Herd Management Research Articles

Economic analysis of different pregnancy rates in dairy herds under intensive management

The pregnancy rate (PR) is nowadays the most informative reproductive parameter, as it encompasses the proportion of cows that become pregnant from the total number of cows eligible for insemination in each estrous cycle. In the international scientific literature, there are several analyses concerning PR change effects on the profitability of dairy herds. In this study, the economic consequences of PR changes in a dairy herd under intensive management was calculated. We developed a mathematical model, based on the Monte Carlo simulation model, to estimate herd performance and economic utility using different pregnancy rates (between 15 and 30). The simulation was done using a fixed conception percentage of 30, so the increment in pregnancy rate only depended on the efficiency of estrus detection (EED) increase. In the generated model scenarios, PR increase had a positive effect on the annual cow income per year; however, the extra income had a quadratic trend with a revenue decline, when PR reached 20 %. So for every percentage point, where PR was increased from 15 to 20 %, an additional cow income of USD 40.46 per year was generated. Furthermore, the additional income for every percentage point, when the PR was increased from 20 to 25 % was USD 21; and USD 6.88, when the increase was from 25 to 30 %. We can conclude that any changes in herd management to increase the EED and thereby the PR should have lower costs compared

Insights into herd management among East Africa's earliest pastoralists: Combining zooarchaeological data and stable isotope analysis

Specialized pastoralists inhabited south-central Kenya approximately 3300 BP to 1200 BP, before the entrance of iron-using agriculturalists. The social and ecological context in which these pastoral groups were managing herds differs from anything documented historically in the region. Detailed zooarchaeological analyses of slaughter patterns and dental hypoplasias, in conjunction with stable isotope data, reveal subtle differences in herd management strategies at three pastoralist sites in Kenya's Central Rift Valley and Loita Plains. Isotopic data show that early pastoralists did not herd livestock seasonally to higher altitudes. The relatively low mobility of early herders allows for the examination of differences in livestock management by herders in different ecologies. We show that frequencies of hypoplasias in cattle are relatively low compared to caprines, and that cattle also have lower frequencies of severe hypoplasias. Hypoplasia data also show that livestock in the Central Rift Valley experienced more stress than those in the Loita-Mara plains. Environmental differences between the Central Rift Valley and Loita-Mara Plains likely influenced herd management strategies, as herders in the plains adjusted slaughter patterns to cope with suboptimal grazing conditions.

Were there royal herds? Understanding herd management and mobility using isotopic characterizations of cattle tooth enamel from Early Dynastic Ur.

During the third millennium BC, Mesopotamia (the land between the Tigris and Euphrates Rivers, in modern Iraq-Syria), was dominated by the world’s earliest cities and states, which were ruled by powerful elites. Ur, in present-day southern Iraq, was one of the largest and most important of these cities, and irrigation-based agriculture and large herds of domesticated animals were the twin mainstays of the economy and diet. Texts suggest that the societies of the Mesopotamian city-states were extremely hierarchical and underpinned by institutionalised and heavily-managed farming systems. Prevailing narratives suggest that the animal management strategies within these farming systems in the third millennium BC were homogenous. There have been few systematic science-based studies of human and animal diets, mobility, or other forms of human-animal interaction in Mesopotamia, but such approaches can inform understanding of past economies, including animal management, social hierarchies, diet and migration. Oxygen, carbon and strontium isotopic analysis of animal tooth enamel from both royal and private/non-royal burial contexts at Early Dynastic Ur (2900–2350 BC) indicate that a variety of herd management strategies and habitats were exploited. These data also suggest that there is no correlation between animal-management practices and the cattle found in royal or private/non-royal burial contexts. The results demonstrate considerable divergence between agro-pastoral models promoted by the state and the realities of day-to-day management practices. The data from Ur suggest that the animals exploited different plant and water sources, and that animals reared in similar ways ended up in different depositional contexts.

