Commercial Herds Research Articles

Relationship between hypocalcemia immediately after calving with metabolic disorders and body condition score in Holstein cows.

Hypocalcemia is one of the most common transition period disorders that affects dairy cows and has been divided into clinical and subclinical types. This study aimed to investigate the relationship between postpartum serum calcium (Ca) concentrations with metabolic disorders and body condition score (BCS) in Holstein dairy cows. Two hundred and seventy-one Holstein cows were blocked from two commercial dairy herds based on parity (primiparous and multiparous) and serum Ca concentrations on calving day, 1 and 2 days postpartum were allocated to 1 of 3 groups: 1) Serum Ca concentration >8.5 mg/dl at the calving day, 1 and 2 days postpartum (normocalcemic); 2) serum Ca concentration ≤8.5 mg/dl on the calving day and 1 or 2 day postpartum (transient subclinical hypocalcemia (TSCH)); and 3) serum Ca concentration ≤8.5 mg/dl on the calving day, 1 and 2 days postpartum (persistent subclinical hypocalcemia (PSCH)). The results showed that the primiparous and multiparous cows had the highest TSCH and PSCH percentages, respectively. Ca status after calving did not affect the BCS changes, incidence of milk fever, hypomagnesemia and hyperketonemia, and clinical and subclinical endometritis. The incidence of retained placenta, metritis, and subclinical mastitis was affected by Ca status after calving, so PSCH cows experienced 6.28, 6.43, and 5.9 times more retained placenta, metritis, and subclinical mastitis than normocalcemic cows, respectively. The culling rate within the first 60 days in milk for PSCH cows was 4.61 times more than for normocalcemic cows. Overall, the results of the study showed that cows with PSCH had a higher incidence of retained placenta; uterine infections, subclinical mastitis, and culling rate, but cows with TSCH were similar to healthy cows in terms of metabolic disorders and culling rate.

Comparative Analysis of Milking and Behavior Characteristics of Multiparous and Primiparous Cows in Robotic Systems.

Robotic milking systems are successful innovations in the development of dairy cattle. The objective of this study was to analyse the milking characteristics and behavior of dairy cows of different calving orders in "milk first" robotic milking systems. The data were collected from a commercial herd located in the Midwest region of Minas Gerais (Brazil), which uses an automatic milking system (AMS TM, DeLaval). Were analysed 26,574 observations of 235 Holstein cows were available. Data were evaluated by multivariate analysis of variance and the Tukey test. - Tthe characteristics milk flow and milking efficiency were more favourable for multiparous cows (p <0.01), while the time in the stall was more favourable for primiparous females (p <0.01). The values of handling time were better in the primiparous cows (p <0.01). Primiparous cows had higher amounts of kick-off (p <0.001), and multiparous cows had higher incomplete milkings (p <0.001). The number of incomplete milkings showed a higher ratio in terms of reduction in milk production in 26.6% in primiparous cows and 26.7% in multiparous cows (p <0.01). Regarding the behavioral characteristics, primiparous cows had higher amounts of kickbacks, while multiparous cows had greater quantities of incomplete milkings.

On fecundity of chum salmon &lt;i&gt;Oncorhynchus keta&lt;/i&gt; in the commercial herd at Iturup Island

Absolute fecundity of chum salmon Oncorhynchus keta is investigated for the commercial herd dwelled at Iturup Island. Currently, the herd is formed mostly by fish of hatchery origin but has retained the same species and regional features that distinguished it when it was formed mainly due to natural spawning. The value of absolute fecundity is determined for 3833 females and ranges from 769 to 4400 oocytes. For the fish of two dominant age groups (3+ and 4+), this number usually decreases with age, with the exception of particularly large older fish with greater fecundity. Same factors that promote abundance of hatchery fish in the herd also contribute to decreasing of abortive processes in the ovaries, therefore the absolute fecundity correlates closely and positively with the catch of chum salmon in the coastal waters.

