1st Lactation Research Articles

Influence of average daily gain of heifers on the age of first insemination

The purpose of this study is to establish the influence of average daily gain (ADG) of heifers at different periods of their development on the age of 1st insemination (A1ins) at 12, 13, 14, 15, 16, 17, 18 months and older and milk yield of first-calving cows for 305 days of lactation according to a sample (n=1289) formed from the Seleсs database of one of the breeding plants in the Leningrad region for breeding the Ayrshire breed of dairy cattle. On average for the sample, the correlation coefficient of milk yield with A1ins indicates a negative relationship between these two characteristics (-0.218), a positive correlation of milk yield with live weight of 1st insemination LW1ins (+0.101) with a negative connection with ADG (-0.110). It was revealed that in all age groups of heifers there is a decrease in ADG at the age of 2 months, and the intensity of further development of heifers depends on ADG at the age of 3, 4, 5 months, at a level of over 800 g, contributes to the achievement of A1ins from 12 to 14 months. At the same time ADG at the age of 9—12 months should be at least 800 g. However, even with ADG 800—900 g at the age of 3—5 months, but when these indicators decrease at 9—12 months below 800 g, A1ins increases to 15—16 months. Low ADG at the age of 3—5 months and at the level of 600 - 700 g at the age of 9—12 months increases A1ins to 17 months and older. Thus, for an earlier A1ins and a high level of productivity in the 1st lactation, one should pay attention to the development of heifers at the age of 3—5 months, maintaining the ADG at a high level (more than 800 g) and avoid low weight gain at 9—12 months (less than 800 g).

ОЦЕНКА ПЛЕМЕННОЙ ЦЕННОСТИ КОРОВ СИММЕНТАЛЬСКОЙ ПОРОДЫ ПО ПОЖИЗНЕННОЙ ПРОДУКТИВНОСТИ В ЗАВИСИМОСТИ ОТ ВОЗРАСТА ВЫБЫТИЯ И ПРОИСХОЖДЕНИЯ

The purpose of research is to study the variability of genetic assessments of cows of different origins for traits of lifelong milk production when varying the age of retirement in the population of Simmental cattle in Russia. The analyzed database included breeding cows of the Simmental breed that were retired in the pe¬riod 2001–2020; the total number of livestock was 47,868 head. Calculation of the breeding value of productive longevity was carried out using the BLUPF90 program based on the BLUP Animal Model methodology. The share of Simmental cows of foreign selection that were eliminated after the 1st and 2nd lactations was 61.2 %, and those lactating longer than 6 lactations was only 4.0 %, while cows of Russian selection were 12.3 % less eliminated during the first two lactation and are able to produce longer. Phenotypic values of lifetime productivity in Simmental cows for an equal number of lactations are significantly higher in animals of foreign selection: from 824 kg of milk when leaving after the 1st lactation to 4,210 kg when leaving after the 10th lactation, from 35.3 to 188.5 kg by lifetime amount of fat and from 27.3 to 190.9 kg by lifetime amount of protein, respectively. The maximum estimates of breeding value for the lifetime productivity of a cow of fo¬reign selection reach +115.7 kg of milk fat and +91.3 kg of milk protein for a productive life by the 7th lactation.In cows of Russian selection, the predicted maximum breeding value estimates are achieved by the 9th lactation with indicators of +111.0 kg of milk fat and +88.4 kg of milk protein during the period of productive use. Lifetime milk productivity is significantly higher in Simmental cows of imported origin (by +824...+4210 kg), as well as estimates of breeding value (by +27.5...+35.9 kg), however, domestic Simmentals had a longer use period – on average for 2 lactations.

Comparison of Blood Mineral Levels of Norduz Goats of Different Ages Fed on Pasture at the End of the Lactation Period

