First-calf Cows Research Articles

The influence of controlled changing factors on the reproductive ability of the firstcalf cows of the sychevskaya breed

The reproductive capacity of livestock can be increased by breeding. The influence of controlled changing factors on the reproductive ability of the Cows of the first calving the Sychevskaya breed was studied, taking into account the inbreeding coefficient in order to improve the breeding process. In breeding work with animals, two methods of crossing are used: outbreeding and inbreeding. A measure of the genetic consequences of inbreeding is the inbreeding coefficient. The studied number of first-calf cows was grouped into groups according to the inbreeding coefficient. Calculated by the intergroups and intragroups differences, the strength of influence and reliability in the cows of first calving the method of variance analysis. The average age of the first calving in inbred cows was 30 months, overestimated in animals with a coefficient of 12.5 and higher. The effectiveness of the multiplicity of inseminations in groups by the first lactation is excellent (1.4-1.5) and good with close inbreeding (1.7). In first-born heifers with an inbreeding coefficient of 0.1-0.59%, the average duration of the period between the calvings is 10 and 9 days less than in animals with moderate, close and closely related breeding. The fertility index of the first heifers of the groups is average, except for animals with close inbreeding. The results of the analysis of variance in breeding work with factors are statistically significant, but have unequal alternative variability. For further breeding work, taking into account the reproductive ability of animals, it is necessary to conduct inbred selection in moderate degrees. It is also necessary to take into account the reliable influence of controlled factors: such as the age of the first calving, the multiplicity of insemination, the fertility index, which allow increasing the efficiency of selection work.

Effect of leptin C528T and leptin C73T polymorphisms and pregnancy on adipose tissue formation and carcass grade in Aberdeen Angus heifers and first-calf cows.

Background and Aim:The leptin (LEP) gene plays a role in the regulation of the activity required to obtain food, energy metabolism, and fat deposition and affects the body composition of animals. Lipogenesis is an ineffective process. A lot of energy from feed is expended on the synthesis of adipose tissue. This study aimed to determine the effect of LEP C528T and LEP C73T polymorphisms and pregnancy on adipose tissue formation and carcass grade in Aberdeen Angus heifers and first-calf cows.Materials and Methods:Heifers (n = 49) and first-calf cows (n = 30) were grouped according to their genotype for LEP C528T and LEP C73T polymorphisms at the age of 24 months. DNA samples were isolated from whole blood. Experimental animals were slaughtered at the age of 24 months, and a chemical analysis of samples of longissimus dorsi muscle and ground beef was performed.Results:The maximum internal fat weight, back-fat thickness, and fat content of the longissimus dorsi muscle and ground beef were determined in heifers heterozygous for both LEP C528T and LEP C73T polymorphisms. The ranking of genotypes in terms of adipose tissue formation did not change in first-calf cows compared to heifers carrying the same LEP gene variants. Pregnancy had a more significant (p < 0.05–0.001) effect on slaughter parameters and lipogenesis in animals of different genotypes than studied polymorphisms. Heterozygosity of the LEP gene was much more strongly expressed in the carcass grade of heifers. ”Prime” grades were assigned to 66.7% of carcasses heterozygous for LEP C528T and “Top Choice” to 58.8% of carcasses with LEP C73T nucleotide substitutions.Conclusion:LEP C528T and LEP C73T polymorphisms were shown to affect the extent of fat formation in Aberdeen Angus heifers and first-calf cows. Animals with heterozygous genotypes exhibited the maximum development of internal fat, back-fat, and intramuscular fat. Pregnancy had a more significant effect on slaughter parameters and adipose tissue formation than studied polymorphisms. First-calf cows had a significantly lower fat content in carcasses than heifers. These results can aid in the production of efficient mature herds of Aberdeen Angus cattle.