Associations of parity and lactation stage with the order cows enter the milking parlor

To explore the effect of lactation stage and parity on the milking order of cows, we collected milking order data of all lactating cows (n = 251) over a period of 12 wk in one commercial Swedish dairy cow herd using a herringbone milking parlor. Cows were kept in 2 housing groups (G1 and G2) and moved from G1 to G2 at approximately mid lactation. Two analyses were conducted to investigate if lactation stage (early: 2–49 d in milk, mid: 50–179 d in milk, and late ≥180 d in milk) and parity are associated with the entrance order to the parlor or a preference of entering a new milking line first. In G1 and G2, cows in first parity entered the milking parlor earlier than cows in higher parities. In addition, in G1 cows in early lactation entered the milking parlor earlier than cows in later lactation. Similar effects were observed for the preference of entering a new milking line first. No effect of mid versus late lactation could be observed in either G1 or G2. The study also found that cows tend to keep their rank within the milking order constant. The results of the study indicate that cows of presumably lower hierarchy (first parity and early lactation) leave the waiting area earlier compared with other cows. This should be considered when planning grouping strategies and preventive measures against mastitis pathogen transmission.

The Immunogenicity of a Foot-and-Mouth Disease Virus Serotype O Vaccine in Commercial and Subsistence Cattle Herds in Zambia.

The recent introduction of foot-and-mouth disease (FMD) virus serotype O (O/EA-2 topotype) in Southern Africa has changed the epidemiology of the disease and vaccine requirements of the region. Commercial and subsistence cattle herds in Zambia were vaccinated with an FMD virus serotype O Manisa vaccine according to a double- or single-dose vaccination schedule. Heterologous antibody responses induced by this vaccine against a representative O/EA-2 virus from Zambia were determined. Virus neutralisation tests (VNTs) showed double-dosed cattle had a mean reciprocal log virus neutralisation titre of 2.02 (standard error [SE] = 0.16, n = 9) for commercial herds and 1.65 (SE = 0.17, n = 5) for subsistence herds 56 days after the first vaccination (dpv). Significantly lower mean titres were observed for single-dosed commercial herds (0.90, SE = 0.08, n = 9) and subsistence herds (1.15, SE = 0.18, n = 3) 56 dpv. A comparison of these results and those generated by solid-phase competitive ELISA (SPCE) tests showed a statistically significant positive correlation by Cohen's kappa coefficient. Therefore, SPCE might be used in assessing the immunogenicity of vaccines in place of VNT. Furthermore, for this vaccine and field strain, a vaccination regime employing a two-dose primary course and revaccination after 4-6 months is likely to be appropriate.

Effects of long-acting injectable progesterone supplementation at early dioestrus on pregnancy maintenance in beef and dairy recipient cattle.

We tested in the present study the hypothesis that supplementation with long-acting P4 (iP4) at different times of the initial dioestrus improves pregnancy rates in dairy and beef recipients submitted to fixed-time embryo transfer (FTET). Recipients from commercial farms had their oestrous cycle synchronized with an E2/P4-based protocol in three experiments (Exp. 1 to 3). In Exp. 1, dairy heifers (n = 76) and cows (n = 104) were randomly assigned to two experimental groups: the control group (n = 89) and the iP4D4 group (n = 91). For Exps. 2 and 3, suckled beef recipients were used. In Exp. 2, recipients were assigned to two experimental groups: Control group (n = 147) and iP4D7 group (n = 144); whereas in Exp. 3, recipients were randomly assigned to three experimental groups: Control group (n = 85), iP4-D4 group (n = 86) and iP4D7 group (n = 81). Recipients in the iP4D4 and iP4-D7 groups received an i.m. administration of 150 mg iP4, on D4 or D7 (D0 was the day of expected oestrus). On D7, all recipients were evaluated by transrectal ultrasonography and those that had a CL received a fresh or vitrified invitro-produced embryo. In Exp. 2 and 3, the CL area was also determined by ultrasonography at the time of FTET. The pregnancy diagnosis was performed at 30 days in Exp. 1, 57 days in Exp. 2, and between 40 and 72 days of pregnancy in Exp. 3. In Exp. 1, the pregnancy rate did not differ (p > .1) between the Control group (38.2% [34/89]) and iP4D4 group (49.5% [45/91]); yet, a parity effect indicated a greater (p < .05) pregnancy rate in heifers (57.9% [44/76]) than cows (30.8% [32/104]). In Exp. 2, the pregnancy rate was greater (p < .05) in the iP4D7 group (45.0% [65/144]) than in the Control group (34.0% [50/147]). Also, a greater (p = .08) pregnancy rate was observed for recipients with a small CL (≤2.75 cm2 ) that were treated with iP4 on the day of FTET than the control recipients (46.4% [32/69] vs. 32.6% [28/86]). In Exp. 3, no significant effects (p > .1) of the treatment group or CL size were detected on pregnancy rates at days 30 and 60. In conclusion, the beneficial effects of iP4 supplementation at early dioestrus on pregnancy maintenance may vary according to the experimental conditions, but its use at the time of FTET can be used as an alternative to enhance the fertility of beef recipients in challenging conditions in commercial herds.

