Milk Loss Research Articles

The economic cost of bovine trypanosomosis in pastoral and ago pastoral communities surrounding Murchision Falls National park, Buliisa district, Uganda

Background:Animal diseases that are endemic like tsetse transmitted trypanosomosis cause the continuous expenditure of financial resources of livestock farmers and loss of productivity of livestock. Estimating the cost of controlling animal trypanosomosis can provide evidence for priority setting and targeting cost-effective control strategies.Methodology:A cross-sectional survey to estimate the economic cost of bovine trypanosomosis was conducted in cattle-keeping communities living around Murchision falls National Park, in Buliisa district Uganda. Data was collected on herd structure, the cost of treatment and control, prevalence of morbidity and mortality rates due to trypanosomosis, and salvage sales losses in cattle herds in the last year.Results:In this study, 55.4% (n = 87) of the households reported their cattle had been affected by trypanosomosis during the previous last year. There was a high economic cost of trypanosomosis (USD 653) per household in cattle-keeping communities in Buliisa district of which 83% and 9% were due to mortality and milk loss respectively/ High mortality loss was due to low investment in treatment. The study showed that prophylactic treatment 3 times a year of the whole herd of cattle using Samorin ® (Isometamidium chloride) at a cost of USD 110 could drastically reduce cattle mortality loss due to trypanosomosis due to trypanosomosis with a return on investment of USD 540 annually per herd. This could be coupled with strategic restricted insecticide spraying of cattle with deltamethrin products.Conclusion:The results show a high economic cost of trypanosomosis in cattle-keeping communities in Buliisa district, with cattle mortality contributing the largest proportion of the economic cost. The high mortality loss was due to low investment in treatment of sick cattle.

Applications to Control the Estrus Cycle in Bovines via Estrus Synchronization: A Review

Estrus Synchronization is the main application of Assisted Reproductive Technologies (ART), it helps in the control of the estrus cycle with the basic help of Hormones and adds controlled Artificial Insemination, reduction in Calving interval which saves time, labor cost and effective dairy farm management. Moreover, old reproductive management is too expensive and it becomes the root of the loss of milk and meat production, it is also costly in case of labor, feed, estrus detection, long inter calving interval, postpartum estrus detection and other disease problems. To get rid of these expensive traditional practices ART has developed many methods to control estrus cycle physiology and endocrinology. Estrus synchronization tools developed in recent breeding management of dairy herds in dairy industries have become an essential part of reproduction. Many of them rely on protocols that allow timed artificial insemination (TAI) to overcome the practical anomalies during estrus detection. Currently developed programs consist of protocols that are used for re-synchronization following first or consequent inseminations. Many programs include scheduled injections of Prostaglandin (PgF2α) and Gonadotropin-releasing hormone (GnRH). Meanwhile, progesterone and estradiol based supplements are also required in many techniques. The main program used for synchronization is "Ovsynch" protocol. Moreover, this review is based on the introduction, history, principles, factors and methods of estrus synchronization that are mostly used for profitable dairy farming, it will assist in the understanding of the basic mechanism that is involved in the control of estrus cycle.

Use of a nonlinear model to estimate milk losses due to subclinical mastitis in Holstein-Zebu cows.

