Level Of Milk Production Research Articles

NUTRIENT DIGESTIBILITY AND NITROGEN UTILIZATION OF LACTATING COWS WHEN RECEIVING A FOOD MIXTURE WITH MINERAL SUPPLEMENTS

The article presents results of studies on giving natural mineral additives from the deposits of Oryol (Stimulus) and Bryansk regions (smectite tripoli) in the composition of the feed mixture to lactating cows of the second lactation of the black-and-white breed in the agricultural enterprise OOO "Mololchnoye" of Bryansk region. A comparative analysis of the effect of two dosages of their inclusion in the ration - 3 and 4% of the dry matter without changing their energy nutritional value on productivity, digestibility of nutrients and nitrogen usage in the organism of lactating cows was carried out. A positive effect on the level of milk productivity of both natural mineral additives was found, however, more significant changes in protein and lipid metabolism occurred in the body of cows who received smectite tripol as part of the feed mixture at a dose of 4% of the dry matter of the ration. Thus, the dry matter digestibility coefficients, including organic matter, as well as protein and crude fat digestibility coefficients of lactating cows that received smectite tripoli (4%) significantly exceeded similar parameters in all experimental groups. Based on the results of the balance experiment, a positive nitrogen balance of lactating cows of all groups was established. Concurrently, a redistribution of digested nitrogen with a higher transformation into products was noted, which is confirmed by a large percentage of its transition into milk (10.3%). This redistribution of nitrogen in the body of lactating cows of the experimental groups became possible due to its lower retention in the body (by 5.9% due to "Stimulus" additive and by 11.0% - smectite tripoli). Therefore, based on the obtained experimental data, it is possible to recommend to include smectite tripoli natural mineral additive at a dose of 4% of the dry matter of the ration into the feed mixture for lactating cows.

Environmental impact of dam-calf contact in organic dairy systems: A scenario study

Systematic separation of cow and calf early after calving is common practice in both organic and conventional dairy farming. The main objective of this paper was to develop different scenarios for dam-calf contact and quantify their effects on milk uptake by the calf and environmental sustainability of the produced milk and meat from these systems.Scenarios were set up of organic dairy systems to analyse the effect of different dam-calf systems with either half-time or full-time contact between cow and calf for 28, 51 or 91 days. Based on experience from practice and literature, we assumed a total milk uptake of 1,110 kg ECM milk with part-time contact and 1,207 kg ECM milk with full-time contact over 91 days. These scenarios were compared to traditional calf rearing systems with direct separation after birth and milk feeding from a bucket with low or high milk feeding levels of 460 and 630 kg ECM, respectively, in the first 91 days. The scenarios were analysed at a milk production level of 9,000 kg ECM per cow per year and with a sensitivity analysis covering yield levels of 7,000, 11,000 and 13,000 kg ECM per cow per year. At a production level of 9,000 kg ECM per year and full-time dam-calf contact throughout the milk period, only 85% of the milk produced could be delivered to the dairy company, compared to 93% when a low-level of milk is fed from a bucket. This means that there were fewer kg products to bear the environmental impacts, and hence the carbon footprint and land use from production per kg of ECM milk and meat sold was increased by between 5 and 9%, while the corresponding increase in impact at the highest yield level of 13,000 kg ECM was only between 4 and 6%. Besides environmental sustainability of cow-calf contact systems, the broader context of such systems need to be analysed including animal welfare and the economic effect for the farmer.

