Swedish Official Milk Recording Scheme Research Articles

Comparisons of recycled manure solids and wood shavings/sawdust as bedding material -implications for animal welfare, herd health, milk quality and bedding costs in Swedish dairy herds

Increasing shortages and costs of common bedding materials have led dairy farmers in Sweden to consider using recycled manure solids (RMS), which are readily available and low-cost, as an alternative bedding material. The main risks are effects on udder health and milk quality, but RMS could also affect animal welfare and claw health. The advantages and disadvantages of using RMS bedding have not been fully investigated, and findings in other countries cannot be directly applied to Swedish conditions and climate. This observational cross-sectional study investigated the use of RMS as bedding regarding associations with certain aspects of animal welfare, herd health, milk quality, and bedding costs in Swedish dairy herds. Thirty-four dairy farms using RMS or wood shavings/sawdust (each n = 17) were compared. Each farm was visited 2 times during the housing period 2020-2021, once in October-December and once in March-May. Dairy barns were observed, animal welfare was assessed, and free-stall dimensions were measured. Farm owners were interviewed about housing system characteristics, herd performance, and herd management. Data on milk production and herd health were obtained from the Swedish official milk recording scheme for the indoor period October-March. The prevalence of claw disorders and abnormal claw conformation were collected from the national claw health database for the period, October-May. On each farm visit, composite samples of unused bedding outside the barn and used bedding material from the free stalls, respectively, were taken for total bacterial count and dry matter analysis. Samples of bulk tank milk for determination of total bacterial count were taken in connection to the visits. In addition, samples of unused and used bedding material and manure from alleys for analysis of 3 Treponema species associated with digital dermatitis (DD) were gathered and analyzed. Total bacterial count was significantly higher in unused (8.50 log10 cfu/g) and used RMS bedding (9.75 log10 cfu/g) than in wood shavings/sawdust (used 4.74; unused 8.63 log10 cfu/g), but there were no significant differences in bulk milk total bacterial count (median 4.07 versus 3.89 log10 cfu/mL) or somatic cell count (median 243,800 versus 229,200 cells /mL). The aspects of animal welfare that were assessed did not differ significantly between the 2 bedding systems, while the prevalence of total claw disorders (25.9 versus 38.0% of trimmed cows), dermatitis (6.9 versus 16.2% of trimmed cows) and sole ulcers (2.0 versus 4.0% of trimmed cows) were significantly lower in the RMS herds. Treponema spp. were not detected in unused RMS material, but all RMS herds had presence of DD recorded at foot trimming. An economic assessment based on the interview results and price level from winter 2021 revealed that the costs of RMS bedding varied with amount of RMS produced. Thus, RMS is a potential alternative bedding material for dairy cows in Sweden and can be a profitable option for large dairy herds. However, the high level of total bacteria in the material requires attention to bedding and milking routines as well as regular monitoring of herd health.

Risk and success factors for good udder health of early lactation primiparous dairy cows

