Cow Characteristics Research Articles

YOLOX-S-TKECB: A Holstein Cow Identification Detection Algorithm

Accurate identification of individual cow identity is a prerequisite for the construction of digital farms and serves as the basis for optimized feeding, disease prevention and control, breed improvement, and product quality traceability. Currently, cow identification faces challenges such as poor recognition accuracy, large data volumes, weak model generalization ability, and low recognition speed. Therefore, this paper proposes a cow identification method based on YOLOX-S-TKECB. (1) Based on the characteristics of Holstein cows and their breeding practices, we constructed a real-time acquisition and preprocessing platform for two-dimensional Holstein cow images and built a cow identification model based on YOLOX-S-TKECB. (2) Transfer learning was introduced to improve the convergence speed and generalization ability of the cow identification model. (3) The CBAM attention mechanism module was added to enhance the model’s ability to extract features from cow torso patterns. (4) The alignment between the apriori frame and the target size was improved by optimizing the clustering algorithm and the multi-scale feature fusion method, thereby enhancing the performance of object detection at different scales. The experimental results demonstrate that, compared to the traditional YOLOX-S model, the improved model exhibits a 15.31% increase in mean average precision (mAP) and a 32-frame boost in frames per second (FPS). This validates the feasibility and effectiveness of the proposed YOLOX-S-TKECB-based cow identification algorithm, providing valuable technical support for the application of dairy cow identification in farms.

154 Forage intake, digestibility, and ruminal fermentation characteristics of beef cows supplemented with a Bacillus-based probiotic

Abstract The aim of this study was to evaluate the influence of a Bacillus-based probiotic supplementation on intake, digestibility, and ruminal fermentation parameters of beef cows consuming a low-quality forage diet (7.0% CP, 60% NDF, 39% ADF, DM basis). Ruminally fistulated Angus × Hereford cows [n = 15; age = 6.1 ± 1 yr; body weight (BW) = 655 ± 57] were used in two identical complete randomized designs, housed in individual pens with water, and forage intake monitored daily. Treatments consisted of 1) 500 g of protein supplement (dry distillers grain + mineral mix) without probiotic (CON n = 15), and 2) 500 g of protein supplement + 3 g of a probiotic containing Bacillus licheniformis and B. subtilis (BOV; n = 15; 2.2 ×109 CFU of the mixture/g; Bovacillus, Novonesis, Hørsholm, Denmark). Each experimental period lasted 33 d, consisting of 21 d of adaptation, 12 d of collection, and 30 d of wash-out between periods. From d 22 to 26, fecal samples were collected to determine intake and nutrient digestibility using titanium dioxide as an indigestible marker. On d 27, ruminal fluid was collected at h 0 (before feeding), 4, 8, 12, 16, and 20 post-feeding to evaluate short-chain fatty acid (SCFA) and N-NH3 concentration. From d 28 to 32, hay samples (4 g) were fitted in Dracon bags and incubated in the rumen for 0, 12, 24, 48, 72, 96, and 120 h to determine nutrient digestibility. Cows receiving BOV had greater (P < 0.001) dry matter intake compared with the CON group (Table 1). Also, cows supplemented with BOV had greater (P < 0.02) dry matter and protein digestibility and a tendency (P ≤ 0.07) for greater NDF and ADF forage digestibility compared with CON. A tendency was also detected (P = 0.09) for the degradability of forage dry matter, which was improved in BOV vs. CON. No effects were observed on rumen fermentation characteristics (P ≥ 0.14; Table 2).). In conclusion, adding bacillus-based probiotics enhanced the intake, nutritional digestibility, and degradability of beef cows fed medium-quality forage diets.

Influence of non-genetic factors on milk production traits of Gangatiri cattle in Varanasi district of Uttar Pradesh

Research was carried out to examine the influence of non-genetic factors on the milk production characteristics of Gangatiri cows. The study was analyzed from 1254 Gangatiri cows across three tehsils (Pindra, Rajatalab, and Sadar) in Varanasi, Uttar Pradesh. The objective was to ascertain the effects of a number of variables on lactation duration, daily milk production, and lactation milk production including the area, calving season, farmer's economic background, parity, and age at first calving. The overall average means for lactation milk production, daily production of milk, and lactation period were discovered to be 794.6413 kg, 3.956 kg, and 203.8327 days, respectively. The comparison of different parameters indicated that non-genetic factors had a significant impact on milk production. These factors include the region where the survey was conducted, the calving season, the financial context of the farmer, parity or lactation, and first calving age. By analyzing the mean of these parameters, we could determine their impact on milk yield potentials. Given the influence of external variables and differences in the qualities under investigation, the study indicates that significant improvements in the population of Gangatiri cattle can be accomplished by improved management.

