scholarly journals THE GROWTH AND REPRODUCTIVE ABILITY OF HEIFERS AND FIRST-CALF COWS UKRAINIAN RED AND BLACK-SPOTTED DAIRY BREEDS IN THE CONDITIONS OF THE CENTRAL REGION OF UKRAINE

2021 ◽  
Vol 61 ◽  
pp. 201-206
Author(s):  
G. D. Ilyashenko

Introduction. The significant and long-term increasing of milk yield is possible only with proper organization of heifer breeding. Therefore, now is important to study the ontogenetic patterns of living mass formation. It is known, that between the growth rate of heifers and their future milk productivity exists correlation. The young age’s animals, which have a high growth energy, in the first lactation give 5000–6000 kg of milk. The force of influence of the live weight the heifers on variability of milk productivity, in depending on the age and lactation, is concluded 8.21–42.87%. The aim of our research was to study the dynamics of live weight, reproductive capacity and the level of their interconnection of heifers and first-born cows of Ukrainian Red and Black-and-White dairy breeds. Materials and methods of research. The research was carried out on first-born, heifers of Ukrainian Red (UR) and Black-and-White dairy breeds (UBS) in SE «SH «Elitne» ISА NAAS». Groups of animals (n = 15) were formed for research by the method of analog pairs. Growth indicators were studied: live weight at 3-, 6-, 9-, 12- and 15-month-old age, at the first insemination. Reproductive ability was studied: age of the first insemination and calving, duration of pregnancy of heifers and first-born, duration of service and intercorporeal periods. Along with the main studied indicators, auxiliary indicators were calculated: reproductive capacity, fertility index and possible yield of calves per 100 cows. The biometric processing of the obtained data was carried out according to the method of N. A. Plokhinsky, using Microsoft Excel software. Research results. The studies of ontogenetic patterns in formation the live weight of repair heifers in controlled herds demonstrated a fairly high level of their cultivation. However, it was found that the growth rate of live weight of heifers in the studied breeds at different ages was different. Thus, at the age of six months, the animals of the Ukrainian Black-and-White dairy breed significantly outnumbered the analogues of the Ukrainian Red dairy breed. The interbreed difference in this period by live weight was 5.0 ± 1.70 kg (P < 0.01). At 9, 12, and 15 months their weight gaining was 15.0 ± 3.42 kg, respectively; 26.0 ± 4.08 kg; and 29.0 ± 6.48 kg, at P < 0.001. In general, during the growing period, the absolute increasing in live weight of UBS heifers by 7.0% exceeded that of UR heifers. At the same time, heifers of the Ukrainian Black-and-White dairy breed were more precocious and had the age of the first insemination, which was 14.5 months at a live weight of 400 kg, while the peers of the Ukrainian Red dairy breed were 15.4 months and 402 kg. Characterizing the coefficient of variation of live weight of heifers, we should note the tendency to decrease with age in both breeds. Thus, the level in the for Ukrainian Red reached 11.6% in three months, for Ukrainian Black-and-White – 15.0%, at the age of 15 months respectively 8.9% and 8.4%. It was established the significant coefficients of recurrence of live weight of heifers during the year with such at 9, 12 and 15 months of age with high degrees of probability. This indicates the possibility of effective early selection. The studies of the reproductive capacity of heifers and first-born demonstrated, that the age of first insemination and calving were significantly lower in heifers of the Ukrainian Black-and-White dairy breed. The difference was 26.0 ± 9.8 days (td = 2.65, at P < 0.05) and 22.0 ± 9.5 days (td = 2.31, at P < 0.05), respectively. However, in terms of duration of pregnancy and service period of first-born cows, Ukrainian Red animals had positively lower values in compare to the analogues of Ukrainian Black-and-White dairy breed, which provided a higher reproductive capacity at the level of (0.90 vs. 0.88) and estimated possibility yield of calves per 100 cows (90.3 vs. 87.7 heads). However, the fertility index for both breeds was at the same level 48.7–48.8. The interconnection of live weight of animals at different ages with the indicators of reproductive capacity was mostly the opposite in direction at an unreliable level in most cases. However, both breeds show a positive interconnection between live weight at 6 months of age and fertility index, between live weight at 1st insemination and age of 1st insemination, and between live weight at 1st insemination and coefficient of reproducibility Conclusions. It was found, that at different ages the heifers of the Ukrainian Black-and-White dairy breed significantly (p < 0.01) outnumbered the analogues of the Ukrainian Red dairy breed, and the coefficient of variation with age on this basis decreased for both breeds. The coefficients of recurrence of live weight of the studied heifers, which are quite significant at high degrees of probability, were revealed, which indicates the possibility of effective early selection. Thus, the live weight of Ukrainian Black-and-White heifers at 9, 12 and 15 months of age can be reliably predicted by its size at the age of three months after birth - heifers of Ukrainian Red dairy breed a little later. There was a positive interconnection between live weight at 6 months age and fertility index, between live weight at the first insemination and age of the first insemination and between live weight at the first insemination and кcoefficient of reproducibility.

