The objectives were to investigate the effect of 3 navel dips on (1) umbilical infection, (2) health events (pneumonia, diarrhea, and arthritis), and (3) average daily gain (ADG) in newborn dairy calves. A secondary aim was to compare the agreement of standardized ultrasonographic examination with clinical examination for the diagnosis of umbilical infection. In a randomized block design, newborn calves were assigned by birth order to 3 treatment groups: Navel Guard (NG; SCG-Solutions Inc., McDonough, GA), 7% iodine tincture (SI), and 2% chlorhexidine gluconate (CH). Treatment consisted of a single dip administration of the umbilicus immediately after removal of the newborn from the calving pen with 1 of the 3 navel dips. Weekly clinical examinations were carried out during the first 4wk of life with special attention being paid to the umbilicus, joints, respiratory tract, and fecal consistency, and included ultrasonographic evaluation of the umbilical structures. Body weight was assessed by using a girth tape at first and last evaluation. Multivariable logistic regression demonstrated no statistical differences in umbilical infection or health events. Multivariable linear regression analysis showed statistical differences in ADG (least squares means ± standard errors) between groups, with 494±29, 571±29, and 516±29g/d in groups NG, SI, and CH, respectively. Overall mortality during the study period was 9.5% (n=40). Postmortem examination identified diarrhea (80%) as the main disorder with 19, 4, and 9 calves in groups NG, SI, and CH, respectively. Kappa values yielded fair [0.30 (95% CI: -0.03-0.63)], good [0.61 (95% CI 0.46-0.75)], moderate [0.53 (95% CI 0.31-0.74)], and moderate [0.49 (95% CI 0.19-0.79)] agreement for detection of omphalitis between clinical and ultrasonographic evaluation in wk 1, 2, 3, and 4, respectively. Agreement was very good for detection of omphaloplebitis, with kappa values (95% CI) of 0.91 (0.80-1.00), 0.87 (0.75-0.98), and 0.90 (0.76-1.00) in wk 2, 3, and 4, respectively, when omphalophlebitis was diagnosed. We detected no difference in the effectiveness of the 3 treatments in the prevention of umbilical infection, pneumonia, diarrhea, or arthritis.

Infections with pathogenic bacteria entering the mammary gland through the teat canal are the most common cause of mastitis in dairy cows; therefore, sustaining the integrity of the teat canal and its adjacent tissues is critical to resist infection. The ability to monitor teat tissue condition is a key prerequisite for udder health management in dairy cows. However, to date, routine assessment of teat condition is limited to cow-side visual inspection, making the evaluation a time-consuming and expensive process. Here, we demonstrate a digital teat-end condition assessment by way of deep learning. A total of 398 digital images from dairy cows' udders were collected on 2 commercial farms using a digital camera. The degree of teat-end hyperkeratosis was scored using a 4-point scale. A deep learning network from a transfer learning approach (GoogLeNet; Google Inc., Mountain View, CA) was developed to predict the teat-end condition from the digital images. Teat-end images were split into training (70%) and validation (15%) data sets to develop the network, and then evaluated on the remaining test (15%) data set. The areas under the receiver operator characteristic curves on the test data set for classification scores of normal, smooth, rough, and very rough were 0.778 (0.716-0.833), 0.542 (0.459-0.608), 0.863 (0.788-0.906), and 0.920 (0.803-0.986), respectively. We found that image-based teat-end scoring by way of deep learning is possible and, coupled with improvements in image acquisition and processing, this method can be used to assess teat-end condition in a systematic and efficient manner.

