Dairy Cattle Management Research Articles

Factors associated with Ontario dairy producers' management and care of down dairy cattle.

The objective of this study was to better understand current management practices for down cows in Ontario, Canada, and to identify factors associated with the adoption of acceptable practices. An online survey was distributed to all dairy producers in Ontario, Canada (n = 3,367) and was available from November 2020 to March 2021, inclusive. Dairy producers were identified through their provincial dairy organization and contacted via email, and the survey was also promoted via social media. The survey was comprised of 134 questions, 31 of which were related to down cow management. Descriptive statistics were evaluated, and 2 logistic regression models were generated using Stata 17, exploring factors associated with 1) relocating down cows with hip lifters and 2) assisting cows to stand within an hour after discovering a down cow. A total of 226 producers responded (7.4%). Participants were predominantly male (68%), farm owners (78%), and 30-39 years old (29%). Producers reported relocating down cows with a boat or sled (32.6%), front-end loader bucket (31.4%), hip lifters (28.0%), or 'other' (with a text box to further describe) (8.0%). The median time to relocating a down cow after identifying her was 1 h (range 0 - 17h). Farms that relocated a down cow sooner after identifying her as down, were more likely to use appropriate methods to move the cow. However, we also found that farms that provided feed and water sooner to down cows, were more likely to use an inappropriate method (hip lifters) to move her. Farms that used hip lifters to move cows had higher odds of assisting a cow to stand within an hour following the discovery of recumbency. Additionally, producers who waited longer to relocate a down cow were less likely to assist the cow to stand within one hour of finding them down. Research has identified effective management practices for down cows, yet there remains a gap in understanding the implementation and the decision-making process of producers. Data from this study will be helpful in designing future research that further explores the barriers and motivations of producers when implementing evidence-based management plans to care for down dairy cows and may help inform current industry extension efforts.

Investigating the genomic background of calving-related traits in Canadian Jersey cattle

Traits related to calving have a significant impact on animal welfare and farm profitability in dairy production systems. Identifying genomic regions associated with calving traits could contribute to refining dairy cattle breeding programs and management practices in the dairy industry. Therefore, the primary objectives of this study were to estimate genetic parameters and perform genome-wide association studies (GWAS) and functional enrichment analyses for stillbirth, gestation length, calf size, and calving ease traits in North American Jersey cattle. A total of 40,503 animals with phenotypic records and 5,398 animals genotyped for 45,101 single nucleotide polymorphisms (SNPs) were included in the analyses. Genetic parameters were estimated based on animal models and Bayesian methods. The effects of SNPs were estimated using the Single-step Genomic Best Linear Unbiased Prediction (ssGBLUP) method. The heritability (standard error) estimates ranged from 0.01 (0.01) for stillbirths (SB) in heifers to 0.11 (0.01) for gestation length (GL) in cows. The genetic correlations ranged from -0.58 (0.11) between calving ease (CE) and SB in heifers to 0.44 (0.14) between calving ease and calf size (CZ) in cows. CE showed the highest genetic correlation between heifers and cows, 0.8 (0.22) respectively. The candidate genes identified, including MTHFR, SERPINA5, IGFBP3, and ZRANB1, are involved in key biological processes and metabolic pathways related to the studied traits. Reducing environmental variation and identifying novel indicators of reproduction traits in the Jersey breed are needed given the low heritability estimates for most traits evaluated in this study. In conclusion, this study provides a characterization of the genetic background of calving-related traits in Jersey cattle. The estimates obtained can be used to improve or build selection indexes in Jersey cattle breeding programs in North America.

Digital and Precision Technologies in Dairy Cattle Farming: A Bibliometric Analysis.