This study was carried out to determine some makro and micro mineral levels in the blood of a total of 26 Norduz goats (at the end of 1st lactation (n=10), at the end of 2nd lactation (n=8), at the end of 3rd lactation (n=8)) fed in pasture at Van Yuzuncu Yil University, Research and Application Farm (Van, Turkiye). For this purpose, blood samples were duly taken from goats that had completed the lactation period at the beginning of June. Some macro mineral’s levels (potassium (K), magnesium (Mg), calcium (Ca), sodium (Na)) and some micro mineral’s levels (cobalt (Co), copper (Cu), iron (Fe), nickel (Ni), manganese (Mn), selenium (Se), zinc (Zn), lead (Pb)) in samples of serum obtained from blood samples collected from goats were determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Results were subjected to all statistical analysis using SPSS 24.0 version (IBM SPSS Inc, Chicago, USA) (SPSS, 2016). All statistically significant differences (P<0.05) were compared and ranked with Duncan's Multiple Range Test. Later, the relationships between minerals were revealed by Pearson Correlation Coefficient (P≤0.05). In addition, in this study, the ranking of macro and micro minerals and the rates of some of these minerals (Ca/Mn, Ca/Mg, Ca/Zn, Cu/Fe, Cu/Zn, Fe/Mn, Fe/Zn, K/Mg, K/Na, K/Mn) were also presented.

Associations of Grazing and Rumination Behaviours with Performance Parameters in Spring-Calving Dairy Cows in a Pasture-Based Grazing System.

This study investigated the relationship of the length of time spent grazing and ruminating with the performance parameters of spring-calved grazing dairy cows (n = 162) over the lactation period for three lactation seasons (n = 54 per season). The cows were Holstein Friesian (HFR), Jersey (JE), and a crossbreed of Holstein Friesian/Jersey (KiwiCross), with 18 cows from each breed. The cows were either in their 1st, 2nd, 3rd, or 4th lactation year, and had different breeding worth (BW) index values (103 < BW > 151). The cows were managed through a rotational grazing scheme with once-a-day milking in the morning at 05:00 h. The cows were mainly fed on grazed pastures consisting of perennial ryegrass (Lolium perenne), red clover (Trifolium pretense), and white clover (Trifolium repens), and received additional feeds on various days in the summer and autumn seasons. This study used an automated AfiCollar device to continuously record the grazing time and rumination time (min/h) of the individual cows throughout the lactation period (~270 days) for three consecutive years (Year-1, Year-2, and Year-3). The milk yield, milk fat, milk protein, milk solids, liveweight, and body condition score data of the individual animals for the study years were provided by the farm. PROC CORR was used in SAS to determine the correlation coefficients (r) between the behaviour and production parameters. A general linear model fitted with breed × lactation year, individual cows, seasons, feed within the season, grazing time, rumination time, as well as their interactions, was assessed to test the differences in milk yield, milk fat, milk protein, milk solids, liveweight, and body condition score. The type I sum of squares values were used to quantify the magnitude of variance explained by each of the study factors and their interactions in the study variables. Grazing time exhibited positive associations with MY (r = 0.34), MF (r = 0.43), MP (r = 0.22), MS (r = 0.39), LW (r = -0.47), and BCS (r = -0.24) throughout the study years. Rumination time was associated with MY (r = 0.64), MF (r = 0.57), MP (r = 0.52), and MS (r = 0.57) in all study years, while there were no effects of rumination time on LW (r = 0.26) and BCS (r = -0.26). Grazing time explained up to 0.32%, 0.49%, 0.17%, 0.31%, 0.2%, and 0.02%, and rumination time explained up to 0.39%, 6.73%, 4.63%, 6.53%, 0.44%, and 0.17% of the variance in MY, MF, MP, MS, LW, and BCS, respectively.

Profil Hematologi dan Protein Plasma Darah Sapi Perah Laktasi di Kelompok Ternak Bojong Kawung Pasir Jambu dengan Pemberian Feed Supplement

Twenty lactating dairy cows with the 1st, 2nd, and 3rd lactation periods and 1st to 5th lactation months as research objects to determine the effect of giving feed supplements on hematology and blood biochemistry. The experimental design used was a completely randomized design (CRD) with an experimental method consisting of 4 treatments and 3 replications. Each treatment consisted of 5 lactating dairy cows. The study was conducted for 10 weeks with the first 2 weeks being used as the adaptation stage. The treatments given were P0 = basal ration without feed supplement (control), P1 = 60% forage + 40% concentrate (97% concentrate + 3% protein by-pass), P2 = 60% forage + 40% concentrate (95% concentrate + 3% protein by-pass + 2% Ca-PUFA), and P3 = 60% forage + 40% concentrate (93% concentrate + 3% protein by-pass + 2% Ca-PUFA + 2% organic minerals). Blood sampling was carried out for each cow so that 20 blood samples were obtained. Blood sampling was carried out twice. The parameters observed in this study were the hematological profile which included Red Blood Cell (RBC), hemoglobin, hematocrit, Man Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin Concentration (MCHC), and platelets. Blood biochemical parameters include glucose, total protein, albumin, and globulin. The results showed that feeding supplementation had a significant (P&lt;0.05) effect on hematology and blood biochemistry, except MCV, MCHC, glucose, and albumin. The hematological and blood biochemical profiles of lactating dairy cows remain optimal through feed supplements in the form of protein by-pass, Ca-PUFA, and organic minerals.