Productive traits of goats of Nubian breed

Milk productivity, composition and properties of goat milk depend on the breed of goats. One of the dairy breeds that have been gained wide popularity among goat breeders is Nubian breed. The study of the economic and biological characteristics of Nubian goats imported and bred in the ecological and climatic conditions of different regions of our country is an urgent task. The purpose of the work was to assess the level of milk productivity and the qualitative composition of milk of Nubian goats of different ages in OOO Nubian-Elite – Healthy Generation in the Leningrad region. The positive age dynamics of milk productivity indicators have been revealed. Goats of the third lactation and older were ahead of animals in the first and second lactation in milk yield by 205,3 kg (P ≤ 0,001) and 94,8 kg (P ≤ 0,001), in fat mass fraction by 0,60 abs.% (P ≤ 0,05) and 0,54 abs.% (P ≤ 0,05), in protein mass fraction by 0,16 abs.% and 0,47 abs.% (P ≤ 0,01), in milk fat yield by 13,78 kg (P ≤ 0,001) and by 7,81 kg (P ≤ 0,001), by milk protein yield by 9,56 kg (P ≤ 0,001) and by 6,53 kg (P ≤ 0,01), by total milk fat and protein yield by 23,34 kg (P ≤ 0,001) and by 14,34 kg (P ≤ 0,05). Animals of all ages produced milk with a fat and protein content significantly exceeding the requirements of State standard 32940-2014 “Raw goat milk. Technical conditions”, that confirms the high nutritional and biological values of the milk of goats of Nubian breed. Thus, the increase in the longevity of economic use of animals will contribute to the increase in the productivity of goats of Nubian breed while maintaining high quality characteristics of milk.

INFLUENCE OF DAIRY FARMING PRACTICES ON MILK PRODUCTION. A CRITICAL LITERATURE REVIEW

Purpose: Dairy farming has been part of agriculture for thousands of years since the early days of man when he decided to start domesticating animals. This paper aims to determine the extent to which dairy animal nutrition and animal health influences the level of milk production. The aim of the study is also to determine the role played by animal hygiene in improving and sustaining milk production as well as the extent to which observance of animal welfare influences the performance of the cattle in terms of mil production.
 Methodology: This paper adopted a desk study review methodology where relevant empirical literature was reviewed to identify main the themes.
 Findings: The study deduced that animal nutrition to a very great extent influence milk production. The study found out that preserving water supplies and feeds from contamination and feeding animals on good quality feeds influenced milk production to a very great extent. Adopting appropriate farm management practices such as milking hygiene, environmental sanitation, and regular veterinary care (e.g., periodic check-ups, prompt treatment of illness) of cows helps to assure the well-being of dairy cows and reduce their risk of infections such as clinical mastitis. It is important to ensure good milking techniques since incorrect techniques can result in a higher mastitis risk and injury to the cow which translates to lower level of milk production or even contamination of milk.
 Recommendations: Creating awareness on the dairy farming practices, changing behavior and being equipped in the necessary skills on dairy farming practices would improve the level of milk production.

Correlations between bulk tank milk analysis with weather conditions in dairy farms under tropical environments

The consequences of climate change on agriculture have generated concern among researchers and decision-makers, especially regarding the effects it will have on this sector. The phenomenon is expected to affect the productivity of livestock systems, even more so in grazing livestock, where cattle and pastures are directly impacted by climatic variables. This study evaluated the climatic influence on bulk tank milk production and quality in 38 tropical dairy farms, using Pearson’s partial correlation and canonical correlation analyses. Farm production level and milk quality traits were merged with meteorological information obtained from climatological stations distributed around the Valle del Cauca department, Colombia. According to farms’ milk production levels, four evaluation groups (EG) were established for the analysis, and within each group, the available information between 2.0 and 8.5 years was included. Pearson’s partial correlations among productive and climatic variables were scarce and low (r <± 0.10) within each EG. On the other hand, canonical correlation analyses between productive and climatic variable sets presented a linear increase since the establishment of EGs from 1 to 4 (r ranging from 0.39 to 0.59). The magnitude of canonical correlation coefficients depended on bulk tank dairy farm production levels, being the most productive systems the most susceptible, especially for meteorological variables related to temperature and relative humidity. As a consequence, dairy farms with higher performances must define mitigation strategies to reduce the weather effects. Multivariate correlations are recommended to evaluate the relationship between milk production, composition, and environmental variables in grazing dairy systems of tropical areas. Highlights Livestock farming in the tropics are more vulnerable to climate change. Heat stress has an impact on the productivity of dairy cows. Dairy production systems not intensive under grazing conditions and adapted breeds of ecology zones are not affected by adverse meteorological conditions.