The advancement of technology has significantly transformed the livestock landscape, particularly in the management of dairy cattle, through the incorporation of digital and precision approaches. This study presents a bibliometric analysis focused on these technologies involving dairy farming to explore and map the extent of research in the scientific literature. Through this review, it was possible to investigate academic production related to digital and precision livestock farming and identify emerging patterns, main research themes, and author collaborations. To carry out this investigation in the literature, the entire timeline was considered, finding works from 2008 to November 2023 in the scientific databases Scopus and Web of Science. Next, the Bibliometrix (version 4.1.3) package in R (version 4.3.1) and its Biblioshiny software extension (version 4.1.3) were used as a graphical interface, in addition to the VOSviewer (version 1.6.19) software, focusing on filtering and creating graphs and thematic maps to analyze the temporal evolution of 198 works identified and classified for this research. The results indicate that the main journals of interest for publications with identified affiliations are "Computers and Electronics in Agriculture" and "Journal of Dairy Science". It has been observed that the authors focus on emerging technologies such as machine learning, deep learning, and computer vision for behavioral monitoring, dairy cattle identification, and management of thermal stress in these animals. These technologies are crucial for making decisions that enhance health and efficiency in milk production, contributing to more sustainable practices. This work highlights the evolution of precision livestock farming and introduces the concept of digital livestock farming, demonstrating how the adoption of advanced digital tools can transform dairy herd management. Digital livestock farming not only boosts productivity but also redefines cattle management through technological innovations, emphasizing the significant impact of these trends on the sustainability and efficiency of dairy production.

Business model development for installation of rubber floor mats to support productivity in dairy farming

Purpose. Ribbed smoked sheet (RSS) rubber gradually loses its quality as it is stored after production. Rubber floor mats are recommended as a marketable upstream production in the Thailand rubber industry to help add economic value to low-graded RSS. However, limited attention in research has been paid to business development, particularly on practical models focusing on the demand perspectives. This study helped fill the knowledge gap by analysing factors influencing labour production in dairy farming and proposing a business model based on productivity analysis. The aim of the project was to create a practical business model for cattle rubber floor mats made of low-graded RSS rubber used for nourishing and housing management to promote labour productivity in dairy farming. Methodology / approach. The study used mixed-methods research. A theoretical framework was developed concerning rubber floor mats used in dairy farming, which helped improve the nourishing and housing management of dairy cattle and promote labour productivity. This research adopted Osterwalder’s business model canvas to examine the demand and supply elements of dairy cattle floor mats made of low-graded rubber. It also used the knowledge-based entrepreneurship concept to scrutinise knowledge-based business development. A questionnaire survey was used to collect data required for multiple regression analysis of labour productivity using the Ordinary Least Square (OLS) method. It also used semi-structured interviews to scrutinise the subjective experiences of farmers. A focus group discussion was conducted to investigate academics and rubber promotional authorities concerning potential technology and the possibility of transfer of production technology to promote knowledge-based business development. Results. The empirical evidence presented in this paper confirmed that rubber floor mats could help enhance cattle nourishment, dairy housing management and labour productivity. Regional knowledge transfer network was revealed as a driver of knowledge-based development for assisting local upstream rubber farmers in pursuing eco-innovation in rubber production, aligning with the national initiatives of Industry 4.0 and Bio-Circular-Green economy (BCG) concepts. Originality / scientific novelty. The originality of this paper is that it presents the results of an empirical study using mixed methods for the first time aiming at clarifying practical elements of the supply and demand sides’ components of the Osterwalder`s Business Model Canvas for developing a business model delivered as a knowledge-based business model for the production of dairy cattle floor mats made of low-graded RSS rubber to help guide practical downstream rubber business development. The qualitative results, together with the quantitative analysis of labour productivity, are based on the perceptions of local farmers in Thailand regarding the use of rubber floor mats on the farm; previous studies scientifically prove its positive relation to an increase in dairy cattle nourishing, hence the daily productivity. Practical value / implications. The novel business model canvas could promote the practical cattle floor mats business development. University engagement and public support were included as the critical drivers in this knowledge-based business model. The model implementation could help encourage rubber farmers and smallholders in upstream rubber production to move towards downstream business development and become knowledge-based entrepreneurs in value-added rubber floor mats production. It could also guide the agricultural policymakers to benchmark and evaluate their policy targeting innovative knowledge-based business development for rubber extension.