Multiple factors shape social contacts in dairy cows

Cattle develop preferential relationships with other individuals in the herd. These social interactions between individuals have a significant impact on both animal welfare and production. Given the relevance of social behaviour in dairy cattle, scientific studies have focused on understanding social interactions among cattle. These may also be influenced by individual area preferences, particularly when animals are housed in confined spaces. Therefore, investigating the relationship between individual area preferences and social interactions is essential for understanding social behaviour in dairy cattle. Real-time location systems provide the opportunity to monitor individual area preferences and social contacts at the same time. This study aims to assess the impact of dairy cows' area preferences on their daily social contacts and to determine the potential implications of overlooking individual area preferences in social behaviour studies. The individual position of the lactating cows was automatically collected once per second for two months on a Swedish commercial farm housing dairy cows inside a free-stall barn. The location data of 243 lactating cows was used to construct the social networks and to estimate the similarity of the area utilisation distributions between these individuals. The effect of utilisation distribution similarity in social networks was investigated by applying separable temporal exponential random graph mixed models. The role of different cow characteristics in the similarity of the utilisation distributions was assessed through a linear mixed model. Our analyses stressed the importance of similarity of area preference, parity, kindergarten effect, and filial relatedness in shaping daily social contacts in dairy cattle. The kindergarten effect refers to the effect on cow behaviour of being grouped together in the early stages of their lives. Similarity of area preference was influenced by the kindergarten effect and relatedness by pedigree, which favoured interactions between these individuals. The described approach allowed to disassociate the area preference from the social contacts between cows, providing more accurate results of the importance of the cow’s characteristics on their social behaviour.

Study of physical and chemical characteristics of cow’s milk evaporated by climbing film evaporator method

Study of physical and chemical characteristics of cow’s milk evaporated by climbing film evaporator method

Physico-chemical characteristics of goat, cow and buffalo milk

The present investigation entitled “Physico-chemical characteristics of goat, cow and buffalo milk” was carried out during March to May 2023 at the Dairy Farm Rajola Livestock Production and Management (Unit), Department of Natural resource management, Faculty of Agriculture, Mahatma Gandhi Chitrakoot Gramodaya Vishwavidyalaya, Chitrakoot – Satna (Madhya Pradesh), to the study physico-chemical qualities of raw milk of goat, cow and buffalo. The results of the investigation regarding the chemical qualities of milk of goat, cow and buffalo have been presented in this chapter with the help of tables and graphs. The study has been divided into the following sub- headings. Protein (%), specific gravity (cc), fat (%), lactose (%), ash (%), total solid (%), water (%) and solid not fat (SNF) (%). In view of the findings and results presented above, it may be concluded that the physico-chemical quality of milk of buffalo was superior to cow and goat milk, due to higher protein. Specific gravity, fat content, lactose, total solid and SNF and lower ash and water content in buffalo milk.

Effectiveness of cooling interventions on heat-stressed dairy cows based on a mechanistic thermoregulatory model

Addressing heat stress in dairy farming is a substantial challenge, and there is an increasing need for efficient cooling systems, even in regions with moderate climates. Accurately predicting the efficacy of diverse cooling options under different climatic conditions is crucial for reducing heat stress in modern high-producing dairy cows, aligning with sustainability goals. This study assessed the effectiveness and feasibility of different cooling measures, including fans, sprinklers with fans, and evaporative air cooling, using a dynamic thermoregulatory model. This 3-node dynamic model was developed based on recent animal data simulating the processes of dairy cows' physiological regulation and heat dissipation under various environmental conditions. The cooling methods were based on two principles: enhancing heat loss from cows using fans with/without sprinklers; lowering the ambient temperature by evaporative air cooling. The predicted results were discussed and partly validated using the experimental data from the literature. The predictions indicated that fan cooling alone was effective in ambient temperatures below 26 °C, while higher temperatures required a combination of fans and sprinklers for effective heat stress alleviation. Consideration of individual cow characteristics and environmental factors, including fan speed and wetting area, is crucial for optimal cooling. In regions with high relative humidity, evaporative air cooling could be counterproductive to some extent. The model's predictions largely aligned with experimental data, demonstrating its capability to forecast cooling effects under various climatic conditions. Future model improvements included refining calculations for water holding capacity, wetted skin area, and dry time, depending on the influence of spraying time and rate.