2019 ◽  
Vol 57 ◽  
pp. 79-86 ◽  
Author(s):  
D. М. Kucher ◽  
A. М. Didkovsky

The selection of animals at the lowest number of indicators is more effective compared to selection on many grounds. The main focus during the selection of Holstein cattle was to increase milk productivity, which meant the neglect of other important features, such as fertility (fecundity) of animals. The purpose of the work was to determine the level of milk productivity of cows of Ukrainian Black-and-White dairy breed in conditions of a particular farm, in which there would be a successful combination of reproductive capacity support for adjusting the selection of animals. The research was carried out in the breeding plant of the Ukrainian Black-and-White dairy breed of farm "Khliborob" of Kozyatinsky district of Vinnytsia region. The material of the research was the information of 212 first-calf cows of Ukrainian Black-and-White dairy breed of this farm. Indicators of dairy productivity were studied in 305 days of lactation according to zootechnical records. Reproductive ability of cows evaluated index insemination, age 1 st calving (months), duration (days) of service period, the period of pregnancy, the period between calving, the dry period, a rate of reproductive capacity (CRF), the calves are emitted per 100 cows (%) and the fertility index. The first-breed differentiation was carried out at a deviation of 0.7 σ from the mean of index (M) of the fertility index. Such a division makes it possible to divide the herd into 3 groups in a ratio of 1:2:1. The highest level of dairy productivity have characterized by animals of the I group with low fertility (the fertility index was on average 40.8), which significantly surpassed their peers of the III group with good fertility for the livelihood for 305 days of lactation for 434 kg, milk protein production – by 15.2 kg, total milk fat and protein production – by 26.0 kg (P ≤ 0.05). The increase in the duration of lactation and deterioration of fertility has associated with an increase in the duration of the service period, which is quite natural, since animals need more time to invade the genital organs and normalize their functioning and restore normal sexual cycle. The difference in the duration of the lactation period when comparing animals with different fertility in all cases was high-reliable at P ≤ 0.001 (td = 3.38–6.00). The effect of cow fertility on the duration of their lactation was ηx = 0.160 (at P ≤ 0.001). The main indicator that characterizes the economic efficiency of the industry is the profit received from the cow due to the receipt of the calfs and milk. Taking into account the duration of the service period, which exceeded the optimum terms, in the first days of the experimental groups, indicators of non-compliance of products in the form of calves per 100 cows were determined, which made 18.5%, 14.1% and 11.4% respectively. The force of influence on the fertility of cows at the age of their first calving was ηx = 0.507 (at P ≤ 0.001). According to the received data, the first-calf cows with a tiredness of 6274 kg of milk showed the highest calving output in the herd is for 100 cows (89.6%) and reproductive capacity (0.91). The lowest calf output (82.5%) and reproductive capacity (0.84) was found in cows with a milk yield of 6708 kg for 305 days of lactation. As the milk productivity increases, the duration of the service period extends from 123.1 to 158.3 days (r = 0.16 ± 0.07, at P ≤ 0.05), and the index of insemination – from 2.35 to 3,02 (r = 0.17 ± 0.08, at P ≤ 0.05). The relationship was straightforward and reliable. It is necessary to focus on improving cow fertility, which is the basis of effective milk production. For the successful management of dairy cattle breeding in the conditions of the "Hliborob" farm, we recommend to select the herds of heifers to be retrieved from animals with satisfactory fertility, since this will be economically beneficial for the farm and physiologically optimal for animals. A negative correlation was detected between milk productivity and reproductive capacity - with an increase in the fertility index per unit of hopes for cows, it would increase by 148.5 kg of milk. Under existing conditions of feeding and keeping on the farm it is expedient to select for further breeding of animals with a productivity level of 6.5 thousand kg of milk for 305 days of lactation. For a more complete realization of the genetic potential of milk production of cows of Ukrainian Black-and-White milk, it is necessary to improve the conditions of their feeding, maintenance.


