Effect of controlled-release monensin on automatically registered body condition score, milk ß-hydroxybutyrate, milk yield and milk lactate dehydrogenase in fresh dairy cows.

The aim of this study was to compare the effect of controlled-release monensin on the automatic registered body condition score (BCS), and biomarkers registered using a fully automated inline analyzer, such as milk ß-hydroxybutyrate (BHB), milk yield (MY) and milk lactate dehydrogenase (LDH). Two experimental groups were formed: (1) monensin group (GK) supplemented with monensin (a monensin controlled release capsule (MCRC) of 32.4 g, n = 42) and (2) control group (GO) (capsule containing no monensin, n = 42). Treatment began 21 days before calving, and the experiment was finished one month after calving. In order to gather data about MY, BHB, and LDH, Herd Navigator a real-time analyzer (Lattec I/S, Hillerød, Denmark) was used together with a DeLaval milking robot (DeLaval Inc., Tumba, Sweden). BCS was measured using 3D BCS cameras (DeLaval, DeLaval International AB). All data were registered at one, 15 and 30 days after calving. The statistical analysis was performed using SPSS 26.0 (SPSS Inc., Chicago, USA) package. It was concluded that in the group of cows with monensin supplement (a monensin controlled release capsule of 32.4 g,), the body condition score was statistically significantly higher at the 15th (+0.24, p=0.003) and 30th (+0.52, p⟨0.001) days after calving, the productivity of cows in this group increased by 10.25% from the 1st to the 15th day and by 22.49% from the beginning of the experiment to the 30th day (p⟨0.001), lactate dehydrogenase activities at the 15th and 30th days after calving in this group were lower (p⟨0.001), and also in this group, the number of cows with a value of ß-hydroxybutyrate of 0.06 mmol/L decreased from the beginning of the experiment to 30 days after calving by 4.70% (from 19.00% to 14.30%) compared with the control group.

Relationship between in-line milk progesterone before and after artificial insemination and fertility outcomes in dairy cows.

The aim of this study was to evaluate the possibility to predict outcomes of artificial insemi- nation (AI) in dairy cows based on in-line milk progesterone (P4) concentration. The research was carried out on the herd of loose housing 245 dairy cows of 2-4 lactations, with average milk yielding 11.000 kg per cow. Milk sampling, measuring, and recording of milk P4 concentration was carried out using the Herd Navigator (HN). The grouping was performed according to the following three indices: the first by reproductive condition - pregnant or not pregnant after AI, the second by P4 concentration from day 20 before AI to day 20 after AI, and the third by P4 concentration at AI time. There was a significant difference in P4 concentration in the group of pregnant cows from day 15 to day 9 before AI, and it was by 18.3% higher com- pared to that in the group of non-pregnant cows in the said period (p⟨0.01). The milk P4 concen- trations began to differ mostly from day 10 after AI. At that time, the average P4 concentration in the group of pregnant dairy cows was by 36.8% higher compared to that in the group of non-pregnant cows (p⟨0.01). A statistically significant difference between the ratio of the cows with high, medium, and low P4 concentration on days 20-16 before AI (p⟨0.01) was determined. The highest number of cows with up to 2-3 ng/ml P4 concentration became pregnant at the AI time. In-line milk P4 records captured on day 10-15 before AI can be used to predict the proper for reproduction period. By P4 concentrations on day10 after AI, the ratio of pregnant cows in herd can be assessed.

Evaluation of biomarkers of heat stress using automatic health monitoring system in dairy cows.

The aim of this study was to evaluate biomarkers of heat stress (HS) from an automatic milking system (AMS), the relationships between measurements of the temperature-humidity index (THI), reticulorumen pH and temperature, and some automatic milking systems parameters in dairy cows (rumination time (RT), milk traits, body weight (BW) and consumption of concentrate (CC)) during the summer period. Lithuanian Black and White dairy cows (n=365) were selected. The cows were milked with Lely Astronaut® A3 milking robots with free traffic. Biomarkers were collected from the Lely T4C management program for analysis. The pH and temperature of the contents of the cow reticulorumen were measured using specific Smax-tec boluses. The farm zone's daily humidity and air temperature were obtained from the adjacent weather station (2 km away). According to this study, during HS, the higher THI positively cor- relates with milk lactose (ML), which increases the risk of mastitis and decreases CC, RT, BW, MY, reticulorumen pH, and F/P. Some biomarkers of HS can be milk yield, milk lactose, somatic cell count, concentrate intake, rumination time, body weight, reticulorumen pH, and milk fat - protein ratio. We can recommend monitoring these parameters in the herd management program to identify the possibility of heat stress.

