Breeder Cows Research Articles

Mammary fat globules as a source of mRNA to model alterations in the expression of some milk component genes during lactation in bovines

BackgroundThe milk's nutritional value is determined by its constituents, including fat, protein, carbohydrates, and minerals. The mammary gland's ability to produce milk is controlled by a complex network of genes.Thereby, the fat, protein, and lactose synthesis must be boost in milk to increase milk production efficiency. This can be accomplished by fusing genetic advancements with proper management practices. Therefore, this study aimed to investigate the association between the Lipoprotein lipase (LPL), kappa casein CSN3, and Glucose transporter 1 (GLUT1) genes expression levels and such milk components as fat, protein, and lactose in different dairy breeds during different stages of lactation.MethodsTo achieve such a purpose, 94 milk samples were collected (72 samples from 36 multiparous black-white and red-white Holstein–Friesian (HF) cows and 22 milk samples from 11 Egyptian buffaloes) during the early and peak lactation stages. The milk samples were utilized for milk analysis and genes expressions analyses using non- invasive approach in obtaining milk fat globules (MFGs) as a source of Ribonucleic acid (RNA).ResultsLPL and CSN3 genes expressions levels were found to be significantly higher in Egyptian buffalo than Holstein–Friesian (HF) cows as well as fat and protein percentages. On the other hand, GLUT1 gene expression level was shown to be significantly higher during peak lactation than early lactation. Moreover, lactose % showed a significant difference in peak lactation phase compared to early lactation phase. Also, fat and protein percentages were significantly higher in early lactation period than peak lactation period but lactose% showed the opposite pattern of Egyptian buffalo.ConclusionTotal RNA can be successfully obtained from MFGs. The results suggest that these genes play a role in glucose absorption and lactose synthesis in bovine mammary epithelial cells during lactation. Also, these results provide light on the differential expression of these genes among distinct Holstein–Friesian cow breeds and Egyptian buffalo subspecies throughout various lactation phases.

Analysis of Farmer's Perception and Constraints on Dairy Cooperatives in Amhara Region, Ethiopia

This study was done to examine the farmer’s perception and constraints on dairy cooperatives in Amhara region, Ethiopia. A sample of 266 smallholder dairy farmers was selected using a multi-stage sampling technique. Perception of farmers was analyzed using relative importance index, and constraints of dairy cooperative performance were analyzed using Henry Garrett's ranking technique. The result indicates that farmers have a positive perception of certain attributes of dairy cooperatives; such as increasing social networks, improving income, and serving as a saving source. This suggests that farmers believe these aspects of dairy cooperatives are beneficial. Conversely, farmers have concerns and dissatisfaction with the way the cooperative is running, the loyalty of members to the cooperative, member's treatment by cooperatives, and the decision-making process. The study also identified that lack of milk processing facilities, poor member awareness, and member involvement in the decision-making process are the foremost internal challenges of dairy cooperatives, while high cost of cross-breed cows, occurrence of animal disease, and low productivity of local breed cows are external constraints hindering dairy cooperative performance. Thus, to enhance farmers' perception and participation in cooperative activities, emphasis should be given to addressing concerns and improving the overall functioning of dairy cooperatives.

Multispecies pasture diet and cow breed impacts on milk composition and quality in a seasonal spring-calving dairy production system

In recent years, there has been significant emphasis on the composition of pasture-based cow feed and the potential benefits of incorporating multispecies swards to improve sustainability and biodiversity. This study compared the effects of a conventional perennial ryegrass (PRG) monoculture supported by high chemical nitrogen (N) usage with a low chemical N application multispecies sward system (MSS) on the composition and quality of milk across lactation using spring-calving Holstein-Friesian (HF) and Jersey Holstein-Friesian (JFX) cows. Bulk milk samples (n = 144) were collected from each group at morning and evening milking on a weekly basis (n = 36) throughout lactation and analyzed for gross composition and physico-chemical properties. Cow breed had a significant impact on milk profile, with milk from HF cows having significantly smaller milk fat globule (MFG) size, higher instability index values, higher yield, and lower total solids levels, compared with JFX cows. Notably, HF cows had increased milk total solids and fat levels when fed on MSS, as opposed to the PRG-fed HF cows. Feeding MSS pasture increased creaming velocity values in mid and late lactation, and resulted in similar milk gross composition to PRG. In comparison to PRG, MSS-fed groups showed significantly increased total solids yield, including higher levels of protein and fat yield. In late lactation, MSS feeding was associated with reduced MFG size. All physicochemical properties studied (MFG size, creaming velocity, instability index) showed decreasing values from early to late lactation stage. Overall, these findings demonstrate the significant effects of cow diet, breed and stage of lactation on compositional and physico-chemical characteristics of milk, with important implications for milk processing and dairy product quality.