Treatment of wound anaerobic infection in great horned animals: clinical example in a cow

External mechanical problems contribute to a wider problem in the surgical field in dairy cattle. The frequency of early injuries is highest in the limbs, and the lowest in the posterior and tail area. Most often, cows have puncture wounds that are susceptible to infection. Infectious complications of injuries and improper care in the aggregate lead to a decrease in productivity, premature culling of animals, and even to their death. Therefore, the analysis of medical methods and their effectiveness in great horned cattle for the aggravation of a accidental wound with anaerobic infection is also relevant. We looked at the clinical episode of a cow of the 1st or 2nd lactation, which had a puncture wound in the sub-breast area, right next to the subscapular area. The cow tried to overcome the fence and was injured by the end of the rebar. The treatment protocol will first help to stop bleeding, wash the cavity of wound with an antiseptic, add antibacterial powder to it and close it with sutures, internally administer ceftioclene. After the development of infectious-flammable structure in the wound and bacteriological investigation, treatment included washing with H2O2, drainage with Levosin and Nitacid ointment, metronidozole, bicilin 3, and granulation with the granulation of wounds: hydrophobic ointments. This is the basis for the use of systemic antibacterial therapy, rational surgical tactics and drainage, local treatment of active pharmacological agents with antibacterial, analgesic and hyperosmodic agents. Key words: cow injuries, wounds, purulent inflammation, ointments on hydrophilic bases.

RESEARCH ON THE DEVELOPMENT AND THERAPY OF PERSISTENT CORPUS LUTEUM IN COWS

"Pathological puerperium can mainly cause significant economic damage through the high losses that accumulate throughout the herd and especially through the high percentage of sterility and infecundity. According to literature data, it is shown that this infertility ratio can range quite widely between 5.0-30.0% of the total bull herd. A criterion in the occurrence of this gynecological disease is the feed, which can vary in terms of quantity and quality, the farming regime to which the cows are subjected and not especially environmental factors (lack of body hygiene, low temperatures during the winter season and prolonged housing). In both research years, the incidence of cows diagnosed with persistent corpus luteum was high at 7.1% in 2021 and 9.9% in 2022 in the non-lactating cows group and after a period of 90 days after parturition. In 2021 the persistent luteal corpus luteum (CLP) in April did not register any cases, the most significant values were recorded in the months: October (1.9%), November (2.5%), December (3.5%) and the highest level of (3.9%) being reached in January. In 2022 the recorded values of persistent corpus luteum were close compared to the first year of investigation, peaking in January at 3.1%. According to the number of lactations, in 2021, 19.3% females, in 1st lactation only 1.5% were diagnosed with this gynecological condition. Also, the highest level of 4.4% was recorded in cows in their 6th lactation and above."

Association between genomic daughter pregnancy rate and expected milk production on the resumption of estrus behavior in Holstein cattle