The influence of lameness on several automatic milking system variables and reproductive performance indicators in dairy cows.

There is an increased interest in using automatic milking systems (AMS) to indirectly assess the welfare of dairy cows, but knowledge on analyzing the association between lameness, milk yield characteristics, and reproductive performance in cows is still insufficient. The main aims of this study were to evaluate the influence of lameness on several AMS variables and reproduc- tive performance indicators during the early stage of lactation and estrus in Lithuanian Black and White dairy cows, as well as to assess the associations between lameness, productivity and repro- ductive efficiency. A total of 418 milking cows (50.3±1.2 d postpartum) without any apparent reproductive disorder were monitored for hoof health status. Cows were assigned to two groups on the basis of visual locomotion scoring: "non-lame"cows (group 1; 74.20%) and cows presen- ting "lameness" (lame cows) (group 2; 25.80%). Productive and milking performances of dairy cows were recorded from 50 to 100 days in milk (DIM) and 1 day after the first estrus. The lameness was predominantly localized on the hind feet (79.60%) and less frequently - on the front feet (20.40%; p⟨0.001). Furthermore, the lameness had a tendency to decrease milk production (4.24%; p⟨0.05) and increase the diffe- rence in milk yield between rear and front quarters of the udder (1.20%; p⟨0.05). The frequency of milking (5.19%) was lower in lame cows (p⟨0.05). The lame cows during estrus showed a more pronounced decrement in milk yield and milking frequency (p⟨0.05), and also higher milk progesterone concentration values (1.55-1.76 time's; p⟨0.001), and an increasing number of inseminations (11.69%; p⟨0.05) were observed. The results highlighted that analysis of data from AMS programs can be a successful tool for reducing risk factors related to the effective management of reproductive performance and hoof health of dairy cows.

Influence of season and breed on serum mineral levels in sheep.

The main objective of this study was to assess the concentration of various minerals (Ca, P, Mg, Cu, Zn, Fe) in the blood of sheep, followed by biochemical analysis in order to reveal possible associations of season and breed. The study was conducted by sampling four herds: Suffolk (n=20), Merino (n=20), Lithuanian blackhead (n=20) and Charolaise (n=7). The first blood collection was conducted in April and the last one was performed in February. The highest level of Ca was estimated in Suffolk ewes, lowest (12.61%) in Merino breed; the highest Mg content was found in Lithuanian blackhead breed, lowest (5.26%) in Charolaise; highest P content was determined in Merino, lowest (24.18%) in Suffolk breed (p⟨0.05). Evalua-tion of the biochemical parameters during different seasons showed a possible environmental effect on the health of the animals. The difference among minerals content showed the highest level in Ca, Mg, Fe in the autumn, P - in the summer, Cu and Zn - in the winter. The lowest differences between seasons were observed in content of Mg (1.24-4.03% from total average of all seasons) and Ca (0.59-8.18%), the highest - in Cu (2.52-18.36 %) and Zn (4.33-24.33%) (p⟨0.05). The significance of this work is the possible use of the data in the prevention of metabolic and production diseases.

Can reticulorumen ph, temperature and cow activity registered before calving act as biomarkers of diseases after calving?

The aim of this study was to determine if reticulorumen ph, temperature and cow activity registered before calving can serve as indicators of diseases after calving.The cows were selected according to those fitting the profile of having had two or more lactations (on average 2.9±0.13 lactations), from 60 to 0 days before and the first 30 days after calving, and being clinically healthy. The clinical examination (identification of diseases after calving) was performed from 60 days before calving to 60 days after calving. Diseases after calving were diagnosed based on clinical symptoms specific to these diseases. The pH and temperature of the contents of the cow reticulorumens and cow activity were measured using specific smaX-tec boluses manufactured for animal care.We found that the highest pH and temperature before calving can serve as biomarkers of healthy cows after calving. The lowest reticulum temperature before calving can serve as an indicator of MF after calving. A positive correlation of reticulum pH and temperature before calving can serve as biomarkers of PR. Decreasing cow activity before calving can serve as an indicator of diseases after calving. For calving prognosis, temperature of the reticulorumen can be used; it decreased 6-7 days before calving.

Inline changes in lactate dehydrogenase, milk concentration according to the stage and number of lactation periods, including the status of reproduction and milk yield in dairy cows.