Влияние роботизированного доения коров на эффективность производства молока

Abstract. Purpose is to study the effect of milk production technology in the SPK “Glinskiy” with the use of robotic milking machines Lely Astronaut, DeLaval and linear milking machine ADM-8A, on the efficiency of milk production. Methods. An analysis of the efficiency of milk production with various technologies of keeping and milking cows was carried out on the basis of materials for accounting for milk productivity obtained for 2016–2019, and also the marketability of milk, the cost per unit of milk and the profitability of milk production during robotic milking and milking in a milk pipeline were determined. Scientific novelty. The analysis of the economic efficiency of milk production in the conditions of one farm is carried out, the differences in the level of milk productivity and milk quality are determined. Calculated: the cost price of 1 kg of milk obtained using the milking machine ADM-8 and automated milking machines Lely and DeLaval, profitability. Results. A large number of factors, both genetic and paratypical, affect the milk production of cows. The main paratypical factor is milk production technology, which includes keeping, feeding and milking livestock. Nowadays, the widespread technology is tethering cows with milking in a long milk pipe in stalls, this technology is considered traditional. She is being replaced by a more productive one – keeping a milking herd without a tether in groups with milking on automatic milking machines (robotic milking). Feeding with these two technologies is organized according to different principles. Our study revealed the influence of milking technology on the efficiency of milk production. As a result of the study, differences in the level of milk productivity and milk quality were determined. Our study revealed a positive effect of milking technology with the help of robotic installations on the efficiency of milk production: milk yield for each lactation increases by 7–28 %, which is confirmed by the lactation constancy index, the content of somatic cells in milk decreases to 2.4 × 105 cells per 1 cm3 providing an increase in the marketability of milk to 97.4%, in terms of physical and chemical indicators, milk of cows, with different methods of keeping, was within the normal range and average values for the herd.

Молочная продуктивность и воспроизводительная способность коров при различных способах содержания

Abstract. The conditions of keeping cattle should meet the biological requirements of the animal body as much as possible and contribute to the fullest realization of their genetic potential. In this regard, the study of the influence of housing conditions on the productive qualities and reproductive ability of cows is an actual, scientifically based research area. The aim of the study is a comparative assessment of tethered and non-tethered content in the study of the reproductive capacity and the level of milk productivity of black-and-white cows in the postpartum period. Methods. The results of the work are based on analytical, biometric, statistical methods and the authors ' own research. Results. In their studies, they found that the highest indicators for most parameters of milk productivity were cows with loose content: milk yield – by 1153.3kg (or 18.2 %), milk yield coefficient – by 198.7kg (or 16.4 %), the amount of milk fat – by 2.7kg (or 1.08 %), protein – by 9.7 kg (or 4.9 %) (P &gt; 0.95) more in comparison with cows with tied content. Despite the manifestation of hunting, early insemination does not have any advantages over insemination at a later time, regardless of the methods of maintenance. Cows on the tethered method of keeping, which pass through three normal sexual cycles before insemination, have good fertilization rates (92.1 %). Cows on the loose method of keeping showed the highest percentage of pregnancy (92.7 %) for three months of accounting and more after calving. In general, the use of a complex of bioregulators allows you to get fairly high results of stimulating hunting, regardless of age and conditions of detention, which is an indicator of the activation of the ovarian follicular apparatus and the normalization of the hypothalamic-pituitary system of animals. The scientific novelty lies in the fact that the indicators of productivity and effectiveness of insemination of cows at different times after calving and on the number of lactation, depending on the tethered or non-tethered methods of maintenance, are established.

Milk productivity and live weight of cows at ООО “PskovAgroInvest”