The objective of this observational study was to evaluate estrous expression at the first estrus occurring between 7 to 30 d in milk (DIM), as detected by an automated activity monitor (AAM), and its association with genomic daughter pregnancy rate (GDPR) and genomic expected milk production (GEM) in lactating dairy cows. A total of 4,119 lactations from 2,602 Holstein cows were included. Cows were enrolled as first lactation (n = 1,168), second lactation (n = 1,525) and third and greater lactation (n = 1,426). Hair samples were collected from the tail switch, and cows were genotyped using an SNP platform (Clarifide, Zoetis, São Paulo, SP, Brazil). Postpartum cows were examined daily by the farm personnel from calving until 10 DIM. Calving was classified as assisted (forced calf extraction) and unassisted (normal calving). Retained fetal membranes (RFM), hyperketonemia (KET), and left displaced abomasum (LDA) were also recorded. Mean GDPR (± SD) was -0.29 ± 1.4, and the intensity and duration of the first estrus event was 15.9 ± 13.1 x-factor (intensity unit measurement) and 11.1 ± 3.8 h, respectively. Cows that had greater GDPR had greater intensity and longer duration of estrus at the alert, independent of parity. Overall resumption of estrous expression, between 7 to 30 DIM, was 41.2% (1,695/4,119), where 58.8% (2,424/4,119) did not have an estrus event, 31.0% (1,274/4,119) of cows had one event of estrus, and 10.2% (421/4,119) of cows had 2 or more events of estrus early postpartum. Mean DIM (± SD) at first estrus event, detected by the AAM, was 19.4 ± 4.4 d. Days in milk at first event for cows with one event was 20.7 ± 1.6 d and 15.9 ± 3.1 d for cows with 2 or more events of estrus. First lactation cows were more likely to have an estrus event early postpartum when compared with second and third and greater lactation cows (45.2 ± 1.4% [530/1168] vs. 41.6 ± 1.3% [636/1525] vs. 37.2 ± 1.3% [529/1426], respectively). There was an interaction of parity and GDPR on the proportion of cows demonstrating an early postpartum estrus. There was no difference in the proportion of cows with an early postpartum estrus between those with assisted or unassisted calving, RFM, or LDA. However, cows that had KET were less likely to have an alert early postpartum when compared with cows that did not have KET. Mean genomic expected milk production (± SD) was 256.8 ± 600.1 kg. There was no interaction between GEM and parity on estrous expression (i.e., intensity and duration). There was no interaction between GEM and GDPR on the proportion of estrus early postpartum.

Study of the influence of dairy raw materials by seasons of the year on technological parameters in the production of soft cheese

Relevance. Milk and milk products are key food products in Russia. The main raw material for the production of cheese as an important component of the diet of citizens is milk, the main source of which is cattle. The Holshire breed is common in the Urals. Studying its features and improving the quality of milk (and therefore dairy products) is an urgent task for the agro-industrial complex of Russia.Methods. The purpose of the work is to study the influence of dairy raw materials by seasons on technological parameters in the production of soft cheese.Results. As a result of the research, it was found that the best quality was a clot from cows' milk for the 3rd and 4th lactation. To obtain it, less calcium chloride and whey were spent than in the manufacture of cheeses from cows' milk according to the 1st and 2nd lactation. It should also be noted that the duration of operations for the formation of a clot and work with it, as well as for self-pressing, was shorter in cows' milk for the 3rd and 4th lactation. In the manufacture of «Adygeisky» cheese on the other side of the enterprise, due to the introduction of rennet, the clot improved and the duration of self-pressing decreased, which had a positive effect on the quality of the product. The peculiarities in the manufacture of fresh «Amateur» and «Table» cheeses have been established, namely, certain differences in some technological operations, their duration and quality indicators of the clot and the separated whey. Thus, milk differed in the consumption of calcium chloride, lactic acid starter culture and rennet. The lowest consumption of these components turned out to be in the manufacture of cheese from milk of age-and-age cows. The milk of cows of the Holstein breed of the Ural selection is suitable for processing into soft cheeses regardless of the season of the year. However, the best indicators of technological properties are found in the milk of age-and-age cows for the 3rd and 4th lactation.

Improvement of the Red Steppe cattle by the Holstein breed gene pool

The results of the comparative assessment of productivity, reproductive ability and profitability of milk production when using cows of the Red Steppe breed and the crossbreeds of different blood relationship by the Holstein breed of the Red-and-White color type are presented. The studies of economically useful traits and profitability were conducted in 2019-2022. The objects of the research were representatives of the Red Steppe breed (control), mixtures with 50% (1st experimental group) and 75% of the blood of the Holstein Red-and-White color type (2nd experimental group). The superiority of the crossbred heifers over their herd mates of the Red Steppe breed in terms of milk yield was established: for the 1st lactation it was 605-673 kg (p &gt; 0.999), for the 2nd lactation it was 714-788 kg (p &gt; 0.999), for the 3rd lactation it was 817-868 kg (p &gt; 0.999). The highest coefficient of the milk yield was observed in Holstein F1 and F2 crossbreeds (9.4-9.7 kg), whose average advantage during all lactations ranged from 0.9-1.2 kg (p &gt; 0.95-0.99). In all analyzed service-periods, the highest fertilization rate after the first insemination was demonstrated by the Red Steppe breed animals; as a result, their semen consumption was on average 0.2-0.5 doses lower than that of the Holstein crossbreeds of different blood relationship. Cows of the Red Steppe breed had the highest reproductive ability coefficient 0.98-1.01 units vs. 0.85-0.95 units for crossbred cows. The analysis of the feed efficiency shows lower costs per unit production by cows of the first and second generations, in which they were 0.95-0.98 EFU, which is lower than in the Red Steppe breed peers, by 1.11-1.12 EFU. Milk production by half-blooded crossbreeds was more profitable 30.8-32.9% with no significant differences between the Red Steppe and high-blooded Holstein individuals.