We compared the management and housing of dairy heifers from calf to calving in herds that were very successful versus less successful in preventing mastitis in early lactation primiparous cows. This retrospective observational study included 170 Swedish dairy herds. Eligible herds were identified from the Swedish official milk recording scheme (SOMRS). Each herd had at least 60 cows per year, production data from 3 consecutive years, and at least 10 primiparous cows per year with their first milk recording 5 to 35 d after calving and their second milk recording 20 to 40 d after the first milk recording. In each herd, primiparous cows with a low (≤75,000 cells/mL) cow somatic cell count (CSCC) at both the first and second milk recording were categorized as low-low (LL); those with a high (>100,000 cells/mL) CSCC at both recordings were categorized as high-high (HH). Cows with high CSCC at the first recording and low at the second were categorized as high-low (HL). The annual proportions of LL, HL, and HH cows within each herd were calculated. Herds with an above-median proportion of LL, HL, or HH cows during the first year of a 3-yr selection period, and above the third quartile proportion of LL, HL, or HH cows, respectively, during the second and third year were identified. These herds (LL herds, n = 129; HL herds, n = 92; HH herds, n = 139) were contacted until a maximum of 60 herds per category had agreed to participate. Field technicians/veterinarians visited each herd once in the mid to late indoor season to collect data on housing and management of the heifers from birth to calving. Additional data were retrieved from the SOMRS. Associations between herd category (LL, HL, or HH) and variables collected were analyzed in 8 multivariable multinomial logistic regression submodels covering herd characteristics, milk-fed calves, heifers in early pregnancy, heifers in late pregnancy, calving and colostrum period, miscellaneous factors, summarized heifer housing data, and general health, culling, and fertility data. A final multivariable model was built from the results of the submodels and univariable analyses. The final model showed that having a standard operating procedure for colostrum feeding was more common in LL and HL herds than in HH herds; the mean bulk milk SCC and overall culling rate due to udder health was higher in HH herds than in LL and HL herds; and automatic milking was less common in LL herds than in HL and HH herds. Several herd and management variables differed between herd categories in the submodels. In conclusion, we identified several success factors for herds with good udder health among early lactation primiparous cows. This knowledge can be used to improve preventive measures in dairy herds to ensure sustainable and economic milk production.

Recovery from udder cleft dermatitis in dairy cows

Udder cleft dermatitis (UCD) is a common skin problem in dairy cows, localized at the fore udder attachment or between the udder halves. The main objectives of this study were to investigate spontaneous recovery from UCD in a longitudinal study and to investigate the treatment effect on UCD of a topical spray containing chelated copper and zinc in an additional treatment trial. Spontaneous recovery was investigated during a 1-yr longitudinal study in which 7 Swedish dairy herds were visited 9 times each, at 6-wk intervals. During the visits, all cows milked in the milking parlor were examined for mild and severe UCD, udder conformation traits, hygiene, and hock lesions. Additional cow and herd data were obtained from the Swedish official milk recording scheme. Recovery was defined as 2 consecutive observations of no UCD after a UCD case (1 or more consecutive observations of UCD). The recovery rate was calculated and factors associated with recovery were analyzed using discrete-time survival analysis. A treatment study was conducted in 4 of the herds after completion of the longitudinal study. Cows with UCD were allocated to treatment or a control group, and cows in the treatment group were treated once every day for 14 to 28 d. At follow-up visits on d 14, 28, and 56, all cows were scored for UCD. To investigate the effect of treatment, an ordered logistic regression model was used, with UCD score on d 56 (no, mild, or severe) as the outcome. Other potential explanatory variables were also included in the model. A total of 38% (126 of 329) of the cows in the longitudinal study made a spontaneous recovery from UCD. A long duration of UCD, severe lesions and higher parity reduced the chance of recovery. Among the recovered cows, 47% (59 of 126 cows) had a recurrent case of UCD after the recovery. In the treatment study, there was no difference in UCD score on d 56 between the treatment and control groups. Factors that affected the UCD score on d 56 were the duration of UCD before the treatment study started, UCD score on d 1 and udder conformation. Our findings emphasize the importance of further studies to identify effective treatment regimens as well as further studies to unravel the pathophysiology of UCD to improve the recommendations on how to prevent these lesions.

Udder health of early-lactation primiparous dairy cows based on somatic cell count categories