Nutritional Value and Technological Parameters of Milk From Organic and Conventional Farms in Poland

Abstract The aim of the study was to assess the nutritional value and technological parameters of milk produced in organic and conventional farming systems, taking into account the breeds of cow, feeding system, and season of production in Poland. A total of 413 milk samples were analysed, of which 220 were from Simmental cows raised on organic farms and 193 were from conventional farms, including 64 from Polish Black-and-White cows fed in a traditional system, as well as 65 from Simmental cows and 64 from Holstein-Friesian cows fed in a TMR (Total Mixed Ration) system. The milk was analysed for content of fat, protein, lactose, and urea; somatic cell count; suitability for processing (active and titratable acidity, casein content, protein-to-fat ratio, heat stability, and rennet coagulation); and content of biologically active substances (whey proteins, fatty acids, and macro- and microelements). Simmental cows from organic farms had the lowest daily milk yield, with the lowest concentrations of basic nutrients. However, it was a richer source of α-lactalbumin, lactoferrin and lysozyme and had the highest content of PUFA s. It also had a favourable protein-to-fat ratio and the shortest rennet clotting time, but it contained less Ca, Mg and Zn than milk from farms using a TMR system. The season of production had a greater influence on the composition, nutritional value and technological parameters of milk from farms using traditional feeding, including organic farms, compared to those using a TMR diet. Milk from organic farms obtained in the summer season contained more dry matter, including total protein, β-lactoglobulin, α-lactalbumin, lactoferrin, and lysozyme. It was also characterised by a more preferable fatty acid profile, i.e. lower content of SFA and higher of UFA, including MUFA and PUFA . In turn, milk from the winter season contained more fat and showed better heat stability. At farms using traditional feeding regimens, both organic and conventional, the production period had a more significant impact on the differentiation of the content of mineral components in milk (mainly macroelements).

Relationship between Selected SNPs (g.16024A/G, g.16039T/C and g.16060A/C) of the FASN Gene and the Fat Content and Fatty Acid Profile in the Milk of Three Breeds of Cows.

Fat is an important energy and nutritional component of milk and consists of fatty acids. FASN (fatty acid synthase) is an enzyme that regulates the synthesis of fatty acids in the milk and meat of cattle. It was hypothesized that knowing the relationships between the genotypes of the tested single nucleotide polymorphisms (SNPs) and the content of fat and specific fatty acids would make it possible to improve milk quality in the selection process during cattle breeding. This study aimed to analyze the relationships of SNPs (g.16024A/G, g.16039T/C) of the FASN gene and their genotypes with the fat and fatty acid content of the milk of the following breeds: Polish Red-White (ZR), Polish Red (RP), and Polish Holstein-Friesian Red-White (RW). The SNP g.16060A/C was included in the study, although its effect on the fat composition of cow's milk has not yet been widely studied. Milk was obtained during test milkings. SNP genotyping was performed using the real-time PCR (HRM) method. The milk from ZR and RP cows was more often characterized by a more favorable fatty acid profile than the milk from RW cows. This information can be used by cattle breeders and consumers of so-called functional food.