Technological approaches in the production of soft cheeses using the milk of cows of the red-mottled breed of the Voronezh type of organic production

The main task of dairy cattle breeding is to increase the productivity of cows, which is closely related to the characteristics of processed raw materials and the expansion of the range of produced cheeses. The aim of the study is to study the influence of the genetic potential of the red-mottled cattle breed on the technological properties and cheese suitability of milk. The results of studies on the effect of the enzyme – probiotic additive "Rumifit" – on the chemical composition and amino acid balance of the milk of the red-mottled breed of cows of the Voronezh type are presented. The production of soft cheeses was from three groups of animals. The 1st group (control) received a standard feed ration, accepted in the conditions of LLC "Bolshevik". The 2nd group of animals received the enzyme-probiotic drug "Rumifit" in a dosage of 80 cm3 per animal head; the 3rd group of animals received the probiotic drug "Rumifit" in a dosage of 60 cm3 per animal head. The prospects of obtaining soft cheeses of a combined composition by including a protein concentrate of masha beans in a normalized mixture to increase their nutritional value are shown. The effect of the dosage of the mash bean concentrate on the duration of milk coagulation at different temperatures has been studied. A comparative assessment of the organoleptic and physico– chemical parameters of the obtained cheeses is presented. The conducted studies have shown that a sample of soft cheese obtained from the milk of first-calf cows receiving the enzyme-probiotic "Rumifit" in the diet at a dosage of 80 cm3 per head for 10 days with a cycle after 21 days during the entire lactation period had high organoleptic characteristics and increased nutritional value. This determines the ways of using this milk in cheese making.

Morphological and functional traits and main disadvantages of the udder in cows of Black-and-White breed

The object of research was the first-calf cows of Black-and-White breed. The groups were formed taking into account the part of blood of Holstein breed. The 1st group included animals with the part of blood than 50 % (an average of 37 % in the group), the 2nd with the part of blood of 50 % and the 3rd more than 50 % (an average of 63 % in the group). An increase in the part of blood in animals in the farm to 63 % had a positive effect on changing the shape of the udder. Thus, in the group of low the part of blood animals there were 78,2 % of cows with a cup-shaped shape and 21,8 % with a rounded one. Among half-blood cows with the cup-shaped udder accounted for 92,2 %, and with the rounded one it was 7,8 %, among the high part of blood it was 94,8 and 5,2 %%, respectively. In terms of udder length and depth measurements, cows with the high part of blood outperformed cows with the low part of blood by 2,5 cm (р &lt; 0,01) and 2,1 cm (р &lt; 0,01), respectively. In terms of udder decline, the difference between these groups of animals was 5,7 abs.% (р &lt; 0,01) in favor of animals with the higher proportion of Holstein breed blood. First-calf cows with half part of blood and the high part of blood of Holstein breed were ahead of their herd mates with the low part of blood in terms of the rate of milk speed out the difference was 0,3 kg/min (р &lt; 0,05) and 0,4 kg/min (р &lt; 0,001), respectively. The most common udder defect (10 %)was narrow rear teats, while in the group with the high part of blood cows its occurrence was the lowest 6,7 %. The sum of the frequencies of udder defects in cows with the high part of blood was 16,7 % versus 23,3 % in the other two groups. We recommend to use purebred Holstein sires for mating with low-blood heifers and cows, and using sires with the part of blood of Holstein breed of 62 to 75 % or breeding “inter se” on heifers and cows with the higher proportion of blood of Holstein breed.

Productivity of cows of Black-and-White breed in association with the technology of their housing

The research of the influence of the method of housing cows on productivity, reproductive ability and productive longevity is relevant. The purpose of the research was to determine the influence of technological factors on productivity, reproductive ability, and longevity of productive use of cows in the Tver region. The research has been carried out on the basis of the breeding farm of ZAO Kalininskoye in the Tver region. In order to conduct the experiment two groups of cows were formed, depending on the method of housing. Animals in the 1st group were free-stall housing; the 2nd group of cows were in tie up housing. The feeding conditions of the experimental animals were the same. The productivity of cows after the first lactation in the 2nd group (tie up housing) exceeded the productivity of cows in the 1st group (free-stall housing). The difference in milk yields was 345 kg (P ≤ 0,01) of milk for 305 days of the first lactation with a slight difference in the mass fraction of fat and protein. The shortest duration of the period of open days with the free-stall housing was established for both first-calf heifers (123 days) and cows of the second calving (101 days) than for herdmates with the tie up housing for 16 and 27 days. The multiplicity of insemination with tie up housing was higher depending on the age, the difference was 0,42 and 0,26 units in favor of the free-stall housing. The lifetime milk yield of cows with tie up housing was 6847 kg of milk or 29,9 % higher than free-stall housing, and their average milk yield with basic fat content (3,4 %) exceeded analogues by 853 kg of milk or 10,6 %, respectively. Calculations indicate that the prim-cost of 1 centner of milk from cows with tie up housing was lower by 165,6 rubles or 10,6 %, and the profit from its sale per 1 cow was higher than the free-stall housing by 24,6 thousand rubles. The evaluation of the conducted studies fully reflects the economic feasibility of further use of the tie up housing method of cows.