The aim of the present study was to investigate inline lactate dehydrogenase (LDH) dynamic changes based on different cow factors - different number and stages of lactation, milk yield, and the status of reproduction in clinically healthy dairy cows. In the Herd Navigator system, LDH activity levels (µmol/min per litre) were measured using dry-stick technology. A total of 378 cows were selected. According to their reproductive status, the cows were classified as belonging to the following groups: Fresh (1 - 44 days after calving); Open (45 - 65 days after calving); Inseminated (1 - 35 days after insemination); Pregnant (35 - 60 days after insemination and pregnant). According to their productivity, the cows were classified into the following groups: ⟨15 kg/day, 15 - 25 kg/day, 25 - 35 kg/day and >35 kg/day. The cows were milked with a DeLaval milking robot (DeLaval Inc. Tumba Sweden) in combination with a Herd Navigator analyser (Lattec I/S. Hillerød Denmark). In conclusion inline dynamic changes in the milk LDH concentration may increase together with the rise in the lactation period frequency. The highest LDH level determinated in the group of the fresh cows ranged from 5 to 10 DIM, while the highest LDH concentration level was found in the fresh cow milk. Thus, there was a positive relationship between the milk concentration of LDH and the milk yield.

Biomarkers from automatic milking system as an indicator of subclinical acidosis and subclinical ketosis in fresh dairy cows.

The objective of this study was to determine the association between subclinical acidosis (SARA) and subclinical ketosis (SCK) with biomarkers from an automatic milking system (AMS) measuring in relation to rumination time (RT), milk yield (MY), bodyweight (BW), milk temperature, the milk fat-to-protein ratio, and the electrical conductivity of milk at the udder quarters-level which can be read in fresh dairy cows. During the course of the study, all of the fresh dairy cows (n=711) were examined according to a general clinical investigation plan. The cows were selected for 1-30 days of milk (DIM) and were milked using Lely Astronaut® A3 milking robots with free traffic. Rumination time shows a statistically significant positive correlation with milk yield (milk temperature) and is negatively correlated with the fat and protein ratio. Healthy cows demonstrated the highest level of rumination time and the lowest milk temperature. The average BW for these cows was 1.64% lower than for the SARA group and the BW kg was 2.10% higher than SCK cows. MY was 14.01% lower in comparison with SARA and 6.42% higher in comparison with SCK. According to these results, some biomarkers from the AMS have an association with SARA and SCK. However, further research with a higher number of cows is needed to confirm this conclusion.

Rumination time as an indicator of stress in the first thirty days after calving.

The objectives of this study were to examine the option of being able to use rumination time (RT) as a form of stress indicator in the first thirty days after calving, and to determine the relationship between rumination time, blood cortisol levels, and lactate concentration levels in dairy cows during the first thirty days after calving. Ninety cows which produced milk (DIM) within 1-30 days were selected and categorised into the following groups: the first group (1) fell within 1-7 days after parturition (dpp) (n=30); the second group (2) fell within 8-14dpp (n=30); and the third group (3) fell within 15-30dpp (n=30) after calving. The cows were milked using Lely Astronaut® A3 milking robots with free traffic. The blood samples were tested using the fluorescence enzyme immunoassay method for cortisol analysis. Lactate concentrations were tested with a Lactate Pro2 ®. The RT increased during all of the exploratory periods (with readings between 1.12-4.90%). A decrease was also observed in the lactate levels (by 1.10 times) and cortisol levels (by 1.98 times, p⟨0.05) of cows which fell within the 8-14dpp group, when compared to an average of 1-7dpp in the previous study period (15-30dpp). However, lactate concentrations increased (by 1.84 times, p⟨0.05) as well as cortisol levels (by 2.09 times, p ⟨0.01) when compared with a figure between 8-14 dpp on the average. The results obtained indicate that, RT increased during all exploratory periods, while a decrease by 1.10 times and 1.98 times was observed in lactate levels and cortisol levels, respectively. During the entire period of the study RT was positively correlated with the lactate concentration levels, and negatively correlated with cortisol levels. Within a period of 1-14 days, a negative correlation was determined with lactate levels along with a 15-30dpp-positive correlation coefficient. In conclusion, RT can be used as a kind of stress indicator for cows in the first thirty days after calving; however, further research is required to ascertain this conclusion.

Can rumination time and some blood biochemical parameters be used as biomarkers for the diagnosis of subclinical acidosis and subclinical ketosis?