The aims were to investigate the prevalence of intramammary infection in early-lactation primiparous dairy cows (PC) in Sweden using milk recording cow composite somatic cell count (CSCC) categories based on classification of CSCC at the first 2 milk recordings after calving as low or high using cut-offs indicating intramammary infection. We also wanted to evaluate if herd-specific patterns in CSCC categories among PC can be identified to indicate success and problem herds as well as cow-level associations between CSCC categories and breed and sire, and herd-level associations between CSCC categories and herd size, milk production, production system, milking system, and year. A total of 1,597 dairy herds were included. Inclusion criteria were enrolment in the Swedish official milk recording scheme and having production data from at least 10 PC per year during 2014, 2015, and 2016. Herd (size, SCC, milk production, production system, milking system) and cow (breed, lactation number, calving date, CSCC, milk production) data were collected from the Swedish official milk recording scheme. Each PC was assigned a CSCC category (low-low, low-high, high-high, high-low, or inconclusive) based on the CSCC at the first 2 milk recordings using the following cut-offs. At each milk recording a CSCC ≤75,000 cells/mL was considered low and a CSCC >100,000 cells/mL was considered high, whereas a CSCC in between those values was considered inconclusive. Associations between CSCC categories and breed or sire of the PC were analyzed using multivariable multinomial logistic regression models. Associations at herd level between number of PC in a CSCC category and herd variables were analyzed using multivariable Poisson or negative binomial regression models. The annual proportions of CSCC categories for all PC were 51.3%, 5.5%, 15.5%, 13.7%, and 14.0% for the low-low, low-high, high-low, high-high, and inconclusive categories, respectively. The distribution of CSCC categories varied markedly between herds. Overall, the median herd prevalence was 50.2 to 54.2% and 11.7 to 13.2% per year for the low-low and high-high categories, respectively. At cow level, both breed and sire were significantly associated with CSCC categories, showing for example that a higher proportion of Jersey PC were categorized as high-high compared with Swedish Holstein (SH) and Swedish Red (SR) PC, and that PC of certain SH and SR sires more often were categorized as low-low or high-high cows than PC of other sires within each breed. All herd factors, except conventional and organic production, were significantly associated with the proportion of PC in a CSCC category at herd level. For example, the proportion of PC in the low-low category was significantly lower in larger herds (≥80 cows) compared with smaller herds (<80 cows) and significantly lower in automatic milking system herds than in herds with other milking systems, but significantly higher in herds with higher milk production. Overall, the results indicate a substantial need for prevention of subclinical mastitis in early-lactation PC as only 50% of these cows had low CSCC at both milk recordings after calving. Moreover, we conclude that CSCC categories may be a useful tool for identifying success and problem herds.

\u03b1-Tocopherol and \u03b2-carotene concentrations in feed, colostrum, cow and calf serum in Swedish dairy herds with high or low calf mortality

BackgroundA study of herd-level risk factors for calf mortality in large Swedish dairy herds showed low serum concentrations of α-tocopherol and β-carotene in 1–7 day old calves to be more common in high mortality herds. Therefore, we aimed to investigate if calf mortality risk at herd level is associated with concentrations of α-tocopherol and/or β-carotene at individual level in feed, colostrum, cow and calf serum, while controlling for herd level covariates. Inclusion criteria were affiliation to the Swedish official milk recording scheme, herd size of ≥ 120 milking cows/year, calf mortality risk (day 1–90) of at least 6% (high mortality; HM) or less than 1% (low mortality; LM) and located within one of two regions in southern Sweden. This cross-sectional study was performed in 2010 in 19 (nHM = 9; nLM = 10) dairy herds. Questionnaires were used to collect information about feed and routines for colostrum feeding. Feed (n = 57), colostrum (n = 162), cow serum (n = 189) and calf serum samples (n = 187) were collected and analysed for α-tocopherol and β-carotene. Other analyses e.g. total serum protein, fat content, and total solids in colostrum were also performed. Linear regression models with vitamin concentrations in feed, colostrum, cow and calf serum as outcome were performed.ResultsCalves in HM herds had lower concentrations of α-tocopherol in serum than calves in LM herds, but the effect depended on total protein status in serum of the calf (P = 0.036). Calves from herds that fed transition milk for 3 days or more had higher α-tocopherol concentrations in serum than calves from herds feeding transition milk up to 2 days (P = 0.013). Fat percentage in colostrum was positively associated with α-tocopherol (P < 0.001) and β-carotene concentrations in colostrum (P < 0.001). A diet containing ≥ 20% (in kg dry matter) maize silage of the total ration was negatively associated with β-carotene concentration in cow serum (P = 0.001).ConclusionsHigh calf mortality risks were associated with lower concentrations of α-tocopherol in calf serum for calves with failure of passive transfer. Feeding transition milk longer was associated with higher concentrations of α-tocopherol in calf serum. In HM herds, evaluation of the calves’ α-tocopherol status is recommended.