Unravelling the genetic variability of host resilience to endo- and ectoparasites in Nellore commercial herds

BackgroundHost resilience (HR) to parasites can affect the performance of animals. Therefore, the aim of this study was to present a detailed investigation of the genetic mechanisms of HR to ticks (TICK), gastrointestinal nematodes (GIN), and Eimeria spp. (EIM) in Nellore cattle that were raised under natural infestation and a prophylactic parasite control strategy. In our study, HR was defined as the slope coefficient of body weight (BW) when TICK, GIN, and EIM burdens were used as environmental gradients in random regression models. In total, 1712 animals were evaluated at five measurement events (ME) at an average age of 331, 385, 443, 498, and 555 days, which generated 7307 body weight (BW) records. Of the 1712 animals, 1075 genotyped animals were used in genome-wide association studies to identify genomic regions associated with HR.ResultsPosterior means of the heritability estimates for BW ranged from 0.09 to 0.54 across parasites and ME. The single nucleotide polymorphism (SNP)-derived heritability for BW at each ME ranged from a low (0.09 at ME.331) to a moderate value (0.23 at ME.555). Those estimates show that genetic progress can be achieved for BW through selection. Both genetic and genomic associations between BW and HR to TICK, GIN, and EIM confirmed that parasite infestation impacted the performance of animals. Selection for BW under an environment with a controlled parasite burden is an alternative to improve both, BW and HR. There was no impact of age of measurement on the estimates of genetic variance for HR. Five quantitative trait loci (QTL) were associated with HR to EIM but none with HR to TICK and to GIN. These QTL contain genes that were previously shown to be associated with the production of antibody modulators and chemokines that are released in the intestinal epithelium.ConclusionsSelection for BW under natural infestation and controlled parasite burden, via prophylactic parasite control, contributes to the identification of animals that are resilient to nematodes and Eimeria ssp. Although we verified that sufficient genetic variation existed for HR, we did not find any genes associated with mechanisms that could justify the expression of HR to TICK and GIN.

Associations of postpartum health with progesterone after insemination and endocrine signaling during early pregnancy in dairy cows

Our objective was to investigate associations of postpartum health with serum progesterone (P4) concentrations after first artificial insemination (AI), expression of interferon-stimulated genes (ISG) in blood leukocytes, and serum pregnancy-associated glycoprotein (PAG) during early pregnancy in dairy cows. In this observational study, Holstein cows (n = 475) from 2 commercial herds were enrolled 3 wk before expected parturition. Body condition score (BCS) and lameness were assessed at enrollment, and total Ca, haptoglobin, and nonesterified fatty acids (NEFA) were measured in serum at 2 and 6 ± 2 d in milk (DIM). Blood β-hydroxybutyrate and metritis were evaluated at 4, 8, 11, and 15 ± 2 DIM, and purulent vaginal discharge (PVD) and endometritis based on endometrial cytology were diagnosed at 35 DIM. Onset of cyclicity was assessed by biweekly P4 measurements. The BCS was assessed at enrollment and at 63 DIM, and lameness at enrollment and at 21 and 49 DIM. First AI was based on estrus detection until ∼75 DIM, or synchronization for timed AI thereafter. Serum P4 was measured at d 8 and 12 after first AI; expression of ISG (ISG15 and RTP4) in blood leukocytes was assessed at d 19; and PAG in serum of pregnant cows was measured at d 29, 33, and 40. Multivariable linear regression models were built including health variables (with metabolites categorized via receiver operating characteristic curve analysis) and covariates (season, milk yield, AI method, DIM), accounting for pregnancy status (for ISG and PAG models), repeated measures (for P4 and PAG models), and herd as random. Results are reported comparing cows affected versus unaffected by each predictor. Serum P4 concentrations were lesser at d 8 after AI in cows that had total Ca ≤2.09 mM (3.6 vs. 4.0 ± 0.2 ng/mL) at 2 DIM or a clinical disease (3.7 vs. 4.0 ± 0.2 mg/mL), and P4 tended to be lesser at d 8 in cows that had PVD (3.6 vs. 4.0 ± 0.2 ng/mL) or any uterine disease (3.7 vs. 4.1 ± 0.2 ng/mL). Among cows pregnant at d 29, relative ISG15 expression (fold change) at d 19 was greater in cows that had lameness (5.10 [4.18-6.18] vs. 3.14 [3.10-3.19]) but tended to be lesser in cows that had endometritis (3.20 [2.89-3.54] vs. 4.29 [4.20-4.35]), and relative expression of RTP4 tended to be lesser in cows that had displaced abomasum (1.02 [0.62-1.67] vs. 1.75 [1.73-1.78]). Serum PAG was lesser at d 29 (3.8 vs. 4.2 ± 0.2 sample-to-positive ratio [S:P]) in cows that had NEFA ≥0.73 mM at 6 DIM, and lesser at d 33 (3.9 vs. 4.5 ± 0.2 S:P) and 40 (3.1 vs. 3.7 ± 0.2 S:P) in cows that had prepartum BCS ≥3.75. These findings suggest long-term effects of metabolic or reproductive tract disorders on luteal function after first AI, pregnancy recognition signaling, and placental function during early pregnancy. These associations may partially explain some of the pathways linking postpartum health and fertility in dairy cows.

