Dairy Cow Population Research Articles

Rapid selection of milk mid-infrared spectra for creating a world representative spectral database of dairy cow population

The advantage of employing mid-infrared spectrometry for milk analysis in breeding lies in its ability to quickly generate millions of records. However, these records may be biased if the calibration process does not account for their spectral variability when constructing the predictive model. So, this study introduces a novel method for developing a World Representative Spectral Database (WRSD) to reduce the risks of spectral extrapolation when predicting dairy traits in new samples. Utilizing a 2-phase selection procedure that is both efficient and minimizes memory usage, we first generate a decomposition matrix via Principal Component Analysis (PCA) on a data set of 2,324,443 records. The next phase iterates spectral selection based on a location index from PCA scores, calculating spectra occurrence frequency for refined barycenter estimations. The chosen spectra's barycenter closely aligns with the entire data set, proving the efficacy of using just 3 principal components (PCs). Applied to 4 varied data sets, totaling over 21 million records, we select 583,440 spectra to represent spectral diversity, with selection rates between 2.00% and 14.88%. This selection illustrates the spectral variability across different dairy populations and data providers. Demonstrated through a hypothetical calibration set of 71 samples, the WRSD's utility for algorithm developers becomes apparent. This calibration set covers between 91.42 to 98.50% of the WRSD variability, except for the Irish data set (3.50%), indicating a need for additional samples to accurately represent Irish variability and minimize spectral extrapolation. This study offers valuable insights into the representativeness of training sets for capturing spectral variability within targeted dairy populations. While the current WRSD does not fully encompass global milk spectral diversity, its development underscores the importance of gathering more data and standardizing spectral information across spectrometer brands. Ultimately, the WRSD proves crucial not just for trait prediction but also for identifying abnormal milk samples, also marking a significant relevance in dairy science technology.

Reasons for disposal and cull cow value of Holstein cows compared with Holstein, Jersey, Montbéliarde, Normande, and Viking Red crossbred cows

Cull cows from dairy farms in the United States account for 10% of the beef market; however, few studies have evaluated the effects of crossbreeding on reasons for disposal and cull value of dairy cows. The objective of the study was to compare reasons for disposal and cull cow value of Holstein and crossbred cows (n = 1,292) in an experimental dairy herd at the University of Minnesota West Central Research and Outreach Center (Morris, MN). Cows were Holstein (n = 272), 1964 genetic control Holstein (n = 161), 3-breed crossbred cows (n = 538) composed of the Montbéliarde, Viking Red, and Holstein (MVH) breeds, and 3-breed crossbred cows (n = 321) composed of the Normande, Jersey, and Viking Red (NJV) breeds. The 1964 genetic control Holstein cows originated from a design initiated at the University of Minnesota for comparison of the 1964 Holstein and contemporary Holstein cows selected for production across time. Records spanned from January 2010 to December 2023. Reasons for disposal were recorded in PCDart Herd Management Software, and cull value and body weight were obtained from receipts from livestock cull markets. For all cows, the primary reasons for disposal were as follows: reproduction (44.4%), mastitis (18%), other reasons (14.6%), death (10.3%), dairy purposes (8.4%), and low production (4.3%). Independent variables for statistical analysis of cull value were the fixed effects of body weight at time of culling, DIM at culling (0-49 DIM, 50-99 DIM, 100-149 DIM, 150-199 DIM, 200-249 DIM, 250-299 DIM, 300-350 DIM, and >350 DIM), year (2010-2023), season (spring, summer, autumn, winter), parity (1, 2, 3, 4, 5+), primary reason for culling, breed group, and sire breed group nested within breed group. Least squares means for body weight at culling was 558 kg for Holsteins, 543 kg for 1964 Holsteins, 551 kg for MVH crossbred cows, and 499 kg for NJV crossbred cows. For the analysis across time, 2014 had the highest cull value ($1,126.98), and 2020 had the lowest gross cull value ($515.21). Cows culled at greater than 300 DIM had the highest cull value and cows culled at less than 50 DIM had the lowest cull value. Cows culled during the spring and summer had higher cull value compared with cows culled during the autumn and winter. The Holstein cows ($730.04) had lower gross value compared with 1964 Holsteins ($804.38) cows and MVH ($767.39) cows. The NJV ($771.39) cows were not different from crossbreds sired by Montbéliarde, Viking Red, and Holstein bulls. Results for comparisons of breed group are from one experimental herd, so inferences to the wider dairy cow population should be undertaken with caution. In summary, dairy producers may receive greater cull value from crossbred cows compared with Holstein cows.