2020 ◽  
Vol 60 ◽  
pp. 92-98
Author(s):  
A. L. Shuliar ◽  
A. L. Shuliar ◽  
S. P. Omelkovych ◽  
V. P. Tkachuk ◽  
V. F. Andriichuk

The intensification of dairy cattle selection determines the need of the systematic evaluation of animals in herds and populations on the main economically useful traits. They have an integrated origin and are controlled by significant groups of factors (genetic, physiological, technological and environmental). In dairy herds, the influence of such genetic factors as belonging to the breed and intrabreed types, the conditional blood share of improving breeds, the linear belonging, the family belonging, the origin by father is realized in the phenotypic performance of economically useful traits of animals with the simultaneous significant influence of environmental conditions. Among the hereditary factors, that determine the level of intergroup differentiation by the main selected traits, are significant the origin by father and the linear belonging. In addition, the world gene pool of the Holstein breed has an impact on the heredity of the Ukrainian black-and-white dairy breed, which requires constant monitoring of breeding groups of animals in different herds. Based on this, the aim of our research was to study the genetic conditionality of the economically useful traits of the cows of Ukrainian black-and-white dairy breed, that is, the study of the influence of such genetic factors as the conditional blood share of Holstein breed, the origin by father and the linear belonging on these traits. The research was conducted in the herd of Ukrainian black-and-white dairy breed of the private agrarian firm «Yerchyky» Popilnia district Zhytomyr oblast during 2015–2019. The study was carried out on the materials of the breeding and productive use of 766 first-calf cows and 497 cows which were disposed from the herd on different reasons. The reasons for their disposal were determined according to veterinary disposal acts. The statistical data processing was done using the method of variational statistics. The power of influence of the conditional blood share of Holstein breed, origin by father and linear belonging on the phenotypic variability of economically useful traits of the cows was determined by One-Way-ANOVA. The results of the study of the influence of genetic factors on the economically useful traits of cows of Ukrainian black-and-white dairy breed are presented. It was found that the power of the influence of the conditional blood share of Holstein breed, origin by father and linear belonging on the phenotypic variability of live weight, measurements and indices of body constitution was 0.4–17.6%; indicators of milk productivity of cows – 0.3–20.8%; morphologo-functional characteristics of the udder – 0.5–21.9%; parameters of reproductive capacity – 2.3–9.3% and lifetime use – 0.1–12.6% (P < 0.05–0.001). The factors of the origin by father and the conditional blood share of Holstein breed had a more significant effect on mass-and-metric parameters and indices of body constitution, and the influence of the linear belonging on these indicators was the smallest. Among the studied genetic factors the origin by father had significant effect on the milk productivity and morphologo-functional characteristics of the udder, while the smallest influence of the linear belonging was on the indicators of milk productivity, and the conditional blood share of Holstein breed had the smallest effect on the characteristics of the udder. Regarding the indicators of reproduction and lifetime use of cows, the effect of the studied genetic factors on them was distributed without any trends. The prospect of further research is to study the influence of paratypic factors on economically useful traits of cows of the Ukrainian black-and-white dairy breed of the private agrarian firm «Yerchyky».


Author(s):  
Ye. I. Fedorovych ◽  
V. V. Fedorovych ◽  
P. V. Bodnar ◽  
S. I. Fyl ◽  
A. V. Dymchuk ◽  
...  