Bunching behaviour in housed dairy cows at higher ambient temperatures

Bunching behavior in cattle may occur for several reasons including enabling social interactions, a response to stress or danger, or due to shared interest in resources such as feeding or watering areas. There is evidence in pasture grazed cattle that bunching may occur more frequently at higher ambient temperatures, possibly due to sharing of fly-load or to seek shade from the direct sun under heat stress conditions. Here we demonstrate how bunching behavior is associated with higher ambient temperatures in a barn-housed UK dairy herd. A real-time local positioning system was used, as part of a precision livestock farming (PLF) approach, to track the spatial position and activity of a commercial dairy herd (∼100 cows) in a freestall barn continuously at high temporal resolution for 4 mo between August and November 2014. Bunching was determined using 4 different spatial measures determined on an hourly basis: herd full and core range size, mean herd intercow distance (ICD), and mean herd nearest-neighbor distance (NND). For hourly mean ambient temperatures above 20°C, the herd showed higher bunching behavior with increasing ambient temperature (i.e., reduced full and core range size, ICD, and NND). Aggregated space-use intensity was found to positively correlate with localized variations in temperature across the barn (as measured by animal-mounted sensors), but the level of correlation decreased at higher ambient barn temperatures. Bunching behavior may increase localized temperatures experienced by individuals and hence may be a maladaptive behavioral response in housed dairy cattle, which are known to suffer heat stress at higher temperatures. Our study is the first to use high-resolution positional data to provide evidence of associations between bunching behavior and higher ambient temperatures for a barn-housed dairy herd in a temperate region (UK). Further studies are needed to explore the exact mechanisms for this response to inform both welfare and production management.

NUTRITIONAL INTERVENTIONS ON DAIRY PERFORMANCE AND PROFITABILITY

Dairy production plays a pivotal role in meeting the global demand for high-quality milk and dairy products, which are essential sources of nutrition for populations worldwide. The primary aim of the study is to find the nutritional interventions on dairy performance and profitability. This research article follows a controlled experimental design to assess the impact of specific dietary interventions on dairy performance and profitability. The study was conducted at a commercial dairy farm, and data were collected over 12 months.The study utilized 120 lactating Holstein dairy cows from the commercial herd. Cows were selected based on similar lactation stages, parity, and health status to minimize potential confounding factors. The experimental Group 1, which received the custom-blend dietary supplements, showed a significant increase in daily milk yield compared to the Control Group (P &lt; 0.05). On average, cows in Group 1 produced 2.5 liters more milk daily. It is concluded that improved milk production and profitability, achieved without compromising health or welfare, underscores the importance of optimizing nutrition for dairy cows. These findings contribute to the evolving field of dairy nutrition and have practical implications for enhancing dairy farm sustainability and economic viability.

Factors affecting birth weight and stillbirth in sows housed in a tropical environment.

