Live Weight Of Heifers Research Articles

The use of targeted premixes in the feeding of replacement heifers

Making optimal conditions for feeding and housing of young animals ensures the correct and timely development of internal organs, including reproductive function, which has a positive impact on the realization of the high genetic potential of animals in adulthood. This can only be achieved by using balancing additives such as premixes developed on the basis of an actual analysis of feeding conditions. The purpose of this work was to study the feasibility of using premixes developed taking into account feeding characteristics (targeted) in the rations of replacement heifers up to 12 months of age. The experiment was carried out at the Staraya Chigla livestock complex of EkoNivaAgro-Severnoye LLC, geographically located in the Anninsky district of the Voronezh region from 2020 to 2023. The heifers were selected by using the analogue pair method and distributed into groups of 12 heads in each (control and experimental groups). It was established as a result of the studies that the use of a targeted premix contributed to the intensity of growth of young animals, which was confi rmed by an increase in the live weight of heifers by the end of the experiment by 5,04 %, an average daily gain by 5,74 %, and a relative gain by 1,91 %. Analysis of the reproductive function of heifers showed that the age of fi rst heat occurred 5,5 days earlier in animals of the experimental group, and the age of fi rst eff ective insemination was 18,09 days earlier. Fertility from the fi rst insemination was higher in heifers that were fed the targeted premix by 8,34 %. The insemination index was also better in the experimental group. Thus, the research has proven the feasibility of developing and using targeted premixes.

Dynamics of indicators of replacement heifers rearing under the conditions of an animal husbandry enterprise

One of the conditions for high productivity of cows is proper, balanced feeding during the rearing of replacement heifers. The purpose of the work was to study the dynamics of indicators of the rearing of replacement heifers under the conditions of an animal husbandry enterprise where Holstein cattle are bred. The results of the analysis of the indicators of the rearing of replacement heifers and their dynamics over 5 years of production activity of the farm breeding Holstein cattle have been presented in the article. It was established that the fi rst insemination of replacement heifers in 2021 was carried out at the age of 13 months with a live weight of 401 kg. The live weight of heifers was 69,7 % of the live weight of fi rst-calf heifers and 69,1 % of the live weight of mature cows, which corresponded to the norm. The live weight of the first-calf heifers during the analyzed period decreased from 580 kg in 2017 to 575 kg in 2021, i. e. by 5 kg or 0,9 %. The live weight of mature cows increased from 557 kg in 2017 to 680 kg in 2021, i. e. by 23 kg or 4,1 %. The live weight of all groups of animals met the minimum requirements for the Holstein breed. Thus, for 5 years of the production activity of the milk production enterprise, it was established that in the farm under study, the growth, development, and age of the fi rst insemination indicators corresponded to the standards for Holstein breed, which indicated a fairly high level of breeding work carried out by the specialists of the farm. An increase in the growth rate of young animals allows us to inseminate heifers at the age of 14–15 months, which reduces the age of the fi rst calving and increases the efficiency of the dairy cattle industry.

Effect of IGF-1 C472T, GH C2141G, and GHR T914A polymorphisms on growth performance and feed efficiency in young Kazakh white-headed cattle.