Milk productivity of first-calf cows depending on the intensity of their breeding

The paper presents the results of studies of milk productivity of black-and-white cows depending on the age of the first insemination and live weight at the first calving in the conditions of the Irkutsk region. The dynamics of heifer rearing by year, milk productivity of cows in the 1st and 3rd lactations depending on the intensity of their development has been studied. The experiment was conducted on farm materials from the Irkutsk Region using generally accepted zootechnical, analytical, variation and statistical research methods from 2016 to 2020. Live weight of heifers at all ages met the requirements of the elite and elite-record classes. Analysis of the data showed that the growth rate of the animals increased during 5 years (6.0%, 6.8, 2.3 and 4.8% respectively with a significant difference p ≥ 0.90). With the increased intensity of heifer rearing, an increase in milk yield over 305 days of the first lactation was observed. The highest milk production was noted in the 1st (5309-5476 kg) and 3rd (5418-5817 kg) lactations in cows with the first fruitful insemination at 13-14 months. The lowest 1st and 3rd lactation yields are obtained from cows inseminated at 20 months of age or older. Higher milk production in the first and third lactations was obtained from cows with a live weight at first calving of 541-550 kg, 551 kg and higher (5197-5164, 5436-5545 kg respectively). Less milk production was obtained from cows with a live weight at first calving of up to 500 kg (4567-5122, 4943-5009 kg). The results obtained make it possible to reveal the influence of the intensity of rearing heifers on the productive qualities of cows.

Молочная продуктивность коров с разными формами наследования удоя и жирномолочности

In the course of the research conducted at Agro-Soyuz LLC (Kabardino-Balkarian Republic, Chegemsky district), the goal was to study the productivity of 69 first-calf cows of the Gomitinsky black-andwhite breed, the daughters of three breeding bulls, depending on the forms of inheritance or the leading breeding characteristics of dairy productivity (milk yield, fat content), for the definitions of which were used by a new methodology, which is a modified version of the methodology widely used in breeding work with dairy cattle.As a result of determining the forms of inheritance of milk yield in experimental first-calf cows, it was found that the largest share among them fell on animals with milk yield due to such a form of inheritance as regression of the mother (44.9%), the smallest share – on first-calf cows with milk yield due to the dominance of the father (7.3%). When determining the forms of inheritance of fat milk, the same trend was observed as when determining the forms of inheritance of milk yield, that is, among 659 first-heifer cows, the most animals were from the mother regression group (42%), and the least were animals from the father dominance group (4,4%). The established difference between groups of first-calf cows with different forms of inheritance of the breeding trait turned out to be quite significant and reached, in some cases, 2368 kg in milk yield per lactation (p&gt;0,999), 0,32% in fat content (p&gt;0,99).

Biological characteristics of Russian black pied cattle

The biological characteristics of farm animals depend on their species and breed differences, but at the same time they are subject to certain variability due to individual heredity. In this regard, from the number of first-calf cows (daughters of different bulls) eight groups of the same age cows were organized and examined. In addition, a group of 65 animals was formed to assess the exterior by the method of random sampling without taking into account their heredity. The current research is aimed to evaluate the first-calf cows in the following options: milk productivity, functional properties of the udder, body type and the main disadvantages of the exterior. As a result of the analysis, Alta Genetics cows showed the best milk productivity among other breeds. The cows of Alta Gost and Alta Samuari breeds turned out to have the best indicators for a number of economically useful traits. The AltaGost cows were characterized by the best milk yield. When assessing the exterior features and constitution, it was found that the greatest number of conformation defects is associated with the limbs: close hocks (35%); wide interdigital cleft (71%); narrow hoof (22%). Nevertheless, a visual assessment of a complex of features allows to refer all the examined cows to a good body type.

