increased by 1.3%, and by 1.9% in the second one. Organic matter was also absorbed better (by 5.4 and 7.4%, respectively) in the groups fed with UDGSS in the main diet - 20 and 25 ml/head/day. It was found out that the UDGSS improved the fruitful insemination of heifers by 25-50%, depending on the dose of the preparation.

Economic rationale for live weight and age during fruitful insemination of red-and-white heifers obtained from bulls of different lines

The article discusses the effectiveness of the growth and development of heifers of the Red-and-White breed grown according to intensive technology in a dairy complex with loose housing in Agrosoyuz-Krasnoe Seltso LLC, Ruzaevsky district of the Republic of Mordovia. Replacement heifers of the Red-and-White breed have an early maturing type and at 13-15 months of age reach a live weight of more than 400 kg at the time of fruitful insemination. Heifers raised by intensive technology have daily gains of more than 850 grams. It was established that under the same conditions of feeding and keeping, the heifers obtained from the bull of the Reflection Sovering line, weighing 398 kg at the first insemination, had an advantage, which is 8 kg more than the young animals obtained from the bull of the Vis Back Ideal line and the age of the first insemination was 417 days or 6 days earlier than from the second line bull Whis Back Idial.