Improving the feed efficiency of beef cattle is necessary to increase the profitability of meat production. Implementing marker-assisted selection breeding systems can improve the genetic potential of beef cattle for increased productivity. This research aimed to study the effects of insulin-like growth factor (IGF)-1 C472T, growth hormone (GH) C2141G, and GH receptor (GHR) T914A polymorphisms on growth performance and feed efficiency in young Kazakh white-headed cattle. Young Kazakh white-headed cattle (n = 50) were grouped after weaning according to sex (28 bulls and 22 heifers) and they were genotyped according to the IGF-1 C472T, GH C2141G, and GHR T914A polymorphisms. The test period was conducted from 8 to 15 months of age. The experimental animals were evaluated for live weight (LW) at the beginning and end of the test period. They were also assessed for average daily gain, hip height, metabolic mid-weight (MMWT), actual dry matter intake (DMI), and residual feed intake (RFI). Significant differences in MMWT were found between the bulls with the IGF-1TT and IGF-1CT genotypes, which was a 2.2 kg increase in heterozygous cattle (p < 0.05). Heterozygous IGF-1CT bulls differed with a higher DMI of 0.087 kg/day (p < 0.05) compared to IGF-1TT homozygotes. Carriers of the IGF-1TT genotype had the greatest feed efficiency at 0.068 kg/day (p < 0.05). Heifers with the GHCC genotype differed in their maximum DMI with an increase of 1.17%-1.57% (p < 0.05) relative to the other genotypes. The G allele in the GH C2141G polymorphism was associated with better (p < 0.05) feed efficiency in the Kazakh white-headed breed. The minimum DMI and RFI in GHR T914A heterozygous heifers were significantly inferior (p < 0.05) to the other genotypes. Association studies of the IGF-1 C472T, GH C2141G, and GHR T914A polymorphisms indicate a relationship between growth, development, and feed efficiency with the genetic characteristics of young Kazakh white-headed cattle. A significant (p < 0.05) dominant effect was found in the IGF-1 gene in bulls and in the GHR gene in heifers, which should be considered when breeding with heterogeneous parental pairs. The negative effect of the allele substitution in the IGF-1 C472T polymorphism was observed in the LW of heifers (-3.25 kg) at the age of 8 months and bulls (-6.05 kg) at 15 months. The substitution in the GH C2141G polymorphism was associated with a significant reduction in DMI by 0.036 kg (p < 0.05) and an increase in feed efficiency by 0.023 kg (p < 0.05) during the rearing of heifers. These results can improve the production efficiency of mature herds of Kazakh white-headed cattle.

Age dynamics of growth of replacement heifers depending on origin from sire

For insemination of the breeding stock of dairy cattle the semen of sires of both domestic and foreign breeding is used. Due to the fact that the issues of herd reproduction have become one of the most important factors of progress in dairy cattle breeding, the rearing of replacement young animals is given great importance. The purpose of the research was to study the age dynamics of the growth of replacement heifers depending on origin from sire. It was found that the diff erence in live weight at calving between heifers from diff erent sires was insignifi cant and amounted to 1,4 kg or 4,7 %. The heifers from the sire Sayan had the highest live weight at the age of 18 months – 425,3 kg, the heifers from the sires Cassio and Mers were slightly inferior to them by 3,6 and 5,3 kg. According to the rearing periods the heifers grew unevenly. The uneven growth of heifers from diff erent sires, although it had a common pattern, but diff ered by groups. So, from 6 to 12 months of age, there was a decrease in absolute gain in all groups, but in the next period (12–15 months), there were features in the change in absolute gains. So, in heifers from the sire Das, the absolute gain remained at the same level, and in heifers from the sires Sayan, De-Su, Touareg, Cassio, it continued to decline, while in heifers from the sires Gavano, Marrs and Bentley it is increased. On average, over the entire rearing period, it ranged from 21,0 to 22,0 kg per month. Thus, the system of rearing of replacement heifers on the farm allows us to get good results. The age of the fi rst insemination of heifers, depending on the origin of the sires ranges from 14,0 to 15,9 months with eff ective insemination at the age of 14,8–16,9 months, which suggests the use of early terms of the fi rst insemination of heifers. The live weight of heifers at the fi rst insemination meets the requirements for cattle of Black-and-White breed, regardless of their origin from sire.

Features of growth and development of young cattle of Hereford breed of different origin

Relevance. In recent years, there has been a decrease in the total number of cattle of both meat and dairy production. In this regard, the study of the features of breeding of beef cattle is relevant. In the studies, the growth and development indicators of the young cattle of Hereford breed were studied, depending on their origin.Methods. The research was carried out in the conditions of a breeding reproducer of LLC "Chebomilk", Cheboksary district of the Chuvash Republic. The dynamics of growth and development were studied by monthly weighing of animals. In newborn calves at the age of 205 days, 6, 8, 9 and 12 months, and in heifers additionally at 15 and 18 months, the height in the sacrum was measured. Based on the data from the weighing results, the absolute and average daily increase was calculated.Results. It was found that the growth rate of heifers and calves on fattening is influenced by the genotype of the father. When comparing the average live weight of young animals at the age of 18 months, the best results were in bulls received from the bull Perets — 375.8 ± 17.5 kg, this is 3.8 kg more than the same indicator for bulls received from the bull Timeline and 7.8 kg more than the bull Emuleishn, and by the live weight of heifers at the age of 18 months the Timeline is leading — 352.6 ± 25.2 kg. Bulls and heifers — descendants of the bull Perets of the Mayer-Verne 88480 line are distinguished by the best growth rate. The average daily increase at 18 months of age in bulls was 931 ± 57.2 g, in heifers — 577 ± 54.1 g, which is higher than their peers by 1.2–12.2%. To improve the productive and breeding qualities of the Hereford breed, it is recommended to carry out targeted selection and selection of parental pairs.