The objective of this observational study was to estimate milk loss from subclinical mastitis (SCM) using a nonlinear one-phase exponential decay function fitted to the relationship between the sum of the California mastitis test scores of productive quarters (x1, 0 to 16) and daily milk production per cow (y, kg/day). The function was y = (a - b)e-c1*x1 + b, where a is the predicted y when x is zero, b is the y when x1 tends to infinity, and c1 is a rate constant. The fitted function was y = (10.02 - 5.76)e-0.06137*x1 + 5.76, with an adjusted coefficient of determination (R2adj) of 0.0692, a standard deviation of the residual (Sy.x) equal to 13.49, and an Akaike's information criterion corrected (AICC) of 3902.8. To this function, we added the multiplicative factors test day (x2, 1 to 12), the number of productive quarters (x3, 2, 3 or 4), months of age of cow (x4, 25 to 209), and days in milk (x5, 2 to 196), to adjust the decay function for their effects. The fitted model was y = [(9.65 - 3.95)e-0.03415*x1 + 3.95] (x2-0.1081) (x30.1049) (x40.1589) (x5-0.1972) with R2 of 0.3166, Sy.x = 11.38, and AICC = 3821.9. We used the adjusted decay function parameters to compute a conversion factor (CF, 0 to 1) each x1 integer value from 0 to 16 to project its actual y to that of an SCM-free udder (x = 0). Then, the CF for a x1 of 0 equals to 9.65/9.65 = 1, and for a x1 of 8 equals 8.28, so its CF would be 8.29/9.65 = 0.8588. A cow with a 5.5kg/day milk production at an x1 score of 8 would have an SCM-free production of 5.5/0.8588 = 6.4kg/day, and its daily milk loss would be 6.4-5.5 = 0.9kg/day. The difference, multiplied by MX$ 5.50 (US$ 0.275), would result in an economic loss of 4.95 Mexican pesos per day. This procedure makes possible the timely on-site estimation of economic losses due to subclinical mastitis.

39. Milk losses due to mastitis in Holstein dairy cows: a modeling approach

39. Milk losses due to mastitis in Holstein dairy cows: a modeling approach

Feed efficiency of lactating Holstein cows is repeatable within diet but less reproducible when changing dietary starch and forage concentrations

Improving feed efficiency has become an important target for dairy farmers to produce more milk with fewer feed resources. With decreasing availability of arable land to produce feeds that are edible for human consumption, it will be important to increase the proportion of feeds in the diets for dairy cattle that are less edible for human consumption. The current research analyzed the ability of lactating dairy cows to maintain their feed efficiency when switching between a high starch diet (HS diet: 27% starch, 29% NDF, 47.1% forages on a DM basis) and a low starch diet (LS diet: 13% starch, 37% NDF, 66.4% forages on a DM basis). Sixty-two lactating Holstein cows (137 ± 23 days in milk (DIM) at the start of experiment), of which 29 were primiparous cows, were utilized in a crossover design with two 70-d experimental periods, including a 14-d adaption period for each. Feed efficiency was estimated as the individual deviation from the population average intercept in a mixed model predicting DM intake (DMI) with net energy in milk, maintenance and BW gain and loss. Repeatability was estimated within each diet by comparing feed efficiency estimated over the first 28-day period and the second 28-day period within each diet, using Pearson’s and intraclass correlations, and the estimation of error of repeatability. Similarly, reproducibility was estimated by comparing the second 28-day period of one diet with the first 28-day period of the other diet. Feed efficiency was less reproducible across diets than repeatable within the same diet. This was shown by lower intraclass correlations (0.399) across diets compared to that in the HS diet (0.587) and LS diet (0.806), as well as a lower Pearson’s correlation coefficient (0.418) across diets compared to that in the HS diet (0.630) and LS diet (0.809). In addition, the estimation of error of repeatability was higher (0.830 kg DM/d) across diets compared to that in the HS diet (0.761 kg DM/d) and LS diet (0.504 kg DM/d). This means that the feed efficiency of dairy cows is more likely to change after a diet change than over subsequent lactation stages. Other determinants, such as digestive processes, need to be further investigated to determine its effects on estimating feed efficiency.