Break-even point analysis for milk production - Selected EU countries

Unstable conditions in the milk market in the Czech Republic (CR) and in the European Union (EU), mainly due to volatility of milk prices, are increasing pressure on dairy farmers to maximise production at the lowest possible production costs. Break-even point (BEP) analysis is a useful tool in dairy herd management for determining minimum requirements for profitability. BEP values for milk yield and milk price were calculated based on data obtained from 95 dairy farms in the CR. BEP values were estimated also for another eight EU countries based upon production and cost data from the EU Farm Accountancy Data Network (FADN). With the milk price ranging from EUR 28 to EUR 38 per 100 L and while excluding subsidies, zero profitability would be achieved on Czech dairy farms with milk yields ranging from 6 706 L to 13 151 L per cow and from 7 450 L to 14 088 L per cow in Czech Fleckvieh (C) and Holstein (H) herds, respectively. In order to achieve 5% profitability, the milk yield would need to increase by 21%. Considerable variability exists among EU countries in estimated BEP values depending upon average milk yields, input prices, and milk prices in different countries.

Later stone age herd management strategies in western South Africa: Evaluating sheep demographics and faunal composition

Most archaeological research of Later Stone Age (LSA) herding in southern Africa focuses on origins, while the complex socio-economic motives have been largely unexplored. This paper investigates evidence for herd management strategies by incorporating ethnohistoric and existing faunal data. We used ternary plots to statistically compare theoretical kill-off patterns (meat, milk, social risk reduction) with sheep age-at-death profiles from both historical meat provisioning stations and LSA herder sites. We found 1) a statistical fit between theoretical meat profiles and historical meat provisioning sites and 2) variability in LSA sheep management practices. The dominance of juvenile sheep and abundant wild fauna at south coast sites indicates dairying. West coast sites reflect a mixed/meat strategy, but the Kasteelberg A ternary plot overlaps all three theoretical models. Jakkalsberg B presents a meat signal by centering on prime adults. The wealth of ochre, beads, and ethnohistoric evidence from Jakkalsberg B suggests that this was an aggregation site with ritualized feasting. Thus, the unexpected abundance of juveniles and old sheep at Kasteelberg A may reflect a palimpsest, longer-term occupation, and/or an intensified period of ritual feasting. This methodological approach can be used in any archaeological context where the age-at-death of domesticates is known.

A cross‐sectional survey of risk factors for the presence of Coxiella burnetii in Australian commercial dairy goat farms

The largest Australian farm‐based outbreak of Q fever originated from a dairy goat herd. We surveyed commercial dairy goat farms across Australia by testing bulk tank milk (BTM) samples using a commercial indirect enzyme‐linked immunosorbent assay and two quantitative polymerase chain reactions (PCRs). Of the 66 commercial dairy goat herds on record, managers from 61 herds were contacted and 49 provided BTM samples. Five of the surveyed herds were positive on at least one of the diagnostic tests, thus herd‐level apparent prevalence was 10% (95% confidence interval [CI] 4 to 22). True prevalence was estimated to be 3% (95% credible interval: 0 to 18). Herd managers completed a questionnaire on herd management, biosecurity and hygiene practices and risk factors were investigated using multivariable logistic regression. Herds with >900 milking does (the upper quartile) were more likely to be Coxiella burnetii positive (odds ratio = 6.75; 95% CI 1.65 to 27.7) compared with farms with ≤900 milking does. The odds of BTM positivity increased by a factor of 2.53 (95% CI 1.51 to 4.22) for each order of magnitude increase in the number of goats per acre. C. burnetii was not detected in samples from the majority of the Australian dairy goat herds suggesting there is an opportunity to protect the industry and contain this disease with strengthened biosecurity practices. Intensification appeared associated with an increased risk of positivity. Further investigation is required to discriminate the practices associated with an increased risk of introduction to disease‐free herds, from practices associated with maintenance of C. burnetii infection in infected dairy goat herds.