Hybrids Performance Indicators of Black Pied and Holstein Cattle Breeds and Fertility Potential

The presented article discusses the issues of milk productivity in the 2nd lactation of Black Pied cows of different genotypes, their biological indicators in the basic and main comparison farms. Observations were made on the fertility of different groups of animals, the age of insemination of heifers, the live weight of heifers at insemination, as well as breeding criteria, reproductive longevity and lifelong fertility of cows.

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

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

The use of balancing additives in the rations of young small ruminants and cattle

The purpose of the research was to study the feasibility of using different balancing feed additives in the rations of young ruminants and cattle. In order to achieve this purpose, two scientific and farm experiments were conducted on the development and use of balancing additives in the rations of young ruminants and cattle. The first experiment was carried out in the Volgograd region on the herd of sheep of Volgograd breed in the IE FARM Kushkalova A. B., the second was carried out in in the Voronezh region on heifers of Holstein breed on the basis of the Korshevo livestock complex OOO EkoNivaAgro. In the first experiment the sheep of the control group were fed a general economic ration, the animals of the 1st experimental group were input with a mineral balancing feed additive instead of the mineral part of the ration recipe No. 1, the 2nd experimental group with the recipe No. 2 and the 3rd experimental group with the recipe No. 3. In the second experiment heifers from the 14th day of life received premix P-62–1 as part of the compound feed, the young cattle of the experimental group as part of the starter feed were replaced with premix P-62-1 with MegamixNoris. After 6 months, the animals of the control group received premix P-63-1 as part of the ration, and the heifers of experimental group received premix MegamixVitulaOpti. The inclusion of the mineral complex in the ration of sheep of the 1st, 2nd and 3rd experimental groups contributed to an increase in the digestibility coefficients. Thus, the digestibility of dry matter was higher than that of analogues from the control by 1,03; 0,59 and 0,21 abs.%, organic matter by 1,95; 1,80 and 1,59 abs.%, crude protein by 1,15; 0,97 and 0,84 abs.%, crude fiber by 1,09; 0,62 and 0,23 abs.%. The nitrogen digestibility in them was higher from the taken by 1,12, 0,79 and 0,63 abs.% and from the digested by 1,18, 0,73 and 0,61 abs.%. The young sheep of the experimental groups significantly exceeded the analogues from the control in live weight at the age of 8 months by 1,82–6,93 %. The input of the tested premixes into the ration of heifers allowed to increase the digestibility of dry matter by 1,29 abs.%, organic matter by 2,26 abs.%, crude protein by 2,54 abs.%, crude fat by 4,18 abs.%, crude fiber by 3,15 abs.%, nitrogen-free extractive substances by 4,16 abs.%. Nitrogen assimilation from the intake increased by 2,18 abs.%. At the same time, the live weight of heifers was increased by 10,37 % compared to analogues from the control group.

The intensity of the gain of live weight of heifers of Black-and-White breed and hybrids with zebu

The first factor in breeding highly productive herds, both in order and importance is the intensive rearing of replacement heifers. The widespread use of Holstein breed as the breeding resources in dairy cattle in Russia in order to improve the economically useful characteristics of cattle of different breeds leads to the leveling of genotypes and a decrease in the valuable qualities of domestic breeds, resistance to diseases, obtaining high-quality replacement young animals. Hybridization especially remote according to many scientists is the greatest factor of evolution and selection and so far the only reliable method of breeding hybrid organisms based on a combination of their useful traits A comparative characteristic of the intensity of the live weight gain of heifers of Black-and-White breed and in comparison with zebu-like hybrid herdmates has been presented in the article. It has been found that the intensity of the live weight gain of heifers obtained by crossbreeding with zebu-like hybrid sires was higher than that of heifers of the same age of Black-and-White breed from birth to 15 months of age. The average daily gain in live weight in zebu-like hybrid heifers from birth to 6 months of age averaged was 733 g, from birth to the age of 12 months it was 739 g and from birth to the age of first insemination it was 704 g. The live weight of hybrid heifers at the age of 15 months was 345,1 kg, which on average was more than that of heifers of the same age of Black-and-White breed. So, from birth to 6 months they were inferior to hybrid herdmates by 6,5 %, at the age of 12 months by 4,2 % and at the age of 15 months by 3,8 %. Thus, the use of zebu-like hybrid sires when crossbreeding with Black-andWhite cows has the positive effect on the intensity of the live weight gain of heifers, which must be taken into account in the breeding of animals in commercial farms.