Removal of antibiotics from milk via ozonation in a vortex reactor

Antibiotics (ABX) residues occur frequently in milk, causing considerable wastage of medicated milk and serious economic losses, and making the issue a burden for the dairy industry. Improper disposal of medicated milk harms dairy production, animal welfare, and the environment. This work studies the use of ozonation in a vortex reactor for removing ceftiofur hydrochloride (CEF), sulfamonomethoxine sodium (SMM), marbofloxacin (MAR) and oxytetracycline (OTC) from milk. In terms of residual concentration, O3 efficiency and the degradation kinetics of the various O3-involving processes in the vortex reactor, ABX removal via ozonation is better using stronger vortexing, which induces hydrodynamic cavitation. CEF undergoes the fastest degradation, followed by SMM, MAR, and OTC. High ABX hydrophobicity favors ABX degradation via ozonation, O3/H2O2, and O3/Na2S2O8. ABX oxidation by •OH at the O3 gas-bubble/milk interface is the principle degradation pathway, except for MAR. ABX degradation follows pseudo-first-order kinetics and is affected by initial ABX concentration, O3 concentration/flow rate, reaction temperature, and milk components to varying degrees. Under optimal ozonation conditions, ABX residues meet the maximum limits as set by the European Commission and no antimicrobial activity was observed. The decontaminated milk was therefore suggested to be reused as calf food, animal feed, organic fertilizer, etc.

Impact of summer cooling management on milk water footprint in dairy cows

The Water footprint (WF) is an indicator of the amount of direct and indirect freshwater used to make a product available, measured over its entire supply chain.Dairy cows are cooled using sprinklers and fans to mitigate heat stress (HS) in summer. Although several studies have already evaluated cows’ milk WF, little information is available on the impact of water sprayed to cool cows on milk WF and fans related energy consumption.The study enrolled six Holstein-Friesian farms equipped with cooling systems, including sprinklers and fans. Based on the volume of water sprayed to cool cows, farms were classified as Low User Spraying Water (Low-USW) and Large-User Spraying Water (Large- USW). For each farm, an alternative no-cooling scenario was modelled considering the water and energy saved, the increment of the drinking water needed from no-cooled cows, and the reduction of milk yield caused by HS.The mean annual WF of the farms involved in the study accounted for 805 ± 225 L water per kg of Fat and Protein Corrected Milk (FPCM) with the following distribution among the green, blue and grey fractions: 67.9%, 21.1%, and 11%, respectively. Cooling operations had a low incidence (0.04%) on the overall milk WF, which was 1.1% lower (8.6 L water kg−1 FPCM−1) than that modelled for the alternative no-cooling scenarios.Although both investigated cooling protocols (Large vs Low) showed a similar capacity to contain milk losses during summer, the study has highlighted differences in their resource use. Compared to the Large-USW, the Low-USW cooling management reduces water use by about 0.4 L water kg−1 FPCM−1 and increases energy consumption by about 0.13 kWh kg−1 FPCM−1.Cooling systems help farmers to mitigate HS in dairy cows during summer. The extra water needed for cooling is compensated by the effects of cooling in limiting the HS-related decline in milk yield. Therefore, the water used to cool cattle does not impact milk's WF. However, further research is needed to find the best solution for sprinklers and fans utilization, optimizing the preservation of animal welfare and environmental sustainability of milk production under climate change scenarios.

The effects of heat stress on milk production and the grazing behavior of dairy Holstein cows milked by an automatic milking system.

The objective of the present study was to evaluate the productive performance and grazing behavior of 25 primiparous and 44 multiparous Holstein cows in a pasture-based automatic milking system (AMS) while experiencing heat stress (defined as a temperature-humidity index [THI] ≥ 68). Productive traits were analyzed according to the THI from days 0, -1, -2, and -3 in relation to the milking day, and grazing behaviors (expressed as the percentage of daily observation time) were related to the average THI only on the day of observation. Milk yield was not associated with the THI on day 0, but a significant linear relationship was found with the THI on the three previous days, decreasing approximately 0.18 kg (primiparous) and 0.40 kg (multiparous) per THI unit increment. In contrast, for multiparous cows only, the milking frequency was positively associated with the THI on the day of evaluation but not on the previous days, increasing 0.01 milking/THI unit increments. Additionally, for each unit of THI increment, cows spent 0.14% more time standing, whereas they exhibited a decrease in grazing, lying, and ruminating behaviors time by 0.30%, 0.04%, and 0.70%, respectively, for both parities. In conclusion, milk loss was related to heat stress conditions from the previous days, but not milking frequency, which increased with the THI of the same milking day. Lower grazing, lying, and ruminating activities and greater standing behavior were observed due to heat stress.