Enhancing dairy cow population through decreasing calf mortality and increasing calving rate in Indonesia: a system dynamics approach

Abstract The dairy industry in Indonesia is facing significant challenges due to the rates of calf mortality and low calving rates. Calf mortality and calving rate became critical factors that influence the sustainability of the dairy cow population. This study aimed to assess reproduction management by decreasing calf mortality and increasing calving rates to enhance the dairy cow population in Indonesia. This study employed secondary data in 2022 using technical parameter coefficients from previous research. A causal loop diagram and a simulation model using a system dynamics approach were developed to investigate the dynamics of the dairy cow population under different scenarios of calf mortality and calving rates from 2023 to 2030. The results showed that decreasing calf mortality by 2% may increase dairy cow population by 1,991 head/year (0.31%), heifer population by 417 head/year (0.63%), and adult female dairy cattle population by 389 head/year (0.09%). The finding of this study also showed that increasing calving rate by 5% may increase dairy cow population by 17,854 head/year (2.75%), heifer population by 3,698 head/year (5.56%), and adult female dairy cattle population by 2,137 head/year (0.51%). It is concluded that reducing calf mortality rates and improving calving rates should be prioritized to enhance the dairy cow population in Indonesia.

Association between a genetic index for digital dermatitis resistance and the presence of digital dermatitis, heel horn erosion, and interdigital hyperplasia in Holstein cows

Digital dermatitis (DD) is a polybacterial disease endemic to most UK dairy farms. It poses a major financial and welfare threat and is characterized by high incidence and recurrence rates. We aimed to investigate the association between the UK EBV for resistance to digital dermatitis, the digital dermatitis index (DDI), and the frequency of DD, heel horn erosion (HHE), and interdigital hyperplasia (IH) in a population of Holstein dairy cows. We enrolled and genotyped 2,352 cows from 4 farms in a prospective cohort study. Foot lesion records were recorded by veterinary surgeons for each animal at 4 time points during a production cycle, starting at approximately 2 mo before calving and ending in late lactation. Importantly, these records were not used in the calculation of the DDI. Lesion records were matched to the animal's own DDI (n = 2,101) and their sire's DDI (n = 1,812). Digital dermatitis index values in our study population ranged from -1.41 to +1.2 and were transformed to represent distance from the mean expressed in SD. The relationship between the DDI and the presence of DD was investigated using a logistic regression model, with farm, parity, and a farm-parity interaction fitted as covariates. A multivariable logistic regression model was fitted to evaluate the relationship between HHE and DDI with farm fitted as a covariate. Finally, a univariable logistic regression model with DDI as explanatory variable was used to investigate the relationship between IH and DDI. The odds ratio of an animal being affected by DD was 0.69 for 1 SD increase in the animal's DDI (95% CI = 0.63-0.76). The odds of HHE and IH were 0.69 (95% CI = 0.62-0.76) and 0.58 (95% CI = 0.49-0.68) respectively for 1 SD increase in DDI. The adjusted probability of DD was 32% (95% CI = 27-36%) for cows with mean DDI value of 0, while it was 24% (95% CI = 20-29%) in cows with a DDI value of +1. Sire DDI breeding values were standardized in the same way and then binned into terciles creating an ordinal variable representing bulls of high, medium, and low genetic merit for DD resistance. The daughters of low genetic merit bulls were at 2.05 (95% CI = 1.60-2.64), 1.96 (95% CI = 1.53-2.50), and 2.85 (95% CI = 1.64-5.16) times greater odds of being affected by DD, HHE, and IH, respectively, compared with the daughters of high genetic merit bulls. The results of this study highlight the potential of digital dermatitis genetic indexes to aid herd management of DD, and suggest that breeding for resistance to DD, alongside environmental and management control practices, could reduce the prevalence of the disease.