Friesian Holstein (FH) Dairy Cows Milk Quality that Experienced Repeated Breeding in Sendang District, Tulungagung Regency

This study observe the milk quality decrease in Friesian Holstein (FH) dairy cows that experience repeated breeding (repeat breedings) at KUD Tani Wilis Sendang Tulungagung when viewed from density, fat content, Total Solid (TS), and Solid Non Fat (SNF). The milk samples to be used in this study were 32 with a ratio of 10 normal cow's milk samples as a control. The milk sample was examined using a lactoscan. The data obtained were analyzed using the Independent T-Test test. The results of the repeat breeding cow's milk samples for specific gravity, fat content, and Total Solids (TS) showed a significant difference (p <0.05) between the treatment group and the control of normal cow's milk. Samples of repeat breeding cow's milk on Solid Non Fat (SNF) showed that it was not significantly different (p>0.05). The average specific gravity of repeat breeding cows was 1.0282 and that of normal cow's milk was 1.0260, which means that there is an increase in repeat breeding cow's milk when compared to normal cow's milk. The fat content of repeat breeding cows was 1.08% and that of normal cows was 4.18%. Total Solid (TS) of repeat breeding cows was 9.38% and normal cows was 12.73%.

Effect of Dietary Supplementation of Wet Brewer’s Grains on Lactation Performance of Jersey Cross Breed Cows

Effect of Dietary Supplementation of Wet Brewer’s Grains on Lactation Performance of Jersey Cross Breed Cows

Increasing the productivity of cows through the use of premixes based on forest and mineral resources in feeding

The influence of premixes based on forest (pine needles, pine nut shells, arabinogalactan) and mineral (bentonite clay, expanded vermiculite) raw materials on dairy productivity of cows has been studied. The experiment was conducted in the Krasnoyarsk region on three groups of Black-and-White breed cows (10 heads per group) at the age of the third calving, with a live weight of 530–550 kg. The control group was fed the basic diet, the 1st experimental group was fed a premix consisting of bentonite clay, pine coniferous flour, pine nut shells, vitamin and mineral complex and arabinogalactan in addition to the basic diet. Cows of the 2nd experimental group were fed a premix of a similar compo sition with the exception of bentonite clay, instead of which expanded vermiculite was included in the premix. The duration of the experiment was 60 days. The cows were kept tethered and walking, milking was automatic in the milk pipeline. The feeding ration corresponded to zootechnical standards. The studied premixes were fed in a mixture with concentrated feeds once a day. The research was carried out according to generally accepted methods using modern certified equipment. Feeding the cows of the studied premixes had a positive effect on milk productivity in both experimental groups, however, the greatest increase in productivity compared with the control was found in cows of the 2nd experimental group who received a premix with expanded vermiculite in the composition. Milk yield of natural fat content in this group increased by 7.60%, milk yield of basic fat content – by 14.02%, the mass fraction of fat in milk – by 0.23 percentage points, the amount of milk fat – by 14.02%, milk protein – by 9.65%. The organoleptic parameters of the milk of experimental cows under the influence of the studied premixes did not deteriorate and met the requirements of the GOST (Russian National Standard) for premium milk.

Relationship between body condition of dairy cows in the peripartum period and selected metabolic parameters in consideration of different breeds

The results of this study describe the relationship between the body condition of dairy cows and selected metabolic parameters during the peri- and post-partum period with special consideration of 3 local dairy cow breed in Upper Bavaria and the Allgau. Three local dairy cattle breeds (Swiss Brown (BV), Simmental (FL), Holstein Friesian (HF)) were examined on 68 farms in southern Germany for 7 consecutive weeks. In dry cows as well as lactating cows (5.-65. day in milk), following blood parameters were investigated: beta-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), creatinine, aspartate aminotransferase, gamma-glutamyltransferase, glutamate dehydrogenase, total protein, albumin, creatine kinase. In addition, body condition (body condition score [BCS] and back fat thickness [BFT]) were recorded. Exploratory and descriptive statistics were used for data analysis. Concerning the difference in condition before and after calving, the FL showed the smallest difference in RFD. For FL and BV a trend towards higher BFT values could be seen in first lactating cows. For FL and HF, the NEFA values of the later lactating cows were below those of the first lactating cows. The higher lactating cows of BV and FL had higher BHB values. The correlation between BFT and BCS showed the highest R2 (0.53) in the HF cows. BV and FL were below at 0.42 and 0.37. BCS and BFT could not be predicted by the variables NEFA, BHB and liver enzymes. BHB levels of all 3 breeds increased at weeks 2-4 post-partum. The NEFA values for all 3 breeds increased primarily in the 1st-3rd week p.p. in parallel to when the BFT p.p. decreased. NEFA values were highest when body condition declined and therefore when fat mobilization peaked. In BV and HF, there was a constant increase in GLDH when the p.p. BCS difference was there. Body condition assessment (BCS at herd and animals` level, BFT at animal level) is an important tool for animal health monitoring. Due to the recognizable breed specificity, the dairy herds can be dealt with more explicitly. The aim is to optimally influence the energy balance of the cow during early lactation in order maintain the health of the animal and its organ systems.

