Factors affecting calving to conception interval (days open) in dairy cows located at Dessie and Kombolcha towns, Ethiopia.

This study was aimed at determining the median days of calving to conception interval (days open) and identifying the major risk factors determining the days open in dairy cows. Both retrospective and longitudinal studies were conducted on dairy cows located in the Dessie and Kombolcha towns of South Wollo Zone, northeast Ethiopia from August 2019 to August 2020. The Kaplan-Meier model of survival analysis was used to determine the median days open and compare the survival distribution of each level of explanatory variables likely to influence the days open of dairy cows. Accordingly, the overall conception rate of dairy cows was 44.7%. The median days open in the study was 154 days. There is a 16% probability of surviving (i.e, the probability that the conception event has not yet occurred) at the end of 210 days postpartum period. The Cox proportional hazard model was used to quantify the effect of each of the explanatory variables on the days open in the first 210 days postpartum. Factors that had a significant effect (p<0.05) on the calving to conception interval were the season of insemination, breeding system, calving to insemination interval, and herd milk yield level. However, the peripartum, postpartum disorders, and the town of the farm are not significant (p>0.05). Accordingly, cows inseminated in the autumn season (HR = 4.45), cows less than or equal to 85 days calving to insemination interval (HR = 2.41), artificially inseminated cows (HR = 1.45), and high herd milk yield cow had a higher probability of becoming pregnant. In conclusion, the management practices and breeding decisions seem to be important determinants to improve the conception rate or decrease the days open in dairy cows.

Dynamics of Florida milk production and total phosphate in Lake Okeechobee.

A central tenant of the Comprehensive Everglades Restoration Plan (CERP) is nutrient reduction to levels supportive of ecosystem health. A particular focus is phosphorus. We examine links between agricultural production and phosphorus concentration in the Everglades headwaters: Kissimmee River basin and Lake Okeechobee, considered an important source of water for restoration efforts. Over a span of 47 years we find strong correspondence between milk production in Florida and total phosphate in the lake, and, over the last decade, evidence that phosphorus concentrations in the lake water column may have initiated a long-anticipated decline.

Mobile Elements Harboring Heavy Metal and Bacitracin Resistance Genes Are Common among Listeria monocytogenes Strains Persisting on Dairy Farms.

Listeria monocytogenes is a foodborne pathogen and a resilient environmental saprophyte. Dairy farms are a reservoir of L. monocytogenes, and strains can persist on farms for years. Here, we sequenced the genomes of 250 L. monocytogenes isolates to investigate the persistence and mobile genetic elements (MGEs) of Listeria strains inhabiting dairy farms. We performed a single-nucleotide polymorphism (SNP)-based phylogenomic analysis to identify 14 monophyletic clades of L. monocytogenes persistent on the farms for ≥6 months. We found that prophages and other mobile genetic elements were, on average, more numerous among isolates in persistent than nonpersistent clades, and we demonstrated that resistance genes against bacitracin, arsenic, and cadmium were significantly more prevalent among isolates in persistent than nonpersistent clades. We identified a diversity of mobile elements among the 250 farm isolates, including three novel plasmids, three novel transposons, and a novel prophage harboring cadmium resistance genes. Several of the mobile elements we identified in Listeria were identical to the mobile elements of enterococci, which is indicative of recent transfer between these genera. Through a genome-wide association study, we discovered that three putative defense systems against invading prophages and plasmids were negatively associated with persistence on farms. Our findings suggest that mobile elements support the persistence of L. monocytogenes on dairy farms and that L. monocytogenes inhabiting the agroecosystem is a potential reservoir of mobile elements that may spread to the food industry. IMPORTANCE Animal-derived raw materials are an important source of L. monocytogenes in the food industry. Knowledge of the factors contributing to the pathogen's transmission and persistence on farms is essential for designing effective strategies against the spread of the pathogen from farm to fork. An increasing body of evidence suggests that mobile genetic elements support the adaptation and persistence of L. monocytogenes in the food industry, as these elements contribute to the dissemination of genes encoding favorable phenotypes, such as resilience against biocides. Understanding of the role of farms as a potential reservoir of these elements is needed for managing the transmission of mobile elements across the food chain. Because L. monocytogenes coinhabits the farm ecosystem with a diversity of other bacterial species, it is important to assess the degree to which genetic elements are exchanged between Listeria and other species, as such exchanges may contribute to the rise of novel resistance phenotypes.