Resilience indicator traits in 3 dairy cattle breeds in Baden-Württemberg

In recent years, research in animal breeding has increasingly focused on the topic of resilience, which is expected to continue in the future due to the need for high-yielding, healthy, and robust animals. In this context, an established approach is the calculation of resilience indicator traits with time series analyses. Examples are the variance and autocorrelation of daily milk yield in dairy cows. We applied this methodology to the German dairy cow population. Data from the 3 breeds (German Holstein, German Fleckvieh, and German Brown Swiss) were obtained, which included 13,949 lactations from 36 farms from the state Baden-Württemberg in Germany working with automatic milking systems. Using the milk yield data, the daily absolute milk yields, deviations between observed and expected daily milk yields, and relative proportions of daily milk yields in relation to lactation performance were calculated. We used the variance and autocorrelation of these data as phenotypes in our statistical analyses. We estimated a heritability of 0.047 for autocorrelation and heritabilities between 0.026 and 0.183 for variance-based indicator traits. Furthermore, significant breed differences could be observed, with a tendency of better resilience in Brown Swiss. The breed differences can be due to both genetic and environmental factors. A high value of a variance-based indicator trait indicates a low resilience. Performance traits were positively correlated with variance-based indicator traits calculated from absolute daily milk yields, but they were negatively correlated with variance-based indicators calculated from relative daily milk yields. Thus, they can be considered as different traits. Although variance-based indicators based on absolute daily milk yields were affected by the performance level, variance-based indicators based on relative daily milk yields were corrected for the performance level and also showed higher heritabilities. Thus, they seem to be more suitable for practical use. Further studies need to be conducted to calculate the correlations between resilience indicators, functional traits, and health traits.

Prevalence and risk factors of Toxoplasma gondii infection in dairy cattle from the Western Region of Thailand.

In total, 901 dairy cow sera and data were collected from 51 farms in Nakhon Pathom, Ratchaburi and Kanchanaburi provinces (Western Region of Thailand). Serum samples were processed via the multispecies ELISA method to detect IgG antibodies against Toxoplasma gondii infection. The results demonstrated that the calculated true prevalence was 1.48% (95% CI, 0.64-2.75%) for the individual-level and 29.41% (95% CI, 18.71-43%) for the farm-level. The univariate risk factor analysis showed that the number of total owned cats, the presence of stray cats, and the frequency of cleaning per day were significant factors (p<0.2). These three factors were subjected to logistic regression analysis, and the results revealed that the frequency of cleaning farms per day was a potential risk factor for T. gondii-seropositive farms (OR=2.745, 95% CI, 1.15-8.69, p=0.02). The frequency of cleaning might increase the T. gondii oocyst distribution within the barn area, thus increasing the possibility of infection. Our findings show that T. gondii continues to circulate in the dairy cow population in the western part of Thailand. The presence of cats on farms was not found to be associated with T. gondii infection, but the high frequency of cleaning the floor was, and contributed to the potential risk of infection.

The milk production of recovered dairy cows from foot-and-mouth disease in the Medowo Village, Kandangan Subdistrict, Kediri

The outbreak of Foot-and-Mouth Disease (FMD) has caused a crisis for Indonesian farmers, particularly dairy cattle in Medowo village. The FMD outbreak affected the whole dairy cow population in Medowo, resulting in major losses defined by high mortality rates and a halt in milk production during the cows' FMD infection. Dairy cows, which are essential for maintaining milk production and providing an economic foundation for Medowo's farmers, led our team to execute community service from January to August 2023. Socialization and data collection on farmers and their cows were followed by laboratory testing for mastitis identification and treatment. The outreach events focused on mastitis care for cows, promoting talks to solve farmers' issues, particularly in livestock health. Farmers were instructed on how to report subclinical mastitis instances to appropriate authorities, were trained on how to prepare fermented feed/silage with probiotics to improve feed quality, and were monitored for overall evaluation. The milk production data collected showed that morning yield produce higher quantity than afternoon yield. The lowest milk production occurs in September, while the highest is observed in November. Overall, data from dairy cow milk production in Medowo Village after FMD outbreak show a satisfactory result, illustrating the success of community service programs. Future initiatives should include collecting data on a regular basis to allow for ongoing evaluation and continued improvement in milk production.