According to the past reports, the utility value of monitoring rumination time (RT) around the time at which calving takes place and, in particular, during the first week of lactation, is a way of identifying in a timely fashion those cows that are at a greater level of risk when it comes to developing disease in early lactation. Recent reports have focused on the role of minerals in disease resistance in ruminants, but little is known about the concentrations blood parameters in dairy cows with subclinical acidosis and subclinical clinical ketosis. According this we hypothesised that rumination time and some blood biochemical parameters (including cortisol and lactate) can serve as biomarkers for subclinical acidosis (SARA) and subclinical ketosis (SCK). Accordingly, the aim of the current study was to determinate the impact of subclinical acidosis and ketosis on rumination time and some blood biochemical parameters. For the current study, of a total of 225 fresh dairy cows (between one and sixty days after calving) a general clinical examination produced a selection of 93 cows: ten of these were diagnosed with SARA, thirteen had SCK and seventy were clinical healthy cows. Rumination time (RT), body weight (BW), and milk yield (MY) were registered with the help of Lely Astronaut® A3 milking robots. It was determining the concentrations of blood serum albumin (Alb), total protein levels (TP), glucose (Glu), urea (Urea), calcium (Ca), phosphor (Phos), iron (Fe), alaninaminotranspherase (ALT), aspartataminotranspherase (AST), Gammagliutamyltranspherase (GGT), and creatinine (Cre). RT decreases and blood lactate rates increase in cases of SARA and SKC, while in cases of SARA the total blood protein levels increased and in the SCK group it decreased.A similar trend of differences between the SARA group and the SCK group in terms of healthy cows could be found in changes in blood urea, glucose, Ca, Mg, P, and Fe. Cows in the SCK group showed statistically higher ALB content levels, while the activity of AST and Crea was at a lower level. According to this, rumination time, and some blood biochemical parameters can be used as biomarkers in the diagnosis ofsubclinical acidosis and ketosis. Future studies, however, are needed so that these results can be compared across a greater number of animals.

Evaluation of rumination time, subsequent yield, and milk trait changes dependent on the period of lactation and reproductive status of dairy cows.

The aim of this research was to determine rumination time (RT) and the subsequent milk yield, along with trait changes during lactation dependent on the reproductive status of dairy cows. 728 cows were selected for evaluation in regards to 1-150 days of milk production (DIM). According to their period of lactation and reproductive status, the cows were selected for the following groups: Inseminated (1-35 days after insemination, n=182), Open (45-90 days after calving, n=126), Fresh (1-44 days after calving, n=45); Not-pregnant (>35-60 days after inse- mination and not-pregnant, n=55); Pregnant (35-60 days after insemination and pregnant (n=320). The animals were milked with Lely Astronaut® A3 milking robots. The daily milk yield, rumination time, bodyweight, milk composition (fat, protein, lactose, somatic cell count and gynecological status date) were collected from the Lely T4C management program for analysis. We estimated the lowest productivity in the pregnant cows, where the average milk yield was 28.72 kg and the highest productivity in the fresh cow (p⟨0.001)(Table 1). The longest rumina- tion time was determined for the inseminated cows, statistically significantly higher at 9.92% (p⟨0.001) than in the non-pregnant cows, whose rumination time was the shortest. The statisti- cally reliably RT positively correlated with productivity (r=0.384, p⟨0.001) of the cows (from r=0.302 in the second lactation and r=0.471 in the first lactation to r=0.561 in multiparous cows; p0.001). Rumination time, according to groups of cows by milk yield, had a tendency to increase (2.14 times) from 202.0± 87.38 (in cows with a productivity of less than 10 kg milk) to 431.6±33.91 (in cows with a milk yield higher than 50 kg) by the linear regression equation: y = 38.02x + 232, R² = 0.721 (p⟨0.001). The relation between the gynecological status and milk fat-protein ratio of the cows was statistically significant (χ2=2.974, df= 8, p ⟨0.0001). The longest rumination time was determined for the inseminated cows (1 - 35 days after insemination), and the shortest for the not-pregnant cows (>35 - 60 days after insemination and not-pregnant). We can conclude that rumination time, subsequent yield, and milk trait change depends on the period of lactation and reproductive status of a dairy cow.

Changes in the real-time registration of milk ß-hydroxybutyrate according to stage and lactation number, milk yield, and status of reproduction in dairy cows.

This study investigated changes in the real-time measured levels of milk ß-hydroxybutyrate according milk yield, lactation number and status of reproduction in dairy cows. A total of 378 cows were selected. According to their reproductive status the cows were classified as belonging to the following groups: Fresh (1 - 44 days after calving. n=43). Open (45 - 65 days after calving. n=78), Inseminated (1 - 35 days after insemination. n=133). Pregnant (35 - 60 days after insemination and pregnant (relatively pregnant) (n=124). The cows were milked with DeLaval milking robot (DeLaval Inc., Tumba, Sweden) in combination with a Herd Navigator (Lattec I/S. Hillerød. Denmark) analyser. We observed that milk ß-hydroxybutyrate (BHB) had a tendency of increasing with an increase of lactation number. The average BHB in multiparous cows was 11.111% higher in com- parison with primiparous cows (p⟨0.001). We found higher BHB concentration in the multipa- rous cows in all reproduction status groups (p⟨0.001). A strong positive statistically significant (p⟨0.001) relationship has been found between BHB and the average milk yield within all groups of primiparous cows although we found a statistically unreliable coefficient of correlation (from -0.202 to 0.057) between highest milk yield and BHB in primiparous and multiparous cows.