Mild and severe udder cleft dermatitis—Prevalence and risk factors in Swedish dairy herds

Udder cleft dermatitis (UCD) is an inflammatory skin condition affecting the anterior parts of the udder of dairy cows. The lesions may present as mild or severe skin lesions and have been associated with mastitis and digital dermatitis. The full etiology and pathogenesis are not understood and no large-scale studies have investigated prevalence and risk factors. Therefore, the main objectives of the study were to investigate the prevalence of mild and severe UCD in Swedish dairy herds and to identify risk factors associated with such lesions. We also wanted to investigate risk factors for all cases of UCD and to determine whether UCD increases the risk for mastitis and culling. A random sample of 100 freestall dairy herds were included in the study, and each herd was visited once. Cows were registered as having no, mild, or severe UCD. Additional cow and herd data were obtained via observations, interviews, and the Swedish Official Milk Recording Scheme. The data were analyzed using logistic regression models to identify risk factors for mild and severe UCD. In total, data from 3,479 cows in 99 herds were analyzed. The prevalence of mild and severe UCD was 19 and 9%, respectively. Lesions were found in 98 of 99 herds but the within-herd prevalence of mild (0-43%) and severe (0-33%) UCD varied notably between herds. Breed (Swedish Red compared with Swedish Holstein), certain udder conformation traits, and higher parity were risk factors associated with increased risk of UCD. In addition, cows with hock lesions and cows in herds with high incidence of culling due to hoof and leg diseases had a higher risk for mild UCD. More days in milk and high milk yield were cow-related risk factors associated with severe UCD. Three housing-related factors (shorter cubicles, mattress as cubicle base, and cubicles installed before 2001 compared with 2001-2005), a high incidence of veterinary-treated clinical mastitis and culling due to udder diseases, and a low incidence of culling of first-parity cows in early lactation were herd-related risk factors associated with increased risk for severe UCD. In addition, cows in herds with a high proportion of heifers older than 17 mo that were not inseminated were associated with lower risk of all UCD. Finally, UCD was not associated with the outcomes milk somatic cell count, veterinary-treated clinical mastitis, or culling in the multivariable analyses. The etiology of UCD is most likely multifactorial, involving udder conformation traits and other cow-related risk factors as well as herd-related risk factors. The high prevalence of severe UCD lesions in Swedish dairy cows emphasizes the need for preventive measures and efficient treatments.

Incidence and duration of increased somatic cell count in Swedish dairy cows and associations with milking system type.

Mastitis is one of the most costly diseases in dairy cows worldwide. Increased somatic cell count (SCC) is an indication of mastitis, often subclinical, which implies bacterial infection without clinical signs of inflammation. The aim was to investigate the occurrence of elevated udder SCC (defined as ≥200,000 cells/mL) over the lactation period, and before and after the dry period, for cows of different parity. The aim was also to analyze the association between prevalence and incidence of increased udder SCC and information on cow and herd level, such as breed and milking system type. Data were extracted from the Swedish Official Milk Recording Scheme between January 1, 2008, and December 31, 2011, including all herds with a yearly average of >60 cows. The data include descriptive information on herd and cow level and the results from the systematic test milking. The data included the following: for 2009, 239,182 cows in 1,633 herds; for 2010, 251,852 cows in 1,680 herds; and for 2011, 247,746 cows in 1,596 herds. The results show a peak in elevated udder SCC during the late summer season and that the highest proportion of cases occurs during the first lactation month; the latter was most prominent for primiparous cows. Forty-seven percent of all cows with elevated SCC recovered during dry period (went from high to low SCC), whereas 34% of all cows with low SCC before the dry period had an elevated SCC at first testing after calving. For first lactation cows, 19% had an elevated SCC at first test milking. When the outcomes for the 3 consecutive years were reanalyzed, it was confirmed that the effect of fixed factors such as breed, milk yield, and parity did not change over time, whereas the effect of milking system type did. For the incidence of becoming a new case and the prevalence of cows with elevated udder SCC, automatic milking system (AMS) was associated with reduced SCC in 2009 but associated with increased SCC in 2011. Regarding the proportion of new cases of elevated SCC per cow and year, AMS appeared to be a risk factor for all 3 yr, but the effect decreased over time. The shift for AMS from protective to risk factor regarding incidence of new cases and number of recordings with elevated SCC might reflect a change of the AMS population over these years. The findings indicate the need for appropriate udder health management customized to the system.