This study analysed data from a commercial swine herd in Thailand equipped with a free-farrowing housing system, comprising 17,196 piglets from 1318 litters, to explore the impact of sow and litter characteristics on the piglet birth weight and the incidence of stillbirth. The piglets were classified into four groups based on the total number of piglets born per litter (TB): ≤9 (n = 1434), 10-12 (n = 3232), 13-15 (n = 6537) and ≥16 (n = 5993). Sows were classified into four groups based on parity number: 1, 2-4, 5-7 and ≥8. The piglets were categorized into quartiles based on their birth order ranking: Q1 (n = 4786), Q2 (n = 4143), Q3 (n = 3808) and Q4 (n = 4456). Piglet birth weight was individually measured before colostrum ingestion. On average, TB, the number of live-born piglets and the incidence of stillbirth were 13.1 ± 3.7, 11.5 ± 3.8 and 6.3%, respectively. Among these litters, 26.6% had TB numbers ≥16. The average piglet birth weight was 1.37 ± 0.36 kg, with 18.3% of piglets weighing ≤1.0 kg at birth. Piglet birth weight was influenced by birth order ranking, as Q4 piglets were found to be heavier than piglets born in Q1-Q3 (p < .001). Moreover, the percentage of piglets with a birth weight of ≤1.0 kg increased from 5.9% in litters with TB of ≤9-25.3% in litters with TB of ≥16 (p < .001). Additionally, primiparous sows had lower piglet birth weights compared to sows with parity numbers 2-4, 5-7 and ≥8 (p < .001). Piglets born in the fourth quartile (Q4) had a higher risk of stillbirth compared to those born in the first (Q1), second (Q2) and third (Q3) quartiles (12.5% vs. 2.2%, 4.1% and 6.6%, respectively, p < .001). The incidence of stillbirth in litters with TB ≥16 was also higher than that in litters with TB ≤9 and 10-12 (p < .05). Furthermore, sows with parity numbers ≥8 had a higher incidence of stillbirth (9.7%) compared to primiparous sows (4.0%, p < .001), sows with 2-4 parity (5.2%, p < .001) and sows with 5-7 parity (7.6%, p = .003). In summary, a high incidence of stillbirth was found in piglets born in the last quartile of litters, in litters with >16 piglets and for sows with parity numbers ≥8. Piglets born in the last quartile of litters were heavier than those born in the first to third quartiles.

Associations of cow-level factors with the risk of poor hygiene in cows housed in free-stall and tie-stall barns

The objective of this study was to identify cow-level factors associated with poor body hygiene. Cows ( n = 2644) from 68 commercial dairy herds (free-stall ( n = 43); tie-stall ( n = 25)) in Ontario, Canada were enrolled. Cows were hygiene scored on each of three visits (7 days apart). Older cows were at higher risk of having a dirty udder and dirty upper legs and flanks in free-stall barns and younger cows were at higher risk of having dirty upper legs and flanks in tie-stall barns. Higher days in milk was associated with better hygiene for cows housed in both free-stall and tie-stall barns.

Monitoring bovine dairy calf health and related risk factors in the first three months of rearing

BackgroundRearing replacement heifers is pivotal for the dairy industry and is associated with high input costs for the preweaned calves, due to their higher susceptibility to diseases. Ensuring calf health and viability calls for systematic approaches in order to mitigate the costs induced by managing sick calves and to ensure animal welfare. The objective of this study was to develop a systematic and feasible health-monitoring tool for bovine dairy calves based on repeated clinical observations and diagnostic results of calves at three time points; the 1st (T0), the 3rd (T1) and the 12th (T3) week of age. The study included observations from 77 dairy heifer calves in nine Danish commercial dairy herds. Immunisation status was assessed by serum Brix% at T0. Clinical scoring included gastrointestinal disease (GD) and respiratory disease (RD). The average daily weight gain (ADWG) was estimated from heart-girth measurements. Pathogen detection from nasal swabs and faecal samples were analysed for 16 respiratory and enteric pathogens by means of high-throughput real time-PCR. All measures obtained in each herd were visualised in a panel to follow the health status of each calf over time.ResultsThe individual clinical observations combined with diagnostic information from immunisation and pathogen detection form each enrolled calf are presented in a herd dashboard illustrating the health status over the study period. This monitoring revealed failure of passive transfer (Brix% < 8.1) in 31% of the 77 enrolled calves, signs of severe GD peaked at T0 with 20% affected calves, while signs of severe RD peaked at T2 with 42% affected calves. ADWG over the first eight weeks was estimated to be 760 g (± 190 g). Pathogen profiles varied between herds.ConclusionsThe large variation in both clinical disease and pathogen occurrence across herds emphasizes the need for herd specific monitoring. Combining the results of the present study from measures of immunisation, health and growth from individual calves in one visualisation panel allowed for the detection of patterns across age groups in the specific herds, showing promising potential for early detection and interventions that can lead to enhanced calf health and welfare.