Effects of 3-nitrooxypropanol (Bovaer10) and whole cottonseed on milk production and enteric methane emissions from dairy cows under Swiss management conditions

The objective of this study was to determine the potential effect and interaction of 3-nitrooxypropanol (3-NOP; Bovaer, DSM-Firmenich Nutrition Products Ltd.) and whole cottonseed (WCS) on lactational performance and enteric methane (CH4) emission of dairy cows. A total of 16 multiparous cows, including 8 Holstein Friesian (HF) and 8 Brown Swiss (BS; 224 ± 36 DIM, 26 ± 3.7 kg milk yield, mean ± SD), were used in a split-plot design, where the main plot was the breed of cows. Within each subplot, cows were randomly assigned to a treatment sequence in a replicated 4 × 4 Latin square design with 2 × 2 factorial arrangements of treatments with four 24-d periods. The experimental treatments were as follows: (1) control (basal TMR), (2) 3-NOP (60 mg/kg TMR DM), (3) WCS (5% TMR DM), and (4) 3-NOP + WCS. The treatment diets were balanced for ether extract, crude protein, and NDF contents (4%, 16%, and 43% of TMR DM, respectively). The basal diets were fed twice daily at 0800 and 1800 h. Dry matter intake and milk yield were measured daily, and enteric gas emissions were measured (using the GreenFeed System, C-Lock Inc.) during the last 3 d of each 24-d experimental period when animals were housed in tiestalls. There was no difference in DMI on treatment level, whereas the WCS treatment increased ECM yield and milk fat yield. No interaction of 3-NOP and WCS occurred for any of the enteric gas emission parameters, but 3-NOP decreased CH4 production (g/d), CH4 yield (g/kg DMI), and CH4 intensity (g/kg ECM) by 13%, 14%, and 13%, respectively. Further, an unexpected interaction of breed by 3-NOP was observed for different enteric CH4 emission metrics: HF cows had a greater CH4 mitigation effect compared with BS cows for CH4 production (g/d; 18% vs. 8%), CH4 intensity (g/kg milk yield; 19% vs. 3%), and CH4 intensity (g/kg ECM; 19% vs. 4%). Hydrogen production was increased by 2.85-fold in HF and 1.53-fold in BS cows receiving 3-NOP. Further, a 3-NOP × time interaction occurred for both breeds. In BS cows, 3-NOP tended to reduce CH4 production by 18% at approximately 4 h after morning feeding, but no effect was observed at other time points. In HF cows, the greatest mitigation effect of 3-NOP (29.6%) was observed immediately after morning feeding, and it persisted at around 23% to 26% for 10 h until the second feed provision, and 3 h thereafter, in the evening. In conclusion, supplementing 3-NOP at 60 mg/kg DM to a high-fiber diet resulted in 18% to 19% reduction in enteric CH4 emission in Swiss HF cows. The lower response to 3-NOP by BS cows was unexpected and has not been observed in other studies. These results should be interpreted with caution due to the low number of cows per breed. Finally, supplementing WCS at 5% of DM improved ECM and milk fat yield but did not enhance the CH4 inhibition effect of 3-NOP of dairy cows.