Short communication: Weak associations between mastitis control measures and bulk milk somatic cell counts in Swedish dairy herds.

Despite the fact that control programs have been available for several decades, mastitis remains an important problem in dairy herds around the world. Possible reasons for this include poor uptake and application of recommended mastitis control measures; poor or variable compliance; or variability in the effects of these measures. The objective of this study was to evaluate the associations between implemented mastitis control measures and bulk milk somatic cell count (BMSCC) in Swedish dairy herds. Data for this study were collected primarily from an extensive self-administered postal questionnaire about the herds, the people responsible for udder health, and details of udder health and mastitis management. A total of 898 questionnaires were distributed, and 428 questionnaires were returned (overall response rate of 48%), but we used the information from only 395 herds in this study. For all herds, we collected data on herd size and geometric average calculated BMSCC from the Swedish Official Milk Recording Scheme. We used logistic regression to assess the association between mastitis control measures and BMSCC, dichotomized as low (<200,000 cells/mL) or high (>200,000 cells/mL). We investigated 21 measures that have been suggested for mastitis control, but found only 2 to be associated with udder health as measured by BMSCC. Not providing dry cows with a specialized mineral feed was significantly associated with increased risk of high BMSCC, and not using post-milking teat disinfectant tended to be associated with increased risk. The lack of association for all other measures was not likely due to low power (because most of these measures had variable implementation rates) but could be due to the relatively narrow range of BMSCC in our study (range 61,000-524,000 cells/mL). However, our results agreed well with those of other recent studies, supporting the call for a thorough review of the current knowledge of mastitis control and for wider application of intervention studies to verify the actual effects of suggested control measures.

Influence of grazing management on claw disorders in Swedish freestall dairies with mandatory grazing

Our hypothesis was that grazing time, the number of days (duration) and number of hours per day, affected claw health. From Swedish freestall herds that fulfilled our criteria of claw-trimming routines, 201 herds were randomly selected for a telephone interview regarding grazing management. Herd data were retrieved from the Swedish Official Milk Recording Scheme. Claw disorders to be analyzed were recorded at maintenance claw trimming before and after the grazing period and included mild and severe dermatitis, severe heel-horn erosion, and sole ulcer (including severe sole hemorrhage). Any remark included one or more of these recorded disorders. The odds for having a recorded claw disorder at the autumn trimming in relation to grazing management, as well as to herd- and cow-related parameters, was tested using multilevel logistic regression models. The final statistical analysis included 17,600 cows in 174 herds, which were distributed from the south to the north of Sweden with decreasing length of mandatory grazing period because of climate. Grazing duration was statistically associated with the risk of sole ulcer, but it was not linear. However, grazing duration was not statistically associated with the odds for any remark, dermatitis, or heel-horn erosion. The odds for dermatitis were lower with access to pasture for 24 h compared with either day or night access. Otherwise, the number of hours that the animals had access to grazing per day was not significantly associated with any of the other analyzed claw disorders. Higher pasture stocking density (number of cow hours per day per hectare) was associated with a higher odds for dermatitis and sole ulcer. For all recorded claw disorders, the highest odds for having a disorder after the grazing period were consistently when the cow had the same claw disorder before the release to pasture. The positive effects of grazing on claw health were less than expected, and the previous known effects of breed, days in milk, parity, production system, housing environment, and management were verified for most claw disorders. If cows in today’s loose housing systems have a more restrictive grazing than cows in tie-stall herds previously experienced, one cannot expect as strong an effect even if grazing is mandatory in all Swedish dairy cattle. Despite some positive effects of grazing, good stall environment and management during the housing period seem to be more important to obtain good claw health.