Isotopic evidence for animal management strategies at Archaic and Classical period Argilos, Greece

This paper utilizes the stable carbon and nitrogen isotopic composition of bulk animal bone collagen to better understand animal management practices in Archaic and Classical period Argilos in northern Greece. The results from Argilos are compared with data from other sites in northern Greece to provide new insights into herd management in the region over time. Our results reveal some changes in cattle and pig diets at Argilos between the Archaic and Classical periods. Throughout both periods cattle and caprines exhibit evidence of having consumed C4 vegetation, likely obtained from the nearby salt marshes in the Strymon river delta. This dietary regime is similar to that observed at other north Aegean sites dating back to the Neolithic, suggesting that the long tradition of animal herding in the marshes was an environmentally specific practice in the region.

The role of gilts in transmission dynamics of swine influenza virus and impacts of vaccination strategies and quarantine management.

BackgroundAlong with an expanding global swine production, the commercial housing and management of swine herds, provide an optimal environment for constant circulation of swine influenza virus (swIAV), thereby challenging farmers and veterinarian in determining optimal control measures. The aim of this study was to investigate the role of gilts in the swIAV transmission dynamics, and to evaluate the impact of different control measures such as quarantine and gilt vaccination.MethodsThe study was conducted as a cross-sectional study in ten Danish sow herds, including five swIAV vaccinated and five unvaccinated herds. Blood- and nasal swab samples of gilts, first parity sows and their piglets were collected at different stages in the production system (quarantine in/out, mating, gestation and farrowing) and analyzed for the presence of swIAV and swIAV antibodies. Associations between the detection of swIAV, seroprevalence, antibody levels, sow and gilt vaccination strategy and quarantine biosecurity were thereafter investigated to identify possible risk factors for swIAV introductions and persistence within the herds.ResultsNine of the ten herds of the study had swIAV circulation and swIAV was detected in the quarantine, mating- and farrowing unit. The prevalence of seropositive gilts and first parity sows was significantly higher in the vaccinated herds, but swIAV was still present in nasal swabs from both gilts, first parity sows and piglets in these herds. Quarantine gilt vaccination and all-in/all-out management resulted in a significant reduction of swIAV positive gilts at the end of the quarantine period.ConclusionThe results underline that herd vaccination and/or quarantine facilities are crucial to avoid swIAV introductions into sow herds.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40813-022-00261-2.

Accounting for residual heterogeneity in double‐observer sightability models decreases bias in burro abundance estimates

AbstractFeral burros (Equus asinus) and horses (E. ferus caballus) inhabiting public land in the western United States are intended to be managed at population levels established to promote a thriving, natural ecological balance. Double‐observer sightability (MDS) models, which use detection records from multiple observers and sighting covariates, perform well for estimating feral horse abundances, but their effectiveness for use in burro populations is less understood. These MDSmodels help minimize detection bias, yet bias can be further reduced with models that account for unmodeled variation, or residual heterogeneity, in detection probability. In populations containing radio‐marked individuals, residual heterogeneity can be estimated with MDSmodels by including a covariate that corresponds to the marked status of a group (MHmodels). Another approach is to use information from detections missed by both observers to account for the characteristics that make groups more or less likely to be detected, or recaptured, by the second observer (MRmodels). We used aerial survey data from 3 burro populations (Sinbad Herd Management Area, UT [2016–2018], Lake Pleasant Herd Management Area, AZ [2017], and Fort Irwin National Training Center, CA [2016–2017]) to develop MDSmodels applicable for feral burros in the southwestern United States. Our objectives were to quantify precision and bias of standard MDSsurveys for feral burros and to examine which model type for incorporating residual heterogeneity (MHor MR) would result in the least‐biased estimates of burro populations relative to the minimum number known alive (MNKA) within the Sinbad Herd Management Area. Standard MDSmodel estimates achieved a mean coefficient of variation of 0.08, while underestimating MNKA by an average of 27.1%. Accounting for residual heterogeneity through recapture probability in MRmodels resulted in estimates closer to MNKA than MHmodels (9.5% vs. 16.5% less than MNKA). Our results indicate that MDSmodels can achieve precise enough estimates to monitor feral burro populations, but they routinely produce negatively biased estimates. We encourage the use of radio‐collars to reduce bias in future burro surveys by accounting for residual heterogeneity through MRmodels.