Effect of oxytocin use during colostrum harvest and the association of cow characteristics with colostrum yield and immunoglobulin G concentration in Holstein dairy cows

Our objectives were to determine the effect of oxytocin use during colostrum harvest on colostrum yield and IgG concentration in Holstein dairy cows on a commercial dairy in New York and to describe associations of cow characteristics with these outcomes. Animals were enrolled between July and October 2023 using a randomized block design, with day of enrollment as the unit of randomization. A median (range) of 10 (3-19) cows were enrolled per day. Treatments were (1) 40 IU oxytocin (OXY40), (2) 20 IU oxytocin (OXY20), and (3) an untreated control group (CNTR). Oxytocin was administered i.m. ∼45 s before unit attachment in a rotary parlor. Colostrum weight was measured using the colostrum bucket-embedded scale or a platform scale when the yield was less than the smallest bucket scale. The concentration of IgG ([IgG]) in colostrum was determined using radial immunodiffusion and used to calculate total IgG, and DM (%) was determined by oven drying. Individual cow characteristics such as parity, calf sex, weight, dystocia score, stillbirth, and milk production in wk 4 of lactation; additionally, for multiparous cows, dry period length and previous lactation dry-off linear SCS were collected. Data were analyzed separately for primiparous and multiparous cows using backward stepwise elimination. To produce final mixed effects ANOVA models, primiparous cows (n = 201) were randomized to 35.8% (n = 72) OXY40, 32.8% (n = 66) OXY20, and 31.3% (n = 63) CNTR. Multiparous groups (n = 435) were randomized to 34.7% (n = 151) OXY40, 29.7% (n = 129) OXY20, and 35.6% (n = 155) CNTR. The median (range) colostrum yield was 6.0 (0-20.6) kg and [IgG] was 98.5 (0.1-293.6) g/L in the study population. In primiparous cows, OXY40 had a higher colostrum yield (LSM [95% CI]) of 5.4 (4.9-5.9) kg compared with both OXY20 (4.1 [3.5-4.7] kg) and CNTR (3.8 [3.3-4.3] kg). In multiparous cows, OXY40, OXY20, and CNTR did not differ in colostrum yield (5.9 [5.3-6.5], 5.7 [5.1-6.3], and 5.4 [4.8-6.0] kg, respectively), but colostrum yield was greater in parity 2 compared with all other parities, cows giving birth to male calves, cows with the highest milk production at wk 4 of lactation, and cows with a dry period of >65 d. Oxytocin use did not affect [IgG] in either primiparous or multiparous cows, but [IgG] was highest in cows in parity ≥4 and lowest in cows dry >65 d. In summary, oxytocin use at 40 IU i.m. was associated with a higher colostrum yield in primiparous cows only and no change in [IgG]. Oxytocin use likely addressed disturbed milk ejection and therefore increased colostrum yield in heifers milked for the first time in a rotary parlor. This study confirms cow characteristics associated with colostrum production within a single herd.