Identification of blaSHV and blaTEM extended spectrum beta-lactamase genes in Klebsiella pneumoniae in the dairy wastewater, East Java Province, Indonesia

Abstract. Dameanti FNAEP, Yanestria SM, Effendi MH, Plumeriastuti H, Tyasningsih W, Ugbo EN, Sutrisno R, Safri MAAS. 2023. Identification of blaSHV and blaTEM extended spectrum beta-lactamase genes in Klebsiella pneumoniae in the dairy wastewater, East Java Province, Indonesia. Biodiversitas 24: 6092-6099. Klebsiella pneumoniae infection in dairy cows causes various livestock production hazards and threatens public health because it acts as a Multi-Drug Resistance Bacteria (MDRB), especially Extended-Spectrum Beta-Lactamase (ESBL) strains. Livestock wastewater is a repository for commensal isolates including K. pneumoniae and potentially can be a reservoir for ESBL spreaders for the environment. The aim of this study was to identify the blaSHV and blaTEM ESBL genes in K. pneumoniae from wastewater of dairy cattle farms in East Java Province. This study used a sample of 342 dairy farm wastewater isolated on 2% BPW media from 6 cities/regencies with the highest population of dairy cows in East Java, Indonesia, namely Pasuruan District, Malang District, Tulungagung District, Blitar District, Batu City and Kediri District. Samples were identified on MCA media, Gram staining, EMBA, and biochemical tests. Confirmation of ESBL phenotypically used the Double Disc Synergy Test (DDST) method and the Polymerase Chain Reaction (PCR) test to detect the ESBL gene. The result showed that bacterial isolation and identification were 14.32% (49/342), confirmed K. pneumoniae. DDST confirmation results of ESBL-producing K. pneumoniae isolates from the wastewater of dairy farms in East Java obtained were 5.55% (19/342). The sample was continued with the PCR test showing positive for the blaSHV gene 63.1% (12/19) and blaTEM 31.57% (6/19). In conclusion, the ESBL gene blaSHV and blaTEM identification in K. pneumoniae isolates, indicate that wastewater from dairy farms has the potential to be a reservoir of ESBL carriers in the environment and pose a threat to public health in East Java Province, Indonesia.

Evaluation of trait preferences and effect of parity, season and lactation stage on production performance of indigenous dairy cow in kaffa zone, southwest Ethiopia

The current research focused on the effects of parity, season, and lactation stage on the milk yield of indigenous dairy cows in selected districts of the Kaffa Zone of southern Ethiopia. The districts of Gesha and Chena were purposefully chosen. The study design for the 384 household surveys was a cross-sectional survey with a simple random sample approach as the sampling method. Following the survey, 192 lactating cows were chosen for a monitored investigation to track nighttime and morning milk supply. In addition to key informants and focus group discussions, primary and secondary data were obtained via a semi-structured questionnaire, interview, and field observation. The most favored features functioning as selection criteria were those favored for production, reproduction, physical appearance, physiological function, and temperament, in that order. Evening milk yield (EMY), mornning milk yield (MMY), daily milk yield (DMY), lactation length (LL) and lactation milk yield (LMY) were 0.91 ± 0.033 L, 1.22 ± 0.037 L, 2.125 ± 0.07 L, 6.36 ± 0.116 months, and 427.10 ± 20.678 L, respectively, with significant difference (p < 0.01) amongst districts, parity, and season. However, there was no significant variation between studies in EMY, MMY and DMY. Significantly higher values of production performances were recorded for interaction among districts, parity, and season. The study also revealed that interaction between district (Gesha) and parity (third), which were signficantlly higher for EMY, MME, DMY, LL, and LMY 1.50 L, 2.00 L, 3.50 L, 8.10 months, and 850.50 L, respectively. The same trend also observed for interaction among district (Gesha), season (wet), and parity (third), which were obtained to be highly significant values of EMY, MMY, DMY, LL, and LMY were 1.35 L, 1.75 L, 3.10 L, 7.65 months, and 716.80 L, respectively. The study region has a large population of indigenous dairy cows and produces higher yields than the national average. However, it falls short of the worldwide production benchmarks, and the trait preferences used as a selection criterion were based on the farmers' indigenous knowledge. Measures to enhance production abilities must be incorporated and selection criteria must be modernized.

Assessment of antibiotic use patterns in bovine mastitis treatment in the dairy sector in Serbia.