Currently, the food problem occupies an important place among the global problems of mankind. Despite a slight increase in food production, the level of nutrition of the population is not reaching optimal levels. This is especially true for Russia. One of the ways to solve this problem is the development of agriculture, in particular animal husbandry. Over the five analyzed years, there has been an increase in the level of milk production in cows of all ages. Milk yield, fat and protein content in the milk of cows of all ages significantly exceed the breed standard. The live weight of cows of all ages for all years also significantly exceeds the breed standard, in particular, full-aged cows are characterized by a weight varying in the range of 599–606 kg. The fat content in milk of cows during this period ranges within 3.70–3.85% with a breed standard of 3.7%, protein content – 3.07–3.26% with a 3.0% breed standard, that is, exceeds the standard for the entire period taken into account. It should also be noted that every year there is an increase in indicators, reaching a maximum in 2020. It should be noted that a number of cows have been in the list of the best in OOO “PskovAgroInvest” for a number of years, improving their milk yield with each lactation. So, from Travinka 1330 in 2018, 10,573 kg of milk with a fat and protein content of 3.63% and 3.12% were milked, and in 2020 – already 11,239 kg with a fat and protein content of 3.71% and 3.18%; from cow Torpedo 234 the corresponding figures for the same years amounted to 9340 kg, 3.75%, 3.06% and 10,504 kg, 3.74%, 3.18% respectively.

Adoption of improved animal husbandry practices by dairy farmers

Livestock sectors plays a very important role in Indian economy. It provides sustainable source of income for many marginal and small farmers. However, the dairy livestock owners are yet ignorant with scientific management practices. If feeding, breeding, health care and other management practices fit in proper operation, it would be possible to reach the desired level of milk production. The present study aims to assess the adoption of improved animal husbandry practicies by dairy farmers. Primary data was collected from 120 dairy farmers of Rajkot district. Adoption Index was used to study the adoption of improved animal husbandry practices by farmers. The results reveald that among improved animal husbandry practices, the highest adoption was of health-care management practices followed by clean milk production practices, breeding management practices, feeding management practices. The lowest adoption was found in calf rearing practices. Full adoption was recorded in feeding of dry fodder, feeding of green fodder, cultivation of fodder crops and observation of ailing animals whereas non adoption of animal husbandry practices was observed in dehorning of calves and feeding of silage.

Factors affecting length of productive life of Brazilian Holstein cows assessed using survival analysis

Context Length of productive life is defined as the number of days from first calving to the last day of milking records, when the cow is no longer sufficiently productive. Although it has economic implications, length of productive life has not yet been included in Brazilian dairy cattle breeding programs because it depends on other traits such as age at first calving, milk production level and disease occurrence. In addition, its evaluation occurs later in life, and heritability coefficients are low. Aims The aim of this study was to identify the effects of both age at first calving and accumulated 305-day milk yield in the first lactation on length of productive life in Holstein cows. Methods Official dairy control data of 31 562 Holstein cows, calved from 2010 to 2014, in 321 herds from Paraná state, Brazil, were analysed by using the Kaplan–Meier estimator and Cox regression model. Key results First calving at &lt;21 months was associated with shortest productive life (1197.01 ± 232.40 days), whereas first calving at 24 months was associated with the lowest hazard ratio (0.572), suggesting that this is the most suitable age of first calving for a longer productive life. Low-yielding cows (first lactation yield &lt;6392 kg) had the second lowest survival probability (47.20%), the shortest productive life (1150.60 ± 234.51 days) and the highest voluntary hazard ratio (1.30) and were prematurely culled from the herds. High-yielding cows (first lactation yield &gt;12 024 kg) had lower culling risk at the first lactation. Conclusions Cows that started their reproductive life ∼16 months of age (first calving at 24 months) had the longest productive life and an average first lactation milk yield ∼9000 kg. Implications Reproductive management practices could affect length of productive life through effects on age at first calving and first lactation milk yield. Most of the Holstein semen used in Brazil comes from countries where longevity has already been included in selection indexes; thus, early identification of cow longevity could be used for culling decisions.