PENGENALAN MANAJEMEN PEMELIHARAAN SAPI PERAH BERDASARKAN PEDOMAN GOOD DAIRY FARMING PRACTICE (GDFP) DI DESA WESALO, KABUPATEN KOLAKA TIMUR

Dairy cows as milk-producing livestock will show their best performance if their maintenance management is carried out well. Good dairy cattle management can be done by referring to Good Dairy Farming Practice (GDFP). This service activity was carried out to increase the knowledge and skills of dairy farmers in Wesalo Village, Lalolae Village, East Kolaka Regency. The stages of this activity include: 1). activity preparation; 2. technical guidance on management of dairy cattle maintenance according to GDPP; 3. monitoring and evaluating activities. This activity is very beneficial for breeders in Wesalo Village because the breeders are new to and starting to raise dairy cattle. During the activity, the breeders were very active in discussing and enthusiastically listening to the speakers' presentations. Breeders are also very enthusiastic and focused on paying attention to the technical guidance provided during direct visits to the breeder's pen. Implementation of GDFP can be carried out by paying attention to aspects: 1). breeding and reproduction; 2). provision of feed and drinking water; 3). management; 4). cages and equipment; 5). livestock health and welfare. This community service activity closed with monitoring and evaluation to determine the level of understanding and help farmers who experience difficulties in raising dairy cattle. This activity can increase the knowledge and skills of farmers so they can maintain and develop dairy cows.

The revolution and future frontiers of reproductive management of dairy cattle

The 21-d pregnancy rate is determined by an interaction be­tween the AI service rate and pregnancies per AI (P/AI) and is a key performance indicator for the reproductive efficiency of dairy farms. Over the past 2 decades, the reproductive per­formance of lactating dairy cows increased. A greater under­standing of endocrinology and the physiology of lactating dairy cows generated fertility programs (the Presynch-Ovsynch and Double Ovsynch protocols for TAI) that increase the service rate and P/AI compared with detection of estrus. Previously, synchronization of ovulation in heifers was associated with poor reproductive performance compared with detection of estrus. Several modifications determined through randomized-controlled studies gave rise to the 5-d CIDR-Synch protocol that has similar and more P/AI when heifers are inseminated with conventional and sexed semen, respectively, compared with detection of estrus. A hierarchy of reproductive needs exists for dairy farms that require fulfillment before a new need can emerge. Dairy farms must have a high 21-d pregnancy rate and good heifer management before adopting other advanced re­productive technologies such as genomic selection, sexed and beef semen, and in vitro-produced embryos. Adopting these ad­vanced reproductive technologies benefits dairy farms, howev­er, challenges still exist that need further investigation through randomized-controlled experiments to maximize the benefits

Adapted Machinery and Technology for Alpine Pasture Dairy Farming

The paper highlights that grazing a dairy herd on ecologically pristine mountain pastures facilitates the production of raw milk at reduced costs. Preserving the native properties of milk and achieving superior product quality necessitates prompt milk processing, particularly through efficient cooling and storage at low temperatures. (Research purpose) The primary objective of this research is to substantiate the methodology for dairy cattle management and to develop technological solutions for milking and primary milk processing in mountainous pastures. (Materials and methods) Prototypes of milking machines and cooling equipment utilizing natural cold sources were developed and produced. Trials were conducted on farms in the Kabardino-Balkarian Republic. A methodology to produce consumable milk has been developed considering the natural and climatic conditions inherent in grazing dairy cattle on mountain pastures and existing machinery for milking and primary processing of raw materials. The technology includes the basic operations such as dairy herd feeding and management, milking, primary milk processing and storage of drinking cow’s milk. (Results and discussion) The technology is poised to enhance milk production by 10 percent, elevate the fat content by 3 percent, and decrease the incidence of mastitis in cows attributed to conventional machine milking tailored for lowland conditions by 40 percent. Moreover, it promises a 15 percent reduction in energy consumption for operating milking and refrigeration equipment as well as an increase in labor productivity. These technical and technological advancements are fortified with patent protection. (Conclusions) The development of dairy farming in mountainous regions, rich in naturally growing, ecologically pristine pasture lands, is an economically attractive direction to produce premium domestic dairy products. Comparative analyses conducted through laboratory assessments and field trials substantiate the viability of employing the proposed technological methodologies and machinery.