Dam–calf contact rearing in Switzerland: Aspects of management and milking

Cow-calf contact (CCC) rearing is becoming an increasingly popular alternative to the common practice of early separation of cow and calf in dairy management. Milkability can be impaired in nursing cows, which contributes to the loss of machine milk yield caused by calf intake, especially in pure dam-calf contact (DCC) systems. The aims of this study were (1) to describe the current status quo of DCC rearing regarding management and milking and (2) to evaluate the effects of DCC (suckling and milking vs. milking alone) and the effects of different types of DCC on milkability parameters, teat condition, and behavior during milking on Swiss DCC farms. By means of 17 telephone interviews with DCC farmers, we collected data on DCC management, housing, separation and weaning processes, milking procedures and techniques, and perceived milkability problems. Subsequently, we collected data on 10 of the interviewed DCC farms (183 cows): 4 DCC farms with a whole-day contact (WDC) system, 3 farms with DCC before milking (CBM), and 3 farms with DCC after milking (CAM). Five farms on which calves had no contact with dams were chosen as reference farms (178 cows). Using a milk flow meter, the occurrence of ejection disorders, bimodality of the milk flow curve, machine milk yield, duration of the decline phase, and duration of prestimulation were measured. The average mouthpiece chamber vacuum during the main milking phase and hind leg activity during milking were measured using a pressure sensor and an accelerometer, respectively. After cluster removal, the teat condition was evaluated, and a stripping milk sample was taken for fat content analysis. The interview results revealed that 8 of the 17 farms surveyed had a WDC system, and 2 farms operated a daytime DCC system. Contact before milking was applied by 3 farms, and 3 farms allowed CAM. On one farm, calves had access to dams 3 times a day. A great diversity in cow-calf management was found. In the on-farm data collection, 20 milkings of a total of 701 milkings examined met the criteria for a clear ejection disorder, with 17 of these observations occurring on WDC farms and none on reference farms. The stripping milk fat content was lower in nursing cows, indicating a lower degree of udder emptying. Machine milk yield was higher in nursing CAM cows than in nursing WDC and CBM cows. Farm types did not differ regarding teat condition, hind leg activity, or the occurrence of bimodal milk flow curves. In conclusion, the large variation in individual management approaches to DCC rearing even within DCC types, such as calf housing or cow breeds, implies caution when interpreting results. Contact after milking may be the system most beneficial for some productivity parameters, but adequate calf supply must be ensured. Higher amounts of milk remaining in the udder after cluster removal indicate that nursing can affect milkability, but future research should consider the effects of udder filling before milking to better interpret the fat content of stripping milk.

Vaginal lipoma with cervicovaginal and rectal prolapse in a cow

A 5-year, mixed breed cow, was presented with cervicovaginal and rectal prolapses. Cow had a vaginal mass on the left caudal aspect of cervicovaginal prolapse. Rectal prolapse was resolved; however, vaginal mass prevented reduction of vaginal prolapse. Next day, vaginal mass was resected that made vaginal prolapse reduction and vulval closure (Bühner stich) possible. Histopathology identified the mass as infected vaginal lipoma.

MicroRNA-2285f regulates milk fat metabolism by targeting MAP2K2 in bovine mammary epithelial cells.

In this study, Holstein dairy cows raised in Ningxia were selected as the research object. Mammary epithelial cells (BMECs) were extracted from the milk of eight Holstein cows with significantly different milk fat expression rates and transcribed for sequencing. Bioinformatics analysis was used to analyse the correlation of fat milk percentage, and the critical miR-2285f regulating milk fat was screened out. The target gene binding sites were predicted, and 293T cells and mammary epithelial cells were used as miRNA and target gene models for functional verification invitro. The tissue difference of miR-2285f Holstein cows was quantitatively analysed by transfecting miR-2285f mimic and inhibitor. Assay (dual luciferase reporter gene assay) and quantitative real-time PCR (quantitative real-time PCR, qRT-PCR), triglyceride (TAG) detection, oil red O detection of lipid droplets, Western Blot assay, Edu and Flow cytometry, The molecular regulatory effects of miR-2285f and target gene MAP2K2 on milk fat metabolism of Holstein dairy cows were studied. The wild-type vector and mutant vector of map2k2-3'utr were constructed, and double luciferase reporting experiments were conducted to verify that MAP2K2 was one of the target genes of miR-2285f. According to qRT-PCR and Western Blot analysis, miR-2285f mainly regulates the expression of MAP2K2 protein in BMECs at the translation level. Bta-miR-2285f can promote cell proliferation and slow cell apoptosis by regulating MAP2K2. Bta-miR-2285f can promote triglyceride (TAG) and lipid droplet accumulation in mammary epithelial cells by targeting MAP2K2. Bta-miR-2285f can regulate protein levels of fat milk marker gene PPARG by targeting MAP2K2. In conclusion, miR-2285f can target the expression of the MAP2K2 gene, promote the proliferation of dairy mammary epithelial cells, inhibit cell apoptosis and regulate the milk fat metabolism in dairy mammary epithelial cells. The results of this study revealed the function of miR-2285f in regulating the differential expression of fat milk in Holstein dairy cows at the cellular level. They provided a theoretical and experimental basis for analysing the regulation network of milk fat synthesis of Holstein dairy cows and the molecular breeding of dairy cows.