Study of metabolic processes in cows with hyperbilirubinemia in the postpartum period

Highly productive dairy farming requires strict adherence to the technology of feeding and keeping cows and competent herd management. Cows with liver pathologies during the transit period are tough to treat. We conducted studies of cows' health status after calving to identify biochemical signs of liver pathology and associated metabolic disorders. The survey of highly productive cows was carried out on four farms in the Leningrad region of the Russian Federation. Cows received different rations, differing in composition and nutritional value. A total of 108 animals were examined. Blood was taken from cows 10‐20 days after calving and examined in a biochemical laboratory for the content of metabolites, enzymes, hormones. The results of the study showed significant differences in the biochemical profile of cows in different farms. The incidence of hyperbilirubinemia in cows ranged from 12.5 to 45.8%. The severity of metabolic disorders was assessed depending on the degree of hyperbilirubinemia. It was found that the minor metabolic effects were observed in cows with bilirubin levels from 7 to 10 μmol / L (n = 11), which was accompanied by a slight increase in the concentration of β‐hydroxybutyrate (1.36 ± 0.12 mmol / L), as well as an increase in activity creatine phosphokinase (CK‐NAC) up to 319.3 ± 27.7 IU / L and lactate dehydrogenase (LDH) up to 1193.9 ± 31.5 IU / L. The concentration of glucose and cholesterol was in the reference range. In cows of this group, the concentration of cortisol and thyroxine was within the reference limits (76.5 ± 2.5 and 50.3 ± 2.7 nmol / l, respectively). In the study of cows with a moderate degree of hyperbilirubinemia from 10.0 to 16.0 μmol / L (n = 9), a predisposition to a decrease in glucose levels to 2.03 ± 0.12 mmol / L was noted against the background of an increased content of β‐hydroxybutyrate 1.84 ± 0.13 mmol / L, the level of cholesterol in cows was 2.43 ± 0.21 mmol / L. The activity of LDH and CK‐NAC was 1310.8 ± 69.3 and 401.5 ± 41.9 IU / L, respectively. A decrease in thyroxine concentration was found in 33.3% of animals, an increase in cortisol concentration ‐ in 55.5% (mean group values ‐ 48.4 ± 3.4 and 78.8 ± 6.5 nmol / l). In cows with the highest degree of hyperbilirubinemia from 17.0 to 39.0 μmol / l (n = 8), the most severe metabolic consequences were revealed, which practically did not give hope for the restoration of body functions. All cows showed an increase in β‐hydroxybutyrate to 2.79 ± 0.39 mmol / L, a decrease in cholesterol concentration to 1.8 ± 0.06 mol / L in the absence of hypoglycemia. In cows, the activity of CPK (1140.7 ± 222.7 IU / L) and LDH (2150.1 ± 94.4 IU / L) are significantly increased. The concentration of thyroxine in the studied cows was 22.03 ± 2.0 nmol / l. All cows in this group showed hypercortisolemia (140.2 ± 11.4 nmol / l). The studies made it possible to identify the relationship between the degree of liver damage and dysregulation of almost all types of metabolism.