Variation in partial direct costs of dry cow therapy on 37 large dairy herds

The objective of this observational study was to estimate partial direct costs of dry cow antibiotic therapy (DCT) protocols used on 37 large dairy herds in Wisconsin and to estimate the potential monetary savings and reduction in antimicrobial usage (AMU) if selective DCT was used. Partial direct costs of DCT were calculated using costs of intramammary (IMM) antimicrobials and teat sealants. Data were retrospectively collected on 37 large dairy farms for a period of one year and included the total number of cows dried-off, types of IMM antimicrobial used, and product prices (obtained from farm invoices). A single farm visit was performed to verify data. Clinical mastitis (CM) and SCC history across lactation were used as the criteria to identify cows eligible to receive only teat sealants (no antibiotic DCT) based on adoption of a hypothetical selective DCT program. Descriptive statistics were performed using PROC MEANS to summarize continuous herd and cow characteristics. Differences in costs among IMM antibiotic products and eligibility to not receive antibiotics at dry off by parity were analyzed using ANOVA. Differences in milk yield at the last test day and DIM at dry-off based on eligibility for selective DCT were analyzed using PROC MIXED. A total of 35,691 cows were dried-off across all herds (n = 37) and most of the herds used IMM antibiotic DCT at dry-off in most of the cows. Teat sealant was used as part of the dry-off protocol in all but 3 herds. Of the enrolled farms, 30 used blanket antibiotic DCT in all quarters of all cows and 7 herds used selective DCT with no administration of antibiotics given to 0.8% to 58% of the dry cows within herd. Across all farms, the average cost of products given per dried cow was $19.57 ± 0.64 and ranged from $8.72 to $24.04. As expected, the cost per dried cow was greater ($23.45 ± 0.38) in herds that used higher-cost intramammary antibiotics as compared with herds that used lower-cost intramammary antibiotics ($16.64 ± 0.40). When using an algorithm based on udder health records to hypothetically select cows that would be eligible to receive teat sealants only (no antibiotic DCT), eligibility ranged from 27.3% to 93.3% within-herds and varied by parity, milk yield at last test day, and DIM at dry-off. If a selective DCT program based on udder health records was used, an overall reduction of $5.37 (27% of total costs) per dry cow would be expected. Likewise, adoption of selective DCT based on udder health records would reduce AMU at dry off by approximately 51%. However, neither of these estimates included potential adverse health complications (such as increased clinical mastitis) that can occur if selective DCT programs are not effectively performed. Variations in partial direct costs at dry-off were observed among herds based on treatment protocols. In herds that have good udder health management and contagious mastitis pathogens controlled, adoption of selective DCT based on SCC and history of clinical mastitis can reduce AMU and partial direct costs of dry cow management.

A comprehensive integration of factors affecting vitamin B12 concentration in milk of Holstein cows: genetic variability, milk productivity, animal characteristics, and feeding management

Daily vitamin B12 (VB12) requirements of humans can naturally be fulfilled by animal product consumption, especially products from ruminants because of bacteria dwelling in their rumen. Indeed, only bacteria can synthesize this vitamin. Milk is hence an excellent source of VB12. This cross-sectional study was undertaken to unravel factors, such as genetic variation, diet and cow characteristics, and milk production, explaining the large variation in milk B12 concentration among cows by using an integrative approach. Milk samples from 2 consecutive milkings were collected from 3,533 Canadian Holstein cows (1,239 first, 932 s, and 1,362 third and more lactations) located in 99 herds with various feeding management. For genetic variation analysis purpose, pedigrees were traced back for 3 complete generations for each sire and dam. A total of 10,021 identities were used in the subsequent genetic analyses. Milk VB12 averaged 4.2 ng/mL with a range between 0.7 and 9.0 ng/mL. Dietary fiber (NDF from forage, dietary NDF, ADF, and lignin) increased and dietary components related to energy (non-fiber carbohydrate, starch, net energy of lactation, and percentage of concentrate) decreased VB12 in milk. Milk VB12 varied with days in milk, with a similar pattern as milk fat and protein concentration lactation curves. Milk VB12 increased as age at calving increased. When disregarding the herd variance, heritability value was 0.37, meaning that milk VB12 can be modified by genetic selection. The final model including factors related to the diet, animal characteristics and milk productivity, and genetic variation explained 79% (pseudo-R2) of the milk VB12 variation. When excluding the random effect of the cow, i.e., excluding the animal and genetic relationships, the pseudo-R2 dropped to 43%, reinforcing the importance of genetic variation in explaining milk VB12 variation. To our knowledge, the present study is the most comprehensive evaluation of factors affecting milk VB12 variation including the greatest number of cows from various lactation stages.

Identification of some genetic markers as productive and reproductive traits in Ukrainian dairy cattle breeding