Associations of inflammatory and reproductive tract disorders postpartum with pregnancy and early pregnancy loss in dairy cows

Our objective was to describe associations of postpartum health with pregnancy and pregnancy loss (P-LOSS) from d 19 to 40 after first postpartum artificial insemination (AI) in lactating Holstein cows. In 2 commercial dairy herds in Ontario, Canada, 468 Holstein cows were enrolled 21 ± 3 d before expected parturition when body condition score (BCS) and lameness were assessed. Serum total Ca, haptoglobin (Hp), and nonesterified fatty acids (NEFA) were measured at 2 and 6 ± 2 d in milk (DIM). Blood β-hydroxybutyrate (BHB) measurement and metritis detection were done at 4, 8, 11, and 15 ± 2 DIM. Cows were examined for endometritis (ENDO; ≥11.5% polymorphonuclear cells in endometrial cytology) and purulent vaginal discharge (PVD) at 35 ± 3 DIM. Lameness was assessed again at 21 and 49 ± 3 DIM and BCS at 63 ± 3 DIM. First postpartum AI occurred primarily (86%) based on detection of estrus by activity monitors, on average (± standard deviation) at 65 ± 9 DIM, and the remaining cows received timed AI at 86 ± 18 DIM. Serum progesterone (P4) was measured on d 8 and 12 after AI, and pregnancy at first AI (P/AI) was estimated by the expression of ISG15 in peripheral blood leukocytes at d 19 after AI and by pregnancy-associated glycoprotein in serum at d 29, 33, and 40 after AI. Each metabolite (Ca, Hp, NEFA, and BHB) was categorized above or below a cut-point identified with receiver operating characteristic curve analysis associated with P/AI confirmed by ultrasound at d 33 from a larger data set. Data were analyzed using multivariable mixed logistic regression models, accounting for parity, health variables, covariates (season at calving and at AI, milk yield at first Dairy Herd Improvement Association test [categorized into terciles], AI method, and DIM), and herd. The proportions of cows classified pregnant at d 19, 29, 33, and 40 after AI were 64%, 54%, 50%, and 45%, respectively. At d 19 after AI, P/AI was less likely in cows diagnosed with ENDO (52% vs. 69%) or PVD (54% vs. 67%). At d 29, P/AI was less likely in cows with Hp ≥1.54 g/L at 2 DIM (38% vs. 55%) or PVD (35% vs. 56%). Both metritis and ENDO were associated with decreased P/AI at d 40 after AI. Cows diagnosed with metritis had greater risk of P-LOSS from d 19 to 29 (43% vs. 22%) or from d 33 to 40 (37% vs. 7%) than cows without metritis. From d 29 to 33, the risk of P-LOSS was greater in cows with NEFA ≥0.73 mM at 2 DIM (13% vs. 5%) or BCS ≤2.75 at 63 DIM (14% vs. 5%). The concentration of P4 on d 8 after AI was positively associated with P/AI at d 29, 33, and 40, and negatively associated with P-LOSS from d 19 to 29. Postpartum health disorders, particularly reproductive tract disease, can have detrimental effects on early pregnancy establishment and on pregnancy maintenance from d 19 to 40 after AI.

Specific and non-specific effects of Mycobacterium bovis BCG vaccination in dairy calves.

Bovine tuberculosis (bTB) is a chronic disease mainly caused by Mycobacterium bovis, a zoonotic pathogen with economic significance as it leads to reduced milk and meat production, and high costs for control measures. The Bacillus Calmette-Guérin (BCG) vaccine, primarily used to prevent tuberculosis in humans, has also been studied for controlling bTB. While showing effectiveness in preventing M. bovis infection and disease in cattle, the BCG vaccine can induce non-specific effects on the immune system, enhancing responses to infections caused by unrelated pathogens, and also having non-specific effects on lactation. The aim of this study is to describe both the specific and non-specific effects of BCG vaccination in calves from a commercial dairy herd in central Chile. Diagnosis of M. bovis infection was performed through the IFNγ release assay (IGRA) using ESAT6/CFP-10 and Rv3615c antigens. The records of milk production, somatic cell count (SCC), clinical mastitis (CM) and retained placenta (RP) during the first lactation were compared between vaccinated and non-vaccinated animals. The breed (Holstein Friesian [HF] v/s HF × Swedish Red crossbred [HFSR]) and the season (warm v/s cold) were also analyzed as categorical explanatory variables. Results of IGRA showed significant differences between vaccinated and control groups, indicating a vaccine efficacy of 58.5% at 18 months post vaccination in HFSR crossbred animals. Although milk production did not vary, SCC and CM showed differences between groups, associated to the breed and the season, respectively. When analyzing CM and RP as a whole entity of disease, BCG showed protection in all but the cold season variables. Overall, the BCG vaccine induced protective specific and non-specific effects on health parameters, which may be influenced by the breed of animals and the season. These results provide new features of BCG protection, supporting initiatives for its implementation as a complementary tool in bTB control.