Factors affecting fertility traits and milk yield of Holstein cattle with different origins raised in Trakya region

This study was conducted with Holstein heifers imported from the United States (US), Germany, and the Czech Republic to a private dairy farm in Kırklareli/Lüleburgaz region in Turkey to evaluate their adaptation in terms of milk production and fertility performance. The first insemination age of the herd was 490.62 days, and the first calving age was 804.24 days. The number of inseminations required per pregnancy was calculated as 3.99, gestation length as 279.72 days, and service period as 213.99 days. The rate of abortion and twin births were higher in those of US origin. Increased first calving age was observed in heifers of German origin due to delayed insemination. The mean actual lactation milk yield in the first lactation periods was 11834.75 Lt, 305 days milk yield was 8573.31 Lt, lactation length was 419.61 days, the dry period was 63.02 days. Milk yield performance of Holsteins of US origin was higher in the first lactation period. In conclusion, milk production was profitable; however, the fertility performance of the herd was poor in general. Poor fertility performance was due to poor herd management and adaptation problems. Therefore, after the calving period, more attention should be paid to oestrus monitoring and insemination activities. In Turkey, the success of live animal imports should be well investigated; in particular, problems occurring during animal selection for importation should be evaluated, and short-/long-term national strategies should be developed.

Use of a cow-side oestrus detection test for fertility management in Kenyan smallholder dairy herds.

Background: The use of artificial insemination (AI) has great potential to improve smallholder dairy herds in Africa, however high costs and often poor success rates have been discouraging. Effective AI requires accurate oestrus detection and the measurement of progesterone (P4) can be used to indicate oestrus as well as non-pregnancy. A cow-side progesterone lateral flow test, P4 Rapid, was evaluated as an aid to detect oestrus and non-pregnancy in Kenyan dairy cows, and assessed for association with AI efficiency. Methods: A total of 527 cows were enrolled in the study, from two counties in central and southern Kenya. Cattle in the test group (n = 308) were presented when suspected to be in oestrus and tested with the P4 Rapid (low P4 = oestrus, medium P4 = inconclusive, high P4 = not in oestrus/pregnant). Cattle with low P4 were inseminated. Cattle in the control group (n = 219) were inseminated when oestrus behaviour was detected i.e. standard practice. Results: Of the total P4 Rapid tests performed (n = 745), 1.5% were inconclusive, with the true accuracy of the test between 87-97%. Conception rates were not significantly higher in the test group (83.9%) compared to the control group (77.9%). Abortion rates were not significantly different between the control (9.5%) and test groups (8.2%). In the test group, 6.2% (19/308) cows showed a medium or high P4 level on day 0 and 9 of these were subsequently found to have been already pregnant. Conclusions: The data indicated that the P4 Rapid test can be a useful tool to assist farmer decision-making in the confirmation of correct timing for AI, and importantly may avoid unnecessary inseminations in pregnant animals, thus reducing the risk of AI-induced abortion.

Effects of Parity and Stage of Lactation on Trend and Variability of Metabolic Markers in Dairy Cows

Simple SummaryThe rise in milk yield per cow, herd size, and the percentage of primiparous cows in dairy herds increasingly requires optimized health management in order to ensure the health of the cows. The transition period (three weeks before to three weeks after calving) has a key role in health problems, because dairy cows undergo tremendous metabolic changes. Metabolic monitoring provides an in-depth insight into how the cows cope with these challenges. A remarkable variability in the metabolic parameters reflects the adaptation of dairy cows during the transition from pregnancy to lactation. In addition, primiparous cows undergo physical adaptations because of growth, first gestation, the maturation of the mammary glands, the onset of lactation, and fighting for social dominance. Previous studies have rarely considered these specific demands due to the influences of parity and the lactation stage. Thus, the objective of our study was to describe the variation in metabolic parameters due to parity and the stage of lactation based on a huge number of primiparous and multiparous cows, observed at all stages of lactation, in a retrospective analysis of laboratory data. The remarkable impact of both parity and lactation was elucidated for most parameters. This should be taken into account for a correct interpretation of the laboratory diagnostics in the framework of metabolic monitoring.Metabolic monitoring is a tool that is helpful with the increasing requirements regarding feeding and health management in dairy herds. This study aimed at describing the trend and variability of different biochemical parameters in blood and urine in relation to the stages of lactation and parity, in a retrospective analysis of laboratory data from clinically healthy German Holstein cows. The results were derived from metabolic monitoring in Thuringia (Germany), during 2009–2019. A total of 361,584 measured values, of 13 different metabolic variables, were assigned to parity (primiparous and multiparous) and stage of lactation (10 classes from −30 to 300 days in milk). The Kruskal–Wallis test was applied for the evaluation of differences regarding parity or the stage of lactation. Non-esterified fatty acids, beta hydroxybutyrate, and the activity of aspartate aminotransferase in serum were clearly affected by parity and lactation. Serum concentrations of cholesterol, bilirubin, and phosphorus, as well as the serum activity of glutamate dehydrogenase, were affected by the stage of lactation, while parity impacted urea concentration. The serum activity of creatine kinase, serum concentrations of calcium, and urine concentrations of net acid base excretion, potassium, and sodium were not affected by parity or lactation. In conclusion, specific reference limits, with respect to parity and the stage of lactation, are necessary.