The dairy sector is essential for the world's food systems, playing a vital role in agricultural production. Yet, mastitis, an inflammation of the mammary gland, affects a considerable portion of the dairy cow population annually, leading to reduced productivity and sustainability. Insight into therapeutic protocols is essential for a better understanding of the situation on farms with the aim of developing new or harmonizing existing protocols in the mastitis treatment. This study conducted on dairy farm in Serbia aimed to explore the most commonly used antibiotics during bovine mastitis treatment and their association with daily milk yield. Data from 100 lactating cows, including therapeutic protocols, lactation numbers, mastitis episodes, milk yield, and antibiotic usage, were obtained from a computerized database and statistically analysed. The results demonstrated a high prevalence of narrow-spectrum antibiotics usage, with the majority of cows treated with combination therapy. The route of antibiotic application did not significantly impact daily milk yield, while treatment duration had no discernible effect. Nonetheless, specific antibiotics were associated with milk yield variations, suggesting the need for careful antibiotic selection and management in mastitis therapy. These findings emphasize the importance of prudent antibiotic use to safeguard animal health and long-term milk production sustainability.

Carbon footprint based on lifetime productivity for future cows selected for resilience to climate-related disturbances

Droughts, which can impact feed production, are projected to become more common under future climate conditions. In light of this, breeding cattle resilient to changes in feeding regimens is increasingly becoming an important topic. Body reserves can play a crucial role when the feed resources are limited. We simulated populations of dairy cows selected with 2 different breeding goals: one reflecting the current breeding goal and the other placing weight on minimum level of body reserves in early lactation and change in body reserves during lactation. We considered this latter as a breeding goal for resilience. We used the 2 dynamic simulation programs ADAM and AQAL to predict performance of the cows after selection. In AQAL, we modeled moderate and severe drought by decreasing feed quality and quantity offered to cows during one year. We compared cows selected with the 2 breeding goals under 3 environments: without disturbances related to climate and with moderate and severe drought. In the environments without disturbances and the moderate drought, the cows selected with the current breeding goal had higher life time lactation efficiency (energy invested in milk / energy acquired from feed) and lower carbon footprint per kg protein in milk and meat than cows selected for resilience. However, with severe drought, cows selected for resilience had higher life time lactation efficiency and lower carbon footprint per kg protein in milk and meat than those selected with the current breeding goal. This suggests that cows selected for high productive performance do not perform well under very limiting conditions, leading to increased climate impact. The importance of inclusion of body reserves as a resilience trait in dairy cattle breeding depends on the future environment in which the cows will be used.

Retained placenta in dairy cows living in an all-day cowshed rearing system

This study aimed to determine the prevalence and factors that influence the incidence of retained placenta in dairy cows reared under an all-day cowshed housing system at KUD Tani Wilis, Sendang District, Tulungagung. This study used 216 dairy cows, that had already calved, that had been identified to have medical and reproductive records for data exploration. Data collected included the sex and weight of calf, single or twin calves, age of the dam, cowshed structure (floor, puddles on the floor, gutter, distance of cowshed to waste disposal, type of floor and roof, and sunlight exposure), feed of the dam (forage, concentrate, mineral supplements), frequency of retained placenta cases on calving intervals and days open of the dams. The prevalence of retained placenta was presented descriptively. Factors related to the retained placenta and its effect on calving interval and days open were analyzed by Chi-square test using Statistical Product and Service Solution (SPSS) software version 20 for Windows. The result showed that the prevalence rate of retained placenta was 19.91% of all dairy cow populations in the district. Furthermore, the sex of the calf, age of the dam, sunlight exposure, and the quantity of feed (forage and concentrate) were related to the retained placenta (p &lt;0.05). In addition, retained placenta increased along with extending of days open and calving interval. It could be concluded that the factors that influenced the prevalence of retained placenta were the sex of the calf, the age of the cow, the feed and concentrate, and the cowshed that is not facing the sun.

