Effects of automated short-term incomplete milking during peak- to mid-lactation on milk production, udder health, and selected metabolic parameters in dairy cows

This study investigated the effects of automated short-term incomplete milking (IM) during peak- to mid-lactation on milk production, udder health, and selected metabolic parameters in multiparous Holstein cows. Forty-six cows (94 ± 47 DIM) were randomly assigned to the complete milking treatment (COMP; n = 23, 95 ± 49 DIM, lactation number 3.0 ± 1.3) or the incomplete milking treatment (INCL; n = 23, 93 ± 46 DIM, lactation number 2.6 ± 0.8). In INCL cows, IM was implemented using specialized software that precisely controlled milk withdrawal. Concentrate allocation was dynamically adjusted based on milk yield and DIM via transponder-controlled stations. All cows had ad libitum access to a partial mixed ration and water via automated weighing troughs and bowls. The IM protocol included a gradual reduction phase (first IM phase: 9% daily reduction to ∼40% over 5.5 d), followed by 3 complete milkings, and a constant reduction phase (second IM phase: 40% reduction over 5.5 d). No clinical signs of mastitis, as well as negative bacteriological results, were observed, confirming udder health. In the week prior to IM, milk yield (reference milk yield, REF) did not differ between treatments, with INCL cows achieving between 26 and 59 kg/d. Compared to REF, the milk yield of the INCL cows decreased by 19% (32.7 ± 1.54 kg/d) on the first day after the first IM phase and by 24% (30.7 ± 1.54 kg/d) on the first day after the second IM phase. After cessation of IM, milk yield increased again by 19% within 2 wk and stabilized further at the REF level. Compared to the COMP cows, milk fat content of the INCL cows decreased by 21% and 43% with the onset of the first and second IM phases. Concentrate intake of INCL cows decreased by 65% from 5.4 ± 0.52 kg/d at the beginning of IM to 1.9 ± 0.39 kg/d at the end of IM due to the feed-to-yield feeding system, reflecting lower energy requirements, and increased thereafter. Udder health indicators remained stable during IM. In the INCL cows that completed the trial, SCC remained consistently below mastitis thresholds and no relevant pathogens were detected. Milk leakage occurred exclusively in INCL cows during IM, but did not compromise udder health. Serum nonesterified fatty acid concentrations decreased by 63% and 58% during the first IM and second IM phases, respectively, indicating reduced lipid mobilization. Concurrently, IGF-1 concentrations increased by 30% and 28% during the respective phases, indicating metabolic adaptations to the reduced energy demand. In summary, automated short-term IM performed on dairy cows in peak- to mid-lactation using specialized software was successful in temporarily reducing milk production and lactation-induced metabolic load without negatively affecting udder health or long-term performance.

Switzerland-wide Neospora caninum seroprevalence in female cattle and identification of risk factors for infection

INTRODUCTION

Neospora caninum is an important cause of abortion in cattle worldwide. Infection in cattle occurs horizontally by ingestion of oocysts shed by canids or vertically, from an infected dam to the fetus, and may result in abortion, stillbirth, or birth of seropositive offspring. The control of bovine neosporosis is difficult and costly. The objectives of this study were to estimate the current nationwide seroprevalence of N. caninum infections in Swiss cattle and to assess risk factors for infection with this parasite.

METHODS

We conducted a cross-sectional study with cattle farms randomly selected and stratified according to population size, resulting in a sample of 780 female cattle. The cattle originated from 161 farms distributed over all Switzerland. The serum samples were tested for antibodies against N. caninum using a commercial ELISA and if inconclusive, retested using an in-house immunoblot technique. To collect farm parameters relevant to N. caninum transmission and prevention, farm owners were mailed a questionnaire which addressed topics putatively related to N. caninum infection such as husbandry, history of abortion, and presence of dogs on farm. Univariate analysis by generalized linear mixed model (with animal seropositivity as outcome variable) and logistic regression modeling (with farm seropositivity as outcome variable) was conducted on farm parameters investigated in the questionnaire.

RESULTS

By ELISA and immunoblot, 4.2% (33/780) of cattle sera yielded positive results. At the farm level, 16.2% (26/161) of the sampled farms had at least one seropositive animal. The return rate of the valid questionnaires was 54.0%. At the animal level, odds for farm seropositivity were 3.8 times higher when rodents had been recorded by the farmer as a problem on the farm. At the farm-level, two protective factors were identified: rearing of replacement heifers and feeding of concentrated feed.

CONCLUSION

We recorded a low seroprevalence of N. caninum in a random sample of Swiss cattle representative for the years 2017-2018. Based on a questionnaire survey, we could identify risk and protective factors for infection with N. caninum, however their biological relevance needs to be confirmed in further studies.