Thermal stress influence on the productive and economic effectiveness of Holstein-Friesian dairy cows in temperate climate

Abstract The aim of this study was to evaluate the heat stress influence on milk production from primiparous and multiparous Holstein-Friesian cows and to estimate economic losses associated with the decrease in the farm’s milk yield. The cows selected for the study were in the middle phase of the 1st, 2nd, and 3rd lactation and were characterized by similar daily milk production. Additionally, the animals were kept in the same conditions and fed with the same feeds throughout the season. The analysis covered two 30-day periods – “cold” (April), in which no days with THI &gt;70 were noted, and “hot” (July), in which THI was above 70 for 90% of the days (74.4 on average). The average daily drop in milk production noted in the hot period was 1.25 kg/cow for multiparous cows and 2.78 kg/cow for primiparous cows. The average daily financial loss resulting from a drop in milk production was €0.55/day/cow in primiparous and €0.46/day/cow in multiparous animals. The calculated daily loss in the profit on production of 1 kg of milk was €0.27/day/kg for primiparous and €0.24/day/kg for multiparous animals. Based on test results, economic losses were simulated depending on the daily milk yield and the size of the primary cattle herd. For the multiparous cows, the estimated losses ranged from €6.07/day (farm sizes 25 cows and average daily milk yield 25 kg) to nearly €219/day (900 cows/25 kg). In larger facilities (900 cows) with an average daily milk yield of 55 kg, the daily loss will be about €481. The obtained results confirmed the assumptions made that with a change in microclimate conditions in the barn, a decrease in the daily production and changes in the milk chemical composition were noted, and the economic efficiency of the studied activity decreased.

МОЛОЧНАЯ ПРОДУКТИВНОСТЬ КОРОВ, ПРОИСХОДЯЩИХ ИЗ ПЕРСПЕКТИВНЫХ ВЕТВЕЙ ГОЛШТИНСКОЙ ПОРОДЫ

The aim of the study was to study the milk productivity of cows originating from different promising branches and lines of the Holstein breed. The population studied was Wis Back Idial 101341, Reflection Sovering 198998, Montvik Chieftain 95679, Siling Traijun Rokita 252803 and Roseife City 267150. The best indicators were established in cows of the line V.B. Ideal for the 1st and 3rd lactation (7086 and 7431 kg of milk with the amount of milk fat 271 and 285 kg and the amount of milk protein 225 and 238 kg), and the difference is statistically significant (P&lt;0.05-0.001) in relation to other lines. In second place are the animals of the Reflection Sovering line. Cows of the line S.T. Rokita had a high milk fat content (3.85 and 3.94%) at P&lt;0.05. In V. Aidial's line, the best milk yield indicators are shown by first-calf heifers of the SWEET-HAVEN TRADITION branch (7143 kg). In the R. Sovering line, cows of the TO-MAR BLACKSTAR-ET branch showed the greatest increase in milk yield by 89-1226 kg, milk fat yield by 4-42 kg, milk protein yield by 2-37 kg (P&lt;0.001), and high milk fat content (3.86%) of the cow of the S-W-D VALIANT line (P&lt;0.01-0.001). According to the 3rd lactation in the line of R. Sovering, cows of the S-W-D VALIANT branch show an advantage in milk yield by 353-831 kg of milk, mass fraction of fat - by 0.05-0.08%, milk fat yield - by 20-36 kg and milk protein yield - by 12-26 kg (P&lt;0.05-0.01). As a result of the study, it was found that the use of animal branches of SWEET-HAVEN TRADITION, ROCKALLI SON OF BOVA, TO-MAR BLACKSTAR-ET and WALKWAY CHIEF MARK makes it possible to obtain high milk productivity from them.