Design and Experiment of an Autonomous Navigation System for a Cattle Barn Feed-Pushing Robot Based on UWB Positioning

The autonomous navigation system of feed-pushing robots is one of the key technologies for the intelligent breeding of dairy cows, and its accuracy has a significant influence on the quality of feed-pushing operations. Currently, the navigation methods of feed-pushing robots in the complex environment of cattle barns mainly include visual, LiDAR, and geomagnetic navigation, but there are still problems relating to low navigation accuracy. An autonomous navigation system based on ultra-wideband (UWB) positioning utilizing the dynamic forward-looking distance pure pursuit algorithm is proposed in this paper. First, six anchor nodes were arranged in the corners and central feeding aisle of a 30 × 86 m rectangular standard barn to form a rectangular positioning area. Then, utilizing the 9ITL-650 feed-pushing robot as a platform and integrating UWB wireless positioning technology, a global coordinate system for the cattle barn was established, and the expected path was planned. Finally, the pure pursuit model was improved based on the robot’s two-wheel differential kinematics model, and a dynamic forward-looking distance pure pursuit controller based on PID regulation was designed to construct a comprehensive autonomous navigation control system. Subsequently, field experiments were conducted in the cattle barn. The experimental results show that the static positioning accuracy of the UWB system for the feed-pushing robot was less than 16 cm under no-line-of-sight conditions in the cattle barn. At low speeds, the robot was subjected to linear tracking comparative experiments with forward-looking distances of 50, 100, 150, and 200 cm. The minimum upper-line distance of the dynamic forward-looking distance model was 205.43 cm. In the steady-state phase, the average lateral deviation was 3.31 cm, with an average standard deviation of 2.58 cm and the average root mean square error (RMSE) of 4.22 cm. Compared with the fixed forward-looking distance model, the average lateral deviation, the standard deviation, and the RMSE were reduced by 42.83%, 37.07%, and 42.90%, respectively. The autonomous navigation experiments conducted on the feed-pushing robot at travel speeds of 6, 8, and 10 m/min demonstrated that the maximum average lateral deviation was 7.58 cm, the maximum standard deviation was 8.22 cm, and the maximum RMSE was 11.07 cm, meeting the autonomous navigation requirements for feed-pushing operations in complex barn environments. This study provides support for achieving high-precision autonomous navigation control technology in complex environments.

Genomic prediction based on a joint reference population for the Xinjiang Brown cattle.

Introduction: Xinjiang Brown cattle constitute the largest breed of cattle in Xinjiang. Therefore, it is crucial to establish a genomic evaluation system, especially for those with low levels of breed improvement. Methods: This study aimed to establish a cross breed joint reference population by analyzing the genetic structure of 485 Xinjiang Brown cattle and 2,633 Chinese Holstein cattle (Illumina GeneSeek GGP bovine 150K chip). The Bayes method single-step genome-wide best linear unbiased prediction was used to conduct a genomic evaluation of the joint reference population for the milk traits of Xinjiang Brown cattle. The reference population of Chinese Holstein cattle was randomly divided into groups to construct the joint reference population. By comparing the prediction accuracy, estimation bias, and inflation coefficient of the validation population, the optimal number of joint reference populations was determined. Results and Discussion: The results indicated a distinct genetic structure difference between the two breeds of adult cows, and both breeds should be considered when constructing multi-breed joint reference and validation populations. The reliability range of genome prediction of milk traits in the joint reference population was 0.142-0.465. Initially, it was determined that the inclusion of 600 and 900 Chinese Holstein cattle in the joint reference population positively impacted the genomic prediction of Xinjiang Brown cattle to certain extent. It was feasible to incorporate the Chinese Holstein into Xinjiang Brown cattle population to form a joint reference population for multi-breed genomic evaluation. However, for different Xinjiang Brown cattle populations, a fixed number of Chinese Holstein cattle cannot be directly added during multi-breed genomic selection. Pre-evaluation analysis based on the genetic structure, kinship, and other factors of the current population is required to ensure the authenticity and reliability of genomic predictions and improve estimation accuracy.