PRODUCTIVE AND ECONOMIC INDICATORS OF FIRST-CALF COWS DURING THE TRANSITION TO LOOSE KEEPING

PRODUCTIVE AND ECONOMIC INDICATORS OF FIRST-CALF COWS DURING THE TRANSITION TO LOOSE KEEPING

Некоторые идеи по менеджменту и регулированию состояния коров в материнском стаде в предотельный период

Cow management and feeding during pre-and post-calving periods is one of the factors of the economic effi-ciency of animal husbandry. There are various methods of feeding lactating cows but at the same time this topic is understudied in Germany. The experiment is based on long-term data on the birth rate and weight of calves at the Eden agricultural enterprise (Saxony-Anhalt, Germany) which was chosen as the main one for the study. The av-erage live weight of calves obtained from first-calf cows was 52 ± 8 kg at birth. The data on the live weight of calves obtained from cows of the first, second, and third lactations are presented. The differences in the live weight of calves revealed immediately after birth. Estimative de-scription of the condition of lactating cows is given. The dependence of the feeding of cows on the quality of the feed material, the content of protein and dry matter is shown. On average, the diet consisted of 99% of forages and had dry matter content of 38 ±6%. The average ener-gy content was 9.8 MJ ME or 5.9 MJ NEL per kilogram of dry matter. Various diets for dry cows were also studied. During the experiment, only the proportions of straw in the diet were changed so that practical conclusions could be drawn. In total, 3 variants were used: TMR with 30% of straw [TMR 1], TMR with 60% of straw [TMR 2] and feed-ing with silage from pure grass after calving. Brief recom-mendations are proposed in the conclusion.

Генетическая изменчивость показателей продуктивности и оценки экстерьера голштинских коров в зависимости от типа телосложения

Abstract. The aim of the research is to study the selection and genetic parameters of the characteristics of productivity and the exterior of Holstein first-calf cows, depending on their body type. Research methods. Based on the data from the SELEX database, we researched the performance indicators and measurements of the trunk of first calving cows in the amount of 4049 heads. Based on the RENUMF90 software shell of the BLUPF90 program, we obtained digital values of the genetic variability of productivity indicators and the external structure of animals in accordance with the equation of the mixed model. Results. The most broad-bodied animals classified as airysomal type had the highest milk yield in the first lactation, and exceeded animals of the leptosomal type by 563.3 kg (p ≤ 0.001). According to the "B" system, broad-bodied cows are superior to narrow-bodied animals: stature – by 1 point (p ≤ 0.001); body depth – by 0.8 points (p ≤ 0.01); rump width – by 1.9 points (p ≤ 0.001); rump angle – by 0.9 points (p ≤ 0.01); fore udder attachment – by 1 point (p ≤ 0.01). Animals of the narrow-bodied type reliably (p ≤ 0.001) had a high genetic relationship between milk yield in 305 days of first lactation and the mass fraction of protein in milk (0.59 ± 0.005). At the same time, the leptosomal type of cows also had the greatest correlation between milk yield and mass fraction of fat (0.51 ± 0.005) (p ≤ 0.001). According to body measurements, the highest correlation coefficients were found in animals of the airysomal type – 0.24 ... 0.50. All Holstein heifers of different body types have high heritability coefficients in terms of fat mass fraction (h2 = 0.37 ... 0.49) and protein mass fraction (h2 = 0.42 ... 0.51). Scientific novelty. For the first time, studies of the genetic variability of productivity indicators and the exterior of Holstein cows, depending on their body type, were conducted.

Heat synchronization and the effectiveness of insemination of cows of Holstein breed under the conditions of the dairy complex

The food security of country is largely determined by the development of animal husbandry branches. Dairy cattle breeding is of particular importance, which has been actively developing in recent years due to the modernization of farms and complexes, the introduction of innovative technologies and the formation of a highly productive breeding herd. The most important link in the development of dairy cattle breeding is the reproduction of the herd. Modern technologies make it possible to use hormonal drugs in order to optimize the reproductive traits of animals. The results of clinical and experimental studies have shown the important role of hormones in the regulation of physiological functions, as well as the possibility of their use for directed changes in metabolism, productivity and fertility of animals. The purpose of the research was to assess the influence of methods of synchronization of heat of cows on the pregnancy rate under the conditions of the dairy complex. The research data on the effectiveness of insemination when identifying animals in visually heat and using Heatime neck strips, as well as when using heat synchronization programs such as Presynch and Double Ovsynch have been presented in the article. The research has been carried out under the conditions of a modern dairy complex on a highly productive herd of cows of Holstein breed. Differences in the effectiveness of insemination by using the studied methods were revealed from 49,1 to 72,5 %. The highest conception rate has been observed in first-calf heifers (83,0 %) and cows (62,5 %) inseminated using the Double Ovsynch protocol. The dependence of the level of conception rate on the presence of diseases suffered by cows during the newcalving period and until the moment of insemination has been noted. In sick animals, the conception rate for groups of first-calf heifers and cows was significantly lower than in healthy animals. Thus, according to the Double Ovsynch insemination protocol, the conception rate in healthy animals was 83,7 %, and in those who were ill – 65,2 %. The research results confi rmed the validity of stopping the use of the Presynch protocol and completely transferring the dairy herd of cows to synchronization and insemination using the Double Ovsynch protocol.