Mechanisms by which mastitis affects reproduction in dairy cow: A review.

Reproductive performance is a key factor in determining the profitability of dairy farm, which is affected by many factors such as environment and diseases. Mastitis is a common and important disease, which has caused huge economic losses to the dairy industries worldwide. Mammary gland infection causes immune responses, resulting in the abnormal secretion of cytokines and hormones and abnormal function of the reproductive system such as the ovary, corpus luteum, uterus and embryo. Cows with mastitis have delayed oestrus, decreased pregnancy rate and increased risk of abortion. The adverse effects of mastitis on reproductive performance are affected by many factors, such as occurrence time, pathogen and cow factors. This paper primarily reviews the progress in the effects and mechanisms of mastitis on reproductive performance, with emphasis on maternal transcriptome, genomic analysis, epigenetic modification, microbiota, inflammatory regulation and immune evasion mechanism of mastitis, aiming to provide directions for the prevention and control of mastitis in the future.

Public attitudes toward dairy farm practices and technology related to milk production.

Dairy farm systems have intensified to meet growing demands for animal products, but public opposition to this intensification has also grown due, in part, to concerns about animal welfare. One approach to addressing challenges in agricultural systems has been through the addition of new technologies, including genetic modification. Previous studies have reported some public resistance towards the use of these technologies in agriculture, but this research has assessed public attitudes toward individual practices and technologies and few studies have examined a range of practices on dairy farms. In the present study, we presented participants with four scenarios describing dairy practices (cow-calf separation, the fate of excess dairy calves, pasture access and disbudding). Citizens from Canada and the United States (n = 650) indicated their support (on a 7-point scale) toward five approaches (maintaining standard farm practice, using a naturalistic approach, using a technological approach, or switching to plant-based or yeast-based milk production) aimed at addressing the welfare issues associated with the four dairy practices. Respondents also provided a text-based rationale for their responses and answered a series of demographic questions including age, gender, and diet. Participant diet affected attitudes toward milk alternatives, with vegetarians and vegans showing more support for the plant-based and yeast-based milk production. Regardless of diet, most participants opposed genetic modification technologies and supported more naturalistic practices. Qualitative responses provided insight into participants' values and concerns, and illustrated a variety of perceived benefits and concerns related to the options presented. Common themes included animal welfare, ethics of animal use, and opposition toward technology. We conclude that Canadian and US citizens consider multiple aspects of farm systems when contemplating animal welfare concerns, and tend to favor naturalistic approaches over technological solutions, especially when the latter are based on genetic modification.

Factors that influence market participation among traditional beef cattle farmers in the Meatu District of Simiyu Region, Tanzania.

Market participation among beef cattle farmers is key to ensuring better income, food security, and sustainable beef supply. Farmers in the traditional beef cattle sector, nevertheless, are well known for their low market participation. This study, thus, sought to examine factors that influenced market participation among beef cattle farmers in the Meatu district of Simiyu region, Tanzania. The study randomly selected a sample size of 393 farmers. The cross-sectional data collected through interviews and questionnaires were analyzed using descriptive statistics and ordinary least squares (OLS) regression models. The descriptive analyses showed that the average age of the interviewees was 53.73 years with a family size of 13.11. On average, the respondents had about 24.14 years of farming experience. Most of the respondents (67.9%) had primary education. Among the respondents, about 61.3%, 4.6%, and 32.6% had access to market information, farm credits, and veterinary services, respectively. The average cattle herd size was 53.46 heads. About 90.1% of farmers had participated in the markets by selling an average of 5 heads each, per year. This study has revealed low volume of sales, low education levels, and poor access to credits and veterinary services as the major factors that limit market participation. Furthermore, econometric results show that the key factors that significantly influenced farmers to increase the volume of beef cattle sales in the market at P < 0.05 included price, herd size, off-farm income, distance to market, age of the farmer, and cattle fattening. Moreover, membership in cooperatives, access to market information, and farming experience also had significant influence at P < 0.05. This study recommends establishment of strategic cooperatives to function not only as a communication channel for farm credits, price, market information, and training on commercial farming, but also to assist farmers in selection of profitable markets.