СОВЕРШЕНСТВОВАНИЕ ЦЕН НА ОПЛАТУ ПОТРЕБЛЕННЫХ ЭНЕРГОРЕСУРСОВ В ЖИВОТНОВОДСТВЕ

At large scale dairy producing enterprises, having an innovative technical-and-technological resource in livestock there is an expanded type of reproducing. At the same time, scientific-and-technological progress in the technical-and-technological production’s improvement in animal breeding, feeding and other areas of dairy cattle management, ensuring a products’ unit in labor intensity and cost reducing is being achieved. Despite the Russian Federation Government’s measures by the agriculture development, dairy cattle breeding have continued a tendency to the number of cows is facilitated by a long industry production cycle reducing, as well as weak material-and-technical base and dairy farms and complexes’ an inadequate energy system supplying. As a result, the milk production sustainability in the regions is low. The methodology of the industry’s power supply systems technical-and-economic assessment in the context of accelerating technical-and-technological reequipment and livestock’s reliable and high quality energy supply to importance is presented. The effectiveness of electrification of technological processes’ technical means for the industry products’ producing using largely depends on the quality of power supplying. In addition the electricity supply reliability, it is necessary the energy supply system efficiency by the electricity’s supply quality parameters influence taking into account the level of economic losses from insufficient reliability of rural power grids increasing. A calculating method for economic feasibility of local energy supply systems using in livestock has been proposed, that has been tested in the divisions of a large, closed cycle meat and dairy products "from field to counter", agroholding "Agropromkomplektatsiya" producing. The results confirming the economic feasibility of local energy supply systems for large scale production using study and of livestock products processing. The energy production by the energy complex cost turned out to be almost in 40% lower than the electricity tariff and more than in 20% lesser than the thermal energy tariff establishing.

GENOMICS AS A TOOL FOR IMPROVING DAIRY CATTLE POPULATIONS

The dairy industry plays a pivotal role in meeting the global demand for high-quality milk and dairy products. To address the ever-increasing need for efficient and productive dairy cattle populations, the integration of genomics has emerged as a transformative tool. Genomic selection, a revolutionary advancement in cattle breeding, has allowed for the identification of superior individuals at an early age based on their genetic potential. Genomic selection has not only accelerated genetic progress but has also minimized generation intervals, leading to more efficient breeding programs. Furthermore, the incorporation of genomic data in selection decisions has increased the accuracy of breeding values, ultimately resulting in the production of dairy cattle with improved milk yield, fertility, and disease resistance. Beyond traditional breeding goals, genomics has also enabled the identification of genetic variants associated with traits that are difficult to measure, such as feed efficiency, heat tolerance, and environmental adaptability. By deciphering the genetic basis of these traits, it is now possible to develop breeding strategies that enhance the resilience of dairy cattle populations in the face of changing environmental conditions. This paper also explores the role of genomics in addressing health and welfare concerns within the dairy industry. Genetic markers associated with susceptibility to diseases and stress-related conditions have been identified, providing opportunities to select for healthier and more resilient animals. Furthermore, genomics has opened avenues for tailoring nutritional strategies to individual cattle based on their genetic predispositions, optimizing feed efficiency and reducing environmental impacts. The utilization of genomic data is not limited to breeding and production. Genomics has facilitated the development of innovative tools for managing dairy cattle populations. Precision management, including genomic-based early disease detection and personalized healthcare, is becoming increasingly viable, enhancing animal welfare and reducing production losses. In conclusion, genomics has revolutionized dairy cattle breeding and management by providing accurate and efficient tools for selecting animals with superior genetic potential, improving production, health, and welfare, and enhancing the overall sustainability of dairy cattle populations. As genomics continues to evolve, the dairy industry stands to benefit from a more precise and sustainable approach to cattle production, ensuring a resilient and productive future for the dairy sector.