Resource allocation and rising complexity during the Iron Age IIA: An isotopic case study from Khirbet Summeily, Israel

Isotopic analyses can be a useful tool in identifying animal exploitation patterns and herding strategies in the southern Levant. Here, carbon, oxygen, and strontium isotope analyses of domestic animal tooth enamel are used to investigate herd management at the Iron Age IIA site of Khirbet Summeily in Israel. The site was located in a prime ecological and political locale along the fringes of the emerging polity (potentially Judah), which ascended to regional significance by the Iron Age IIB. In order to understand the diets and movement of sheep, goats and cattle, we undertook intra-tooth sequential sampling and isotopic analyses of mandibular molars (n = 20). Results suggest that the livestock recovered at Khirbet Summeily were raised in different locations with varied management patterns. Variation in the dietary intake of sheep and goats indicates that they were pastured in different ecological zones. While some goats were mobile across long-distances, the majority of livestock were from local and regionally managed herds. Alongside material evidence of exotic goods from nearby polities, our findings lend further support to the idea that Khirbet Summeily acted as a resource allocation outpost strategically located on the edge of a political entity (potentially Judah), suggesting a trend towards increased economic complexity during the Iron Age IIA.

Challenges and opportunities for manureshed management across U.S. dairy systems: Case studies from four regions.

The manureshed represents cropland needed to safely assimilate manure nutrients from an animal feeding operation. Dairy manuresheds can be contained on-farm but may need to involve additional farms that can assimilate excess nutrients. We present case studies reviewing challenges and opportunities to manureshed management in four major dairy-producing states using available information on local manuresheds. Additionally, geographic information system software was used with data from regulated Minnesota dairies to assess cropland assimilative capacities and transport needs surrounding large dairies. Manureshed requirements vary across regions, but increased import of feed and soil phosphorus accumulation constrain on-farm manure utilization across the United States. In Minnesota, a growing proportion of Jersey cattle and differences in continuous corn (Zea mays L.) vs. corn-alfafa (Medicago sativa L.) rotations contribute to the amount of land needed to absorb dairy manure nutrients. Farm-gate budgets reveal that N-based manuresheds can be contained within Idaho dairies, but P-based manuresheds extend beyond the farm. In New Mexico, relocation of surplus manure nutrients off the farm is common via informal networks, but incentives to strengthen these networks could ensure sustainable manureshed management. Evaluation of manureshed requirements in Pennsylvania is often complicated by the need for additional nutrient management planning and greater understanding of nutrient balances on the preponderance of small dairies. Nutrient imbalances with highly concentrated dairy production often lead to the need for manure transport off-farm. However, advances in herd and cropland management offer opportunities to improve on-farm nutrient efficiencies, and emerging networks and technologies promise to facilitate manure export when needed.