DNA methylation and gene expression changes in mouse mammary tissue during successive lactations: part II – the impact of lactation rank

ABSTRACT Mastitis is among the main reasons women cease breastfeeding. In farm animals, mastitis results in significant economic losses and the premature culling of some animals. Nevertheless, the effect of inflammation on the mammary gland is not completely understood. This article discusses the changes to DNA methylation in mouse mammary tissue caused by lipopolysaccharide-induced inflammation after in vivo intramammary challenges and the differences in DNA methylation between 1st and 2nd lactations. Lactation rank induces 981 differential methylations of cytosines (DMCs) in mammary tissue. Inflammation in 1st lactation compared to inflammation in 2nd lactation results in the identification of 964 DMCs. When comparing inflammation in 1st vs. 2nd lactations with previous inflammation history, 2590 DMCs were identified. Moreover, Fluidigm PCR data show changes in the expression of several genes related to mammary function, epigenetic regulation, and the immune response. We show that the epigenetic regulation of two successive physiological lactations is not the same in terms of DNA methylation and that the effect of lactation rank on DNA methylation is stronger than that of the onset of inflammation. The conditions presented here show that few DMCs are shared between comparisons, suggesting a specific epigenetic response depending on lactation rank, the presence of inflammation, and even whether the cells had previously suffered inflammation. In the long term, this information could lead to a better understanding of the epigenetic regulation of lactation in both physiological and pathological conditions. Abbreviations: RRBS, reduced representation bisulphite sequencing; RT-qPCR, real-time quantitative polymerase chain reaction; MEC, mammary epithelial cells; MaSC, mammary stem cell; TSS, transcription start site; TTS, transcription termination site; UTR, untranslated region; SINE, short interspersed nuclear element; LINE, long interspersed nuclear element; CGI, CpG island; DEG, differentially expressed gene; DMC, differentially methylated cytosine; DMR, differentially methylated region; GO term, gene ontology term; MF, molecular function; BP, biological process

Influence of Heat Stress on Milk Production in Fraternal Twins

The aim of this study was the evaluation of heat stress in milk production in dairy cows (daily milk yield; milk production in 1st lactation). The comparison was performed between fraternal twins (full sisters), produced on the same farm and same parity. One of the twins produced in a hot period whereas her sister produced in a cooler period. Also, there can be differences in milk production between fraternal twins. Therefore, a second group of fraternal twins was also created that produced without heat stress. Databases of fraternal twins were analysed using PROC GLM analysis of Statistica&#174; with selected effects. In conclusion, a negative effect of heat stress on milk production was found. There was an obvious tendency (in some cases insignificant) for worse milk production during heat stress in both the daily milk yield during hot days and in 1st lactation started in the hot season. Fat content (in %) was also lower in the hot period but differences were insignificant. On the other hand, there was found very low differences in milk production (and milk components) between fraternal twins produced in season without heat stress.

Important health and management reasons of early sow removal

Gilt and sow management practices are key factors for the reproduction and production efficiency of any production system. In Poland, the number of piglets born alive per sow per year and the number born alive per sow per lifetime are relatively low. This may have a number of causes. One of them is an unsuitable parity distribution. According to some data, most females are removed from the herd after the first or second parity. As a consequence, the number of piglets born alive per sow per lifetime is small. In some countries, the number of litters per sow per lifetime varies from 3.3 to 5.6, with a total number of 32 to 73 piglets weaned. The average longevity of a sow in various countries ranges from 467 to 969 days. For Poland, precise data are unfortunately lacking, but unpublished data suggest that the number of litters per statistic sow does not exceed 5, although in particular farms this parameter ranges from 3 to 7. According to data available from different farms, early sow culling takes place mostly after the first or second parity. The causes include errors in gilt’s rearing and introduction into the herd, stall acclimatization, and boar exposure. A gilt’s longevity and performance are also determined by her body weight and age at first breeding, feed intake in the lactation period, as well as body weight gained during gestation and 1st lactation. If properly developed and managed, a gilt with high immunity will perform well as a P1 and will continue to be highly productive throughout her lifetime. Otherwise, she will perform poorly in her first parity, after which her longevity is likely to be short. This paper also reviews health-related causes of early sow culling in Polish farms. The most important ones are infertility, embryonic death, stillbirth, mastitis, and MMA (mastitis, metritis, agalactia), as well as infectious pathogens (viruses), such as IAV-S, PRRSV, PCV2, PPV, ECMV, ADV, CSF, or bacteria: Leptospira spp., Brucella suis, and Erysipelothrix rhusiopathiae.