INFLUENCE OF GENOTYPE AND PHENOTYPE FACTORS ON MILK PRODUCTIVITY OF COWS

The article examines the influence of genotypic and phenotypic factors on the milk productivity of cows of the Ukrainian red-spotted dairy breed in the conditions of LLC "Agrofirma "Sonyashnyk" of the Globyn district of the Poltava region. Based on the results of our own research, it was established that first-born cows of the studied lines differ in terms of milk productivity, which indicates the hereditary influence of genealogical formations. The highest indicators of milk productivity have animals of three lines - Marshal, Cadillac Rf and Cavalera Rf: Nadia - 7501.0-8775.9 kg, milk fat - 279.5-332.4 kg, milk protein - 234.9-271.4 kg Animals of the Eleveishna and Butmeike lines have the lowest indicators of milk productivity - 5065.2-5112.4 kg, 187.4-199.4 kg, 162.1-163.6 kg, respectively (P&lt;0.05, P&lt;0.01 , P&lt;0.001). The highest milk yield and milk fat are characterized by the daughters of the bulls Savva, Sapphire Et Red, V. Vilmos, Matrix Et Red and K. D. Lily Red Et - 8408.4-9007.0 kg and 319.5-347.3 kg, which on 772.5-3951.9 kg and 133.2-155.2 kg more than peers, respectively (P&lt;0.05, P&lt;0.01, P&lt;0.001). The highest fat content is 4.0% in the daughters of Paradox Red Etn and Shchyglyk Et (P&lt;0.05). Our research proves that the live weight of firstborns at the first calving likely affects their milk productivity. With an increase in live weight up to 700 kg - their hope increases by 1545.3 kg, milk fat - 62.7 kg, protein - 53.5 kg (P&lt;0.05). According to the results of our research, it was established that the year of birth of first-born cows affects their hope. Thus, first-born animals born in 2018 probably exceeded animals born in 2012 in terms of milk yield by 2735.2 kg, milk fat - 90.2 kg, and protein - 87.7 kg (P&lt;0.05, P&lt;0.01, P &lt;0.001). It was established that indicators of milk productivity of first-born cows depend on genotypic factors by 10.1-24.5%. Paternal origin has the greatest influence, its influence on hope is 23.5 %, the content of fat and protein in milk is 15.2-24.5 % (P&lt;0.05, P&lt;0.01, P&lt;0.001) . The second place is occupied by linear belonging, its influence on the above indicators is 20.7, 10.1-12.3 % (P&lt;0.05, P&lt;0.01). The obtained data on the influence of phenotypic factors, including the year of birth, testify to the influence of the year factor on the milk productivity of first-borns. Quantitative signs depend on the conditions created for raising young animals or keeping first-born cows in a specific year of their birth. The strength of influence on hope, milk fat and protein content was 5.2, 15.1 and 5.7 % with high probability criteria (P&lt;0.05, P&lt;0.01, P&lt;0.001). The obtained results make it possible to develop comprehensive measures to increase the level of milk productivity of cows of the Ukrainian red-spotted dairy breed.

THE SPECIFICS TO STRUCTURE THE SYSTEM OF PARAMETERS AND STANDARDS FOR TECHNOLOGICAL AND TECHNICAL SOLUTIONS IN THE CREATION OF SMALL-SCALE PRODUCTION FACILITIES

The results of monitoring and analysis of production and organisational indicators of more than 50 farms have been presented, identifying the main elements that characterise them. There have been covered the main principles of forming the system of technology parameters, the directions of minimizing the determining conditions that negatively affect the production process. It has been explained that enlargement of farms with 50-100 cows considerably raises the technological level of milk production and storage. There were determined the parameters of technological and technical solutions of the enterprises with the number of cows from 50 to 120 heads. There were determined limits of parameters limitation, produced energy efficiency was evaluated and modelled on the example of minimal size (50 cows with annual productivity from 7000 kg to 9000 kg of milk per head). The structure of energy intensity of production was calculated by types - milk, live weight of culled animals, gain of breeding animals received brood. The energy intensity of excrement and litter has been taken into account. It was calculated that the highest proportion in the structure of the energy content of products appropriate for feeding belongs to the energy content of milk produced - 85.7-88.6 %, and since it was the most influential factor in the coefficients of energy efficiency of the main and general products, the functional correlations of the energy content of products and fat were determined. The influence of changes in qualitative indicators of other types of products on energy consumption in production was calculated namely fatness of culled cattle and animals from which growth was obtained. The functional determined correlations allow us to form the key elements of the cattle breeding production system interrelations, taking into account the peculiarities of a particular system of parameters, determine the energy efficiency of technological processes, and influence effectively the use of all kinds of resources.

Leptin receptor expression and its change in association with the normalization of EGF profile after seminal plasma treatment in repeat breeder dairy cows.