Scenario tree modelling to inform surveillance design for maintaining freedom from Coxiella burnetii infection in Australian commercial dairy goat herds.

We used scenario tree methods to determine how different disease detection methods might be used to provide quantitative evidence that Australian dairy goat herds are free of coxiellosis. The aim of our proposed C. burnetii surveillance programme is to find evidence of the absence of antigen as well as evidence of an absence of an immune response to C. burnetii infection in individual dairy goat herds. We defined a C. burnetii infected dairy goat herd as a herd in which at least one doe was showing evidence of either active infection or past C. burnetii exposure using four candidate surveillance system components (SSCs): (1) testing of individual doe whole blood using the C. burnetii com1 PCR; (2) testing of individual doe whole blood using the C. burnetii ELISA; (3) testing bulk tank milk (BTM) using the com1 PCR and the C. burnetii ELISA; and (4) investigations of abortions and stillborn kids submitted to a diagnostic laboratory for testing. Of eight candidate surveillance strategies (combinations of the SSCs listed above) individual doe ELISAs every six months combined with monthly BTM PCR and ELISA testing returned the highest surveillance system sensitivity of 0.963 (95% probability interval [PI] 0.911-0.982) for the lowest cost, at AUD 28.94 (95% PI 28.38-30.59) over a 12-month period, for every one percent increase in surveillance system sensitivity. Assuming a probability of disease freedom of 0.10 at the start of the surveillance program and a probability of C. burnetii introduction per month of 0.01 we estimate that 95% confidence that C. burnetii was absent from a herd could be achieved after a single round of individual doe ELISAs followed by period of 6 consecutive monthly BTM PCR and ELISA tests. The results of this study show that selection of the most efficient combination of surveillance system components requires a good understanding of initial herd C. burnetii status and the probability of introduction of infection and how this may change over time. Scenario tree analyses results have provided insight into the key determinants of C. burnetii detection ability.

Supernumerary teats in goats

Supernumerary or extra teats in ruminants are defined as any teats that exceed the normal number. The presence of five or six teats is not normal in a cow or goat, but it is not unusual. Which of these are extra? It is usually very obvious; sometimes it is helpful to look at the placement, size and sphincter development of all teats to identify normal versus extra. Most additional nipples in goats are "blind"and are not attached to the mammary tissue. An extra nipple is not able to produce milk. Blind teats are often found in pairs. It is not uncommon in cattle or goats to find a pair of "button-like" protrusions on the hindquarters or a few less developed hanging teats next to the functional ones. Causing little more than an unsightly rear udder image, blind teats in a commercial cattle or goat herd are usually not a problem.

Nonlinear modeling of carbon dynamics in soil treated with tannery sludge

In 2020, the Brazilian commercial cattle herd was the largest in the world, representing 14.3% of the worldwide herd, with201.7 million heads. Although this activity yields significant profits, contributing to the economic and social development ofBrazil, it has been the target of concerns, mainly due to the large production of waste/effluents associated to bovine leatherprocessing. In this scenario, mineralization is important because nutrients essential for plant growth are released duringthe process of organic waste decomposition, and the dynamics of carbon release can be described by nonlinear regressionmodels. Thus, this study aimed to model the mineralization of organic carbon in the soil for 6, 12, 24, and 36 megagramsdoses per hectare (Mg ha−1) of tannery sludge using the Stanford &amp; Smith, Cabrera, and Juma nonlinear models. Very clayeysoil samples were used: eutroferric red nitosol (NVef). Mineralized carbon was measured in 21 observations over time untilthe 105th day of incubation. Parameters were estimated using the least squares method. Adjustments were compared usingthe corrected Akaike information criterion (AICc) and the adjusted coefficient of determination (R2aj) as selection criteria. The Cabrera model had the best adjustments for doses 6, 12, and 24 Mg ha−1 and Juma for dose 36 Mg ha−1, based on the selection criteria used. Although the Stanford &amp; Smith model is the most widely used in the literature to model soil carbon dynamics, its use was not the most appropriate for any of the doses evaluated in this study. The higher the dose of tannerysludge, the greater the amount of potentially mineralizable carbon.