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.

Влияние быков айрширской породы на хозяйственно полезные признаки дочерей

The purpose of the study was the influence of Ayrshire bulls on economically useful signs of daughters, which were carried out according to a sample of 1,446 first-calving cows from 58 bulls. On average, the cows in the sample were calved at the age of 27,3±0,1 months. With a live weight of 487±0,4 kg and milked for lactation 6409±33.4 kg of milk .The one-way analysis of variance (ANOVA) method the strength of the influence of breeding bulls was calculated, which strongly influenced the growth and development of proband in different periods of ontogenesis: height at withers (58,0 %), live weight at birth, at 10, 12, 18 months (from 49,0 to 51,9 %) and on the level of productivity of daughters (41,6 %), which is quite high. A high correlation between the live weight of heifers at birth, at 10, 12, 18 months with the height at the withers of cows after the first calving was revealed (+0,555; +0,487; +0,487; +0,509) and with milk yield for the first lactation (+0,591; +0,522; +0,550; +0,584), as well as the height at the withers with milk yield (+0,457). Therefore, the productivity of cows after the 1st lactation depends on their development in heifers. It was found that the descendants of breeding bulls who exceeded the average sample values for milk yield also had a large live weight at 10 and 12 months and height at the withers.

The effect of the genotype of servicing bulls on the growth and development of Hereford young stock

In the studies, the growth and development indicators of the Hereford young stock were studied, depending on the origin. The average daily growth of calf bulls aged 824±16.4 g, 8 months – 962.5±14.6 g, 9 months – 981.5±18.6 g, 12 months – 986.1±19.2 g. The height at hips of calf bulls aged 205 days was 109±11.7 cm, 8 months – 111±9.4 g, 9 months – 112±6.8 cm, 12 months – 124±7.9 cm. The average daily increase in heifers aged 205 days was 853.6±11.3 g, 8 months – 854.2±17.5 g, 9 months – 870.3±18.2 g, 12 months – 850±10.5 g, 15 months – 831.1±15.6 g, 18 months – 777.8±16.5 g. The height at hips of calves aged 205 days was 106±9.8 cm, 8 months – 109±7.8 g, 9 months – 110±11.1 cm, 12 months – 118±8.9 cm, 15 months – 121±10.9 cm, 18 months – 125±13.2 cm. It was found that the growth rate of calves and calf bulls on fattening is influenced by the father genotype. When comparing the average live weight of young stock at the age of 18 months, the best results were in calf bulls received from the bull Perets 3989 – 375.8±17.5 kg, this is 3.8 kg more than the same indicator for calf bulls received from the bull Timeline 2930348, and 7.8 kg more than the bull Emulation 2909514, and by the live weight of heifers at the age of 18 months the leader is the Timeline 2930348- 352.6±25.2 kg.

Features of the growth of repair heifers depending on the inbreeding degree

The Ural type of the domestic black-and-white breed is distinguished by high productivity indicators, good suitability for use in the conditions of industrial milk technology. To obtain modern dairy cattle, related breeds were used in the herds, a significant number of animals obtained as a result of closely related breeding were revealed. the study of the influence of the degree of inbreeding on the growth and development of repair young is relevant and has practical significance. It was found that the live weight of heifers in all accounting periods practically did not differ, that is, it can be said that the method of obtaining heifers using unrelated or related selection did not affect the dynamics of live weight during their cultivation. The average daily gains in live weight differed slightly by growth periods and by groups. So they were higher in the periods from the first to the first fruitful insemination and from 10 to 12 months, lower gains were noted in the period from the moment of fruitful insemination to 18 months of age. The highest milk yield for lactation was obtained from the first heifers with a remote degree of inbreeding.