Evaluation of Control Program Against Streptococcus agalactiae Infection in Dairy Herds During 2019-2021 in Emilia-Romagna Region, Northern Italy.

Streptococcus agalactiae (group B Streptococcus, GBS) is a causative agent of mastitis in dairy cattle, mainly causing a subclinical disease associated with a high somatic cell count (SCC), and a consequent decrease in production yield and quality of milk. GBS has been almost eradicated in many Northern European countries, but there are warnings of its re-emergence as a zoonotic threat. In Italy, only two regions carry out a GBS control program: Lombardy and Emilia-Romagna. In Emilia-Romagna, the program has been in place since 2019 and provides for the bacteriological culture of bulk-tank milk (BTM) of all dairy farms every 6 months and the voluntary application of herd eradication programs in the case of positive results. To assess the progress of the program in Emilia Romagna, in terms of herd-level prevalence and GBS transmission between herds, we analyzed the results of 17,056 BTM cultures from 2,831 dairy herds, sampled bi-annually in the period 2019–2021 (six rounds total). The impact of GBS infection on SCC and milk production was also evaluated. The results show a decreasing trend in both the incidence rate (from 3.0 to 1.5%) and apparent prevalence (from 8.9 to 5.2%) of GBS over the study period. By using a susceptible-infected-susceptible (SIS) model for the estimation of the transmission parameters, a basic reproductive number R0 of 1.4 was calculated, indicating an active spread of GBS in the dairy cattle population of the Emilia-Romagna region. GBS infected farms have a consistently higher BTM SCC than negative ones (+77,000 cells/ml), corresponding to a 0.4 kg/cow/day milk loss. Moreover, GBS infected herds resulted in almost three times more likelihood of having non-marketable milk by exceeding the legal SCC limit. This study demonstrates the need to maintain the current control program against GBS to lower its occurrence and prevent significant market losses to farmers.

Analysis of Epidemiological and Economic Impact of Foot-and-Mouth Disease Outbreaks in Four District Areas in Thailand.

Foot and mouth disease (FMD) is one of the most important infectious animal diseases impacting livestock production in Thailand. Despite a national vaccination program, FMD outbreaks are reported every year. We studied the epidemiological impacts of FMD outbreaks in four districts of Thailand between 2015 and 2016. Epidemiological data were collected from 193 FMD-affected dairy farms, 55 FMD-affected beef farms, and 25 FMD-affected pig farms. A significant difference in morbidity rates were observed between the dairy farms in the different areas, which could be explained by the differences in FMD outbreak management in each area. The morbidity rates in dairy and beef cattle also significantly differed between each animal age category, with the lowest morbidity rate observed in calves. Remarkably, vaccination was not significantly associated with the morbidity rate. In addition, the economic impact of FMD was calculated for 60 dairy farms in Muak Lek district. The economic losses were determined as the sum of milk production loss, mortality loss, additional labor costs, and veterinary service and medical costs, which averaged 56 USD per animal on the farm (ranging from 2 to 377 USD). Milk loss had the largest economic impact, although it varied substantially between farms. The farm size and outbreak duration were significantly associated with the total economic losses per farm. These results affirm the substantial epidemiological and economic impact of FMD on farms in Thailand, emphasizing the importance of FMD control.

Advantages and Challenges of Differential Immune Cell Count Determination in Blood and Milk for Monitoring the Health and Well-Being of Dairy Cows

A key challenge of the 21st century will be to provide the growing world population with a sustainable and secure supply of food. Consequently, the dairy farming’s primary task is to lower milk losses and other inefficiencies associated with diseased cows. Moreover, a shift from curative to preventive health management would be desirable for mastitis and a wide variety of other infectious and non-infectious cattle diseases, some of which are known to have profound negative effects on the performance and well-being of cows. Differential cell counting (DCC), a procedure that aims to determine the proportions of different somatic cell types in raw milk samples, has not only the potential to optimize mastitis diagnostics, but it could furthermore serve as a diagnostic tool for monitoring the general and overall health status of dairy cows. Based on a broad search of the literature, the practical utility of various types of DCC is summarized and discussed in this review. Since it might be of advantage to interpret DCC with the aid of data from studies in humans, differences between the immune systems of humans and dairy cattle, with a special focus on surface marker expression profiles and γδ (gamma delta) T-cell characteristics, are also described.