Factors associated with high milk production levels have been linked to alterations in the endometrial epidermal growth factor (EGF) profile, a cause of reduced fertility in dairy cows. Therefore, we examined the leptin system that connects nutritional status and reproduction in dairy cattle related to reduced fertility in repeat breeder cows. Plasma leptin concentrations were measured in 18 heifers, 20 high-yielding control cows, and 26 repeat breeder cows, showing an altered EGF profile. Then, all repeat breeder cows were infused with seminal plasma (SP) into the vagina at the next estrus to normalize the EGF profile, while heifers and control cows were infused with vehicle alone. All animals were examined for EGF profiles. Eighteen repeat breeder cows, nine heifers, and nine control cows were also determined for leptin receptor (Ob-R) expression levels in the estrous cycle before and after the infusion. SP normalized the EGF profile in 53.8% of the repeat breeder cows. Leptin concentrations were similar in all groups, regardless of the treatment results for the EGF profile. In contrast, Ob-R levels in repeat breeder and control cows were similar and higher than those in heifers before SP treatment. Ob-R in repeat breeders showing a normal EGF profile after treatment decreased to an intermediate level between heifers and control cows and may provide a clue to take measures against repeat breeding in dairy cows.

EFECTOS DEL ESTADO ENERGÉTICO Y PROTEICO SOBRE PARÁMETROS REPRODUCTIVOS Y PRESENCIA DE CETOSIS SUBCLÍNICA EN VACAS BROWN SWISS POSPARTO

This study aimed to determine protein and energy metabolites in postpartum Brown Swiss cows and their effect on the presence of subclinical ketosis and reproductive parameters. One hundred cows from four farms in the Mantaro Valley (Junín, Perú) were grouped according to parity (1, 2, 3 and 4). The variables of the metabolic profile (total proteins, blood urea nitrogen [BUN], glucose, βhydroxybutyrate [B-HB]), milk production and body condition were estimated between 7 to 60 days postpartum in 7-day intervals. Likewise, the calving-first heat interval and the pregnancy rate at first service were recorded. The determination of subclinical ketosis was based on a semi-quantitative analysis by levels of B-HB in milk (µmol/l) using a commercial kit. BUN levels ranged between 11.74 and 15.92 mg/dl, being higher in fourth parity cows (p&lt;0.05). The averages of total protein (6.54-7.90 g/dl) were homogeneous between calvings. The glucose values presented an inverse response, being lower in cows of third and fourth parity compared to cows of first and second parity (p&lt;0.05). Similarly, the highest levels of milk production were observed in third parity cows (14.41 ± 5.42 l/d) and fourth parity (15.43 ± 4.36 l/d) with respect to first and second calvers (p&lt;0.05). Body condition was lower in cows with subclinical ketosis. The calving - first heat interval and the pregnancy rate at first service were lower in cows with subclinical ketosis (p&lt;0.05).

Многофакторный регрессионный анализ молочных признаков коров голштинской породы

Abstract. The purpose of the research is the possibility of applying the equation of multiple two-factor regression to reveal the reliable conjugacy of signs affecting the level of milk productivity of Holstein cows. Research methods. The research was carried out in CJSC BP “Aksin’ino” of Stupinskiy district of the Moscow region. Based on the IAS “SELEX”, a database was created, including a sample of 11 017 heads. Data on milk productivity were taken for 305 days of 1st, 2nd, 3rd and maximum lactation. Results. For 305 days of the 1st lactation, milk yield averaged 7909.5 kg of milk, for the 2nd – 8289.1 kg (p ≤ 0,001) and the 3rd lactation – 8446.2 kg (p ≤ 0,001). Milk yield for maximum lactation was 8964.3 kg of milk (p ≤ 0.001). The fat and protein content in cow milk between the 1st and 3rd lactation is 4.03–4.08 and 3.22–3.23 %. The multiple two-factor regression coefficient represents the response bias from 7787.81–8239.00 (1st, 2nd, 3rd lactation) to 8841.63 (maximum lactation). The scattering diagrams of the multiple regression model show that the value of the variable "milk yield" is statistically dependent on the indicators of the mass fraction of fat and the mass fraction of protein in milk. The coefficient of determination at the level of 0.997–0.998 indicates that the regression equation explains 99.7–99.8 % of the variance of the effective feature. The significance of Fischer’s F-test indicates the high reliability of the results and the absence of randomness and the presence of a pattern justified in our study. The fat and protein content had a negative relationship with milk yield (p ≤ 0,001) by lactation. High values of the relationship between milk yield and protein content (–0.518…–0.766), fat and protein content (0.626–0,784) were obtained. Scientific novelty. For the first time, studies were conducted on the correspondence of the equation model to the experimental data obtained, and the presence of the number of independent variables (mass fraction of fat and protein) included in the equation to describe the dependent variable (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