Efficiency of application of fodder additive "Bibatsil dry" in the diets of agricultural animals and birds

The article presents the results of the effectiveness of the use of the feed additive "Bibatsil dry" in the diets of farm animals and poultry. It was found that feeding the probiotic "Bibacil dry" to dairy calves contributed to an increase in the absolute increase in live weight of heifers and bull calves in the experimental group by 1.3 kg, average daily gain by 2.8% compared to the control group. The use of the probiotic "Bibacil dry" with drinking water when feeding weaned pigs causes an increase in the average daily gain in live weight of 9.4% and an increase in the safety of the livestock by 5.5% in comparison with analogs from the control group. Consumption of the probiotic “Bibacil dry” in the composition of drinking water by laying hens of the “Brown Nick” cross showed an increase in the intensity of egg production by 2.6% and an increase in egg yield by 3.0%.

REPRODUCTIVE ABILITY OF FIRST-CALF COWS OF SIMMENTAL BREED IN ORGANIC AND CONVENTIONAL MILK PRODUCTION

The aim of the work was to study the influence of biological periods of reproduction of first-born cows of Simmental breed on their productive features of organic and conventional milk production.&#x0D; Research materials and methods. The research was carried out in the herds of Simmental breed PС "Halex-Agro" (organic milk production, n = 272) and LLC "Myroslavel-Agro" (conventional milk production, n = 120) Novograd-Volyn district of Zhytomyr region according to conventional methods.&#x0D; Research results. The article presents the results of research on the influence of the age of the first fertile insemination, age of first calving, the duration of service and dry periods of Simmental cows in their productive traits in organic and conventional milk production.&#x0D; The best indicators, regardless of the technology of milk production, were characterized by animals of the middle group, the age of the first fertile insemination of these animals in PE "Galex-Agro" ranged from 526 to 678 days, and in STOV "Miroslavel-Agro" – from 505 to 648 days. The value of this indicator within farms was 462.5 and 458.0 kg, respectively. Therefore, both early insemination and late insemination were not desirable for this herd, because with early insemination farmers don’t get enough milk and there is a high probability of giving birth to calves with lower live weight, while with late insemination there is an irrational overuse of investments in uncovered heifers. their future milk productivity.&#x0D; In the conditions of both farms there is a clear pattern that animals with an earlier age of the first fertile insemination are characterized by more intensive formation of live weight. Animals of the first and second experimental groups were statistically significantly superior to peers of the third experimental group in live weight at the age of 3 to 18 months in PE "Galex-Agro", and from 6 to 18 months in STOV "Myroslavel-Agro" (P &lt; 0.05–0.01). There is almost the same live weight of heifers at different ages in both farms, due to the common origin of the breeding stock imported from the Czech Republic.&#x0D; It has been established that with increasing age of the first calving milk productivity of cows increases. The highest yield for 305 days (6117.2 and 5937.6 kg) and all lactation (6920.9 and 6953.4 kg) were observed in cows whose age of first calving was 995 and older and 917 and older days in the conditions of PE "Galeks-Agro” and STOV “Myroslavel-Agro” respectively. The lowest yield for 305 days (5733.9 and 5863.0 kg) and all lactation (6528.2 and 6424.6 kg) were in cows with the age of the first calving 835 and less and 778 and less days in both farms, respectively.&#x0D; There was a statistically significant effect (P &lt; 0.01–0.001) of the duration of the service period in both farms on the duration of lactation of cows (58.6 and 63.9%), hopes (22.8 and 34.2%), as well as on the fat content in milk (2.2%) only in the conditions of PE "Galex-Agro". In the conditions of intensive management of the dairy industry in organic and conventional production, it is necessary to take into account the rate of reproduction of the herd, which is largely determined by the length of the service period. The service period is one of the key indicators that determines not only the reproduction of animals, but also their future milk productivity.&#x0D; Conclusions. According to the results of our own research, it was found that the extension of the service period leads to an increase in the duration of biological periods of reproduction and to a decrease in the coefficient of reproducibility (from 1.06 to 0.68; from 1.05 to 0.72), which is predictable. Statistically significant effect (P &lt; 0.001) of the value of the service period was found in the conditions of PE "Galex-Agro" and LLC "Miroslavel-Agro" on the duration of the interbody period (74.2 and 68.8%), the coefficient of reproducibility and 78.2), as well as the duration of the dry period (2.6%) and the age of the first calving (2.7%) only in the conditions of PE "Galex-Agro".&#x0D; When comparing animals with a shortened and optimal duration of the dry period, a statistically significant difference was found in the conditions of organic production in the duration of lactation (25.3 days), milk yield during lactation (673 kg) and 305 days (359 kg), milk fat (13.7), milk protein (13.4 kg), total milk fat and protein production (26.2 kg). In terms of conventional production, animals with a shorter dry period are characterized by longer lactation and higher milk yield.

