Herders Research Articles

Case Study: On-farm Demonstration for the Impact of Applied Reproductive Technologies

Abstract Demonstrating the implementation of, and results from, applied management technologies on privately held farms is an essential method for Extension educators. A commercial cow/calf herd, for which the management was being transitioned to a younger family member, was used for this multi-year demonstration. Beginning summer 2019, the cow herd was inventoried and evaluated, and a plan was put in place to improve profitability through enhanced reproductive management. Initial evaluation showed an overall pregnancy rate of 75.6% with a 153 d calving season for cows and breeding age heifers (n = 209). Non-pregnant and un-sound cattle were sold (n = 56). The average initial BCS was a 4.5 (1 to 9 scale). Estrus synchronization for natural service was utilized in the first breeding season (Fall 2019) to condense the subsequent calving season. Melengestrol acetate (MGA) was fed at a rate of 0.5 mg/head/d for 7 d and bulls introduced on he last day MGA was fed. Also in year 1, timed artificial Insemination was used to breed purchased (n = 37) and home raised (n = 18) replacement heifers. A group of pregnant cows ranging in age from 5 to 8 years (n = 47) were also purchased in year 1. Ultrasonography was used to detect pregnancy and estimate calving date on 30 d post AI, and 30 d post bull removal. Year 2 pregnancy rate was 93% for heifers and 88% for cows with a 131 d estimated calving interval for all cows and heifers (n = 255), with 94% expected to calve in the first 90 days. In summary, while it is difficult to eliminate year-over-year variables, a combination of culling strategy and estrus synchronization for both natural service and AI resulted in an increased proportion of cows and heifers calving earlier in the calving season, which is expected to improve marketing potential and profitability of the resulting calf crop. Condensing the calving interval provides opportunity to introduce additional reproductive management practices. Results from this demonstration will be incorporated into Extension educational curricula.

Assessment and selection of the recipient cows' corpus luteum at the time of embryo transfer, and its influence on conception rate.

To describe the influence of physical traits of the corpus luteum (CL), as described by transrectal ultrasonography on day 6 post-oestrus, on the conception rate following embryo transfer (ET) in recipient beef cows. To investigate if higher recipient utilisation rates were achievable, without compromising conception rates to ET. Data were analysed from Holstein Friesian embryos (n=1075) frozen in ethylene glycol thawed for direct transfer into one herd of Angus recipient cows. For pregnancies achieved in the program (n=693), no statistically significant effect was found for the physical traits of the recipients' CL on conception rate (CL volume (P=0.20), CL side (P=0.14). Conception rates were similar for recipients with a central lacuna (62%, n=245) and recipients with no central lacuna (66%, n=448) (P=0.10). Of the pregnant recipients with a central lacuna (n=245), 98.3% had no remaining luteal cavity by the 30-day pregnancy ultrasound. No effect on conception rate was found with either the small (<50% of CL diameter) or large (>50% of CL diameter) central lacunae (P=0.18). For recipients with CLs that did not meet previous industry selection guidelines (n=172, 16% of study population), the conception rate (63%) was not significantly different to the routinely selected recipient CLs (n=903, conception rate 65%) (P=0.83). The suitability of a potential ET recipient is determined by observing an appropriately timed oestrus and a detectable CL, regardless of size or quality.

The influence of clinical and chronic forms of magnesium deficiency on the haematological parameters of dairy cows