Retained placenta in dairy cows living in an all-day cowshed rearing system

This study aimed to determine the prevalence and factors that influence the incidence of retained placenta in dairy cows reared under an all-day cowshed housing system at KUD Tani Wilis, Sendang District, Tulungagung. This study used 216 dairy cows, that had already calved, that had been identified to have medical and reproductive records for data exploration. Data collected included the sex and weight of calf, single or twin calves, age of the dam, cowshed structure (floor, puddles on the floor, gutter, distance of cowshed to waste disposal, type of floor and roof, and sunlight exposure), feed of the dam (forage, concentrate, mineral supplements), frequency of retained placenta cases on calving intervals and days open of the dams. The prevalence of retained placenta was presented descriptively. Factors related to the retained placenta and its effect on calving interval and days open were analyzed by Chi-square test using Statistical Product and Service Solution (SPSS) software version 20 for Windows. The result showed that the prevalence rate of retained placenta was 19.91% of all dairy cow populations in the district. Furthermore, the sex of the calf, age of the dam, sunlight exposure, and the quantity of feed (forage and concentrate) were related to the retained placenta (p &lt;0.05). In addition, retained placenta increased along with extending of days open and calving interval. It could be concluded that the factors that influenced the prevalence of retained placenta were the sex of the calf, the age of the cow, the feed and concentrate, and the cowshed that is not facing the sun.

Analysis of the relationship between short tandem repeats and lactation performance of Xinjiang Holstein cows

Microsatellite markers, also known as short tandem repeats (STRs), are important for marker-assisted selection to detect genetic polymorphism, and they are uniformly distributed in eukaryotic genomes. To analyze the relationship between microsatellite loci and lactation traits of Holstein cows in Xinjiang, 175 lactating cows with similar birth dates, the same parity, and similar calving dates were selected, and 10 STR loci closely linked to quantitative trait loci were used to analyze the correlation between each STR locus and four lactation traits (daily milk yield, milk fat percentage, milk protein percentage, and lactose percentage). All loci showed different degrees of genetic polymorphism. The average values of observed alleles, effective alleles, expected heterozygosity, observed heterozygosity, and polymorphic information content of the 10 STR loci were 10, 3.11, 0.62, 0.64, and 0.58, respectively. Chi-square and G-square tests showed that all populations of loci were in accordance with the Hardy–Weinberg equilibrium. Analysis of the correlation between STR locus genotype and lactation performance in the whole lactation period showed three loci (namely, BM143, BM415, and BP7) with no significant correlation with all lactation traits, two loci (BM302 and UWCA9) related to milk yield, three loci (BM103, BM302, and BM6425) related to milk fat percentage, two loci (BM302 and BM6425) related to milk protein percentage, and three loci (BM1443, BM302, and BMS1943) related to lactose percentage. The microsatellite loci selected in this study showed rich polymorphism in the experimental dairy cow population and were related to the lactation traits, which can be used for the evaluation of genetic resources and early breeding and improvement of Holstein dairy cows in Xinjiang.

Comparison of cattle derived from in vitro fertilization, multiple ovulation embryo transfer, and artificial insemination for milk production and fertility traits

The use of assisted-reproduction technologies such as in vitro fertilization (IVF) is increasing, particularly in dairy cattle. The question of consequences in later life has not yet been directly addressed by studies on large animal populations. Studies on rodents and early data from humans and cattle suggest that in vitro manipulation of gametes and embryos could result in long-term alteration of metabolism, growth, and fertility. Our goal was to better describe these presumed consequences in the population of dairy cows produced by IVF in Québec (Canada) and to compare them to animals conceived by artificial insemination (AI) or multiple ovulation embryo transfer (MOET). To do so, we leveraged a large phenotypic database (2.5 million animals and 4.5 million lactations) from milk records in Québec aggregated by Lactanet (Sainte-Anne-de-Bellevue, QC, Canada) and spanning 2012 to 2019. We identified 304,163, 12,993, and 732 cows conceived by AI, MOET, and IVF, respectively, for a total of 317,888 Holstein animals from which we retrieved information for 576,448, 24,192, and 1,299 lactations (total = 601,939), respectively. Genetic energy-corrected milk yield (GECM) and Lifetime Performance Index (LPI) of the parents of cows were used to normalize for genetic potential across animals. When compared with the general Holstein population, MOET and IVF cows outperformed AI cows. However, when comparing those same MOET and IVF cows with only herdmates and accounting for their higher GECM in the models, we found no statistical difference between the conception methods for milk production across the first 3 lactations. We also found that the rate of Lifetime Performance Index improvement of the IVF population during the 2012 to 2019 period was less than the rate observed in the AI population. Fertility analysis revealed that MOET and IVF cows also scored 1 point lower than their parents on the daughter fertility index and had a longer interval from first service to conception, with an average of 35.52 d compared with 32.45 for MOET and 31.87 for AI animals. These results highlight the challenges of elite genetic improvement while attesting to the progress the industry has made in minimizing epigenetic disturbance during embryo production. Nonetheless, additional work is required to ensure that IVF animals can maintain their performance and fertility potential.