Association between production and reproduction parameters based on parity and breed of dairy cows in the Czech Republic

Abstract. Milk production and the efficiency of dairy cow breeding are significantly influenced by reproductive factors. The purpose of our research was to examine the relationships between selected milk production and reproductive parameters. We evaluated 659 dairy cows, including 444 purebreds from the Czech Fleckvieh and Holstein breeds and 215 crossbreds. Our primary objective was to assess the impacts of breed and parity on specific milk production and reproductive parameters. The study revealed significant results regarding the interaction between certain breed groups and parity. In particular, there was a noticeable increase in milk yield with parity. Furthermore, it was also evident that the highest milk yield values were related to the milk content. Breed group H, which represents cows with a more than 50 % Holstein bloodline, had the highest values of the monitored milk content. Our findings show that first-lactation crossbred Czech Fleckvieh cows had a reduced milk yield, decreased fat, and lactose content in milk. However, they had a more favourable calving interval when compared to purebred Czech Fleckvieh and higher-parity Holstein crossbreds. Crossbred H, in comparison to C100 and C50, whether purebred or crossbred with Czech Fleckvieh, showed a relatively higher content of some milk components. The results for service periods and calving intervals were not statistically significant. The findings of this study highlight the promising potential of higher-parity Holstein crossbred cows in terms of milk yield and the advantages of lower-parity ones concerning milk contents.

A large population study to assess the magnitude of prenatal programming in dairy cattle

The performance of an adult dairy cow may be influenced by events that occur before her birth. The present study investigated potential effects of 2 prenatal groups of factors, Assisted Reproductive Techniques (ART) and maternal characteristics (e.g., dam parity), on offspring performance during their first lactation, in populations of 2 dairy cow breeds: French Holstein and Montbéliarde. The different ART studied included the type of semen (conventional or X-sorted) used for Artificial Insemination (AI) and the technology of conception used (AI, embryo transfer, or in vitro fertilization). Three maternal characteristics were considered: (1) the dam age at first calving, (2) dam parity number, and (3) indicators of dam udder health during gestation (somatic cell score and events of clinical mastitis). First, we investigated whether heifer survival from 3d to 18 mo old was associated with any of the prenatal factors considered. We then estimated the associations of these prenatal factors with 8 traits of commercial interest: (1) stature, (2-4) milk, fat, and protein yields, (5) somatic cell score, (6) clinical mastitis, and (7-8) heifer and cow conception rate, all measured on genotyped cows. Linear models were used for this study with the prenatal factors as covariates in the model, and for the 8 traits, phenotypes were adjusted for their corresponding genomic estimated breeding value. The results indicated that the survival rate of heifers born from embryo transfer was significantly higher than that of heifers born from AI (probably due to preferential management practices), while the other prenatal factors did not explain differences in heifer survival. Among the Montbéliarde cows born from AI, those born from X-sorted semen showed a lightly but significantly lower milk yield than those born without X-sorting of the semen (-52 kg of milk in the first lactation). Among the Holstein cows, those born from embryo transfer presented significantly lower milk performance than cows born from AI. Regarding the maternal characteristics, none or very weak associations were found between the dam age at first calving and the offspring performance in both breeds. Dam parity, on the other hand, was associated with offspring performance for milk, fat, and protein yield in both breeds, however not in the same direction. In the Holstein breed, an increase in dam parity was favorable for offspring performance for milk, fat, and protein yield, whereas in the Montbéliarde breed, an increase in dam parity was associated with lower milk and protein yield and no association was found for fat yield. The udder health of the dam during gestation was not or only weakly associated with the traits studied in the offspring. Although some significant associations were identified due to the large sample size, the effects were modest, typically less than 1% of the phenotypic mean, and were not consistently observed across the 2 breeds.