The aim of the study was to determine the influence of hypomagnesaemia on the haematological status and predictive values of haematological tests in the diagnosis of magnesium (Mg) deficiency in dairy cow herds. The study was carried out on 100 dairy HF cows, divided into two experimental groups and a control one.The two experimental groups (I - clinical form of hypomagnesaemia, II - chronic form of hypomagnesaemia) consisted of 40 cows and the control group consisted of 20 healthy cows. Blood samples were collected twice: before the commencement of the therapy and after three months. In both hypomagnesaemic groups, low erythrocyte count, haemoglobin (Hgb) concentration and hematocrit (Ht) index values were observed. The indirect parameters of the erythrocyte system were within the standard reference range, with the exception of the mean corpuscular hemoglobin (MCH) index, which, in approx. 45% of animals, was below the lower limit of the normal range. Haemolytic normocytic normochromic anaemia was detected through the hypomagnesaemia of the cows. In the first and second group, at the first blood sampling an increase in the eosinophil count was observed, which was statistically significant in relation to the second sampling. In the blood smear test, a variety of erythrocyte sizes (anisocytosis), polychromasia and Howell-Jolly bodies were detected in the affected cows. After supplementation with magnesium, the concentration of Mg in the serum of the treated animals returned to normal more rapidly than the haematological parameters. The authors assumed that these in the haematological parameters may be helpful in indicating the need for Mg supplementation.

Movement orders in spontaneous group movements in cattle: 6-year monitoring of a beef cow herd with changing composition

Few studies have investigated group movements of domestic ungulates in farming conditions where the groups are subjected to repeated composition changes across years. We stocked a beef cow herd (23–34 cows; some with a calf) maintained in a farm in a grazing plot comprising two subplots, and monitored inter-subplot movements of cows on 39 days for 6 years. Movements of the entire cow herd, pooled over the two directions, occurred 4–23 times daily. Time required for individual movements ranged from < 1 to 34 min, with nearly 90% of the movements being completed within 10 min. Daily movement orders of cows were consistent (Kendall’s W = 0.13–0.36, P < 0.05) on 34 days out of the 39, with some cows appearing in the first three (front) or last three (rear) positions more frequently than the chance (binomial P < 0.05). The front- and rear-positioned cows did not differ (P ≥ 0.05) in age, body weight, years from the first introduction into the herd, days from the last calving, days in pregnancy, or proportion of days with a calf. More studies are needed to understand the factors affecting leadership to use this trait for management of herd movements.

English

Most available data on Taenia saginata taeniosis/cysticercosis risk factors in Botswana neither associate risk factors with Batswana&rsquo;s lifestyle nor rank risk factors&rsquo; contribution to observed prevalence. This disconnect undermines usability of data for bovine cysticercosis control. This study identified bovine cysticercosis risk factors and quantitatively ranked risk factors&rsquo; contributions to observed prevalence. Visual observation and interviews using Likert scale-formatted questionnaire was employed in collecting primary data from beef industry&rsquo;s stakeholders (149). Fourteen (14) out of eighteen (18) risk factors jointly predicted bovine cysticercosis prevalence (p &lt;0.05), but the only factor of &lsquo;beef sold at non-licensed premises&rsquo; predicted prevalence individually. Top 20% important risk factors were absence or distant pit latrines in farms (p &lt;0.05; MD=1.288; CI: 1.15-1.43), proximity to uncontrolled human defecate (p &lt;0.05; MD=1.184; CI=1.03-1.34), access to contaminated pasture (p &lt;0.05; mean=4.13; MD=1.131), and failure to deworm herd boys (p &lt;0.05; mean=4.10; MD= 1.097). Current prevention strategies in Botswana emphasizes proper disposal of human defecate. However, this study showed that minimizing butchers buying and slaughtering animals without proper ante-mortem and post-mortem examination would yield more efficient result. By adopting Pareto principle, this study modeled that controlling these top 20% important risk factors instead of targeting a repertoire of risk factors would result in 80% prevalence drop. Respondents showed greater consensus on risk factors with high odds to cause bovine cysticercosis. This consensus provides platform for driving attitudinal change, since risk factors were lifestyle-related. Associating people&rsquo;s lifestyle with risk factors of this zoonosis while targeting top 20% risk factors yields more efficient control outcomes. Key words: Batswana&rsquo;s lifestyles, Taenia saginata/cysticercosis, ranking risk factors, prevalence, Pareto principle, efficient control and prevention.