Welfare assessment in intensive and semi-intensive dairy cattle management system in Sicily.

The present study aimed to compare the welfare of dairy cows kept in two traditional husbandry systems (semi-intensive and intensive farming) in south-eastern Sicily. A total of 18 dairy farms (nine semi-intensive and nine intensive) were evaluated with a multicriteria system adapted for Sicilian conditions and obtained simplifying the model of the European Food Safety Authority (EFSA). Values of welfare measures, collected by inspections of the farms (general well-being indicators, ventilation system, resting areas [cubicles or bedding], flooring, milking parlours and waiting area, manger and watering equipment), and those of health categories (cases of abortions, hypocalcemia, displacement of abomasum, acidosis/ketosis, enteritis, hoof problems, and mastitis) obtained through the farm records, were compared using Mann-Whitney and Chi-squared tests, respectively. Data showed significant differences (p ≤ .05) about the variables related to welfare categories such as housing ventilation system, resting area, manger, and water equipment that were better in the semi-intensive system than the intensive system. No significant differences were observed about the variables related to health indicators. The results demonstrated that in Sicily the semi-intensive farm is better than the intensive to satisfy the conditions of animal welfare.

Yield gap in milk production is considerable in Indian Himalayan state of Meghalaya.

Yield gaps in milk production are here defined as the differentials between the actual yield obtained by the dairy farmer and the potential farm yield (production achieved by the top 10% of farmers: Gap 2) as well as the differential between this potential farm yield and the yield registered in the research stations (Gap 1). Assessment of yield gaps provides valuable information on potential production enhancement and drivers behind yield gaps. Milk production can be increased by narrowing the predominant large yield gaps in resource-poor smallholder farming system. Hence, this study assessed the milk yield gap and factors affecting the yield gap in Ri-Bhoi district of Meghalaya, a state located in the north-eastern Himalayan region of India. This research paper provides a scope for exploring the possibilities for improving dairy production in the state as well as contributing to literature through incorporating crucial determinants responsible for milk yield gap. A sample of 81 respondents was drawn purposely from two blocks of the district. The results indicated that the average number of cattle per household was 9.38 in standard animal units. The total yield gap was estimated at 6.20 l (91.06%) per day, composed of 0.80 l (11.76%) per day of yield gap I and 5.40 l (79.30%) per day of yield gap II. This demonstrates that the top performing farms were achieving a production level not dissimilar to that obtained on the research stations, but many were doing far less well. The size of cattle shed, dairy farming experience, concentrate price and human labour were the important determinants of the yield gap. Hence, encouraging the right stocking density of cattle, training on the preparations of home-made concentrates, access to cheap and quality concentrates, incorporating training and experience sharing on proper dairy management practices and use of technology could benefit the dairy farmers of the region.

High exposure to pathogenic leptospires by the population residing in dairy farms in Hidalgo, Mexico.

Leptospirosis is a neglected zoonotic disease of unknown magnitude that has been overlooked and underreported, influenced by complex interactions established among humans, animals, and the environment; certain occupations, such as working with livestock, have an increased risk of exposure. We conducted a cross trans-sectional study in 374 serum samples obtained from workers and residents of dairy farms in the Tizayuca Basin, Hidalgo, Mexico, to determine the prevalence of anti-Leptospira antibody and the risk factors associated to this type of environment. The determination of anti-Leptospira antibodies was obtained by microscopic agglutination test. Seropositivity was defined from titles > 1:100. Seropositivity of anti-Leptospira antibodies among the population was 46.8% (176/374) (95% Cl 41.9-52.1). Thirty-nine percent (146/74) of the analyzed serum reacted to the Hardjo serovar (Sejröe serogroup). Eighty-eight percent (8/9) slaughterhouse workers tested were seropositive. Those who belonged to an ethnic group had OR 1.78 (IC 1.02-3.11, P = 0.041). Seropositivity was associated with having a secondary school level or lower, with OR 1.79 (IC 0.97-3.29, P = 0.058). Exposure to Leptospira in a dairy production farm is a risk factor for humans. Our findings can contribute to strengthening the intervention of the Public Health System to prevent this zoonosis that prevails in dairy farm environments.