The state of the adrenal cortex in cows with different levels of productivity and their breed affiliation

Purpose: the goal is to study the condition and functional reserves of adrenal cortex in cows with different levels of dairy productivity and their breed accessories.Materials and methods. In the first experience, the object of the study was cows of a holstered black-motley breed with a high and relatively low level of milk productivity (n = 10 in each group). The second experience was carried out on four breeds of lactating cows: Holsteinated black-made, red-made, Montbeliard and Jersey (n = 10 in each group). The blood of animals were taken from the tail vein 1 time per month during lactation to morning feeding. In both experiments, in the third month of lactation, all animals were performed by a two-time functional load of ACTH (dose – 0,5 units / kg of alive mass intramuscularly). After one hour, blood selection was performed and re-injected by adrenocorticotropic hormone in the same dose. After the second introduction, the ACTH was selected through 1.2 and 3 hours. The calculation of the index of the functional activity of the adrenal cortex was carried out according to the JACN = K2 / K1 formula where K1 is the level of cortisol 1 hour after the first load, K2 is the level of cortisol after the second load of the ACTH.Results. In the 1st experience of the highest values, the level of cortisol reached a 3 month lactation. In a highly productive group, the level of cortisol was 86,1 ± 5,3 nmol / l, and in the low product group 74,5 ± 5,7 nmol / l. At 8 months, the lowest cortisol concentration levels are fixed, followed by an increase of 10 months. Differences between groups on 2, 3 and 4 months of lactation are noted as statistically significant (p&lt;0,05). After the load of the ACTH, an index of the functional activity of the adrenal cortex (JACN) was established - in the first high productive group, it was 1.42, and in the second less productive group it was lower and amounted to 1,04.In the 2nd experience at the peak of lactation, which also corresponded to 3 months, the level of cortisol concentration increased from a holstered black-motley breed, Mont Belärd, Red-motley and Jersey to 79,3 ± 5,5; 70,2 ± 3,7; 80,3 ± 3,2; 80,5 ± 3,6 nmol / l, respectively. For 8 months of lactation, this figure decreased with the subsequent increase of the 10th month. After establishing Jacnes in a holstered black-motley breed, Montbeliard, red-motley and jersey recorded the following indicators: 1,21; 1,24; 1,18 and 0,89, respectively.Conclusion. The studies have indicated that in all periods of lactation relative to the high level of cortisol recorded in cows with a higher level of milk productivity. When comparing different rocks, it was established that the limit of the functioning of the adrenal glands in the cows of the Jersey breed was implemented after the first functional load of the ACTH, which gives reason to consider it less stress-resistant with respect to rocks a holstered black and motley, red-motley and monobeldam.

Genetic factor affecting the milk production of mares

The article presents the results of studies to establish the influence of the record productivity of mothers’ mares on milk yield and the duration of productive life of mares-daughters of the Lithuanian heavy draft breed. It was found that the high level of milk productivity of mothers during the period of highest lactation (up to 4000 kg of milk) enabled their daughters to become leaders already during the first lactation. With an increase in the record milk yields per lactation in mothers, the heritability coefficient in mother-daughter pairs decreased and turned into negative values. The daughters of mares with record milk yields of up to 8000 are the most dairy among their contemporaries. The research results indicate that intensive milk production of mares during the first lactation can cause a reduction in the terms of their economic use due to the large loads on the developing fragile animal organism. The highest rates of productive life, number of lactations and life-long milk yield were obtained from daughters whose mothers had record milk yields per lactation from 7000 kg to 8000 kg of milk.