EFFICIENCY OF APPLICATION OF THE PREPARATION ON THE BASIS OF IODINE FOR MASTITIS IN COWS

The article presents the results of establishing the effectiveness of the use of an experimental preparation based on iodine for various forms of cow mastitis in a farm for the production of commercial milk. Inflammation of the mammary gland is the most common condition in productive herds of cows. Subclinical mastitis, which does not manifest with typical clinical signs for this pathology, is a particular health hazard, but qualitative changes in milk are determined by laboratory tests. Also huge economic losses on farms are recorded during the diagnosis of clinical forms of mastitis in the livestock, which often lead to premature culling of cows, a decrease in the quantity and quality of milk received from them. A set of measures for the diagnosis, treatment and prevention of mastitis also requires constant expenditure of funds. The work was carried out during 2020 in a farm that specializes in the production of commercial milk. The experimental drug under study contains iodine as the main active ingredient, which has a pronounced bactericidal and bacteriostatic effect against a wide range of microorganisms - causative agents of mastitis. It also has a general stimulating effect on the immune system of the udder. As synergistic components, the experimental drug contains compounds with pronounced analgesic, decongestant and astringent effects at the site of the development of the pathological process. At the first stage of the research, the influence of the experimental drug on the qualitative characteristics of milk was determined.&#x0D; The number of somatic cells was determined in milk after application of the experimental agent after 24, 48, 72 hours and 7 days. At the second stage of the research, we compared the effectiveness of various methods for diagnosing subclinical mastitis in cows during the dry period.&#x0D; When we analyzed the data obtained on the effect of the investigated experimental drug based on iodine on the number of somatic cells in the milk of cows with subclinical and clinical (catarrhal and purulent-catarrhal) forms of mastitis, we established a positive dynamics of their gradual decrease. This indicator reached the maximum level of decrease on the seventh day after application of the drug, both in subclinical and in clinical forms (catarrhal and purulent-catarrhal) mastitis, which amounted to 298.6 ± 11.6; 308.6 ± 14.4 and 328.6 ± 34.4 th./ml. The introduction of a drug with a similar compositional composition for the main active ingredients, it was not possible to achieve a similar effect on the dynamics of the reduction of somatic cells.

The impact of consumer personality on purchasing behavior in the dairy market in terms of psychological factors

Since the 1990s of the 20th century, the Slovak dairy industry has undergone many significant changes which have been related to the reduction of the herds of cattle and milk cows, the decrease of quantity of milked milk, low purchase prices of milk, the decline of a great number of milk producers and processors. The consumption of cow´s milk and dairy products in Slovakia is very low in comparison with the countries of the European Union (about 320 kg), Europe (293 kg), the Czech Republic (280 kg), and the rest of the world. It varies around 170 kg per capita per year, which is also considerably lower consumption than the dose of 220 – 240 kg per capita per year recommended by doctors. Since 1990 the production and consumption of dairy products and cheeses have decreased significantly. In Slovakia, the consumption is twice even three times less than in the developed countries of Europe. The reason for this situation is the behavior of a consumer and the factors having an impact on the consumption of cow`s milk and dairy products. The objective of the paper is to indicate the impact of the personal consumers` characteristics on the purchasing decisions on the market of the products of cow`s milk origin, based on the processed answers of the respondents participating in the questionnaire survey. The primary data were obtained via the questionnaire survey, which was conducted with 786 respondents. The questionnaire consisted of four parts – Eysenck`s personality test, the questions targeted at the detection of factors influencing the consumers` purchasing behavior and decision making, the questions related to expressing opinions about cow`s milk and dairy products, and the classification questions providing the information about the respondents. The data were processed by the methods of quantitative and qualitative statistics – Chi-square statistic χ2 test of square contingency, Chi-square χ2 goodness of fit test, two proportion test, Kolmogorov-Smirnov test, the test of hypotheses of relative proportion.

Dairy Woes in Wisconsin: What about the Amish?