Diagnosing lameness with the Random Forest classification algorithm using thermal cameras and digital colour parameters

Lameness is a serious disease that affects the health and welfare of dairy cattle whilst also causing yield and economic losses. The primary goal of this study is to determine if lameness can be detected early on in herd management using the Random Forest (RF) algorithm and the surface temperatures of the cows' hoof soles, as well as the digital colour parameters generated by processing these thermal camera images. Ages, hoof sole temperatures, and digital colour characteristics of 40 Simmental cattle were used as independent variables in this study, while lameness was evaluated by scoring and employed as a dependent variable after being updated as a binary variable. The parameters ntree= 100 and mtry= 3 were used to develop the RF algorithm for predicting lameness in animals. As a result, the RF algorithm correctly classified 19 of 22 healthy animals and incorrectly classified 3, while it correctly classified 15 of 18 unhealthy animals and incorrectly classified 3. The classification success of the RF algorithm was 85%, sensitivity, specificity and area under the ROC curve (AUC) were 0.864, 0.833, and 0.848±0.059, respectively, and it was successful in detecting lameness. Also, AUC, which is one of the RF algorithm's classification performances, was found to be statistically significant (P<0.05). As a direct consequence it can be stated that the RF algorithm is a suitable classifier in terms of the use of animal hoof sole temperatures and digital colour parameters obtained through image processing in the detection of lameness in herd management.

CHARAKTERYSTYKA CECH ROZRODU KRÓW REKORDZISTEK POD WZGLĘDEM ŻYCIOWEJ PRODUKCYJNOŚCI MLECZNEJ

The aim of this study was to characterise basic reproduction indexes and to investigate the effect of selected factors on values of analysed fertility parameters in cows (100 head) with record lifetime milk yields. The experiments were conducted on Polish Holstein-Friesian Black- -and-White cattle. Cows with lifetime milk yields of min. 100 thousand kg milk were considered record holders. Animals were selected at random from herds covered by performance testing in the Poznań testing region in the years 2003–2016. It was shown that analysed cows with record lifetime milk yields exhibited slightly reduced fertility. The animals had the preferred mean age at first calving and adequate average length of pregnancy. Relatively high numbers of semen doses required for successful insemination resulted in an extended length of calving interval, interpregnancy period and artificial mating service.In the management of dairy cow herds focusing on high lifetime productivity and fertility traits it is recommended to control reproduction so that calvings take place in winter and cows calve for the first time at the age of maximum 27 months.

Effect of Culling Management Practices on the Seroprevalence of Johne's Disease in Holstein Dairy Cattle in Central Italy.

A study was performed in Umbria, central Italy, to find out whether different culling strategies adopted by farms to control Johne’s disease (JD) infection exerted effects on the seroprevalence in dairy cattle. Fifty Fresian dairy herds in the Perugia and Assisi districts were visited and an audit of herd management was conducted. Among the 50 herds, 20 were selected for the consistency of management practices and, according to the culling strategy, two groups were created: group A (aggressive culling protocol, with average herd productive life <1100 days) and group B (lower culling rate, with productive life greater than 1500 days). The presence of antibodies to Mycobacterium avium subspecies paratuberculosis (Map) in the serum was determined using a commercial enzyme-linked immunosorbent assay (ELISA) kit. It was found that 3.3% (n = 14) of the cows of group B (n = 422, from 17 herds) were positive for Map antibodies, in comparison with 5.7% (n = 21) of the cows from group A (n = 366, from three herds). The odds ratio from multiple logistic regression (adjusted odds ratio 2.446, 95% confidence interval 0.412 to 14.525) showed that Johne’s disease prevalence in herds with a greater productive life was not higher than in herds with typical modern management characterized by more aggressive culling. This is a significant finding, indicating that aggressive culling may not be necessary. Current JD control recommendations are derived from data obtained in high-prevalence paratuberculosis areas (northern Europe, including northern Italy), while methods of information transfer to dairy farms in low-prevalence areas should be reassessed to ensure that the correct measures, including basic calving management and calf-rearing practices, are thoroughly implemented. Using the manufacturer’s suggested cut-off for a positive ELISA test and the sensitivity and specificity claimed, the overall true prevalence in Umbria dairy cattle was calculated as 7% (95% confidence interval 5.2% to 8.8%).