Survey of perceptions and attitudes of an international group of veterinarians regarding antibiotic use and resistance on dairy cattle farms.

Veterinarians are the main source of information for farmers regarding the responsible use of antibiotics in farm animals and how to reduce the risk of antibiotic resistance. Consequently, understanding how veterinarians perceive their clients' and colleagues' antibiotic use and their own beliefs about the development of antibiotic resistance is essential to determining areas in which antibiotic use practices can be improved to minimize the emergence of antibiotic resistance. An international cross-sectional study was carried out using a questionnaire designed to elucidate perceptions, attitudes, and concerns of dairy veterinarians regarding antibiotic use and the emergence of antibiotic resistance in dairy farming. The questionnaire was initially administered to veterinarians attending the International Bovine Mastitis Conference in Milano, Italy, 2018, followed by veterinarian members of the National Mastitis Council, and all conference registrants. A total of 71 participants from 21 countries participated in the survey, the majority were from the United States and member countries of the European Union. Logistic regression analysis was conducted to identify predictors of veterinarians' level of concern about the development of antibiotic resistance on their clients' farms. Associations were described with odds ratios (ORs) and the associated 95 % confidence intervals (95 % CIs). Free text responses where participants shared their views on the reason for overprescribing antibiotics by veterinarians were analyzed using thematic analysis. Participants perceived that nearly half of their clients overuse or inappropriately use antibiotics, and nearly half of their colleagues overprescribe or inappropriately prescribe antibiotics. After controlling for other factors, the odds of veterinarians being concerned about antibiotic resistance on dairy farms they served decreased by a factor of 0.91 for each additional year of participants' experience working with dairy cattle (OR = 0.91, 95 % CI = 0.84-0.99). Participants concerned about antibiotic resistance on clients' dairy farms were also more likely to consider better adherence to drug labelling as important for reducing farmers' antibiotic use (OR = 6.86, 95 % CI = 1.21-38.93). Thematic analysis revealed four themes surrounding the perceived reasons for veterinarians' overprescribing of antibiotics: (i) knowledge, (ii) attitudes, (iii) barriers, and (iv) rules and regulations. The study findings will aid in the development of strategies to improve antibiotic use in dairy farming and educational initiatives looking to enhance the communication between veterinarians and farmers about judicious use of antibiotics.

Heat stress in dairy animals and current milk production trends, economics, and future perspectives: the global scenario.

Animal's well-being, growth, and production are modulated by environmental conditions, and managemental practices and can be deleteriously affected by global warming phenomenon. In the recent years, unprecedented climatic fluctuations like sustained higher temperatures and humidity, heat waves, and solar flares have led to economic losses in $ billions to both milk and meat industry. It is estimated that by 2050, the US dairy industry alone will borne more than $1.7 billion loss. As human dependency on animal products like milk, meat, and eggs for nutrition is exponentially rising, there is urgency for maximum production. The high yielding animals are already under tremendous metabolic pressure making them more susceptible to adverse climatic conditions. When exposed to heat stress, livestock display a variety of behavioral and physiological acclimatization as essential survival strategies, but at the cost of decreased milk, meat, or egg production. Most of the studies have explored the heat stress in animals and its effect on different milk productions in a specific region or country. A clear understanding of the impact of global warming on dairy enterprise is yet to be comprehended. So this exploratory study will analyze impact of global warming on current milk production trends, economics, and future perspectives.

Association of Exposure to Cattle with Self-Reported History of TB Among Dairy Workers.