The Occurrence of a Negative Energy Balance in Holstein-Friesian and Simmental Cows and Its Association with the Time of Resumption of Reproductive Activity.

Intensive lactation (lactogenesis) in cows is conducive to a negative energy balance (NEB), so the search for traits associated with the physiological capacity to cope with its consequences is a current area of research. This is especially important because NEB overlaps with the resumption of the reproductive cycle, which determines the profitability of herds. This study analysed the relationship between NEB and the time of resumption of reproductive activity in cows with varying genetic potential (Simmental and Holstein-Friesian), fed a similar diet (TMR). The aim of the study was to analyse the dependencies between NEB markers and changes in progesterone levels between 25 and 31 days postpartum. A strong positive correlation was shown between daily milk production (DMP) and loss of body condition (LBCS; 0.772; p ≤ 0.05). These parameters were associated with the levels of NEB biomarkers. Higher values of NEB indicators (LBCS, C16:0, C18:1, NEFA, and BHBA) were usually noted during periods with higher DMP (II and III). The trends observed were confirmed by positive correlation coefficients (r), which ranged from 0.324 to 0.810 (p ≤ 0.05). The reverse trend was noted for glucose and leptin, which decreased as productivity increased, as confirmed by r values from −0.368 to −0.530 (p ≤ 0.05). In both breeds, the glucose and leptin levels decreased as DMP increased. Higher values for NEB indicators were shown to be negatively correlated with progesterone levels (r from −0.300 to −0.712; p ≤ 0.05), and a lower progesterone level was associated with a longer calving-to-first-service interval and calving-to-conception interval. The rate of postpartum triglyceride release depends on daily milk production, and therefore the adaptability of the liver should be considered an important element of mitigation of the consequences of NEB. This may have practical applications by extending productive life, which is often shortened due to deteriorating reproductive performance.

Investigation of the prevalence of enzootic bovine leukosis in cattle in Ardahan region

Enzootic bovine leucosis (EBL) is a retroviral infection which is common all over the world. EBL causes huge economic losses due to milk loss, yield loss and death. In this study, it was aimed to investigate the presence of EBL by ELISA method from blood samples taken from cattle which were determined to be healthy because of clinical examination in Ardahan province and its counties in March-April 2021. For this, 500 cattle of different breeds and sexes between 1-10 years of age in different enterprises were sampled and the antibody response against EBL in the blood serum samples obtained was investigated with a commercial ELISA test kit. All 500 blood serum samples tested by ELISA were negative for EBL. As a result, EBL seropositivity was determined as 0% in Ardahan region as the studied area and time period.

Vulnerability assessments in dairy cattle farms based on individual sensitivity to heat stress.

Climate change (CC) is expected to increase temperatures and the frequency of extreme weather events, which renewed interest in heat stress (HS) effects on dairy cattle farms. Resilience is a key concept that should be considered to better understand the dairy farms exposure to HS and to combat CC-related risks. Thus, this study aimed to investigate the aspects of HS vulnerability for Tunisian dairy cattle farming systems. Historical milk test-day records from official milk recording were merged with temperature and humidity data provided by public weather stations. Firstly, different models relying in two heat load indices were applied for HS exposure assessment. Secondly, broken line models were used to estimate HS thresholds, milk losses, and rates of decline of milk production associated with temperature-humidity index (THI) across parities. Thirdly, individual cow responses to HS estimated using random regression model were considered as key measures of dairy farming system sensitivity assessment to HS. Dairy farms are annually exposed for 5months to high THI values above 72 in Tunisia. The tipping points, at which milk yield started to decline over parities with 3-day average THI, ranged between 65 and 67. The largest milk decline per unit of THI above threshold values was 0.135 ± 0.01kg for multiparous cows. The milk losses estimated due to HS in the Holstein breed during the summer period (June to August) ranged between 110 and 142kg/cow in north and south, respectively. A high HS sensitivity was proved especially in dairy farms characterized by large herd size and high milk production level. Hence, providing knowledge of dairy farms vulnerability to HS may provide the basis for developing strategies to reduce HS effects and plan for CC adaptation.