Wisconsin has steadily lost dairy farms for decades, yet the number of Amish dairy herds grew both numerically and proportionately into early 2018. Facing low milk prices, the overall rate of loss of dairy farms in Wisconsin accelerated since then. During 2019, the state lost over 1% of its dairy herds monthly, losing two to three herds daily. The expansion of Amish dairying also ended. Between April 1, 2018, when Wisconsin had 1,160 Amish dairy herds or 12.9% of the state's total, and November 1, 2019, the state lost 165 Amish herds. Losses are continuing.This paper focuses on the impact of the departure of many Amish farms from dairying, relying on examination of dairy producer licenses and a survey of bishops and ministers in Wisconsin's Amish church districts. The loss of Amish herds of dairy cows is greater than the overall departure of the Amish from dairying, inasmuch as the Amish have nearly doubled their milk goat herds over the past five years. Those settlements producing milk transported in cans have been more likely to leave dairying unless their community operates its own cheese factory. Yet dairying is declining in most Amish communities, other than in several recently established settlements. Expanding involvement in growing produce and in woodworking were seen.

Genetic parameter estimations and genomic insights for teat and udder structure in young and mature Canadian Angus cows.

Poor teat and udder structure, frequently associated with older cows, impact cow production and health as well as calf morbidity and mortality. However, producer culling, for reasons including age, production, feed availability, and beef markets, creates a bias in teat (TS) and udder scores (US) assessed and submitted to the Canadian Angus Association for genetic evaluations toward improved mammary structure. In addition, due to the infancy of the reporting program, repeated scores are rare. Prior to the adoption of genetic evaluations for TS and US in Canadian Angus cattle, it is imperative to verify that TS and US from young cows are the same traits as TS and US estimated on mature cows. Genetic parameters for TS and US from all cows (n = 4,192) and then from young cows (parities 1 and 2) and from mature cows (parity ≥ 4) were estimated using a single-trait animal model. Genetic correlations for the traits between the two cow age groups were estimated using a two-trait animal model. Estimates of heritability (posterior SD [PSD]) were 0.32 (0.07) and 0.45 (0.07) for young TS and US and 0.27 (0.07) and 0.31 (0.07) for mature TS and US, respectively. Genetic correlation (PSD) between the young and mature traits was 0.87 (0.13) for TS and 0.40 (0.17) for US. Genome-wide association studies were used to further explore the genetic and biological commonalities and differences between the two groups. Although there were no genes in common for the two USs, 12 genes overlapped for TS in the two cow age groups. Interestingly, there were also 23 genes in common between TS and US in mature cows. Based on these findings, it is recommended that producers collect TS and US on their cow herd annually.

Поліморфізм систем білків крові та його значення у репродуктивній функції корів української чорно-рябої молочної породи

Goal. To assess the reproductive capacity of livestock, to determine in the blood serum polymorphic systems of protein macromolecules and enzymes, and to establish their relationship with indicators of reproductive function, resistance to obstetric and gynecological pathology in cows. To study the options for using molecular genetic analysis of cattle to identify immunogenetic markers to theoretically substantiate their use for the formation of highly productive and resistant to obstetric and gynecological pathology of dairy cows. Methods. The study was conducted in “Dairy Rivers, Ltd.” on 75 cows of the Ukrainian black-spotted dairy breed (Western intra-breed type) aged 5-9 years, live weight 550-600 kg. Obstetric and gynecological examination of cows was performed according to the method elaborated by M. Kosenko et al. (2005). Criteria for assessing the reproductive function of cows were as follows: duration of pregnancy, time of the first insemination after calving, service period, insemination index; fertility after the first insemination, all fertilized (total number of fertilized animals during the study period), the birth of twins. Results. The material selected for genetic and biochemical studies (blood samples from 75 cows) contained the following polymorphic protein systems: post-albumins, transferrins, haptoglobin, and isoforms of enzymes: catalase, peroxidase, and succinate oxide dismutase. The genetic frequency of alleles of polymorphic systems of proteins and serum enzymes was determined using the Hardy–Weinberg formula. The frequency of allele A of the transferrin locus in cows is lower, and that one of allele D is higher by 0.11 units. This indicates that the genetic frequency of the studied polymorphic systems of proteins and serum enzymes of cows in different herds is not the same. Conclusions. In cows-homozygotes and cows-heterozygotes tested for catalase isoforms, no significant difference in the studied indicators of reproductive function was found, because the phenotypes of isoforms of glutathione peroxidase and superoxide dismutase during their separation in polyacrylamide gel were monomorphic. The birth of twins was observed in K-AA homozygotes.