ЭКСТЕРЬЕРНО-КОНСТИТУЦИОНАЛЬНЫЕ ОСОБЕННОСТИ КОРОВ - ПЕРВОТЕЛОК ЧЕРНО-ПЕСТРОГО СКОТА ПРИ РАЗНЫХ СОЧЕТАНИЯХ ПОДБОРА

The development of dairy cattle breeding largely depends on the culture of young cattle breeding. It is very difficult to obtain and preserve young animals. Correct rearing of young cattle of dairy breeds contributes to the appropriate exhibition of genetically inherent productive abilities of animals during the first stage of their growth and development. When organizing breeding and feeding, animal growth and development characteristics are taken into account, which are determined by heredity and environmental conditions, especially feeding. The article provides a comparative analysis of the dynamics of live weight, measurements and body indexes of first-calf heifers of various selection combinations. First-calf heifers of the fifth experimental group, obtained from fathers and mothers belonging to the cross lines, exceeded animals in the control group, whose parents belonged to pure lines, in live weight and gains. Under the same housing and feeding conditions, the heifers of the studied groups did not grow in the same way, and certain differences were revealed in the process of ontogenesis. The first-calf heifers of the 5th group had the greatest live weight in different age periods and exceeded the peers of the 1st, 3rd and 4th groups from 10 to 23 kg with relevant difference. The animals of the 5th experimental group had the highest average daily gains till 6 months old. For the entire growing period (18 months), the animals in the control group had the highest relative gain, which was significantly higher than the gain in the experimental groups. The following body indexes were calculated: long-legged, elongation, pelvic-thoracic, thoracic; blockiness and bone index, as well as milk production coefficient which determined the direction of productivity of animals. First-calf cows were included into dairy-meat productivity direction according to the long-legged and elongated index. According to blockiness and thoracic index, animals of all groups belong to dairy direction of productivity, and according to bone index, to meat direction.

INDICATORS OF WEIGHT GAIN OF FIRST-CALF COWS OF BLACK-AND-WHITE, HOLSTEIN BREEDS OF DIFFERENT SELECTION AND THEIR FIRST-GENERATION CROSSBREEDS

The article presents the indicators of live weight, growth and relative growth rate of cows of the&#x0D; first heifers of the black-and-white breed, peers of the Holstein breed of German selection, holsteins of&#x0D; Dutch selection, crossbreeds of ½ holsteins of German selection x ½ black-and-white, crossbreeds of ½&#x0D; holsteins of Dutch selection x ½ black-and-white. It was found that due to the effect of crossing,&#x0D; crossbred Holstein animals of groups IV and V outperformed purebred peers of the black-and-white breed&#x0D; of group I in live weight at the beginning of the experiment by 29.67 kg (6.29%, P&lt;0.01). It is&#x0D; characteristic that the first heifers of the Holstein breed of the Dutch selection of group III, being inferior&#x0D; in live weight at the beginning of the experiment to the peers of the Holstein breed of the German&#x0D; selection of group II, surpassed the purebred animals of the black-and-white breed of group I in their level&#x0D; by 36.33 kg (7.71 %, P&lt;0.05). The obtained data and their analysis indicate that the rank of distribution of&#x0D; the first-calf cows of the experimental groups by live weight, established at the beginning of the&#x0D; experiment, was also noted at the end of the study. The data obtained on the intergroup differences in live&#x0D; weight at the end of the experiment are largely due, along with its different level at the beginning of the&#x0D; experiment, to the unequal value of its absolute increase during the observation period. At the same time,&#x0D; the leading position in terms of the gross increase in live weight was occupied by the first-calf cows of the&#x0D; Holstein breed of the German selection of group II.