Prevalence and associated factors of gastrointestinal helminthiasis of lactating cow and effect of strategic deworming on milk quantity, fat, and protein in Kucha, Ethiopia

BackgroundGastrointestinal helminthiasis poses economic impacts on the dairy sector by reducing milk production. This study aimed at estimating the prevalence of gastrointestinal helminthiasis, the burden of helminths, and appraising potential factors associated with the prevalence in lactating cows. The study was also designed to elucidate the effects of anthelmintic treatment on milk yield, milk fat, and protein content in the Kucha district.MethodsA cross-sectional and field clinical trial study designs were used. Standard parasitological techniques (floatation and sedimentation) were employed to detect cows’ infection status. McMaster and Stoll’s egg counting methods were used to estimate helminths' burden. All putative factors that might have been linked with infection were recorded by field observations and farmers' interviews. Sixty cows tested positive for the parasitic infection in the cross-sectional study design were randomly assigned into one of the two groups (dewormed Vs control). Milk yield, milk fat and protein contents were recorded in both groups on day zero and then on weekly basis. Descriptive statistics, binary logistic regression, and repeated measure ANOVA were used to analyze the data.ResultsOverall, of 422 examined cows, 150 (35.5%, 95% CI; 30.9-40.3%) were infected with at least one of the gastrointestinal helminth parasites. Strongyle nematode was the predominant type accounting for 52% of the total record. Analysis of fecal egg count (FEC) in infected cows depicts the highest record of Parampistomum egg, accounting 457.14 ± 275.45 Egg per gram (EPG) of feces. The prevalence of gastrointestinal helminthiasis in cow that had an average body condition score of 1.7 was over two fold higher (OR = 2.19, 95% CI = 1.17–4.17, P = 0.016) than in cows with 6.3 body condition score. A significant improvement in milk yield, milk fat, and milk protein was observed in dewormed cows over 28 days period.ConclusionGastrointestinal helminthiasis is threatening the welfare of lactating cows in Kucha, Ethiopia given its negative association with the body condition score. Gastrointestinal helminths are responsible for the reduction of milk yield and loss of milk fat and protein. However, an improvement in milk yield, milk fat, and milk protein after deworming using Tetrox® (Tetramisole and Oxyclozanide combination), a new drug to the area/ a drug used by relatively few farmers in the study area, proves the effectiveness of strategic deworming.

Identification of chronic stress biomarkers in dairy cows

Stress in dairy herds can occur from multiple sources. When stress becomes chronic because of a long duration and inability of animals to adapt, it is likely to deeply affect the emotional state, health, immunity, fertility and milk production of cows. While assessing chronic stress in herds would be beneficial, no real consensus has emerged from the literature regarding the indicators of interest. The goal of this study was to compare and evaluate potential biomarkers for chronic stress after inducing stress over a 4-week period through severe overstocking, restricted access to feed and isolated unusual events. A total of 30 cows were involved in the experiment and two similar groups were constituted. Over a 4-week period, the 15 cows of the stress group were housed in overstocked conditions, with 4.6 m2 per cow, including resting and feeding areas. In this area, only seven individual places at the feeding area were available for the 15 cows to generate competition for feed access. Twice during the trial and over a period of 2 h, an additional stress was induced by moving cows to an unfamiliar barn and diffusion of stressing noises (dog barking). Meanwhile, the 15 cows of the control group stayed in the original barn, with more than 10 m2 per cow and more individual places at the feeding area than cow number. On a weekly basis, several variables considered as potential biomarkers for chronic stress were recorded. Collected data were analysed using single trait linear repeated mixed models. No differences were observed regarding milk yield, BW of cows or body condition score but the milk loss was more pronounced in the stress group. The activity was more heterogeneous and the rumination of cows was lower in the stress group. The heart rate was lower in the stress group and showed more heterogeneity at the end of the stress period. No differences were observed regarding salivary cortisol, blood glucose, β-endorphin, thyroxine and leucocyte profile. A higher level of hair cortisol and blood fructosamine were observed in the stress group at the end of the stress period. Regarding the practical use of the highlighted biomarkers, milk loss may be an effective and easy way to detect general problems, including stress. The blood fructosamine and the hair cortisol concentrations are promising indicators to assess chronic stress in commercial farms.