Effect of inseminator on reproductive performance in dairy cattle.

The reproductive efficiency of dairy cattle is critical to the economic success and sustainability of the enterprise. Due to its many advantages, artificial insemination has inevitably taken its place in herd management today, and different artificial insemination methods have been developed until today. At the same time, artificial insemination is carried out by commercial artificial insemination operators or do-it-yourself operators in cattle farms. One of the factors affecting the success of artificial insemination is inseminators. The aim of this study was to determine the effect of inseminators on conception rates in reproductive challenges and to reveal the differences between the success rates of inseminators. A total of 227,297 artificial insemination acts carried out by 35 inseminators for 4years belonging to the Konya Cattle Breeders' Association in Turkey were assessed for this purpose. In the study, the insemination success rate was determined as 41.36%. In addition, the percentage of inseminators with a total insemination success rate of more than 50% is very low, such as 2.9%, and the percentage of those who achieved 35.9% and below was 9.3%. As a result, it can be stated that the inseminators having a lower success rate than the overall should be retrained to avoid costs or losses in the farms.

Genetic and phenotypic variation and consistency in cow preference and circadian use of robotic milking units

Many dairy herds use automatic milking stations (AMS), with cows in large herds often having access to 2 or more AMS, and must choose between them when they go for milking. Individual cows acquire routines of either consistently using a specific milking box or consistently using any available milking box. Here, we hypothesized that the degree of use of the same milking box was an expression of preference, and quantified it as preference consistency score (PCS). The PCS was calculated as a ratio between the excess frequencies of the first choice over the base frequency of "not first choice" over 15-d segments of lactation. This ratio was 0 if all choices were taken equally, and became 1.0 if only the first choice was taken in all events. We investigated the consistency of milking box preference in 2 cohorts (one Holstein and one Jersey) across 6 commercial dairy herds in Denmark (n = 4,665 cows total). In addition to PCS, we recorded and analyzed associated milking and behavior traits, including a time profile index showing use of specific clock hours when cows were milked (Time_profile, based on excess use of specific clock hours), milking frequency, time spent in the milking box, and milk yield. Records from each milking event were condensed into 15-d segments based on days in milk. The data were analyzed using a linear mixed model, with random genetic and individual cow effects, to estimate heritability (h2), repeatability (t), and individual level correlations (ri) between traits. The average PCS was 0.43 and 0.41 in Holstein and Jersey, respectively, showing that cows developed routines for consistently using the same milking box; however, some cows had lower preference (i.e., greater flexibility in use). The Time_profile indicated that some cows were milked in a few hour-bins, whereas others were more flexible. The PCS and Time_profile traits had low heritability (h2, PCS/Time_profile = 0.07 ± 0.02/0.11 ± 0.02 Holstein, 0.13 ± 0.03/0.04 ± 0.02 Jersey) and moderate repeatability (t, PCS/Time_profile = 0.47/0.40 Holstein, 0.50/0.42 Jersey). The 2 traits were weakly correlated with each other (ri = 0.18 and 0.17), and were weakly correlated with milk yield (ri range: 0.0 to -0.10). However, the time profile was strongly correlated with milking frequency (ri range: -0.81 to -0.73), and was moderately correlated with daily box time (ri range: -0.43 to -0.35). In general, Holstein and Jersey parameter estimates were of similar size, and thus in good agreement. Overall, individual cows covered a broad spectrum of preference consistency, both regarding the use of specific milking boxes and time profiles, with these 2 traits representing different aspects or dimensions of milking behavior. The findings that some cows have strong preferences for specific AMS may be most useful in herd management and farm design. The weak correlation to milk yield indicated that yield minimally affected these 2 milking associated behavior traits. In conclusion, although the traits were repeatable, heritability was low; thus, genetic selection for milk yield might minimally affect these 2 traits.