BACKGROUND: Mycobacterium bovis (bTB) is a potential health hazard to dairy workers. This study uses the One Health wholistic framework for examining bovine tuberculosis (TB) and its relationship to human health. This approach can help bridge surveillance data gaps and contribute to disease control and prevention programs for dairy farm workers, cattle, and the environment. The primary objective of this study was to compare the self-reported history of TB among dairy workers in Bailey County, Texas, with occupational categories of risk and exposure to TB. METHODS: A cross-sectional study was conducted among dairy workers. Job positions were used as a proxy for exposure to cattle-high and medium/low. We employed bivariate analyses to examine differences between groups using both the chi-square test and the nonparametric Kruskal-Wallis test. RESULTS: Of the 293 dairy workers invited, 77.0% (n = 225) participated. No statistically significant associations were found between job categories and reported history of TB exposure. Workers in the high group were younger, Guatemalan males with lower levels of formal education, more likely to be single with no children, and cohabitating with coworkers compared with the medium/low group. CONCLUSION/APPLICATION TO PRACTICE: Self-reported TB history among dairy workers is an imprecise measure of being previously diagnosed with TB. Dairy workers at risk for occupationally acquired TB could be tested for TB before employment and tested periodically thereafter, and more expeditiously treated if a positive test is obtained. Future studies should focus on the feasibility of offering on-farm health services, such as TB screening.

Analysis of the effects of thermal stress on milk production in a humid tropical climate using linear and non-linear models.

The decline of milk production in crossbred cattle during the onset of summer was evaluated using lactation records of the cows (n = 48) maintained at the Livestock Research Station, Thiruvazhamkunnu, for the period between January 2019 and March 2019. Climate data were obtained from an automatic weather station maintained on the campus. The temperature-humidity index (THI) was used to assess the thermal stress on animals. Values varied between 70.78 and 83.93 during the study period, indicating that the cows were exposed to mild and moderate stress. Highly significant negative correlations (p < 0.01) were observed between the average temperature, THI, and milk production. Linear, logarithmic, power, and polynomial models linking milk production and THI were used to fit the data. The coefficient of determination (R2) in general exceeded 0.85 and these equations could be used to model the drop in milk production or predict production loss due to thermal stress. The rate of decline in daily milk production observed in the study was 2.13% per unit increase in THI. A general linear model that included THI, parity, and the stage of lactation as independent variables, and milk production as a response variable, was also tested. Parity and stages of lactation were observed to influence forenoon and afternoon milk production significantly (p < 0.01). The temperature-humidity index also had a significant effect on forenoon milk production (p < 0.05) and afternoon milk production (p < 0.01).

Knowledge affecting foot-and-mouth disease vaccination behavior: traditional dairy farmers in the dry zone of Sri Lanka.

The aim of this study was to identify social and farm factors influencing the knowledge of foot-and-mouth disease (FMD), factors influencing participation in FMD vaccination, and vaccination coverage. The study was conducted with 180 traditional dairy farmers who were engaged in cattle and buffalo farming located in three veterinary ranges of the Ampara district in the eastern province of Sri Lanka, during September and October 2019. The probit and tobit regression models were applied to determine the factors. On an average, the scores for knowledge of FMD and hygiene management were calculated as 54.5% and 49.2%, respectively. Farmers' knowledge of FMD was strongly associated with gender, level of education, and participation in the farmer training program (p < 0.01). The vaccination behavior was enhanced significantly by the number of animals, farming experience, knowledge of FMD score (p < 0.05), and hygiene management score (p < 0.1). It was revealed that social and farm factors contributed to the knowledge of FMD and vaccination behavior. Therefore, we recommend that the livestock educational training program will motivate better participation in the FMD control plan in Sri Lanka.

Aflatoxin M1 in raw cow milk and associated hepatocellular carcinoma risk among dairy farming households in Malawi.

In the present study, a total of 112 raw milk samples were collected between October and December of 2018 from dairy farming households in Malawi and analyzed for aflatoxin M1 (AFM1) using VICAM aflatest fluorometry procedure. These data together with the consumption data obtained through a milk consumption frequency questionnaire were used for the calculation of AFM1 exposure and its association with hepatocarcinoma (HCC) risk in dairy farming population. Average daily milk intake by children and adults were approximately 300 ± 0.07 and 541.7 ± 0.14 mL, respectively. All raw milk samples tested positive to AFM1 averaging 0.551 µg/L. Probable mean daily exposure to AFM1 for adults was 4.98 ± 7.25 ng/kg BW/day almost half that of children (8.28 ± 11.82 ng/kg BW/day). Estimated risk of AFM1-induced HCC associated with consumption of milk among children and adults were 0.038 and 0.023 cases per 100,000 individuals per year, respectively. Although the results of this investigation suggest a low risk of HCC, other negative health effects of AFM1 justify its continuous monitoring and update of the risk assessment. This work presents the first insight in the occurrence of AFM1 in cow milk in Malawi as well as associated AFM1 exposure in dairy farming population.