The research was conducted on cattle of Black-and-White breed (Holstein and Ukrainian Black-and-White dairy breed) at LLC “Veleten” Glukhiv district of Sumy region (n = 1956) and PJSC “Breeding Plant “Stepnoy” of Kamyansko-Dniprovsk district of Zaporizhzhia region (n = 1981). Based on retrospective data analysis (“Uniform-Agri” – program of dairy herd management) for the period from 2004 to 2017 it was studied the live weight of cows in growing period (newborns, 6, 12; 18 months, at first insemination and after the first calving), body measurements of heifers (height at shoulders, chest depth, chest width, chest girth behind the shoulder blades, oblique body length, width of hips, wrist girth) and traits of reproducibility (age at first insemination, age at first calving, duration of service period, insemination index, fertility index) and milk productivity of cows (milk yields for 305 days, fat and protein content in milk for the first, second and third lactation). Based on our previously obtained data by correlation analysis method it was studied the relative variability of phenotypic traits and indicators of dairy productivity of cows. It is established that the connections of live weight of cows during their rearing with traits of milk productivity were multidirectional and ranged from slightly improbable to moderately significant values. At the same time, in both farms, the most significant highly probable connection was noted between the live weight of animals at the age of 12 months and the milk yield of first-borns that indicates the possibility of selecting heifers at the specified age to provide them future high milk productivity. There was significant variability of the relationship between body measurements and the amount of milk yield of cows for the first, second and third lactation. However, cows of both farms, had direct connection, but a bit weaker in animals at PJSC “Breeding Plant “Stepnoy”. Positive correlation coefficients between indicators of exterior and milk yields of cows give reasons to claim the efficiency of indirect selection of heifers by body measurements. Rational management of dairy farming and high profits depend a lot on knowledge of regularities of correlative variability of productive traits of cows and indicators of reproductive capacity. It is established that the connections between the traits of milk productivity and reproductive capacity of animals were different and ranged from weak to medium and from reliable to improbable. The most significant highly reliable, however, with negative correlation coefficients were observed between milk yield of cows for all studied lactations and their age at the first insemination and the first calving


2022 ◽  
Vol 51 (6) ◽  
pp. 77-83
Author(s):  
L. L. Petrukhina

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.


2020 ◽  
Vol 50 (5) ◽  
pp. 47-55
Author(s):  
S. L. Belozertseva ◽  
L. L. Petrukhina

The paper presents the results of studying the effect of sire lineage on reproductive qualities and milk yield of cows. The study was carried out inIrkutskregion on a herd of Holsteinized black-andwhite cattle of Pribaikalsky type. The analysis of the main characteristics of reproductive capacity of herd cows on a farm was performed during 2013–2018. The material of the research work was based on the informational database of animals from the program of breeding register Selex. Cows were divided according to sire lineage and milk productivity into five groups by the level of milk yield: from 5000 to6500 kg, 6501-8000, 8001-9500, 9501-11000 and more than11001 kg. Successful insemination of heifers took place at the age of 15.7-16.6 months with the live weight of more than400 kg, which corresponds to zootechnical standards. The earliest (15.7 months) insemination was in heifers of Reflection Sovereign sire line, the age of first calving was 753 days with the live weight of561 kg. The latest (498 days) successful insemination was observed in heifers of Montvik Chieftain bull line with the live weight of498 kg. Cows of Sealing Trygen Rocket (8766 kg) and Reflection Sovereign (8704 kg) sire lines had the highest milk productivity with a significant difference (p ≥ 0.90). The cows of these lines had the longest service period (164 and 179 days), as well as the length of the calving interval (445 and 458 days), respectively. The coefficient of reproductive capacity of cows of different sire lines ranged from 0.80 to 0.88, which is a low indicator.