Evaluation of Bulls and Related Groups of the Jersey Breed on Dairy Productivity and Reproductive Capacity of Offspring

The article presents the results of research on the influence of paternal origin and belonging to a related group on the level of milk productivity of cows and the reproductive capacity of Jersey cows in the farm “Dan-Milk” of the Zhytomyr Region. The purpose of this study is to establish the influence of paternal origin and belonging to a related group on the level of milk productivity and reproductive capacity parameters of Jersey cows. The study established a substantial level of differentiation in the main economically useful features between groups of half-sisters by father. The best quantitative indicators of milk productivity were noted among the daughters of bulls DJ Jante 302761 (P&lt;0.001) and Headline 114114336 (P&lt;0.001), the worst indicators – among daughters of Karl 67037285. The highest indicators of fat and protein content in milk were noted in the cows bred from the bull Legal 61929249, the lowest – from the bull Karl 67037285. The influence of the origin of cows by father on the variability of milk yield and yield of milk fat and protein was 20.3–30.3% (up to P&lt;0.001), the content of fat and protein in milk decreased to 13.2-20.0% (P&lt;0.01 and P&lt;0.05), and according to the reproductive capacity features – to 7.8-19.0% with an unreliable level of statistical significance. Prepotent as to milk yield are bulls Legal 61929249 and Headline 114114336, as to the content and yield of milk protein – Legal 61929249. Cows of the related group bred from the bull Observer 553236 are characterised by the highest milk yield and yield of milk fat and protein for both the first and best lactation, and cows of the related group bred from Surville 604694 are characterised by the worst yield. The influence of belonging to a related group on the studied features was several times lower (0.2-10.5%) compared to the influence of paternal origin. With an increase in the milk yield of cows over the first lactation, there is a stable and substantial decrease in the reproductive capacity coefficient due to the lengthening of the service period between the first and second calving. Such natural antagonism does not imply the goal of increasing the duration of the service period to obtain maximum milk yields for firstborn cows, since this will lead to a decrease in the yield of calves and render timely replenishment of the herd impossible. It is optimal to milk the firstborn up to 8 tonnes over 305 days of lactation while maintaining a satisfactory reproductive level

PSII-19 The Effects of Maternal Programming on Dairy Bull Calf Response to an Intravenous Glucose Tolerance Test

Abstract Calves are prone to health issues with high mortality observed during the first 3 weeks of life. We hypothesized that dam milk production levels and/or mastitis infection during gestation will lead to reduced insulin production and increased circulating glucose concentration in response to an Intravenous Glucose Tolerance Test (IVGTT) in young dairy bull calves. Calves (n = 45) were selected from dams classified has high producers (HI; Top 25% for herd M305; n = 7), high producers with high somatic cell count (SCC; HIMAST; SCC test during gestation over 200,000 cells/mL; n = 15), moderate producers (MOD; lower 60% for herd M305; n =17) or moderate producers with high SCC (MODMAST; n = 6). IVGTT were performed on the calves at 7 weeks of age. Blood samples were collected prior to (-30, -15 and 0 min) infusion of glucose. After glucose (0.15 grams /kg bw) administration, samples were collected at 2, 5, 10, 15, 30, 60, and 120-minutes post infusion. Serum insulin and glucose concentrations were determined at Cornell Veterinary Medical Diagnostic Laboratory (Ithica, NY). Data were analysed in SAS using Proc Mixed. Insulin:glucose ratio was analysed using Proc Mixed with repeated measures for treatment x time. No effect of maternal milk production and/or mastitis infection during gestation was observed on calf baseline insulin, insulin AUC, baseline glucose or glucose AUC (P ≥ 0.12). Similarly, no difference in Insulin:Glucose ratio was observed in these calves (P = 0.66). In conclusion, high maternal milk production and/or mastitis infection may not have an effect on circulating insulin production in calves in response to an IVGTT. Correlation analyses will be performed on these data, as well as additional analyses, to determine if insulin sensitivity or response (ie: phase 1 response) was altered further.