The Deviation between Dairy Cow Metabolizable Energy Requirements and Pasture Supply on a Dairy Farm Using Proximal Hyperspectral Sensing

This study aimed at determining the extent to which the deviation of daily total metabolizable energy (MEt) requirements of individual cows from the metabolizable energy (ME) supplied per cow (DME) varied throughout the production season in a pasture-based dairy farm using proximal hyperspectral sensing (PHS). Herd tests, milk production, herbage and feed allocation data were collected during the 2016–2017 and 2017–2018 production seasons at Dairy 1, Massey University, New Zealand. Herbage ME was determined from canopy reflectance acquired using PHS. Orthogonal polynomials were used to model lactation curves for yields of milk, fat, protein and live weights of cows. Daily dietary ME supplied per cow to the herd and ME requirements of cows were calculated using the Agricultural Food and Research Council (AFRC) energy system of 1993. A linear model including the random effects of breed and cow was used to estimate variance components for DME. Daily herd MEt estimated requirements oscillated between a fifth above or below the ME supplied throughout the production seasons. DME was mostly explained by observations made within a cow rather than between cows or breeds. Having daily estimates of individual cow requirements for MEt in addition to ME dietary supply can potentially contribute to achieving a more precise fit between supply and demand for feed in a pasture-based dairy farm by devising feeding strategies aimed at reducing DME.

OLD ORDER DAIRY FARMERS IN WISCONSIN

Dairying among Wisconsin’s Amish and Old Order Mennonite farmers expanded through 2017, and by early 2018 Amish farms contained 12.9 percent of the state’s total dairy herds of cows, goats, and sheep. Old Order Mennonite herds comprised 5.0 percent. Faced with a variety of challenges, Wisconsin lost 198 Amish herds between April 2018 and July 2020, yet its number of Old Order Mennonite herds grew. Together, these groups operated over half of the dairy farms within 59 of Wisconsin’s towns in 2020. The paper examines the spatial patterns of expansion and contraction of Old Order dairying between 2012 and 2020, noting and explaining differences between the Amish and Mennonite farmers, as well as among the three conferences of Old Order Mennonites. Losses among the Amish were the greatest for can milk producers, yet 19 percent of Wisconsin’s Amish dairy herds were on certified organic farms in 2020.

Relationship between in-line milk progesterone before and after artificial insemination and fertility outcomes in dairy cows.

The aim of this study was to evaluate the possibility to predict outcomes of artificial insemi- nation (AI) in dairy cows based on in-line milk progesterone (P4) concentration. The research was carried out on the herd of loose housing 245 dairy cows of 2-4 lactations, with average milk yielding 11.000 kg per cow. Milk sampling, measuring, and recording of milk P4 concentration was carried out using the Herd Navigator (HN). The grouping was performed according to the following three indices: the first by reproductive condition - pregnant or not pregnant after AI, the second by P4 concentration from day 20 before AI to day 20 after AI, and the third by P4 concentration at AI time. There was a significant difference in P4 concentration in the group of pregnant cows from day 15 to day 9 before AI, and it was by 18.3% higher com- pared to that in the group of non-pregnant cows in the said period (p⟨0.01). The milk P4 concen- trations began to differ mostly from day 10 after AI. At that time, the average P4 concentration in the group of pregnant dairy cows was by 36.8% higher compared to that in the group of non-pregnant cows (p⟨0.01). A statistically significant difference between the ratio of the cows with high, medium, and low P4 concentration on days 20-16 before AI (p⟨0.01) was determined. The highest number of cows with up to 2-3 ng/ml P4 concentration became pregnant at the AI time. In-line milk P4 records captured on day 10-15 before AI can be used to predict the proper for reproduction period. By P4 concentrations on day10 after AI, the ratio of pregnant cows in herd can be assessed.