Innovations in Dairy Cattle Management: Enhancing Productivity and Environmental Sustainability

Abstract The dairy industry stands at the intersection of two critical global challenges: the need to meet rising demands for high-quality dairy products and the imperative to reduce its environmental impact. This study’s primary aim is to bridge the historical-to-modern gap in dairy cattle management practices and to provide a comprehensive perspective that encompasses the industry’s historical evolution and contemporary realities. It engages in a meticulous examination of the multifaceted dimensions of dairy cattle management, commencing with an exploration of historical methodologies and advancing into the realms of modern breeding and genetics, nutritional advancements, innovations in housing and welfare, environmental sustainability, and the integration of precision farming technologies. Throughout this research, there is an unwavering emphasis on the compelling necessity for sustainable and innovative approaches to confront prevailing challenges, particularly in domains such as animal health, welfare, and the reduction of the industry’s environmental footprint. The findings of this study shed light on the critical importance of adopting sustainable and inventive methodologies in the realm of dairy cattle management. It not only encourages cattle managers but deems it crucial for them to fuse historical practices with contemporary technologies, with a special focus on enhancing breeding strategies, refining precision farming techniques, and upholding principles of ecological responsibility. Paramount in these considerations are the promotion of animal welfare, the minimization of environmental impact, and the pursuit of heightened productivity, all of which are indispensable for the industry’s long-term sustainability. From a pragmatic standpoint, this research offers actionable recommendations for dairy farmers. For example, the implementation of sustainable practices holds the promise of not only enhancing economic viability but also of bringing the operations of dairy farms in alignment with societal expectations. These practices have the dual potential to amplify profitability while mitigating environmental repercussions, thereby fostering societal acceptance. While the study duly acknowledges the inherent limitations associated with the complex and multifaceted nature of the dairy industry, it confidently lays the foundation for prospective research endeavours. In conclusion, this research serves as a pivotal starting point for the advancement of dairy cattle management in terms of sustainability, economic viability, and societal alignment.

Review on performance responses of dairy cattle against thermal stress

This manuscript is aimed at reviewing the performance responses of dairy cattle against thermal stress resulting from climate change. Climate change is the major factor that largely affects the dairy industry. Thermal stress (TS) is the perceived discomfort and physiological strains associated with exposure to excessive ambient temperature. Temperature and Humidity Index (THI) have been adopted to describe thermal conditions that drive thermal stress in dairy cattle. The effects of TS are devastating in the dairy industry if not managed well. The thermo-neutral zone for dairy cattle and calves in the tropics is THI <72. Milk yield reductions of up to 50% have been reported for Holstein cows due to thermal stress under summer climate conditions. Moreover, thermal stress is associated with alterations in milk composition. TS reduces the length and intensity of estrus manifestation. Moreover, 80% of estrus may be unnoticeable during the summer season in temperate regions, which further reduces fertility. Conception rates of dairy cows may drop up to 20–27% in the summer season. Climate-induced thermal stress resulted in a decrease of 3.5 kg and 25 kg in the birth weight and weaning weight of Fogera calves, respectively. Dry matter feed intake was reduced by 9.6%. Commonly used thermal stress reduction strategies included modification of the physical environment, breeding for heat-tolerant dairy cattle, and nutritional management. The productive and reproductive traits are susceptible to the negative impacts of thermal stress with an increase in THI above 68.0 for Holstein Frisian cattle and their crosses and 72 for tropical cattle under an open shed system. Mitigations of thermal stress by breeding heat-tolerant animals, using a loose house system, and season-based feeding should be considered an integral component of the dairy cattle management system.