Влияние инбридинга на удой и причины выбытия коров айрширской породы

The analyzed sample included data on milk yield, BV of milk yield and inbreeding of 672 cows with different reasons for culling with an average milk yield for the 1st lactation of 8601 kg of milk, which is –124 kg less than their peers, and quality indicators of 3,97 % fat and 3,32 % protein. All cows are divided into 13 classes due to retirement. On average, the inbreeding coefficient for the sample is 3,50 % with a variation in groups from 2,16 to 4,59 %. The most inferior in terms of milk yield for the 1st lactation were cows with the cause of retirement low productivity and culling (–415 kg), diseases of the udder (–222 kg) and legs (–144 kg), gynecological diseases and barrenness (–134 kg). The relationship of inbreeding with absolute indicators and BV of productive traits is low, but negative with milk yield (–0,022 and –0,014, respectively) and positive with fat content (+0,053 and +0,036, respectively) and milk protein content (+0,048 and +0,027, respectively). Using a one-way ANOVA, a high and significant effect of the breeding method and the degree of inbreeding on the milk yield and the reasons for the disposal of the analyzed animals was revealed (35,1 and 24,8 %, respectively). The distribution of cows culled for various reasons, depending on the method of breeding and the degree of inbreeding, showed that among them there are more cows crossed (59,7 %) compared to intraline (40,3 %) and the proportion of culling in the first group is higher due to gynecology and barrenness (19,1 vs. 18,5 %), diseases of the limbs (14,8 vs. 12,9 %), metabolic diseases (15,6 vs. 12,2 %). When considering the degree of inbreeding, regardless of the method of breeding, it was revealed that most of the sample are cows with a moderate degree of inbreeding (63,2 %), and 28,3 % with closely related, and in the group of moderately inbred cows for the main reasons for disposal, the proportion of animals is greater by 1,4–6,6 %. Thus, the conducted studies confirm that when selecting pairs, it is necessary to take into account not only the method, but also the degree of inbreeding in the proband.

Association of genotypes of cows of the Kholmogory breed by beta-casein with milk productivity

The aim of the study is to identify the frequency of occurrence of various allelic variants and genotypes of beta-casein in cows of the Kholmogory breed and their relationship with dairy productivity. The tasks of the research are genotyping of cattle of the Kholmogory breed by the beta-casein locus and establishing its connection with qualitative and quantitative indicators of dairy productivity. As the objects for the research there were taken 150 cows of the 1st, 2nd and 3rd lactation. An allele-specific variant of the PCR method (AS-PCR) was used to identify A1 and A2 beta-casein. As the result it had been established that in the studied part of the herd, 23 % of animals had the A2A2 genotype, 43 % of animals had the A1A1 genotype and 34 % of animals had the A1A2 genotype. For 100 days of the first lactation, animals with A1A2 genotype showed the highest value in milk yield. Animals with A2A2 genotype for 305 days of lactation had the highest milk yield and the amount of milk protein, however, the difference was not statistically significant compared to the animals with A1A2 genotype. Genotype A1A1 has lower indicators by all the parameters studied, with a significant difference relative to genotypes A1A2 and A2A2. Thus, the study of CSN2 is a promising area of scientific research, and the results of the study of beta-casein genotypes can be used as a marker selection in improving the herds of the Kholmogory breed.

Characteristics of Biological and Economic Qualities Holstein Cattle

In the presented article, the milk productivity of cows of the Black Pied breed of different genotypes in the 1st lactation is considered. The biological indicators of cows in the base farms and farms of comparison are analyzed. Features of the shape of the udder of cows in the early period of childbirth, the size and functional characteristics of the udder of heifers, as well as quantitative differences in the protein content in the milk of Holsteinized and reference cows.

Long-term effects of early-life rumen microbiota modulation on dairy cow production performance and methane emissions.