Quantifying current and future raw milk losses due to bovine mastitis on European dairy farms under climate change scenarios

Bovine mastitis is an infectious disease that causes udder inflammation and is responsible for raw milk losses across European dairy farms. It is associated with reduced cow milk yield and contributes to elevated Somatic Cell Count (SCC) in raw milk. Staphylococcus aureus is one of the most prevalent mastitis pathogens that cause subclinical and clinical mastitis and can be present as a coloniser bacterium in cows. Climate change and geographical variability may influence the prevalence of this pathogen. Thus, this research aimed to predict the raw milk losses in three major dairy-producing regions across Europe (i.e. Mediterranean, Atlantic and Continental) under climate change scenarios. An exposure assessment model and a stepwise probabilistic model were developed to predict potential cow milk yield reduction, S. aureus and SCC concentrations in the bulk tank milk at dairy farms. Baseline (i.e. present) and future climate change scenarios were defined, and the resultant concentrations of SCC and S. aureus were compared to the actual European regulatory limits. Across the three regions, raw milk losses ranged from 1.06% to 2.15% in the baseline. However, they increased up to 3.21% in the climate change scenarios when no on-farm improvements were considered. Regarding geographical variation, the highest potential milk losses were reported for the Mediterranean and the lowest for the Continental region. Concerning the fulfilment of the regulatory limits, the mean of S. aureus and SCC levels in milk did not exceed them either in any region or scenario. Nevertheless, when looking at percentiles, the 10th percentile remained above the limits of S. aureus in Atlantic and Mediterranean, but not in the Continental region. The findings provide a snapshot of climate change impacts on raw milk losses due to mastitis. They will allow farmers to detect weaknesses and prepare them to develop adaptation plans to climate change.

Economics of reducing antibiotic usage for pathogen-specific clinical mastitis through genomic selection and disease management

The recent introduction of the mastitis resistance trait into the US genomic selection index, Lifetime Net Merit 2018 (NM$), is expected to reduce the incidence of pathogen-specific clinical mastitis (PS-CM) incidence in U.S. dairy herds. To maximize the herd performance by reducing the PS-CM incidence, we compared the herd performance of 6 different replacement selection and PS-CM disease management strategies. We used an agent-based dairy simulation model in which the performance of individual animals was affected by the genetic traits included in the NM$. The genetic trends for the sires used affected the 15 yr herd performance. Each animal had a daily underlying base probability of contracting 5 different types of PS-CM (Staphylococcus aureus, Streptococcus dysgalactiae, Strep. uberis, Escherichia coli and Klebsiella) during lactation. On top of this base probability, the genetic and environmental components of the mastitis resistance trait (MAST) determined the actual incidence of PS-CM. Genomic estimated breeding values were simulated for each animal, based on which replacement selection decisions were made. The PS-CM associated milk loss, increased somatic cell count, decreased conception, and increased mortality and culling were accounted for in the simulated genomic estimated breeding values of different correlated production and reproduction traits included in NM$. The 6 different strategies illustrate the effects of replacement selection and PS-CM management decisions on PS-CM incidence, herd antibiotic use (ABU) and herd economics, over the course of 15 yr. Due to the genetic gain in the MAST, the incidence of PS-CM decreased on average by 10% points in 15 yr, which trickled down to overall reduction in herd ABU. Our PS-CM treatment and prevention strategies were assumed to be based on precise information about the 5 different PS-CM causative pathogens. Hence the corresponding ABU further decreased over the course of 15 years, when compared to blanket PS-CM therapies, which used antibiotics for all cases of CM. Our strategies illustrated the fact that herds combining genomic selection and following precise treatment and prevention strategies for PS-CM could reduce the 15-year cumulative ABU against PS-CM significantly. Capitalizing on the genetic gain in NM$ traits, the average profit per cow per year was higher on average by $1209 in year 15 when compared to year 0 for the 6 strategies simulated. We concluded that three decision strategies (genomic selection for NM$, selective therapy for PS-CM, and selective dry cow therapy for PS-CM prevention) when combined can reduce the incidence of PS-CM and the associated ABU, while increasing the profitability of the herd.