The objectives were to study the effect of 2 different automatic cluster remover settings on (1) milking characteristics, (2) milk component yields, (3) teat tissue condition, and (4) udder health. In a randomized controlled field trial, Holstein cows (n = 689) from 1 commercial dairy farm with a thrice-daily milking schedule were allocated to 2 treatment groups. Treatment consisted of a cluster remover take-off milk flow threshold of 1.2 (ACR1.2) or 0.8 kg/min (ACR0.8) for 57 d. Milking characteristics (milk yield; and milking unit-on time, MUOT) were obtained with electronic on-farm milk meters. Composite milk samples were collected and analyzed for fat, protein, lactose, and somatic cell count. Machine-milking-induced short- and long-term changes to the teat tissue condition were assessed visually. General linear mixed models demonstrated differences in MUOT, whereas no meaningful differences in milk yield were detected. Milk yield (least squares means, 95% confidence interval) was 11.3 (10.9-11.8) and 11.3 (10.8-11.8) kg in groups ACR1.2 and ACR0.8, respectively. The effect of treatment on MUOT was modified by parity. Milking unit-on time in first-, second-, and ≥third-lactation cows, respectively, was 260.7 (252.0-269.4), 257.8 (247.4-268.1), and 260.2 (252.6-267.9) s in group ACR1.2; and 273.7 (264.9-282.5), 279.1 (269.4-288.8), and 295.7 (287.9-303.6) s in group ACR0.8. We detected no meaningful differences in milk component yields or linear somatic cell score. Least squares means in groups ACR1.2 and ACR0.8, respectively, were milk fat yield, 0.42 (0.40-0.44) and 0.42 (0.40-0.44) kg; milk protein yield, 0.36 (0.35-0.37) and 0.37 (0.36-0.37) kg; milk lactose yield, 0.61 (0.60-0.63) and 0.63 (0.61-0.64) kg, and linear somatic cell score, 1.9 (1.8-2.0) and 1.9 (1.8-2.0). A generalized linear mixed model revealed an effect of treatment on machine-milking-induced short-term changes. The odds of short-term changes to the teat tissue were lower for cows in group ACR1.2 [odds ratio (95% confidence interval) = 0.78 (0.63-0.96)]. No meaningful differences were detected in machine-milking-induced long-term changes between treatment groups. Increasing cluster remover take-off milk flow threshold from 0.8 to 1.2 kg/min decreased individual milking duration and alleviated machine-milking-induced short-term changes to the teat tissue without adversely affecting milking performance or somatic cell count. Future studies are warranted to investigate the effect on milk production and udder health over a whole lactation period.

The objectives were to study the effect of 2 different premilking stimulation regimens, with and without manual forestripping, on teat tissue condition and milking characteristics in dairy cows. In a randomized controlled crossover study, 130 Holstein cows milked 3 times daily were assigned to treatment and control groups. Premilking udder preparation for the treatment group consisted of: (1) predipping with 1% iodine, (2) sequential forestripping of 3 streams of milk per quarter, (3) wiping of teats, and (4) attachment of the milking unit. Premilking udder preparation for the control group was identical except that the forestripping step was omitted. The mean tactile stimulation durations were 16 s and 7 s for the treatment and control group, respectively. The time spent from first tactile stimulus (either forestripping or wiping of teats) to milking unit attachment was kept consistent at 90 s for both groups. The study lasted for 14 d with 2 periods, each consisting of a 2-d adjustment time followed by 5 d of data collection. Machine milking-induced short-term changes to the teat tissue were assessed by palpation and visually. The following milking characteristics were assessed with electronic on-farm milk meters: milk yield (MY), milking unit-on time (MUOT), 2-min MY (2MIN), and time spent in low milk flow rate (LMF). Generalized linear mixed models were used to describe the effect of treatment on the outcome variables. The odds of machine milking-induced short-term changes to the teat tissue were lower for cows that received forestripping compared with cows that were not forestripped (odds ratio = 0.31; 95% confidence interval = 0.22-0.42). Least squares means (95% confidence interval) for cows that were forestripped and animals that were not forestripped, respectively, were 12.7 (12.2-13.2) and 12.7 (12.2-13.2) kg for MY and 6.1 (5.8-6.4) and 5.6 (5.3-5.9) kg for 2MIN. There was an interaction between treatment and MY for LMF. Time spent in LMF for cows that were forestripped and received no forestripping, respectively, were 18 (17-20) and 24 (23-26) s for a MY level of 10 kg; and 13 (12-14) and 15 (14-16) s for a MY level of 15 kg. The effect of treatment on MUOT was modified by parity. Milking unit-on times for animals in first, second and third or greater lactation, respectively, were 230 (219-243), 249 (236-262), and 260 (249-272) s for cows that were forestripped, and 245 (232-258), 252 (239-266), and 268 (257-281) s for cows that received no forestripping. In this study, cows that were forestripped had shorter MUOT, higher 2MIN, lower LMF, and lower odds of exhibiting changes to the teat tissue after machine milking. We conclude that wiping of teats during premilking udder preparation alone and omitting forestripping of teats without compensating for the loss in stimulation time may not provide sufficient tactile stimulation to elicit the cows' maximum physiological milk-ejection capacity. This can aggravate the adverse effects of vacuum-induced forces on teat tissue during machine milking, diminish animal well-being, and possibly affect udder health.