Accidents with Animals While Hiking in the Swiss Alps

Accidents with Animals While Hiking in the Swiss Alps Abstract. Mountain hiking is very popular. However, despite potential benefits, there are risks, also by animals. Retrospectively, all mountain hiking emergencies (n = 10 185) from the years 2009-2018 were analyzed using the registry of the Swiss Alpine Club (SAC), with 104 mountain emergencies caused by animals. The average NACA score was 3.2 ± 1.6, and more than half of the mountain emergencies had a NACA score >4, which can be associated with a life-threatening condition. More than half of the emergencies were caused by insects (bees, wasps, bumblebees, hornets), and just under a quarter each by hoofed animals and snakes, respectively. Three of these events were mortal, and all of these were caused by hoofed animals (mother cow herd, horse, bull). Therefore, it is recommended to keep a safe distance from these animals when passing them.

Real-Time Cow Detection and Identification Using Enhanced Particle Filter

In this paper, demonstration of how an individual cow can be tracked and identified in a herd of cows using an enhanced particle filter is presented. In a typical agricultural setup, it is not uncommon to witness cases of cow swapping and rustling. In the past, different methods were recorded in literatures for the monitoring of herds. However, advancement in technology has rendered those methods less effective, resulting to demand for continual improvement on the state-of-the-art methods for tracking individual cows. To achieve this, we employed off-the-shelf networks for end-to-end individual cow identification in up-to-down motionless imagery acquired from stationary camera. The dynamic trajectory of the herd was captured by a camera installed on a pole near a passageway through which the cows passed almost every day and the video processing system was employed for the processing of the herd’s trajectory. Report was made on the model initialisation, mean shift algorithm, particle-Kalman filter, and the target model is updated in order to overcome the change in the target object appearance over time. To our utmost knowledge, this work is the first to apply combination of mean-shift based tracker and particle-Kalman filter as enhanced particle filter to real-time cow detection and identification to curtail occlusion and non-linear tracking problem.

On the adequacy of the adaptive control model and the use of L-distribution of the rotary-conveyor milking process on “Karusel” type installations

The article reflects the degree of adequacy of the use of G-distribution and the constructed mathematical model of adaptive control, which allows increasing the productivity of conveyor-ring milking machines of the “Karusel” type. This paper discusses the results of research on the process of milking a herd of cows on a carousel-type milking machine. Based on the methods of variational statistics the influence of the parameters of the statistical distribution of the duration of milking performance of a milking machine is studied, a theoretical analysis of the timeline of its work is carried out. Models and algorithms for adaptive speed control of milking pipeline with the use of specialized software, including the system of analytical calculations Maple are developed. This software allows you to perform analytical transformations of large amounts of information and display the results of calculations in tabular graphical form and in animation mode.