Reproductive qualities of dairy cows at different levels of milk yield

The article presents the results of the analysis of the reproductive ability of cows depending on the level of their milk productivity. The studies were conducted in the Republic of Mari El on cows of the Holstein black-and-white breed (n = 3828). There have been studied the influence of different levels of milk yield on the duration of the service period and period between calvings, the output of calves per 100 cows, the coefficient of reproductive ability. The studies used the comparison method, correlation, regression and one-factor analysis of variance. It has been established that the milk yield increases with the age of cows, but at the same time the duration of the service period and calving interval increases. In first-calf cows, the service period was 128.8 days (Cv = 75.1 %), the calving interval was 403.6 days (Cv = 23.5 %). By the third lactation, with an increase in milk yield by 1030 kg (15.4 %), the duration of the service period increased by 7.2 days (5.6 %), the calving interval -by 12.3 days (3.0 %). The share of the impact (ƞ2x) of milk yield on the duration of the service period was 5.4 %, the calving interval -4.7 %. The correlation coefficients between milk yield for 305 days of the first lactation and the duration of the service period and calving interval were 0.24 and 0.22 (p&lt;0.05), with milk yield for the entire lactation 0.81 (p&lt;0.05). The optimal indicators of the service period (89.4 days), the calving interval (369.4 days), the reproductive capacity (0.94) and the output of calves (1.0) were possessed by the first heifers with low milk productivity-milk yield less than 5000 kg of milk. In animals with the milk yield of 6000-9000 kg of milk or more, the duration of the service period was 12.4-249.6 % higher, the calving interval -by 1.9-32.5 % (p&lt;0.05). According to the regression coefficients, on average, each increase in milk yield per 1000 kg increased the duration of the service period by 25.9 days, the calving interval -by 23.1 days, which worsened the output of calves by 0.24 %, and the coefficient of reproductive ability decreased by 16.0 %.

Biochemical Blood Parameters and Mineral Metabolism in the Adaptive Period in the Bovine Cattle in the Conditions of the Voronezh Region

The study of the process of adaptation of the Belgian breed bovine cattle to the conditions of the Voronezh Region was based on the biochemical blood parameters and mineral metabolism. The experiment included 20 animals divided into four groups (five heads in each group): Group I – covering age heifers, Group II – heifers, Group III – first-calf cows a month after calving, Group IV – one-month-old heifers. In some groups, adaptation processes resulted in deviations from the reference values. In Group II, the level of BUN was 4.7% higher than the norm. In Groups I and IV, the levels of glucose were higher by 7.6% and 38.5%, respectively. In Groups II and III, ALT levels were higher than the norm by 9.1%; in Group I – by 15.7%. In Group II, the level of AST was higher by 5.8% in comparison with the norm. The analysis of mineral metabolism showed that the content of iron was lower than the reference values in first-calf cows in Group III and in heifers in Group IV by 14.4 and 10.8%, respectively. In Group II, the content of copper met the upper border of the reference values. In Group IV, it was elevated by 18.2% in comparison with the norm. The specified deviations indicated the intensification of the metabolic processes during the adaptation of animals to new conditions. The study results showed that the animals of the Belgian breed were capable of adaptation, which provided successful adaptation to new conditions of the Voronezh Region (Russia).

Результаты оценки племенной ценности линий при помощи методов сравнения со сверстницами и BLUP на поголовье крупного рогатого скота Мурманской области

Abstract. The aim of the study is to compare two methods for assessing the breeding value of cows (comparison with peers and BLUP) during the analyzing process of the influence of lines on milk production. It is necessary to identify the most accurate and objective method for further use in the system for assessing of genealogical groups by a set of characteristics. Methods. We used one- and two-way analysis of variance. Comparative analysis of breeding values for milk production of genealogical groups (lines) using the methods of comparison with peers and BLUP. The ranking of genealogical groups by the results of assessing of breeding value and the calculating of the Spearman’s rank correlation coefficient were made. Results. According to the results of the analysis of variance, the strength of the influence of the environmental factor “year and season” on the milk productivity of first-calf cows was +0.62 of the total variance (P &lt; 0.01). Hereditary factors were assessed by the method of two-way analysis of variance of an uneven complex. The strength of the influence of the lines on the milk productivity of first-calf cows was 0.011 of the total variance (P &lt; 0.05). The use of the method of comparison with peers, the dependence on a sufficient number of representatives of the genealogical group was revealed. BLUP analysis of lines changed their ranking. The number of animals in the studied groups does not affect the distribution of ranks with this method of assessment. The rank correlation between BLUP and peer comparison methods was 0.65. It has been established that the BLUP assessment is currently the most objective and takes into account the bias of the assessment under the influence of an insufficient number of animals. The novelty of the study is the first time the use of the BLUP method was tested on the livestock population in the Murmansk region to assess the breeding value based on the milk productivity of the lines.