Comparison of metrics to assess antibiotic use in small ruminants at a university referral clinic between 2005 and 2019.

Monitoring antibiotic use is essential to provide a framework enabling veterinarians to use antibiotics prudently. Electronic medical records from the University of Veterinary Medicine's Clinic for Ruminants in Vienna were analysed with respect to sheep and goat antibiotic doses administered over a 15-year period (2005-2019). Antibiotic use was assessed using total milligrams per kilogram (mg/kg), total milligrams, number of doses administered, defined daily doses (DDD) for cattle and estimated DDD for sheep. A total of 5113 antibiotic doses were recorded over the 15-year period. Urinary tract disorders required the highest number of doses administered per animal (mean 16.9; median 16.0). Antibiotic use patterns varied according to the metrics used for analysis. By mg/kg, the largest proportion of antibiotics administered were penicillin/streptomycin (43.0% of the total mg/kg), followed by tetracyclines (17.3%) and sulphonamide/trimethoprim combinations (15.2%). By number of doses administered, the most frequently used antibiotics were penicillins (excluding combinations with streptomycin) (33.9% of total number of doses administered), fluoroquinolones (25.1%), third/fourth-generation cephalosporins (13.6%) and penicillin/streptomycin (13.4%). As the university clinic was a city-based referral centre, this analysis cannot be compared directly with antibiotic use in commercial herds or flocks. The considered choice of antibiotic use metrics is essential for an effective and meaningful analysis of the responsible use of antibiotics by veterinarians in practice.

Postpartum health is associated with detection of estrus by activity monitors and reproductive performance in dairy cows

The objective of this prospective observational study was to investigate associations of postpartum health with estrus detection (ED) by activity monitors and pregnancy outcomes in dairy cows. A total of 1,743 Holstein cows from 2 commercial dairy herds in Ontario, Canada were enrolled 3 wk before expected parturition and examined for health variables until 9 wk postpartum. Body condition score (BCS) and lameness were measured at 3 wk prepartum, and serum concentrations of total Ca, haptoglobin (Hp), and nonesterified fatty acids were measured at 2 and 6 ± 2 d in milk (DIM), and blood β-hydroxybutyrate (BHB) and metritis were assessed at 4, 8, 11, and 15 ± 2 DIM. Cows were examined for purulent vaginal discharge (PVD) and endometritis (ENDO) by endometrial cytology at wk 5, for lameness at wk 3 and 7, for BCS at wk 9 postpartum, and for time to onset of cyclicity by biweekly serum progesterone (P4) measurements. Additional disease data were obtained from farm records. Reproductive management for first AI was primarily based on ED by activity monitors until at least 75 DIM, and cows not detected in estrus were synchronized. Data were analyzed in multivariable logistic or Cox proportional hazards regression models including blood markers, health variables, potential covariates, and herd as a random effect. Estrus was detected in 77% of primiparous and 66% of multiparous cows between 50 or 55 DIM and 75 DIM. In 1,246 cows, the model-predicted probability of ED (percentage point difference) was lower in cows that had retained placenta (-14%), ENDO (-7%), PVD (-8%), delayed cyclicity (no P4 > 1 ng/mL by wk 9; -12%), or ≥0.5-point BCS loss (-14%) compared with cows without each of these risk factors, and it was negatively associated with blood BHB at 15 DIM. Considering only variables measured on farm (not requiring laboratory analysis), the probability of ED was lower (56 vs. 81%) in cows with >1 risk factor compared with cows without risk factors. The predicted probability of pregnancy at first artificial insemination (percentage point difference) was lower in cows that had ENDO (-7%) or PVD (-7%), and negatively associated with serum Hp at 6 ± 2 DIM. In cows detected in estrus by 75 DIM (n = 888), risk factors for reduced pregnancy rate by 250 DIM (adjusted hazard ratio (AHR); 95% confidence intervals) included difficult calving (AHR: 0.67; 0.45 to 1.00), metritis (AHR: 0.79; 0.61 to 1.01), PVD (AHR: 0.79; 0.65 to 0.97), or lameness (AHR: 0.79; 0.62 to 1.01), and it was negatively associated with serum Hp at 6 ± 2 DIM. Monitoring postpartum health may be used to identify cows that are more or less likely to be detected in estrus by activity monitors and to become pregnant in a timely manner. This would support a selective reproductive management program with targeted interventions.