The evaluation of the relationship of lactose to production and reproduction traits in different breeding conditions of the Slovak Spotted dairy cows

The evaluation of the relationship of lactose to production and reproduction traits in different breeding conditions of the Slovak Spotted dairy cows

Comparison of the effectiveness of selenium and vitamin E supplementation on the health of the mammary gland of sheep

Article Details: Received: 2020-10-14 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.75-79 In this study we observed the effect of peroral and parenteral supplementation of Selenium (Se) and vitamin E (VTE) on the selected antioxidant parameters in blood and on the incidence of mastitis in ewes after the first lambing. Of the 350 sheep of Improved Walachian and Lacaune breeds, situated in eastern Slovakia under standard zootechnical and animal hygiene conditions, we selected thirty one-year-old ewes before their first lambing. The ewes were divided into three groups according to the method of supplementation of Se and VTE. The blood samples from vena jugularis were collected on day 30 before lambing (control sampling) and on days 3 and 30 after lambing. Ewes were checked for mastitis on days 10 and 30 after lambing. On the day of the control sampling the ewes from the B1 group were perorally supplemented with 0.3 mg Se/kg/DM in the form of Na2SeO3 and 50 IU/vitamin E/kg/DM, while ewes from the B2 group were injected subcutaneously Se with VTE at a dose of 6.6 mg/Se and 1,000 IU/VTE. Changes in the concentration of Se and VTE in the blood plasma of ewes were determined only in the perorally supplemented group (B1) on day 3 after lambing. At 30 days after lambing the the incidence of mastitis in this group was half as lower (10%) as in the control group (20%). Keywords: sheep, mastitis, supplementation, glutathione peroxidase, selenium, bacteria References Cohen, RD a kol. (1991). Účinky parenterálnej suplementácie tehotných hovädzích kráv selénom / vitamínom E na selén kravy a teľaťa a produktivitu. Konzerva. Vet. Jour . 32,113-115. https://www.ncbi.nlm.nih.gov/pubmed/17423734 Grešáková, L. a kol. (2013). Retencia selénu u jahniat kŕmených krmivom doplneným selénom z anorganických zdrojov. Výskum malých prežúvavcov , 111, 76–82. https://doi.org/10.1016/j.smallrumres.2012.10.009 Fthenakis, GC (1995). Kalifornský test na mastitídu a Whitesideov test na diagnostiku subklinickej mastitídy mliečnych bahníc. Výskum malých prežúvavcov, 16, 271–276. https://www.sciencedirect.com/science/article/pii/0921448895006382 Hess, D. et al. (1991). Simultaneous determination of retinol, tocopherols, carotenes and lycopene in plasma by means of high-performance liquid chromatography on reversed phase. International Journal of Vitamin and Nutrition Research , 61, 232–238. https://pubmed.ncbi.nlm.nih.gov/1794952/ Kafilzadeh, F. et al. (2014). Comparing the effect of oral supplementation of vitamin E, injective vitamin E and selenium or both during late pregnancy on production and reproductive performance and immune function of dairy cows and calves. The Scientific World Journal , 5. http://dx.doi.org/10.1155/2014/165841 Misurova, L. et al. (2009). Selenium metabolism in goats – maternal transfer of selenium to newborn kids. Veterinarni Medicina 54, 125–130. https://www.agriculturejournals.cz/publicFiles/05520.pdf Paglia, D. E, Valentine, W. N. (1967). Studies on the quantitative and qualitative characterization of erytrocyte glutathione peroxidase. The Journal of Laboratory and Clinical Medicine , 70, 158–169. http://garfield.library.upenn.edu/classics1989/A1989T143200001.pdf Persson, W. K. et al. (2007). Supplementation of RRR-alpha-tocopheryl acetate to periparturient dairy cows in commercial herds with high mastitis incidence. Journal of Dairy Science , 90, 3640–3646. http://dx.doi.org/10.3168/jds.2006-421 Pavlata, L. et al. (2002). Selenium status of cattle in the Czech Republic. Acta Veterinaria Brno , 71, 3–8. https://actavet.vfu.cz/71/1/0003/ Pavlata, l. et al. (2012). Direct and indirect assessment of selenium status in sheep – a comparison. Veterinarni Medicina , 57, 219–223. http://vri.cz/docs/vetmed/57-5-219.pdf Smith, K. L. et al. (1997). Dietary vitamin E and selenium affect mastitis and milk quality. Journal of Animal Science , 75, 1659–1665. https://pubmed.ncbi.nlm.nih.gov/9250530/ Spears, J. W., Weiss, W. P. (2008). Role of antioxidants and trace elements in health and immunity of transition dairy cows. The Veterinary Journal , 176, 70–76. https://pubmed.ncbi.nlm.nih.gov/18325801/ Vasiľ, M. a kol. (2018). Patogény stožiar izolované izolované od vzoriek mlieka v chove oviec nachádzajúcich sa v okrajových častiach Slovenska. V infekčné a parazitárne choroby zvierat, 6. ročník medzinárodnej vedeckej konferencie , 13.-14. Septembra, Košice. s. 244–248. ISBN 978-80-8077-583-4