Analysis of adoption trends of in-parlor technologies over a 10-year period for labor saving and data capture on pasture-based dairy farms.

The use of precision technology is increasingly seen as an option to improve productivity, animal welfare, resource use efficiency, and workplace features on dairy farms. There is limited research related to longitudinal adoption patterns of precision dairy technologies and reasons for any patterns. The aim of this analysis was to investigate trends in technology adoption regarding both the amount (number of farms with a technology) and intensity (number of technologies per farm) of adoption. Surveys of parlor technology adoption were conducted on New Zealand dairy farms in 2008, 2013, and 2018, with 532, 500, and 500 respondents, respectively. Technologies were grouped into labor-saving (LS, such as automatic cluster removers) or data-capture (DC, such as in-line milk meters) categories. Trends were examined for farms that had only LS, only DC, or LS+DC technologies. Technology adoption increased over time; the likelihood of technology adoption in 2018 (and 2013 in parentheses) increased by 21 (22), 7 (68), and 378% (165) for LS, DC, and LS+DC technology groups, respectively, compared to 2008. Farms with LS+DC technologies also had a greater proportion of LS technologies compared to non-LS+DC farms, although this relationship declined over the 10-yr period. The use of a rotary versus herringbone parlor was estimated to be associated with 356 and 470% increase in the likelihood of adopting LS technologies and LS+DC, respectively, from 2008 to 2018. Regional differences in adoption were also found, with the likelihood of adopting DC and LS+DC technologies found to be 46 and 59% greater, respectively, in the South Island of New Zealand, compared to the base region of Waikato. The results highlight the importance of understanding spatial and temporal farm characteristics when considering future effect and adoption of precision dairy technologies. For example, the analysis indicates the occurrence of 2 trajectories to technology investment on farms, where larger farms are able to take advantage of technology opportunities, but smaller farms may be constrained by factors such as lack of economies of scale, limited capital to invest, and inability to retrofit technology into aging parlor infrastructure.

Factors associated with calf mortality and poor growth of dairy heifer calves in northeast Germany.

A cross-sectional study was conducted on fifty German dairy farms to identify risk factors for high mortality and poor growth in calves. Between 2012 and 2014, farm visits took place and a questionnaire on farm management practices was completed by in-person interview. In addition, heart girth measurements of calves around weaning were performed to estimate average daily weight gain. Furthermore, blood and faecel samples of calves were collected and a score addressing calf welfare was determined. The epidemiological associations between risk factors and high mortality and poor growth were estimated using two regression models. The factors significantly associated with high calf mortality (> 5%) were a high rate of calves with failure of passive transfer (> 25%) and the metaphylactic use of halofuginone lactate. A small amount of concentrates consumed around weaning, relocating calves more than twice until weaning and a low incidence risk of milk fever (< 5%) were found to be significantly associated with poor growth (median: 675 grams). Although the fifty farms cannot be considered as a representative sample for North-East Germany, the results indicate that the farm management has a big impact on growth and survival of dairy calves and needs to be addressed more thoroughly when raising the future dairy cow.

Effects of hay provision and presentation on cognitive development in dairy calves.