ВНУТРИЛИНЕЙНЫЙ ПОДБОР И КРОСС ЛИНИЙ ПРИ СОЗДАНИИ ВЫСОКОПРОДУКТИВНЫХ СТАДА МОЛОЧНОГО СКОТА

The aim of the research was to evaluate the compatibility of lines and improve on this basis the traditional selection methods for creating breeding herds in dairy cattle breeding. The results of the analysis showed that the best milk yield among the other lines were the first-born heifers (n=39) of the Holstein line Vis Back Idial (6441 kg of milk). The analysis of the results of the intra-linear selection showed that the best milk yield was also distinguished by the first-born heifers of the Vis Back Idial line – 6721 kg of milk. Analyzing the cross-line of the Vis Back Idial with other lines of the Holstein breed (MCH, RS, and PG), it should be noted that they are superior to their first-calf peers by 253-530 kg of milk. The first-calf cows, derived from the cross of the Montwick Miftaine line and the Reflection Sovering and Pabst Governer lines, also have some superiority over their peers. Thus, when improving breeding herds of dairy cattle, it is necessary to use both intra-linear selection and cross-lines, taking into account their compatibility.

СПОСОБ ОТБОРА КОРОВ ТЕХНОЛОГИЧЕСКОГО ТИПА ДЛЯ РОБОТИЗИРОВАННОГО ДОЕНИЯ

The technological properties of the udder of cows have been studied under the conditions of using a robotic milking system. The research material was Holstein cows in the peasant (farm) economy of the Republic of Tatarstan, serviced by "Astronaut A4" robotic milking from "Lely Industries N.V.". A method for selecting cows for robotic milking has been developed. At the same time, in the herd, first, cows of the 1st lactation at 2-4 months of lactation are assessed according to the duration of milking and animals with duration of milking from 3 to 6 minutes are selected. Then, cows are selected from this group, whose lactation intensity indicator at 2-4 months of lactation exceeds the average value of this group by 0.5 sigma (M + 0.5σ), where M – the arithmetic mean of the indicator; σ – the standard deviation of the indicator. The proposed selection method makes it possible to form a breeding core and increase the milk yield in 305 days of lactation in the group of first-calf cows by 9.5 % (P˂0.01), daily milk yield – 14.4 % (P˂0.001), the milk flow rate – 33 % (P ˂ 0.001) and reduce the duration of cows' stay in the boxing by 17.5 %, the duration of milking cows – 21.7 %. When using this method, the efficiency of using robotic technology for milk production is increased.

ЛАКТАЦИОННАЯ ДЕЯТЕЛЬНОСТЬ КОРОВ-ПЕРВОТЕЛОК В УСЛОВИЯХ РОБОТИЗИРОВАННОГО ДОЕНИЯ

Studies have been conducted to assess the lactation productivity of Kholmogory breed Tatarstan type first-calf cows with robotic milking systems. The frequency of milking distribution during the day was observed: in the interval of 4-6 hours, the minimum number of milking occurs (6.4 %), in the interval of 12-14 hours, the maximum number (10.7 %). Most milking (34.7 %) is carried out in 6-8 hours after the previous one. More frequent milking (after 4-6 hours) is rarely observed is in 6 % of cases. 48.6 % of milking occurs after the 8-12 hour interval. For an interval of more than 12 hours occurs for 10.7 % of milking. With an increase in the milking interval, the milk yield also increases. At 4-6 hour interval, the milk yield is 5.2 kg, at 6-8 hour is 6.0 kg. An increase in the milking interval by 2 hours is accompanied by an increase in the single milk yield by 0.8-1.3 kg. During the first month, the cows were milked the least number of times, which was 75, or 2.4 times per day; during the second month, they were milked 86 times (2.8 per day). By the 4th month, milkings reached a peak of 93 times (3 per day). By the 5th month, a decline was observed (by 11 % compared to the 4th month). The peak milk production takes place during the second month of lactation, 681.3 kg. By the third month, a decline was observed by 4.8 %, to 648.1 kg. The maximum decrease in milk production, by 12.4 %, occurred between the 5th and 6th month of the tested lactation period.