On-farm culture (OFC) systems facilitate pathogen-based mastitis management and can facilitate antimicrobial stewardship on dairy farms. Interpretation of the results, however, may present a challenge for those with limited microbiology experience. Here, we compared results of 3 OFC systems interpreted by trained and untrained observers against results of a standard laboratory reference method (aerobic culture and mass spectrometry). Milk samples (280 quarter and 60 composite) were selected from submissions for routine diagnostic testing to Quality Milk Production Services (Cornell University, Ithaca, NY) between August 2017 and January 2018. Samples were cultured simultaneously using the standard laboratory reference method and 3 commercially available OFC systems that varied in detail of pathogen identification (provided in parentheses) as follows: (1) Minnesota Easy Culture System II Bi-plate (University of Minnesota Laboratory for Udder Health, St. Paul; gram-positive, gram-negative), (2) Minnesota Easy Culture System II Tri-plate (gram-positive, gram-negative, some genus level), and (3) FERA Diagnostics and Biologicals AccuMast plate (Ithaca, NY; genus level, some species level). After 18 to 24 h of incubation, OFC plates were interpreted by 1 trained observer (>10 yr of experience in milk microbiology) and 6 untrained observers with no previous milk microbiology training, using only the manufacturers' instructions for guidance. Strength of agreement (κ) between observer groups and the reference method was determined for the available outcomes of each system. Interpreted by the trained observer, agreement was moderate for identifying gram-positive organisms (Bi-plate, κ = 0.56) and substantial for Streptococcus spp. (Tri-plate, κ = 0.64, AccuMast κ = 0.61). Interpretation by untrained observers resulted in fair agreement (κ = 0.29-0.37) for these organisms. Moderate agreement (κ = 0.43-0.59) was found across all 3 OFC for the identification of gram-negative organisms (Bi-plate), non-aureus staphylococci (Tri-plate and AccuMast), Lactococcus spp., and Enterococcus spp. (AccuMast) when interpreted by the trained observer, and fair to moderate agreement was found (κ = 0.31-0.53) among untrained observers. Across all 3 OFC, agreement was almost perfect (κ = 0.80-0.89) for Staphylococcus aureus for the trained observer, and moderate to substantial (κ = 0.56-0.61) for untrained observers. We concluded that all 3 OFC appeared suitable to support pathogen-based mastitis management when operated by trained observers. Training beyond the instruction manual is a prerequisite to make OFC systems useful for pathogen-based mastitis management.

Changes in teat canal diameter as induced by machine milking are thought to be related to teat canal penetrability and susceptibility to new intramammary infections. The objective of this study was to describe the effects of machine milking on teat canal dimensions as assessed by ultrasonography and to evaluate postmilking changes of teat canal dimensions throughout an 8-h milking interval. Ultrasonographic images were taken of the left front and right hind teats of 80 Holstein cows milked 3 times per day. Imaging occurred before attachment of the milking unit after completion of premilking udder preparation (t-1), immediately after removal of the milking unit (t0), and then every hour after milking until 8 h had elapsed (t1 to t8). Teat canal length and teat canal diameter (at the proximal, middle, and distal regions) were measured. General linear mixed model analysis indicated differences in the relative change of teat canal length (compared with t-1) with least squares means (LSM) and 95% confidence interval (95% CI) of 11.1% (8.7-13.4%) after machine milking (t0). Teat canal length decreased throughout the 8-h milking interval but remained elevated relative to t-1. Teat canal diameter at the proximal and middle regions increased near the end of the milking interval, whereas that at the distal region did not change meaningfully during the 8 h of observation. Our findings suggest that the teat canal and its surrounding tissue is in a state of near-constant remodeling in cows milked 3 times daily. Future work is warranted to study the association between ultrasonographically assessed changes of teat canal dimensions after machine milking and teat canal penetrability to mastitis-causing pathogens.