GENEALOGICAL STRUCTURE OF THE UKRAINIAN BROWN DAIRY BREED

GENEALOGICAL STRUCTURE OF THE UKRAINIAN BROWN DAIRY BREED

Role of Molecular diagnostic technique , improving management and hygiene in Control of Subclinical Mastitis in diary Cattles

Sub clinical mastitis is a common disease caused by lack of good management and biosecurity of dairy cattle which cause expensive losses due to decrease milk production effect on the quality efficiency of milk losses in livestock production. the study designed to review the researcher's study to detect important strategies controlling of subclinical mastitis resulting from environmental & contagious pathogens such as E.coli, k.pneumonia, proteus spp.,Enterobacter spp., Staphylococcus aureus , Streptococcus agalactia and mycoplasma pyogenes, also other microorganism in dairy cow. A wide range of genetic diagnostic methods can be using for investigation of mastitis such as RT-PCR and MPCR methods.Further accurate improving hygiene and improve management considerable for controlling of the disease in dairy cattle they are commitment of hygiene procedure as milking, animal condition and floor that incorporated management strategies. Regard to dry period of cattle the usage of antibiotic treatment , supplements foods ,optimization of animal body condition ,scientific management of milk procedure and ventilation are considered important factor to control of bovine mastitis. on the other hand,this review provides the role using advance diagnostic technologies of this disease. and can provide safeguard of dairy animals as well as improving hygiene as a good controlling of mastitis pathogens..

Biogas as methane mitigation path on dairy cattle waste management

Greenhouse gas (GHG) caused global warming. The GHG emissions in ruminants come from enteric fermentation and manure management. Some of manure management of large ruminants (dairy cattle and beef cattle) are Biogas and manure stacking. Biogas in manure management is the most suggested, since beside reduce the GHG emission, it’s also produced an alternative energy source. Biogas system had been applied by many sectors including small holder farmers. There is no data available on the reduction value of GHG emission resulted from Biogas system. Therefore, the equation of methane mitigation from biogas was needed to predict the potential mitigation from this activity. This study aimed to create a simple equation to predict methane mitigation from manure management activity of dairy cattle, also to predict added value as an energy source in manure management. A correction factor of emission from dry stacking of manure compared to emission from biogas is also required in the calculation. Equations formed from the study are EB=(940,57 CO2-eq/AU/year) x N, EBB=130,73 CO2-eq/AU/year x N, and EDS=0,659281 x EB or EDS=4,74336 x EBB. These equations used to predict greenhouse gas production in the manure of dairy cattle. The final result showed that manure management of dairy cattle should be done by using Biogas. Gases produced in biogas can be used as alternative energy by burning it and contribute to reducing the GHG production in manure management.

Assessing the effect of case-based teaching compared with lecture-based teaching on students' knowledge and perceptions in a senior undergraduate dairy cattle management course.

Animal science students need to apply the knowledge acquired during their degree program to real-life scenarios in future careers. Little to no research exists evaluating the effects of case-based (CB; material presented as a case study) and lecture-based (LB; material presented as a lecture) teaching in animal science in higher education. The objectives of this study were to determine the effects of CB and LB teaching methods on student performance and to assess students’ attitudes toward CB and LB teaching methods in a senior dairy cattle management course. A cross-over study design was conducted over two course modules (1 = “calf health” and 2 = “lameness”) with a washout period of 2 wk. Students (n = 25) were randomly assigned to CB or to LB in module 1 and received the other method in module 2. Students completed a pre- and post-quiz in each module that consisted of 10 multiple-choice questions and 3 short-answer questions. Three separate linear mixed regression models were used to assess the effect of teaching method (CB or LB; predictor) on three different continuous outcomes for student performance: change (post-score − pre-score) in short-answer quiz scores, change in multiple-choice quiz scores, and the change in total quiz scores. Students completed an attitude assessment after each module that consisted of 8 Likert-scale statements and 2 free-response questions. Data were deidentified, and two researchers blinded to students’ CB or LB status analyzed free responses to identify themes. A logistic regression, which controlled for module and included student as a repeated measure, was used to determine if the proportion of students who agreed (outcome: yes/no) with each Likert-scale statement was different between CB and LB. There was a tendency for CB teaching methods to improve change in multiple-choice quiz scores (P = 0.06). The change in total quiz scores and the change in short-answer quiz scores did not differ between CB and LB groups (P > 0.1). For the survey statements “I enjoyed the teaching method used in this module” and “I wish this teaching method was utilized in more of my classes,” more students in LB agreed than in CB (P < 0.05). The themes preference, perceived benefits, and perceived drawbacks were mentioned in 80%, 44%, and 28% of CB comments, and in 84%, 40%, and 18% of LB comments, respectively, and suggest that students enjoy case studies but prefer to receive information via lecture first.