In the dairy industry, feeding management has considerable influence on calf behavioral development, yet there is limited understanding of how aspects of diet or accommodating more varied feeding behavior may affect cognitive development in young calves. The objective of this study was to evaluate effects of provision and presentation of hay on the cognitive ability of pre-weaned dairy calves. Individually-housed Holstein heifer calves were assigned at birth to 1 of 3 treatments: pelleted starter only (n = 10), hay (chopped to 5 cm) and starter provided in separate buckets (n = 12), or hay and starter offered as a mixture (n = 11). During week 5 of age, calves were tested daily in a learning task consisting of a T-maze with a milk reward (0.2 L milk) placed in one arm. Calves were subjected to an initial learning and reversal learning stage, where the reward location was changed to the opposite arm of the maze. Calves received 5 sessions/d until they met learning criterion (moving directly to correct side in 3 consecutive sessions) for initial and reversal learning. Dietary treatment did not affect pass rate or the number of sessions required to pass the initial learning stage. During the reversal learning stage, calves provided only starter had a lower pass rate (0.038, during first 8 testing session) early during testing than calves provided hay separately (0.20; P = 0.020) and tended to have a lower pass rate than calves provided hay as a mixture (0.14; P = 0.057). Calves provided only starter also tended to require more sessions to meet the learning criterion (15.8) than both calves provided hay separately (10.8; P = 0.089) and as a mixture (11.8; P = 0.10). Calves provided hay also kicked less and spent more time sniffing or licking the testing area. The results of this experiment indicate that provision of hay may affect behavioral flexibility in dairy calves.

Evaluation of candidate genotype of leptin gene associated with fertility and production traits in Hardhenu (Bos taurus × Bos indicus) cattle.

The present study was conducted on Hardhenu cattle to screen genomic region of leptin gene with an objective to find the association of genotypes with fertility and production traits. The association analysis with traits under study was analysed by least squares analysis of variance by taking SNPs genotype as fixed effects in the statistical model. The genotypic frequencies with respect to targeted loci g.92450765 G > A indicated that AG (0.54) genotype was highest in Hardhenu cattle. Chi-squared tests showed that g.92450765G > A SNP meet with the Hardy-Weinberg equilibrium (p > .05).The association analysis revealed significant association of genotypes with total milk yield (TMY) and 305 days milk yield (MY) (p < .05). Service period (SP) and calving interval (CI) were also found significantly associated with genotypes (p < .05). Whereas, lactation length (LL), dry days (DD) and age at first calving (AFC) did not divulge any significant association with genotype. The AG and GG genotypes were associated with higher milk yields as compared to AA genotype, indicating that allele G was associated with superior milk performance. However, AA genotyped cattle found to be favourable with SP, CI and artificial insemination (AI) per conception compared to AG and GG genotyped cows. Chi-square analysis revealed that genetic variants of g.92450765 G > A SNP of leptin gene differ significantly with regard to reproductive disorders incidence (p < .05). The frequency of GG genotype (88.89%) in the affected animal group was very high followed by AG. The animals with GG genotype were found to be more susceptible to reproductive disorders as suggested by the higher odd ratio value (16.00) in logistic model. These observations and their differential association with the fertility and production traits can be utilized as an aid to selection for genetic improvement of antagonistic traits in dairy cows.

Seroepidemiology of bovine brucellosis in Colombia's preeminent dairy region, and its potential public health impact.

A cross-sectional study was conducted to determine the associated factors of brucellosis in Colombia's preeminent dairy region declared in quarantine. A total of 656 samples were collected from cows ≥ 2-year-old from 40 herds. Samples were screened by the Rose Bengal Plate Test, and the Fluorescence Polarized Assay test and Competitive ELISA were used as confirmatory tests. A cow was classified as positive if the screening and both confirmatory tests were positive. A herd was classified as positive if at least one cow was seropositive. The factors associated to seropositivity were tested using a logistic regression model with explanatory variables regarding cattle management, zootechnical parameters, and sanitary practices. The seroprevalence at the animal level was 6.6% (43/656) and at herd level 27.5% (11/40). In the model, five variables explained the animal cases: purchase or animal transfer between owner's farms (OR = 2.79, 95% CI 1.42, 5.49), history of abortion (OR = 4.22, 95% CI 1.91, 9.33), birth of weak calves (OR = 13.77, 95% CI 2.75, 68.91), use of a bull for mating (OR = 9.69, 95% CI 2.23, 42.18), and the vaccination in adulthood (OR = 3.03, 95% CI 1.04.8.78). In the model at the herd level, two variables explained the cases: birth of weak calves (OR = 9.60, 95% CI 1.54, 59.76) and purchase or animal transfer between owner's farms (OR = 7.22, 95% CI 1.03, 50.62). These results justify the need for a quarantine declaration in the region and the implementation of epidemiological studies as a public health measures used to combat outbreak.