EFFICIENCY OF ECONOMIC USE OF COWS DIFFERENT COUNTRIES AND HERD OF SELECTION

EFFICIENCY OF ECONOMIC USE OF COWS DIFFERENT COUNTRIES AND HERD OF SELECTION

CORRELATIVE VARIABILITY OF SELECTIVE TRAITS OF RED DAIRY CATTLE

CORRELATIVE VARIABILITY OF SELECTIVE TRAITS OF RED DAIRY CATTLE

ANALYSIS PEDIGREE OF LIVESTOCK OF POLISSIAN BEEF CATTLE BREED IN SFG «VERES»

ANALYSIS PEDIGREE OF LIVESTOCK OF POLISSIAN BEEF CATTLE BREED IN SFG «VERES»

Microbiological starter culture of probiotic action in the prevention and treatment of disbacteriosis in heifers and its effect on live weight gain

Scientists of the Bashkir Research Institute of Agriculture of the Ufa Federal Research Center of the Russian Academy of Sciences are conducting scientific research on the development of biotechnological methods for housing and feeding calves of the preweaning rearing period using probiotic drugs. The purpose of the research was to conduct scientific and economic tests of the universal microbiological starter culture of probiotic action Biolax-U for the prevention and treatment of dysbiosis in heifers and to determine its effect on the live weight gain of young animals. Experimental investigations have been conducted in two farms in the Republic of Bashkortostan, where two groups of heifers (control and experimental) of Black-and-White breed of the preweaning rearing period have been formed, selected according to the method of pairs of analogues, taking into account origin, age, live weight. The expediency of using the universal microbiological starter culture of probiotic action Biolax-U as a medicinal product in the diets of calves has been investigated. Feeding of the universal microbiological starter culture of probiotic action Biolax-U allowed us to increase the average daily gains in the live weight of young animals, to improve the functioning of the gastrointestinal tract. It has been found according to the results of control weighings of heifers that the live weight of heifers of the experimental groups was higher by the end of the experiment than the control herdmates in both experiments, and in the first experiment the difference was statistically significant at P &lt; 0,01. It has been found that the absolute gain in the live weight of animals of the experimental groups receiving Biolax-U exceeded the control herdmates in the first experiment by 8,3 kg or 10,0 %, in the second experiment by 7,6 kg or 9,9 % as the result of improving the digestive system, increasing the digestibility and availability of feed in the diet. The heifers of the experimental groups in both experiments had an advantage in terms of average daily gain. For example, in the first experiment this advantage was 93 g/day or 10,0 %, in the second experiment it was 84,4 g/day or 9,9 %.

Peculiriaties of Growing Breeding Replacement Young Animals on the Farms of Ayrshire and Black Pied Cattle

The high genetic potential of productivity and a similar level of animal feeding underlie the intensive technology of rearing young animals for dairy cattle breeding. The realization of the genetic potential of dairy productivity of livestock largely depends on the efficiency of rearing young animals. Therefore, proper feeding of livestock is one of the main factors contributing to the maximum realization of this potential of animals. The conducted studies have shown that the breeding plants of the studied region successfully solve the issues of intensive cultivation of repair young animals. The increase in live weight of heifers allows for the first insemination at 16–17 months with the corresponding live weight. However, in the whole region, the data on the growth and development of heifers are significantly inferior to the indicators of breeding plants and the first insemination is carried out at 19 months and older. As a result of the conducted research, a plan for the growth of repair young animals was developed and the average daily live weight gains for the growing periods were recommended. The demand of reared young cattle for metabolic energy and crude protein is calculated.