Risk factors associated with on-farm mortality in Swedish dairy cows

Dairy cow mortality (unassisted death and euthanasia) has increased, worldwide and in Sweden. On-farm mortality indicates suboptimal herd health or welfare and causes financial loss for the dairy producer. The objective of this study was to identify cow-level risk factors associated with on-farm cow mortality. Cows with at least one calving between 1 July 2008 and 30 June 2009 from herds enrolled in the Swedish official milk recording scheme with >40 cow-years were included. Each cow was followed from the day of calving until she calved again or left the herd (died, slaughtered or sold). The effects of potential risk factors on on-farm cow mortality were analysed using a Weibull proportional hazard model with a gamma distributed frailty effect common to cows within herd. The event of interest (failure) was euthanasia or unassisted death. An observation was right censored if the cow was slaughtered, sold, calved again or had an on-going lactation at 500 days after calving. The lactations were split into seasons (January to April, May to August and September to December) and at 30 and 100 days in milk in order to evaluate seasonal effects and the effect of disease in different lactation stages. Primiparous and multiparous cows were analysed separately. The highest hazards for both primiparous and multiparous cows were found for traumatic events and diseases, both in the lactation stage in which the cow died and in the preceding stage. The hazard was higher in early lactation and lower in 2nd parity compared to higher parities. Increased age at first calving (for primiparous cows), calving between January and April, dystocia and stillbirth also increased the mortality hazard. Differences were also found between breeds, between milk production parameters at first test milking and between management types. The results from this study show the importance of good management and preventive health actions, especially around calving, to avoid mortality in dairy cows.

Associations between calf mortality during days 1 to 90 and herd-level cow and production variables in large Swedish dairy herds

The aim of the study was to describe large Swedish dairy herds with high and low mortality risk in calves during the first 90 d of life, using herd-level data, and to evaluate if high calf mortality risk is associated with other herd-level management variables that influence cow health. A total of 57 Swedish dairy herds met the inclusion criteria of affiliation to the Swedish official milk recording scheme, herd size of ≥140 and ≥160 cows in 2008/2009 and 2009/2010, and calf mortality risks, classified as high (HM; calf mortality risk at least 3.5% in 2008/2009 and 5.5% in 2009/2010; n=28) or low (LM; calf mortality risk less than <1.5% in 2008/2009 and 2009/2010; n=29), and were thus included in the study. The data used in this study were collected from the Swedish Dairy association during the milking year 2009/2010. For LM herds, the calf mortality risk ranged from 0 to 1.46 (median=0.66) in 2008/2009 and from 0 to 1.48 (median=0.67) in 2009/2010. For HM herds, the calf mortality risk ranged from 3.57 to 11.52 (median=6.15) in 2008/2009 and from 5.88 to 18.23 (median=8.39) in 2009/2010. Median age at death was 28 d for HM and 37 d for LM herds. Associations between type of herd (HM or LM) and the production variables were evaluated using multi-correspondence analysis and logistic regression models covering the areas “mortality and culling,” “health,” “herd/production variables,” and “fertility.” Herds with HM risks during d 1 to 90 were associated with higher on-farm mortality rate in cows, lower average milk yield, higher incidence of antibiotic treatment, and a higher proportion of purchased animals. These results indicate that herds with HM risk during d 1 to 90 have coexisting issues concerning cow management and health. Future research is needed to evaluate if identifying HM herds and working with advisory and preventive manners at these herds also can be positive for a reduction of on-farm mortality and antibiotic usage, which are important issues from a global perspective.