Husbandry practices and constraints of smallholder dairy production in Dilla Zuriya district, Gedeo Zone, Ethiopia

The study assessed dairy cattle management practices and identified constraints at smallholder dairy farms in Dilla-Zuriya District. A cross-sectional survey was undertaken on 120 purposely selected smallholder dairy farmers from three potential kebeles (Chichu, Andida and Gola). A Structured questionnaire was developed and applied to collect data. Descriptive statistics procedures of SPSS were followed to analyse the collected data. The result showed that most farmers (70.9%) produce milk primarily for income generation under a mixed crop-livestock production system. The herds mean of the local and cross breeds cattle in the study area were 5.23 and 2.41, respectively. Banana and Enset leaves and stems were the primary feed resources of the study area. Besides, farmers use natural grazing pasture and home fruit and vegetable leftovers as animal feed. The watering frequency was twice a day, either from river or pipe. Traditional houses made from locally available construction materials like mud and wood are the typical dairy cattle housing system. Except for calves, all types of dairy cattle were kept together in the same house. Feed shortage, limited access to, and the high purchasing cost of improved dairy heifers were the top two pressing constraints of dairy production in the study area. Therefore, enhancing the quality and accessibility of feed and applying breed improvement technologies are highly recommended to support dairy production.

Using commercial enzyme immunoassay for measuring pregnancy-associated glycoproteins to diagnose pregnancy in dairy cows under field conditions in Algeria

The purpose of the present work was to study effectiveness for early pregnancy diagnosis in cattle of the new enzyme immunoassay (EIA) sandwich kit commercially available based on the measurement of pregnancy-associated glycoproteins (PAGs). 120 Holstein-Friesian cattle of mixed age and parity were comprised from different dairy herds. The pregnant females (n = 68) were diagnosed by ultrasonography at day 35-40 after artificial insemination and confirmed by transrectal exploration at 2-3 months after AI. The non-pregnant females (n = 52) were housed in the absence of males during the experimental period. Blood samples were collected from coccygeal vessels of females into EDTA tubes. The serum was obtained by centrifugation and the serum was stored at - 20 C until assay. The PAG concentrations in pregnant and non-pregnant females were determined in serum by EIA kit. The reproducibility inter- and intra-assay of the PAG-EIA is satisfactory (2.78 and 13.19 %, respectively). The accuracy ( 94.8 %) and the test of parallelism were largely acceptable. No cross-reaction was observed with the different hormones tested at different dilutions. PAG-EIA system gave 100 % sensitivity and negative predictive values. Whereas, specificity and positive predictive value were 91.93 and 71.15 %, respectively. The accuracy of pregnancy diagnosis by PAG-EIA was 87.5 %. In conclusion, the present study shows clearly that the EIA kit can be used to measure PAG in serum cows for the detection of gestation in Algeria. Therefore, this alternative technique could be recommended to replace the radioactive methods in immunoassays to improve the reproductive performances and an efficient tool for reproductive management of dairy cattle.