Milk Production and Reproductive Performance of Holstein Friesian Dairy Cattle in the Working Area of ​​South Bandung Pangalengan Animal Husbandry Cooperative (KPBS) Bandung Regency

Increasing the population and productivity of dairy cows is one of the way to boost national milk production capacity. This study was aimed to determine and investigate the performance of milk production and reproduction of Friesian Holstein (FH) dairy cows in the Working Area of KPBS Pangalengan, Bandung Regency. This research used FH dairy cows with a complete milk production and reproduction record. In total, there were 90 heads of cows in the Pangalengan District and 178 heads of cows in the Kertasari District. This study used the survey method to collect the data. A Multistage Random Sampling Method was used in this research. Sampling was carried out in two stages, the first stage was sampling from two sub-district locations in Pangalengan and Kertasari Districts. In the second stage, two villages were selected from each district: Pangalengan and Margamukti Villages in Pangalengan District, and Santosa and Tarumajaya Villages in Kertasari District. Farmers and their cows were chosen by simple random sampling. Data on milk production and reproduction records were obtained from farmers and their cows through direct observation and interviews related to the identity of the cattle they owned. The results showed that the average performance of the milk production characteristics of FH dairy cows was: an average milk production of 3779.2±497.48 liters/head/day, an average length of lactation of 307.8±31.30 days, and an average dry period of 72.14±21.43 days. The lactation period had a significant effect (P&amp;lt;0.05) on milk production. The peak of milk production was reached in the fourth lactation period. The mean of reproductive traits consisting of the first postpartum mating was 77±20.5 days, the average length of days open was 96±26.4 days, the average number of services per conception was 1.8±0.85 times, and the average calving interval was 381.05± 24.5 days. In conclusion, FH dairy cows raised in Pangalengan and Margamukti Villages, Pangalengan District, Santosa and Tarumajaya Village, Kertasari District, in the working area of Pangalengan KPBS during the Covid-19 pandemic indicated a fairly good performance of milk production and reproduction characteristics.

Descriptive network analysis and the influence of timescale on centrality and cohesion metrics from a system of between-herd dairy cow movements in Ontario, Canada

Previous research has demonstrated that static monthly networks of between-herd dairy cow movements in Ontario, Canada were highly fragmented, reducing potential for large-scale outbreaks. Extrapolating results from static networks can become problematic for diseases with an incubation period that exceeds the timescale of the network. The objectives of this research were to: 1) describe the networks of dairy cow movements in Ontario, and 2) describe the changes that occur among network analysis metrics when conducted at seven different timescales. Networks of dairy cow movements were created using Lactanet Canada milk recording data collected in Ontario between 2009 and 2018. Centrality and cohesion metrics were calculated after aggregating the data at seven timescales: weekly, monthly, semi-annual, annual, biennial, quinquennial, and decennial. There were 50,598 individual cows moved between Lactanet-enrolled farms, representing approximately 75% of provincially registered dairy herds. Most movements occurred over short distances (median = 39.18 km), with fewer long-range movements (maximum = 1150.80 km). The number of arcs increased marginally relative to the number of nodes with longer network timescales. Both mean out-degree, and mean clustering coefficients increased disproportionately with increasing timescale. Conversely, mean network density decreased with increasing timescale. The largest weak and strong components at the monthly timescale were small relative to the full network (267 and 4 nodes), whereas yearly networks had much higher values (2213 and 111 nodes). Higher relative connectivity in networks with longer timescales suggests pathogens with long incubation periods and animals with subclinical infection present increased potential for wide-spread disease transmission among dairy farms in Ontario. Careful consideration of disease-specific dynamics should be made when using static networks to model disease transmission among dairy cow populations.