Methods for assessing phosphorus overfeeding on organic and conventional dairy farms

Phosphorus (P) losses from dairy farms can severely damage aquatic ecosystems, so it is important to have tools to assess overfeeding of P. This study screened P intake and faecal excretion of different P fractions in dairy cows on conventional and organic farms, compared the P feeding level of the herds against the recommendations and analysed different sampling and analysis methods for assessing the general status of P feeding on the farms. The organic (n=14) and conventional farms (n=15) were of comparable size and were located in southern Sweden. On each farm, feed intake was registered for 10 cows representing four different lactation stages and their P intake was calculated and related to current recommendations. Faecal samples taken from the same cows were analysed for total P (TP) and soluble P. Milk production data for the cows were obtained from the Swedish official milk recording scheme. TP was determined in one slurry sample per farm. More than 70% of the cows studied, representing both conventional and organic herds, consumed P in excess of the recommendations. Conventional herds had higher P content in the ration than organic herds, and lactating cows in conventional herds had higher faecal concentrations of total and soluble P than those in organic herds. However in dry cows, the P content of the ration and soluble P and TP in faeces did not differ between the two management systems. Soluble P was well correlated to TP in faeces, and both were good indicators of P overfeeding.

Associations Between Herd Characteristics and Reproductive Efficiency in Dairy Herds

Dairy herds worldwide are experiencing a decline in reproductive efficiency at the same time as management methods are changing. This study aimed to investigate the extent to which herd-level characteristics were associated with reproductive performance. Data from herds using artificial insemination (AI) in the Swedish Official Milk Recording Scheme that had more than 45 cows were included in the study (total of 2,728 herds). Reproductive performance was measured as the average for each herd for the calving interval, calving to first AI interval, calving to last AI interval, number of AI per animal submitted for AI, and culling attributed to reproductive problems. Herds with mainly Swedish Holstein cows had longer calving intervals, calving to first AI, and calving to last AI compared with herds with mainly Swedish Red and White cows. Large herds had shorter calving to first AI but a greater number of AI than small herds, whereas small herds had greater culling attributed to reproductive problems than large herds. Low-yielding herds had longer calving intervals, calving to first AI, and calving to last AI and had greater culling attributed to reproductive problems than high-yielding herds, whereas herds with high milk yields had a greater number of AI than low-yielding herds. Herds with automatic milking systems had shorter calving intervals, calving to first AI, and calving to last AI and had lesser odds for culling attributed to reproductive problems when compared with herds with ordinary pipeline milking systems. Herds that used Advanced Feed Advisory Services had shorter calving to first AI but a greater number of AI and greater culling attributed to reproductive problems. Herds using TMR had longer calving intervals and calving to last AI than herds that did not. Herds with tie stalls had longer calving intervals, calving to first AI, and calving to last AI, and organic herds had shorter calving intervals, calving to first AI, and calving to last AI compared with conventional herds. We found that herds with do-it-yourself inseminations had longer calving intervals and calving to first AI. Our study showed numerous associations between herd characteristics and reproductive performance. When allocating advisory service resources to improve reproductive performance, the focus should be on herd characteristics that are easy to influence, such as TMR and do-it-yourself inseminations.

Data management affects reproductive performance indicators in Swedish dairy herds

We studied how data management affected reproductive performance indicators at herd level and how herd characteristics affected the agreement of the indicators. Data from 483 herds in the Swedish Official Milk Recording Scheme was used. The herd level performance indicators were: number of inseminations per animal submitted to artificial insemination (AI), percentage of non-returns at 56 days, number of days from calving to first and last insemination, percent pregnant per insemination and per animals submitted to AI, and fertility index. Agreement was assessed by the change in performance indicators from a routine calculation to an extra calculation where updated data was included. Changes of more than ±5% were considered indicative of disagreement. The amount of disagreement for the reproductive performance indicators was variable. Percentage of non-returns at 56 days showed no disagreement, while number of inseminations per animal submitted to AI showed largest disagreement. Some herd characteristics, e.g. do-it-yourself-inseminations, percent pregnancy checked and rate of inseminations, affected amount of disagreement.