Permanence time in the herd and milk production of Holstein cows with up to five successive extended lactations.

A total of 1338 high-yielding cows with five lactations from a large well-managed commercial dairy operation in a hot environment of northern Mexico were used to evaluate milk yield and reproductive performance of cows undergoing unplanned extended lactations (EL; > 450 days). The null hypothesis that cumulative milk yield during five consecutive lactations is the same in cows not having unplanned EL and cows with several EL was tested. All EL resulted from cows failing to become pregnant with ≥ 4 services. Cows were allocated to 1 of 6 groups according to the number of EL (EL0 for cows with no EL to EL5 for cows with 5 EL). Cumulative milk yield was highest (P < 0.01) for EL5 cows (95,499 kg) and lowest for EL0 cows (56,236 kg). Likewise, cumulative days in milk were greatest (P < 0.01) in EL5 (2968 days) and lowest in EL0 (1857 days) cows. Mean milk yield per lactation increased linearly with the increase in the number of extended lactations with a maximum of 19,099 kg of milk/lactation for EL5 cows. Mean daily milk yield/productive life was lowest (P < 0.01) for EL0 (30.2 kg) and highest for EL5 (32.1 kg). The percentage of days in milk relative to days from birth to the end of the fifth lactation was highest for EL5 (78.1%) and lowest for EL0 (59.6%), with EL2 to EL4 cows intermediate. Length of calving interval was longest (P < 0.01) for EL5 (24.7 months) and shortest for EL0 (15.5 months) cows. It was concluded that it is worthwhile maintaining high-yielding cows incapable to conceive before 230 days in milk because they did conceive again and produced considerable amounts of milk during their productive life, which substantially prolonged their permanence time in the herd.

Determining the reproductive potential of repair heifers

Reproduction and culling of productive animals are the main factors that affect the number of cows in a herd. Timely determination of fertility in replacement heifers with subsequent culling of problem heifers will help reduce direct economic losses in breeding dairy cattle. When making a diagnosis, veterinarians should exclude all forms of temporary or permanent infertility, including Congenital anomalies (infantilism, freemartinism, deformities, etc.).In order to establish the hormonal status of heifers-freemartin in the blood serum, the concentration of sex hormones (progesterone, estradiol-17ᵦ, and testosterone) and anti-Müllerian hormone (AMH) was determined.Studies of the level of AMH using an enzyme-linked immunosorbent assay in blood serum have proven the possibility of early assessment of fertility in heifers. This method will allow early culling of Freemartin heifers from a productive herd. The study of AMH levels showed that its amount directly correlates with fertility in cattle, regardless of the period of the estrous cycle. When the concentration of AMH in the blood serum is below 100 pg / ml, heifers are not capable of fruitful insemination, while a high level of anti-Müllerian hormone (more than 380 ng / ml) makes it possible to successfully fertilize animals on the first attempt. All clinically healthy replacements obtained during a single pregnancy were successfully inseminated. At low concentrations of anti-Müllerian hormone, Freemartin heifers were sterile, even after hormonal stimulation (Co-Synx) and sperm doses were administered without clinical manifestation of sexual desire.The introduction of testing for the level of AMH by the ELISA method in the mandatory gynecological clinical examination of cattle in livestock enterprises is expedient and effective.