A Selection based on DNA markers is a breeding technique grounded in the genomic selection value of animals. The aim of the research is to study the genotypic profile of cows of different breeds in Ukrainian breeding in relation to the genes LEP, CSN3, TG5, BLG, and Pit-1 and to identify the probability of using them as markers for reproductive traits in cows. During the study, the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method was used to analyze the genes and determine their polymorphic characteristics. The obtained data indicated that the same gene variants have varying effects in the studied breeds due to their diverse influences on the genomic background. Specifically, the homozygous state of leptin genes (LEPCC) and pituitary-specific transcription factor (PIT-1BB) was observed to impact the reproductive characteristics of cows in the evaluated breeds. Meanwhile, for the genes casein (CSN3AB), thyroglobulin (TG5CT), and beta-lactoglobulin (BLGAВ), the heterozygous state of alleles was found to influence the key reproductive traits of dairy cattle of Holstein origin. The polymorphism of the genes CSN3, βLG, TG, PIT-1, and LEP indicated the presence of genetic potential for the reproductive function of cows and can be utilized as molecular markers in selective breeding, providing significant progress in improving not only the traits of dairy cattle productivity but also reproductive function. Therefore, in the implementation of selective breeding work, it is advisable to consider genotyping for the genes CSN3, βLG, TG, PIT-1, and LEP as an additional criterion for the selection of animals to enhance both their milk and reproductive characteristics.

Effect of Steam Pressure Toasting Duration on Snowbird Faba Bean Seeds and the Impact on the Intestinal and Metabolic Characteristics in Dairy Cows

The response of feedstuffs to thermal processing depends on the type of feed and the thermal processing methods being applied. Steam pressure toasting (SPT) has been used to modify the nutrient degradability and enhance the nutritional quality of pulses, including faba bean seeds (FBS). Strategic feeding approaches are essential for balancing diets and maintaining adequate nutrition, especially in high-performing ruminants. This research aimed to determine the effects of SPT duration in FBS on the intestinal and metabolic characteristics of dairy cows. Faba Bean seeds (three harvesting years) were processed at 121 °C for 0, 30, 60, 90, and 120 min. Rumen degradation and intestinal digestion were determined using the in situ and modified in vitro three-step techniques. The true protein supplied to the small intestine was also determined using the NRC and DVE systems. Our results showed a reduced total digested DM (TDDM) with longer SPT duration (quadratic, p = 0.02). The intestinally digested crude protein (IADP) increased from 62 to 220 g/kg DM with 0 to 120 min of SPT, respectively (p < 0.01), whereas the total tract digestible starch (TDSt) gradually decreased from 321 to 182 g/kg DM based on SPT time (p < 0.01). On the other hand, the truly digested protein in the small intestine (DVE) and the total metabolizable protein (MP) increased from 138 to 282 g/kg DM and 129 to 282 g/kg DM, respectively, with 0 to 120 min of SPT (quadratic, p < 0.01). The Feed Milk Value (FMV), based on both the DVE/OEB and NRC dairy nutrition systems, also increased with SPT (Quadratic, p < 0.01). The processing of FBS with SPT at 121 °C effectively reduced the highly degradable protein fraction in the rumen, shifting to a higher rumen undegraded protein (RUP) which was able to reach the small intestine. In the current study, the total MP, DVE, and FMV in dairy cows showed an overall increase with SPT in FBS.

Quality assessment of chemical and microbiological characteristics of cow’s milk and some dairy products in the New Valley governorate

Quality assessment of chemical and microbiological characteristics of cow’s milk and some dairy products in the New Valley governorate

Comparative Analysis of Milking and Behavior Characteristics of Multiparous and Primiparous Cows in Robotic Systems.

Robotic milking systems are successful innovations in the development of dairy cattle. The objective of this study was to analyse the milking characteristics and behavior of dairy cows of different calving orders in "milk first" robotic milking systems. The data were collected from a commercial herd located in the Midwest region of Minas Gerais (Brazil), which uses an automatic milking system (AMS TM, DeLaval). Were analysed 26,574 observations of 235 Holstein cows were available. Data were evaluated by multivariate analysis of variance and the Tukey test. - Tthe characteristics milk flow and milking efficiency were more favourable for multiparous cows (p <0.01), while the time in the stall was more favourable for primiparous females (p <0.01). The values of handling time were better in the primiparous cows (p <0.01). Primiparous cows had higher amounts of kick-off (p <0.001), and multiparous cows had higher incomplete milkings (p <0.001). The number of incomplete milkings showed a higher ratio in terms of reduction in milk production in 26.6% in primiparous cows and 26.7% in multiparous cows (p <0.01). Regarding the behavioral characteristics, primiparous cows had higher amounts of kickbacks, while multiparous cows had greater quantities of incomplete milkings.