Гомеостаз концентрацій кальцію, калію, натрію сперми бугаїв і матково-вагінального слизу корів

The difference in concentration indicators (mM) of alkali metal ions (Са2+, К+, Na+) and the calculated ratio indices (RI:1) of their pairs (Nа+:Са2+, К+:Са2+, Nа+:К+) in bull semen samples and uterine-vaginal mucus (UVM) of the Ukrainian black-spotted breed cows was determined and suggests that the ability of sperm to passively and/or actively move through the channels and ducts of the genital organs can be associated with the physicochemical processes of passive diffusion and active transport of substances that occur in the "sperm – UVM " system. The power of the energy of chemical and electrochemical concentration gradients and the power of ion pumps of the osmotic pressure of inorganic and oncotic – organic substances promotes the movement of spermatozoa to the place of their contact with the egg cell. In favor of the proposed hypothesis indicate the obtained probable (Р ˂ 0.001) results of the stoichiometry parameters of the concentrations of Ca2+ (10 vs. 6) and Na+ (62 vs. 1066 mM) of sperm and UVM, respectively. The determined difference is also illustrated by the unequal indices of ion pair concentration ratios. If their value in sperm samples is directed from the pair Na+:К+ to the pair Na+:Са2+ (1.4:1 → 5:1 →6:1), then in the samples of UVM – from К+:Са2+ to Na+: Ca2+ (8:1 → 23:1 → 193:1). The difference in indices of a number of pairs (К+:Са2+ → Nа+:К+ → Nа+:Са2+) of sperm and UVM is directed from a smaller to a larger value (3:1 ˂ 22:1 ˂ 187:1). If the calculated changes are expressed as percentages, then the difference in indicators in the samples of the UVM, respectively, is 41; 94 and 97 %, which is in 2; 16 and 30 times more than sperm samples. This may mean that the determined significant difference in the physical and chemical state of organic and inorganic substances in the environment of the channels and ducts of the genital organs of cows creates conditions that contribute to the active and passive movement of sperm through the channels and ducts of their genital organs

MILK COMPOSITION EVALUATION IN DIFFERENT BREEDS OF LOCAL DAIRY TYPE ANIMALS IN PUNJAB

The current study was carried out during the reign of July 2022 to June 2023 involving 1682 collected milk samples to evaluate the effect of species on milk composition including fat, protein, solid not fat (SNF) and total solids (TS) from indigenous livestock species of Punjab, Pakistan kept for milk purpose under local conditions including cow, sheep, goat and camel. The study was carried out a Livestock Production Research Institute, Bahadurnagar, Okara. The objective of current study was to investigate the effect of species on composition of milk for. For this purpose the milk samples were collected from different species and breeds within including pure Sahiwal cow, cross bred Sahiwal cow with Friesian, local non-descript cow, Lohi sheep, goat and camels maintained at different livestock experiment stations under Livestock and Dairy development department Punjab, Pakistan. Results showed lacto meter reading (LR) was highest in Lohi sheep 30.02 followed by camel 29.59, buffalo 30.15 and then cow breeds. Milk fat was highest in Lohi sheep 7.17 percent followed by camel 5.63 percent, buffalo 6.76 percent and goat 4.73 percent. Milk fat content of purebred Sahiwal, cross bred Sahiwal and local Qadirabad cow is 4.77, 4.52 and 5.19 percent respectively. Solid not fat (SNF) content was highest in Lohi sheep 8.98 percent followed by Buffalo 8.84 and camel 8.51 percent. SNF content for goat is 7.55 and for purebred Sahiwal, cross bred Sahiwal and local Qadirabad cow is 7.50, 7.28 and 7.79 respectively. Total solids (TS) was found to be highest in Lohi sheep 16.12 followed by buffalo 15.83 and then camel 13.97 and cow. The milk protein content was found to be highest for goat 4.82 percent followed by sheep 4.75, camel 3.95 and then by cow and buffalo.

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.