2018 ◽  
Vol 51 ◽  
pp. 112-118
Author(s):  
V. V. Machulnyi

Milk yield of cows in breeding herds, Cherkassy region, for last completed lactation averaged 6442 kg of milk with 3.62 % fat content. Currently the question of interconnection of cows’ milk production and reproductive capacity is especially important, because the significant increase in milk yields makes minimize calves. The successful conduct of breeding had set the goal to detect the best options for combining milk production and reproductive ability of animals.To characterize the level of milk production including reproductive ability of cows we used indicator of daily average milk yield per one day of periods between calving (PBC). The best service period can be considered period of 51-90 days, that allows you to get one calf per cow per year (average PBC is 351 days) and maintain high milk production (6431 ± 39.6 kg during 305 days of lactation). With this service period all indicators of milk production and reproductive ability are at high level. Reduced service period below recommended levels will reduce the duration of lactation and milk production, and increasing service period will increase the duration of lactation with a simultaneous reduction in milk production for 305 days. Herewith deterioration of reproductive ability is marked and manifested in the increase of the insemination index, decline in the reproductive capacity, increase of periods between calving and as a result, reduce of calves and culling barren cows.Analysis of genealogical structure of the studied herds points to low diversity (Ukrainian Black-and-White dairy cows belong to 6 lines and Ukrainian Red-and-White dairy cows – to 8 ones) with high affinity (by Chief 1427381.62 to R. Sovereign 198998 bloodline, by Starbuck 352790.79 to Elevation 1491007 and Ideal1013415 bloodlines).Genealogical structure of the herds is saturated a lot of bulls genealogical groups of Holstein cattle: Chief 1427381 – 11 bulls in the array of Ukrainian Black-and-White dairy breed and 5 ones in Ukrainian Red-and-White dairy breed, Starbuck 352790.79 – 10 sires in the array of Ukrainian Black-and-White dairy cattle and 3 ones in Ukrainian Red-and-White dairy breed, Elevation 1491007.65 – 4 sires in the array of Ukrainian Black-and-White dairy cattle and 3ones in Ukrainian Red-and-White dairy breed.Currently the sires of Chief 1427381.62 (7712-3,76-289,9-3,14-242,1), Starbuck 352790 (7857-3,87-295,4-3,07-241,2), Jocko Besne 694028588.94(6687-3,88-259,5-3,03-202,6), and Bell 1667366 bloodlines (61341-3,95-242,3-3,02-185,2) among sires of Ukrainian Black-and-White dairy cattle and the sires of Cavalier 1620273.72 (7285-3,98-289,9-3,08-224,4), Chief 1427381.62 (7522-3,76-282,8-3,00-225,7),Starbuck 392405 (7667-3,87-296,7-3,00-230,0), and Elevation 1491007.65 bloodlines (7544-3,80-286,7-3,5-230,0) among sires of Ukrainian Red-and-White dairy breed are classified to a highly productive and promising for breeding and wider use by productive qualities.After the first insemination the lowest proportion of fertilized cows is among offspring belonging to Chief 1427381 bloodline which is only 38 % among both breeds. However, the milk yield of breeding stock belonging to this bloodline is 7712 kg with 3.76 % fat content for Ukrainian Black-and-White dairy cows and 7522 kg of milk with 3.76 % fat content for Ukrainian Red-and-White dairy cows. Daughters belonging to Elevation1491007, Valiant 1650414, and Hanover 1629391 bloodlines with yields of 4566-5478 kg of milk per lactation had a part of fertilized cows, after the first insemination, at the level of 41-49 %. Fertilization after the first insemination above 50% was in daughters belonging to Cavalier 1620273.72 (52%), Starbuck 392405(50-55 %), Bell 1667366(56%) and Jocko Besne 694028588.94 bloodlines (64 %). The level of performance of these animals for milk yield ranged from 6134 kg to 7857 kg.Heritability coefficients of milk yield and duration of service period were low (0.118-0.289). A positive correlation can be explained by the fact that extension of service period (to a certain level) leads to growing number of milking days (duration of lactation) and defers a decrease in productivity of cows by physiological reasons, namely as a result of pregnancy. Low rates of heritability indicate little genetic diversity of traits and the significant influence of physiological and environmental factors in their formation.As Ukrainian Black-and-White and Ukrainian Red-and-White dairy breeds have a high proportion of heredity of Holstein breed which has genetically large fetus, there is need to study the characteristics of nature passing calving in cows of these breeds. Itis found the number of first-calf heifers which needed help was 52.4%. Animals calve alone in 47.6 % of all cases. Calving was without complications if the live weight of calves not exceeding 6-7% of mother’s weight. The cows calved without help of staff exceeded by 11.7% of the width of the pelvis in the buttocks, 7.5 % of the width of the ilium, and 7.1 % of its oblique length compared with animals of same age.