Clinical and hematological indicators of cows belonging to different selections of the holshtin breed by seasons

This paper examines the hematological (erythrocyte, leukocyte, total protein, hemoglobin, glucose) and clinical (respiration, heart rate, body temperature, belly movement) characteristics of Holstein dairy cows from various selections. These results showed that the blood of cows in our republic is saturated with morphological elements due to the same kind of feeding that they receive throughout the seasons, including concentrate feeding.

Using a Model to Compare Cooling System Design Factors For Lactating Cows

Highlights Cow mass, milk yield, solar load, air velocity, dry-bulb and dew-point temperature impact lactating cow respiration rates. Modeled respiration rates align with published studies dealing with milk yield, solar load, and evaporative cooling. The model can be used to assess cooling systems for conditions that might be difficult to capture in field measurements. Abstract. The risk of lactating cows experiencing heat stress is increasing because of increased productivity. A steady-state process-based model described by Nelson and Janni (2023) and assessed by Janni et al. (2023) was used to compare additional combinations of environmental conditions (e.g., air dry-bulb and dew-point temperatures, air velocity, solar load) and lactating cow characteristics (e.g., body mass and daily milk yield) on modeled respiration rate. Respiration rate was linked to qualitative heat stress levels, based on work by Renaudeau et al. (2012). The model demonstrates how cows with greater body mass have larger inspired volumes of respired air (i.e., liters per minute) because they have larger tidal volumes (i.e., liters per breath) while they have lower respiration rates (i.e., breaths per minute) compared to cows with smaller body masses. The modeled results support previous studies that demonstrated heat stress increases with greater daily milk yields, solar load, and air dry-bulb and dew-point temperatures. The model finds conditions where increasing air velocity at cow level can help cows reduce heat stress levels due to solar load, and high air dry-bulb and dew-point temperatures. A comparison to a field study demonstrates the need to align field data collection and model input needs to explore the actual or potential impacts of mitigation methods like shade, evaporative cooling, and air velocity (i.e., via fans). This report demonstrates how the model can be used by engineers to investigate the impact of ventilation system designs on respiration rates using current and future technologies. Keywords: Air velocity, Cow mass, Dairy, Dew-point temperature, Dry-bulb temperature, Heat stress, Milk yield, Respiration rate, Solar load.

Development of Physico-chemical and Technological Parameters for the Production of Dairy Products for Sports Nutrition in Pavlodar Region

Main problem:The article considers the results of research and design of basic formulations of dairy products for sports nutrition in Pavlodar region. The authors analyzed the problems in the field of development of modern food technologies of a specialized orientation. Purpose: To develop physical, chemical and technological parameters for the production of dairy products for sports nutrition in Pavlodar region. Methods: structural-mechanical, physico-chemical, organoleptic. Results and their significance: Reliable research results have been obtained: the fatty acid composition of goat and cow's milk for the production of a new product has been determined, the physico-chemical and structural-mechanical characteristics of goat and cow's milk (raw materials) have been studied. The authors concluded that in the protein composition of goat's milk in the spring and summer period, there is a slight excess of total protein by 0,27 %, whey and casein proteins by 0,07 % and 0,2 %, respectively, non-protein nitrogenous substances by 0,01 % compared with cow's milk. A comparative analysis of the physico-chemical composition of the research objects (goat and cow's milk) was carried out and it was concluded that the mass fraction of solids in the milk of Zaanen goats is 12,8 %, respectively, and significantly exceeds the same indicator of cow's milk – 12,41 %. In the milk of Altai and Alpine goat breeds, the mass fraction of solids ranges from 11,85 % to 11,94 %, which is significantly lower than in cow's milk. The study found that the dry matter content in goat's milk is 8,59 %, which is 0,19 % more than the dry matter in cow's milk. There is a greater amount of protein, respectively, by 0,1 %, while the amount of fat is less than in cow's milk, by almost 1 %.

Productive, reproductive and bioenergetic characteristics of cows with different body condition score