Usefulness of Acidity and Temperature of the Rumen and Abomasum in Diagnosing SARA in Dairy Cows after Calving.

The aim of the research was to determine the relationship between the acidity and temperature of the contents of the reticulorumen and abomasum in the first 10 days after calving and to evaluate these factors as predictive traits for the diagnosis of subclinical acidosis. The acidity and temperature of the contents of the reticulorumen and abomasum were measured using specific smaXtec boluses manufactured for animal care. According to the directions of the manufacturer, the boluses were inserted into the reticulorumen of the cows researched with the help of a specific tool. The boluses were inserted into the abomasa by way of surgery, laparotomy and abomasotomy through the right flank. The readings of 7 cows were taken on a total of 10 days, twice a day (at 9 a.m. and at 9 p.m.). In total, 140 measurements were taken. The acidity of the reticulorumen is associated with the acidity of the abomasum. The acidity of the rumen increases, if the acidity of the reticulorumen increases also. A negative correlation was observed between the pH of the contents of the abomasum and this temperature. The increase in the acidity (decrease of pH) of the contents of the reticulorumen increases its temperature and also increases the temperature of the contents of the abomasum. There is a positive statistically significant dependence between the reticulorumen content temperature and the rectal temperature. Through measurement of the ruminoreticular temperature, it is possible to predict the health status of a cow's stomach in regard to acidosis.

Changes in reticulorumen content temperature and pH according to time of day and yearly seasons.

The monitoring of rumen content temperature can be useful for the evaluation of cow health condition and heat. The aim of this research was to evaluate the influence of the circadian rhythm (time of day) and season on reticulorumen acidity (pH) and temperatures (RT) in lactating dairy cows. The research was performed on ten 2nd - lactation, clinically healthy Lithuanian Black and White fresh dairy cows (up to 1 day after calving). The cows were milked twice daily at 05:00 and 17:00. The cows were kept in a loose housing system, and were fed a feed ration throughout the year at the same time, balanced according to their physiological needs. Cow feeding took place every day at 06:00 and 18:00. The pH and temperature of the contents of cow reticulorumens were measured using specific smaXtec boluses manufactured for animal care. The temperature starts rising 6 hours after the evening feeding and milking, whereas 1 hour after the morning milking, it starts decreasing. The lowest temperature observed in the springtime was 38.81±0.001, and the highest was in autumn 39.17±0.001. The pH starts decreasing 3 hours after the morning feed, whereas 4 hours after the evening feed, it starts increasing. The lowest pH was observed in the summertime - 5.99±0.001, and the highest was in autumn and springtime - 6.18±0.001. In conclusion the reticulorumen temperature in lactating cows was found to be influenced by the circadian rhythm and season. The acidity of the reticulorumen content changes similar to the temperature. The pH of the reticulorumen contents was also found to be influenced by the circadian rhythm and season.

The interrelationships between milkability traits and subclinical mastitis in cows.

The investigation was conducted during 2005-2006 on 4010 dairy cows. Having performed statistical data analysis, we determined that the lowest somatic cell count (SCC) in Red and Red-White cow population was obtained when the milking time was 5-6 min., milking speed was higher than 1.5 kg/min., high milk flow was from 2.51 to 4 kg/min., and in Black-White cow population having a milking time was higher than 7 min., milking speed was from 1.01 to 2 kg/min., a high milk flow --from 2.01 to 4 kg/min. (p<0.001). In Red and Red-White cow population with subclinical mastitis, milking time was longer and milking speed was slower than in healthy cows. High milk flow values were least in healthy Black-White cow population. This determines a more equal milk flow which is desired in milking cows mechanically. Most sensitive to udder infection are 1st lactation cows which have a higher milk flow. A larger phenotype correlation coefficient in Red and Red-White cow population was between the SCC and milking time (-0.089, p<0.01) and between high milk flow (0.086, p<0.01) and milk yield (-0.071, p<0.05). However in Black-White cow population, correlation was found between SCC and milk yield (-0.117, p<0.01) and milking speed (-0.110, p<0.01). Contagious mastitis pathogens were identified in Red and Red-White cow milk samples primarily from productive cows having a milking speed of 1.01-1.5 kg/min., and in Black-White cow population having a milking speed of 1.51-2.0 kg/min.