Multilayer networks of plasmid genetic similarity reveal potential pathways of gene transmission

Antimicrobial resistance (AMR) is a significant threat to public health. Plasmids are principal vectors of AMR genes, significantly contributing to their spread and mobility across hosts. Nevertheless, little is known about the dynamics of plasmid genetic exchange across animal hosts. Here, we use theory and methodology from network and disease ecology to investigate the potential of gene transmission between plasmids using a data set of 21 plasmidomes from a single dairy cow population. We constructed a multilayer network based on pairwise plasmid genetic similarity. Genetic similarity is a signature of past genetic exchange that can aid in identifying potential routes and mechanisms of gene transmission within and between cows. Links between cows dominated the transmission network, and plasmids containing mobility genes were more connected. Modularity analysis revealed a network cluster where all plasmids contained a mobM gene, and one where all plasmids contained a beta-lactamase gene. Cows that contain both clusters also share transmission pathways with many other cows, making them candidates for super-spreading. In support, we found signatures of gene super-spreading in which a few plasmids and cows are responsible for most gene exchange. An agent-based transmission model showed that a new gene invading the cow population will likely reach all cows. Finally, we showed that edge weights contain a non-random signature for the mechanisms of gene transmission, allowing us to differentiate between dispersal and genetic exchange. These results provide insights into how genes, including those providing AMR, spread across animal hosts.

USING OF GENETIC-POPULATION STUDIES RESULTS FOR ASSESSMENT OF SELECTION WORK IN DAIRY CATTLE POPULATIONS

The article presents the results of complex research that continues previous work aimed at determining the polymorphism of the CSN2, PRL, LEP, and TNF-α loci and analyzing the productivity of dairy cattle with different genotypes for these loci. The goal of the work is to analyze the selection work with populations of dairy cows based on the results of typing individuals for allelic variants of the CSN2, PRL, LEP, and TNF-α loci, which are associated with economically valuable traits but are not directly evaluated by traditional phenotype-based methods. To analyze the data, the observed (Ho) and expected (He) heterozygosity and Wright's fixation index (Fis) were used. Individual animal typing was performed using AS-PCR (CSN2), SSCP (TNF-α), and PCR-RFLP (PRL, LEP) methods. The studies revealed an excess of heterozygous individuals for the CSN2 and TNF-α loci and a significant predominance of homozygous individuals for the LEP locus in the population of Ukrainian Black-and-White dairy cows. For the prolactin (PRL) and leptin (LEP) genes, a deviation from genetic equilibrium was shown due to the increase in the number of homozygous individuals. In the population of Ukrainian Red-and-White dairy cows, a high level of inbreeding (39%) was found for the PRL locus, which was reflected in a deviation from the genetic equilibrium state (χ2 = 13.50). In the case of the beta-casein and leptin loci, the situation is opposite, with a marked excess of heterozygous individuals (-0.24 and -0.18, respectively), but no deviations from the equilibrium state were observed in the population (χ2 values of 2.06 and 2.42, respectively). For both populations, there were no significant changes in the ratio of different alleles and genotypes for several loci investigated, and the impossibility of fixing desired alleles using traditional breeding methods was demonstrated. Based on a comparative analysis of different types of DNA markers and typing methods (AS-PCR, SSCP, and PCR-RFLP), the sensitivity of the Ho, He, and Fis parameters to the number of alleles at the locus was established, which should be taken into account when conducting genetic-population studies. Keywords: polymorphism, population, cows, allele, genotype, homozygosity, variability, fixation.

Dairy Agribusiness to Improve Farmers’ Welfare in Kabupaten Banyumas

This study aimed to identify factors affecting the dairy agribusiness, to develop mapping for dairy agribusiness development and to determine its strategy improvement. Action research was undertaken followed by descriptive quantitative statistics analysis to present the current condition of the business. Potency and constrains of dairy farming were identified using SWOT analysis. LQ (Location Quotient) analysis followed by series of focus group discussions was conducted to develop the grand design of dairy agribusiness. Research showed that trend of the dairy cow population in Banyumas is relatively stagnant despite an increasing trend on the previous year. LQ analysis showed that sub districts suitable as the basis for dairy development are Kecamatan Baturraden, Pekuncen, Karanglewas, Kedungbanteng and Cilongok. SWOT analysis reported that dairy farming in Banyumas is at quadrant I which indicates an S-O (Strength – Opportunity) strategy focusing on utilizing the strength to maximize the opportunity existed to improve the productivity of dairy cattle.