The aim of this work was to study the influence of fattening of dairy cows body condition score on reproductive traits, productivity and bioenergetic indicators. The research was conducted during May-August 2021 in the conditions of the Terezine of the Vilnotarasivske branch (Kyiv region). The values of average monthly temperatures were within the limits of thermoneutrality for cows of dairy breeds. Three groups of second-lactation cows were formed for the study. The first group (n=14) included animals with a fatness score of 2.0 to 3.0 points, and the second group (n=24) with a score of 3.0 to 3.75 points and to the III-rd group (n=15) – 4 and above points. Assessment of fatness in groups of animals was carried out during the period of deep body. The productivity of cows during the first 120 days of lactation was determined using computer records and the DelPro program. Cows of the II group had a somewhat shorter dry period (by 3 and 1 day) compared to animals of the I and III groups. The shortest service period was observed in the first group of cows – 164 days, which is 7 and 24 days less than in animals of the second and third groups, respectively. Cows of the II group had the highest average daily productivity during each of the first 4 months of lactation (120 days). At the same time, productivity was the lowest in cows of the III group, and intermediate values were observed in the animals of the I group. At the same time, cows of the III-rd group had the lowest productivity during the same period. Analyzing the bioenergetic characteristics of cows of different levels of fatness, it was established that the highest rate of net energy expenditure for the production of 1 kg of 4 % milk was in cows of the IIIrd group – 3.71 MJ, and the lowest in animals of the IInd group – 3.49 MJ. Research results showed that cows of different fattening levels before calving had high energy indices – from 50.25 to 53.99 %, productive – from 0.260 to 0.286 kg for specific net energy loss from 1.852 to 1.988 MJ per 1 MJ of milk energy. Key words: dairy cows, fatness, productivity, reproduction, bioenergetic characteristics.

Review and analysis on fertility and milk production in commercial dairy farms with customized lactation length during the last ten years

Approximately 150 million households around the globe are engaged in milk production. In most developing countries, milk is produced by smallholders, and milk production contributes to household livelihoods, food security and nutrition. Milk provides relatively quick returns for small-scale producers and is an important source of cash income. In recent decades, developing countries have increased their share in global dairy production. This growth is mostly the result of an increase in numbers of producing animals rather than a rise in productivity per head. In many developing countries, dairy productivity is constrained by poor-quality feed resources, diseases, limited access to markets and services (e.g., health, credit and training) and dairy animals’ low genetic potential for milk production. Unlike developed countries, many developing countries have hot and/or humid climates that are unfavourable for dairying. Traditionally, dairy farmers are recommended to aim for a 1-yr calving interval, as this would maximize milk production and income. Longer calving intervals would extend the period in late lactation, when milk production is lower. However, there may be several reasons to re-evaluate the traditional lactation length, including increased productivity of modern dairy cows, and potential benefits of longer lactations for cow health and welfare. Moreover, although farmers are advised to aim for a 1-yr calving interval, in practice calving intervals mostly exceed 1 yr. Some cows might be better suited for an extended CInt than others, due to differences in milk yield level, lactation persistency, or health status, which would justify a customized CInt based on individual cow characteristics. This study aims to investigate 13 farms with customized CInt, with respect to calving to first service interval (CFSI), accomplished CInt, services per conception (SC), conception rate at first artificial insemination (CR1AI), peak yield, lactation persistency, 305-d yield, and effective lactation yield. In total, 4,858 complete lactations of Holstein Friesian cows between 2012 and 2022 from the 13 farms were grouped by parity and CFSI or CInt.

New insight into social relationships in dairy cows and how time of birth, parity, and relatedness affect spatial interactions later in life

Social interactions between cows play a fundamental role in the daily activities of dairy cattle. Real-time location systems provide on a continuous and automated basis information about the position of individual cows inside barns, offering a valuable opportunity to monitor dyadic social contacts. Understanding dyadic social interactions could be applied to enhance the stability of the social structure promoting animal welfare and to model disease transmission in dairy cattle. This study aimed to identify the impact of different cow characteristics on the likelihood of the formation and persistence of social contacts in dairy cattle. The individual position of the lactating cows was automatically collected once per second for 2 weeks, using an ultra-wideband system on a Swedish commercial farm consisting of nearly 200 dairy cows inside a free-stall barn. Social networks were constructed using the position data of 149 cows with available information on all characteristics during the study period. Social contacts were considered as a binary variable indicating whether a cow pair was within 2.5 m of each other for at least 10 min per day. The role of cow characteristics in social networks was studied by applying separable temporal exponential random graph models. Our results revealed that cows of the same parity interacted more consistently, as well as those born within 7 d of each other or are closely related by pedigree. The repeatability of the topological parameters indicated a consistent short-term stability of the individual animal roles within the social network structure. Additional research is required to elucidate the underlying mechanisms governing the long-term evolution of social contacts among dairy cattle and to investigate the relationship between these networks and the transmission of diseases in the dairy cattle population.