Author(s):  
S. Voitenko ◽  
O. Sydorenko

It has been highlighted the data of researches as for the influence of natural and climatic zones of Ukraine on display of economically useful signs of the most numerous cattle in the country like Ukrainian black-spotted dairy breed. It was the grounds to assert the efficiency of resources use in those conditions to which they are most adapted and have genetically determined potential. It was found that cowsof lactation breeding herds in the Forest-steppe zone produced 7344 kg of milk, which is 242 kg and 1125 kg more than in the Steppe and Polissya regions due to significant variation of the characteristic within each climatic zone (Cv = 11.6– 27,5%). The Polissya zone, where the animals' yieldwere 5764 kg, while in other climates 6982–6992 kg, does not contribute to the high productivity of the first lactation cows. It is proved that the duration of the service period in cows of three natural and climatic zones of Ukraine varied from 106 days in Polissya to 126 days – Forest-steppe, but it did not agree with the output of calves per 100 cows, which in 81 Polissya amounted to 82 and Forest-steppe – 79. The heifers of the Steppe zone are inseminated with live weight of 391 kg at the age of 477 days, and the Forest-steppe and Polissya with slightly less 385 kg and 387 kg, respectively, at the age of 493 days and 517 days. There is no significant difference in live weight at the ages of 6, 12 and 18 months between heifers of different natural and climatic zones of Ukraine, but the degree of development of the trait after 6 months was slightly better in cattle of the Steppe zone. A positive correlation was found between milk yield of first lactation cows of all natural climatic zones and their live weight at 6, 12 and 18 months of age, as well as negative calf age at first insemination (-0.587 ... -0.810) with significant correlation from the cattle of the Steppe zone. A high correlation coefficient (+0.703) was found in cows between live weight of heifers at first insemination and first lactation in the Polissya region. Key words: natural and climatic zones, Ukrainian Black-and-White Dairy breed, cows, yield, lactation, live weight, reproductive ability indicators, selection traits.


2020 ◽  
Vol 50 (2) ◽  
pp. 57-63
Author(s):  
L. L. Petrukhina ◽  
S. L. Belozertseva

The materials of the long-term (2008–2018) research into the reproductive function of cattle of the black-and-white breed of Baikal type in Irkutsk region are presented. The influence of the age at the first insemination and live weight on cows’ milk productivity, lifelong productivity and productive longevity was studied. The experiment was conducted on the basis of materials from the breeder-farm for breeding cattle of Baikal type on the groups of cows of different ages: up to 14–20 months and older. Cows inseminated at 16 months (7917 kg) had the best milk yield in the first lactation. The largest milk yield was obtained from inseminated cows with live weight of 401-410 kg. Milk production of these heifers was 7902 kg in the first lactation, 8792 kg – in the second and 8710 kg – in the third. It was revealed that age of cows and their live weight at the first successful insemination had a positive effect on the lifelong productivity and productive longevity of cows. Cows whose age at the first successful insemination was 15 or 16 months had a longer duration of productive use (productive life span of animals was 2561–2558 days, respectively). The highest lifelong productivity (34379–34585 kg) was obtained from the cows of this group. The economic efficiency of lifelong milk production was determined depending on the age of the first insemination. The highest lifelong milk productivity was obtained from cows, which were first inseminated at the age of 15–16 months. The largest revenue from sales of additional products was also received from the cows of this group (366,058–370,480 roubles per head). The results obtained allow to develop effective methods for increasing reproductive capacity of cattle.


2020 ◽  
Vol 11 (3) ◽  
pp. 22-33
Author(s):  
А. А. Klimkovetskyi ◽  
D. K. Nosevych

The productivity of cows with the first calving depending on live weight and average daily gains of heifers during rearing studied. The data of animals of Ukrainian Black-and-White dairy breed of Kyiv factory type used for the research. Every three months, from birth to 18 months of age, heifers were determined live weight and average daily gain. According to the indicators of weight growth, the heifers divided into 5 groups of the standard deviation principle from the mean. In animals included in these groups studied the performance of the first lactation. It found that obtaining a live weight of 3-month-old heifers over 127 kg can significantly reduce the age of the first calving. The advantage over animals belonging to the groups with less weight is 2.7-3.5 months. Increasing the live weight of heifers at 12 and 15 months also allows reducing the age of the first calving. Moderate (less than 722 g per day) growth of heifers at the age of 6-9 months also has a positive effect on the reduction of the age of the first calving. The weight of newborns heifers during lactation was associated with first calving cow’s milk yield. Heifers born with the lowest live weight (less than 28 kg) had after the first calving milk yield per lactation 145… 1956 kg more than in other groups. The live weight of 3-month-old heifers is of the greatest importance for the formation of high milk productivity of cows. Obtaining live weight of heifers of this age 117-127 kg with an average daily gain of 902-1037 g provided in first the lactation the largest milk yield with an advantage over animals of other groups up to 3119 kg. In older age periods, the influence of growing heifers on the formation of milk productivity is less pronounced, and the optimal live weight and growth rate was at the level of the average size of the herd. The research results can used to optimize the growth plans of heifers and their selection.


Sign in / Sign up

Export Citation Format

Share Document