Rumen microbiota modulation during the pre-weaning period has been suggested as means to affect animal performance later in life. In this follow-up study, we examined the post-weaning rumen microbiota development differences in monozygotic twin-heifers that were inoculated (T-group) or not inoculated (C-group) (n = 4 each) with fresh adult rumen liquid during their pre-weaning period. We also assessed the treatment effect on production parameters and methane emissions of cows during their 1st lactation period. The rumen microbiota was determined by the 16S rRNA gene, 18S rRNA gene, and ITS1 amplicon sequencing. Animal weight gain and rumen fermentation parameters were monitored from 2 to 12 months of age. The weight gain was not affected by treatment, but butyrate proportion was higher in T-group in month 3 (p = 0.04). Apart from archaea (p = 0.084), the richness of bacteria (p < 0.0001) and ciliate protozoa increased until month 7 (p = 0.004) and anaerobic fungi until month 11 (p = 0.005). The microbiota structure, measured as Bray-Curtis distances, continued to develop until months 3, 6, 7, and 10, in archaea, ciliate protozoa, bacteria, and anaerobic fungi, respectively (for all: p = 0.001). Treatment or age × treatment interaction had a significant (p < 0.05) effect on 18 bacterial, 2 archaeal, and 6 ciliate protozoan taxonomic groups, with differences occurring mostly before month 4 in bacteria, and month 3 in archaea and ciliate protozoa. Treatment stimulated earlier maturation of prokaryote community in T-group before month 4 and earlier maturation of ciliate protozoa at month 2 (Random Forest: 0.75 month for bacteria and 1.5 month for protozoa). No treatment effect on the maturity of anaerobic fungi was observed. The milk production and quality, feed efficiency, and methane emissions were monitored during cow's 1st lactation. The T-group had lower variation in energy-corrected milk yield (p < 0.001), tended to differ in pattern of residual energy intake over time (p = 0.069), and had numerically lower somatic cell count throughout their 1st lactation period (p = 0.081), but no differences between the groups in methane emissions (g/d, g/kg DMI, or g/kg milk) were observed. Our results demonstrated that the orally administered microbial inoculant induced transient changes in early rumen microbiome maturation. In addition, the treatment may influence the later production performance, although the mechanisms that mediate these effects need to be further explored.

Reasons for culling cows from a productive herd

The article provides data on the causes and premature culling of cows. Extraordinary activities are a matter of productivity of cows, which significantly affect the efficiency of milk production in livestock farms. First of all, the number and intensity of manifestations of other pathological processes in the body to enhance the quality of milk (grade, bacterial contamination, etc.). The next factor in the economic condition of both an individual economy and the industry as a whole is the length of the productive period. Premature culling of cows entails damage from inefficient use of feed, costs for the unproductive period (from birth to 1 calving), losses from undersupply of calves and often loss of breeding value of the livestock. The aim of the work was to establish the reasons for the culling of cows, which affects the efficiency of the enterprise, especially at the age of 4-6 years (3-5 lactations). At the same time, we used the data of the Uniform-Agri accounting program of the Astarta-Kiev agricultural holding, statistical research methods, and the processing of the data obtained was carried out using a Microsoft Excel 2016 spreadsheet processor. It was found that during 2017-2019. out of 47,282 16538 head retired, which amounted to about 35.0% of the total breeding stock, the largest number of retired cows was observed in the first lactation - 4602, which is 27.8%. In 37.1% of cases, obstetric and gynecological diseases and pathological conditions of the mammary gland were diagnosed. At the same time, 24.5% of culled cows were diagnosed with surgical pathology. In addition, 20.8% of cows dropped out due to metabolic disorders, due to violations of the parameters of keeping and feeding. The next step was to determine the proportion of cow culling due to obstetric (23.9%), gynecological (49.0%), surgical (59.1%) pathology and breast diseases (27.7%). It was also important that 30% of the culled cows had a diagnosis of maceration and mummification of the fetus or ordinary abortion. It should be noted that the vast majority of animals had obstetric, gynecological and surgical pathology at the same time. The culling of animals by age was: after the 1st lactation 31.9%, the 2nd lactation decreased by 12.6 %, and the 3rd, 4th and 5th and more lactations, respectively, by 3.0%. 2.9 and 4.3% Key words: cow, culling, obstetric, gynecological, surgical pathology.