The use of ozone in the treatment of bovine mastitis: Report case

Mastitis is defined as inflammation of the mammary gland and is characterized by causing significant alterations in the composition of milk and economic losses and endless perjuries to the dairy industry. For this reason, and in view of the growing demand for antibiotic-free and quality products for human consumption, alternatives are being sought for current broad-spectrum antibiotic-based mastitis treatments. Within this framework, this article aims to demonstrate through a case report the effectiveness of the use of ozonized solutions in the treatment of clinical mastitis in dairy cows. For which a cow that presented clinical mastitis in 2 quarts was treated, with an ozonated solution (10 ml of solution in total, 5 ml of ozonated sunflower oil plus 5 ml of ozonated physiological serum in a concentration of 12 mg/ml), this treatment was compared with a usual commercial antibiotic treatment (Masticine L). At the end of the treatments, a favorable change was perceived in terms of visible physical aspects in both treatments, the antibiotic having a better performance in this regard, however the treatment with ozonized solution had favorable effects in terms of milk composition, improving its quality and lowering treatment costs therefore the use of intramammary ozonated solutions is recommended for the treatment of clinical mastitis in dairy cows.

Estimating the nonlinear association of online somatic cell count, lactate dehydrogenase, and electrical conductivity with milk yield

Reduction of milk yield is one of the principal components in the cost of mastitis. However, past research into the association between milk yield and mastitis indicators is limited. Past research has not been based on online or in-line daily measurements and has not fully explored nonlinearity and the thresholds at which milk yield starts to decrease. In dairy herds with automated milking systems equipped with sensors, mastitis indicators of individual cows are measured on an intraday frequency, which provides unprecedented avenues to explore such effects in detail. The aim of this observational study was primarily to investigate the nonlinear associations of lactate dehydrogenase (LDH), electrical conductivity (EC), and somatic cell count (SCC) with milk yield at various stages of lactation, parity, and mastitis chronicity status (i.e., whether the cow had SCC ≥200,000 SCC/mL for the last 28 d). We also investigated thresholds at which mastitis indicators (LDH, EC, and SCC) started to be negatively associated with milk yield. We used data from 21 automated milking system herds measuring EC and online SCC. Of these herds, 7 of the 21 additionally measured online LDH. We operationalized milk yield as milk synthesis rate in kilograms per hour. Applying a generalized additive model, we estimated the milk synthesis rate as a function of the 3 mastitis indicators for 3 different subgroups based on parity, stage of lactation, and mastitis chronicity. Partial dependence plots of the mastitis indicators were used to evaluate the milk synthesis rate to study if the milk synthesis rate was associated with mastitis indicators at a specific level. Results showed that milk synthesis rate decreased with increasing SCC, LDH, and EC, but in a nonlinear fashion. The thresholds at which milk synthesis rate started to decrease were 2.5 LnSCC (12,000 SCC/mL) to 3.75 LnSCC (43,000 SCC/mL), 0 to 1 LnLDH (1-2.7 U/L), and 5.0 to 6.0 mS/cm for EC. Additionally, another substantial decrease of milk synthesis rate was observed at thresholds of 5.625 LnSCC (277,000 SCC/mL) and 3 LnLDH (20 LDH U/L) but not for EC. Having chronic mastitis decreased milk synthesis rate in all models. The identified nonlinearities between mastitis indicators and milk synthesis rate should be incorporated in statistical models for more accurate estimations of milk loss due to mastitis.