Reproductive activity of dairy cattle in the postpartum anestrus period

Objective: To review the metabolic and hormonal processes that regulate reproductive activity in dairy cattleduring the postpartum anestrus period.Design/methodology/approach: Analysis of scientific documents and systematization of information relatedto the reproductive physiology and management of dairy cattle in postpartum anestrus.Results: Postpartum anestrus is an event that occurs naturally and is necessary for restoration of the homeostasisof the cow’s body following calving. However, failure to reestablish this homeostasis actually increases itsduration and negatively affects the subsequent reproductive performance of the individual cow.Limitations on study/implications: Reproductive management decisions must be based on scientificknowledge.Findings/conclusions: Management of dairy cattle in the postpartum anestrus period should focus onreestablishment of the state of homeostasis and the subsequent reproductive activity, with nutritional andhormonal strategies implemented to induce cyclicity, ovulation and formation of the first corpus luteum in thatperiod, through application of exogenous hormones after day ten postpartum.

Developing Country-Specific Methane Emission Factors and Carbon Fluxes from Enteric Fermentation in South Korean Dairy Cattle Production

Dairy cattle farming contributes significantly to greenhouse gas (GHG) emissions through methane (CH4) from enteric fermentation. To complement global efforts to mitigate climate change, there is a need for accurate estimations of GHG emissions using country-specific emission factors (EFs). The objective of this study was to develop national EFs for the estimation of CH4 emissions from enteric fermentation in South Korean dairy cattle. Information on dairy cattle herd characteristics, diet, and management practices specific to South Korean dairy cattle farming was obtained. Enteric CH4 EFs were estimated according to the 2019 refinement of the 2006 Intergovernmental Panel on Climate Change (IPCC) using the Tier 2 approach. Three animal subcategories were considered according to age: milking cows &gt;2 years, 650 kg body weight (BW); heifers 1–2 years, 473 kg BW; and growing animals &lt;1 year, 167 kg BW. The estimated enteric CH4 EFs for milking cows, heifers, and growing animals, were 139, 83 and 33 kg/head/year, respectively. Currently, the Republic of Korea adopts the Tier 1 default enteric CH4 EFs from the North America region for GHG inventory reporting. Compared with the generic Tier 1 default EF of 138 (kg CH4/head/year) proposed by the 2019 refinement to the 2006 IPCC guidelines for high-milking cows, our suggested value for milking cows was very similar (139 kg CH4 /head/year) and different to heifers and growing animals EFs. In addition, enteric CH4 EFs were strongly correlated with the feed digestibility, level of milk production, and CH4 conversion rate. The adoption of the newly developed EFs for dairy cattle in the next national GHG inventory would lead to a potential total GHG reduction from the South Korean dairy sector of 97,000 tons of carbon dioxide-equivalent per year (8%). The outcome of this study underscores the importance of obtaining country-specific EFs to estimate national enteric CH4 emissions, which can further support the assessment of mitigation actions.

Impact of Exposure to Chronic Light-Dark Phase Shifting Circadian Rhythm Disruption on Muscle Proteome in Periparturient Dairy Cows.

Muscle tissue serves as a key nutrient reservoir that dairy cows utilize to meet energy and amino acid requirements for fetal growth and milk production. Circadian clocks act as homeostatic regulators so that organisms can anticipate regular environmental changes. The objective of this study was to use liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine how chronic circadian disruption in late gestation affected the muscle tissue proteome. At five weeks before expected calving (BEC), multiparous Holstein cows were assigned to either a control (CON, n = 8) or a 6 h forward phase shift (PS, n = 8) of the light–dark cycle every 3 days. At calving, all animals were exposed to CON light–dark cycles. Muscle biopsies were collected from longissimus dorsi muscles at 21 days BEC and at 21 days postpartum (PP). At p < 0.1, 116 and 121 proteins were differentially abundant between PS and CON at 21 days BEC and 21 days PP, respectively. These proteins regulate beta oxidation and glycolysis. Between pregnancy and lactation, 134 and 145 proteins were differentially abundant in CON and PS cows, respectively (p < 0.1). At both timepoints, PS cows exhibited an oxidative stress signature. Thus, dairy cattle management strategies that minimize circadian disruptions may ensure optimal health and production performance.