Lactation Number Research Articles

Use of a glycogenic precursor during the prepartum period and its effects upon metabolic indicators and reproductive parameters in dairy cows

The aim was to evaluate if 1-2 propanodiol plus calcium propionate (glycogenic precursor) supplementation during the transition period in high yielding dairy cows reduces metabolic and reproductive dysfunctions during early lactation. Cows (n=202) where divided into two homogeneous groups regarding number of lactations and body condition score. 1) Treated Group (GG; n=112) received 60g/cow/day 15d of a glycogenic precursor during the transition period. 2) Control Group (GC; n = 90) received no treatment. Postpartum levels of BHB (GG= 0.9±0.2 mmol/L vs GC =1.3±0.2 mmol/L; P < 0.05), and NEFA (GG= 0.6 ± 0.1 mEq/L vs GC = 0.8 ± 0.1 mEq/L; P < 0.05) were higher for GC. Likewise, GC-cows had a higher percentage of retained placenta (23% vs. 13%; P ≤ 0.06) subclinical ketosis (GG = 10%, GC = 56%; P < 0.05), and mastitis (GG = 8%, GC = 16%; P < 0.05). Metritis, dystocia, abortions, clinical ketosis, hypocalcemia and ruminal acidosis showed no differences. Administration of a glycogenic precursor during the transition period demonstrated a positive effect upon BHB and NEFA blood levels during early lactation. Also, levels of subclinical ketosis and retained placenta were reduced.

Research on the determination of heat and water vapor emissions of Anatolian water buffaloes under indoor environmental conditions

This study was carried out to determine the amount of total heat, sensible heat, latent heat, and water vapor emitted by Anatolian water buffaloes in a closed barn located in the Thrace region of Turkey. At the research farm, a group was formed by randomly selecting water buffaloes based on their genetic similarities and lactation numbers. The buffalo group formed was housed in a closedtype barn. The inside and outside air temperatures, relative humidity, and milk yield values of the buffaloes were recorded for 1 year. According to the results of this research, the Anatolian water buffaloes emitted 653 kcal/h AU sensible heat, 351 kcal/h AU latent heat, and 518 g/h AU water vapor during the winter, while they emitted 421 kcal/h AU sensible heat, 536 kcal/h AU latent heat, and 916 g/h AU water vapor during the summer in the barn environment under optimum design conditions. These values can be used to control indoor climatic environmental conditions, design ventilation systems, select structural properties, and determine insulation requirement in terms of animal welfare.

THE GROWTH RETARDATION EFFECT IN EARLY HEIFERS ONTOGENESIS ON DAIRY COWS PRODUCTIVITY

The objective of the study is to determine, whether the growth retardations of replacement cows are admissible, and in which periods of culture they most significantly affect the further productivity of the cows. The subject of the analysis was the number of animals who at the age of 15 months had the live weight no less than 300 kg (which complied with the breed standard or was inferior to the requirements for 10 % maximum). The animals were divided into 5 groups. The first group included the animals with growth retardation before the age of 3 months. The second one – at the age of 3-6 months; the third one – 6-9 months and the fourth one – 9-12 months. The fifth one was the control group, without growth retardation. The growth retardation referred to the live weight reduction at the end of the period in comparison with its beginning or the average daily weight gain less than 500 g. The authors measured the live weight, first lactation productivity and the lifetime productivity of the animals. It has been established that the growth retardation of the heifers before the age of 3 months negatively affected the growth rate in the following three-month period. They can completely compensate the growth retardation only at the age of 18 months. The other group animals compensated the live weight retardation in comparison with the control group by the age of 15 months. The firstlings which had the growth retardation at the age of 0-3 and 3-6 months, has the highest milk productivity. The same trend was observed in milk fat and protein output and the age of the first calving. However, in the growth retardation group the livability of firstlings, the number of lactations and the productive live was worse. The lifelong milk yield in the growth retardation group was 15-37 % lower than in the control group. Growth retardation at the age of 6-9 months negatively affected the higher lactation productivity. The highest daily milk yield in this group of cows was lower in the control group by 14 % (p < 0.05). Therefore, growth retardation had no negative effect on the milk yield of the firstlings, but resulted in lower survival of the animals, shortened the productive life and lifetime yield. The later the growths retardation occurs, the sooner the heifers can compensate it and the lower is its effect on the lifetime productivity of the cows. In view of the reduction of lifetime productivity, it is purposeful to draft out the animals with the growth retardation.

Blood markers of osteoclastic differentiation in periparturient dairy cows at different parities, with and without milk fever

Osteoprotegerin (OPG) inhibits osteoclast (OC) differentiation. TRAP5b (tartrate-resistant acid phosphatase 5b) secreted by OCs reflects the numbers of mature OCs. This study assessed these OC-related markers around parturition in cows of different parities and in cows with milk fever (MF). The blood OPG and TRAP5b concentrations, as well as the ratio of OPG to TRAP5b (O/T), were measured beginning 3 weeks before (−21 d) and over a few days after calving in 49 Holstein Friesian cows at first (n = 8), second (n = 17), third (n = 12), and fourth or greater (n = 12) parities. The ratio of O/T at −21 d to O/T at calving (PreCOT) was also calculated. In the third and greater parities, seven cows developed MF (non-MF, n = 17). Regardless of the development of MF, the serum OPG started to decline in the last week of gestation only in the cows entering the second lactation, while the blood TRAP5b increased at calving in all cows. O/T decreased toward parturition only in multiparous cows. The decrease in O/T at caving was less pronounced in MF cows. PreCOT was negatively correlated with lactation number only in multiparous cows (n = 41, ρ = −0.50, P < .01). This study implied that OC differentiation toward calving was tapered in cows with advanced parities, and these indexes predict the risk of MF.

PRODUCTIVE QUALITIES OF COWS OF DIFFERENT BREEDING GROUPS OF THE BUKOVINSKY FACTORY OF THE UKRAINIAN RED-AND-WHITE DAIRY BREED

The studies were conducted on the materials of the breeding record of the breeding plant of JSC "Mirne" of Chernivtsi region - the basic farm of the Bukovyna factory type of the Ukrainian red-speckled dairy breed. 360 cows were selected for analysis, based on live weight, yields, fat and protein content of milk, total milk fat and protein content.&#x0D; The intensification of dairy cattle breeding necessitates the systematic evaluation of animals in herds and populations on the basis of economically useful traits.&#x0D; Analysis of the productive qualities of the cows of the different breeding groups showed that, by live weight, milk yield, milk fat and protein content, the two-breed (II breeding group) animals were better than the three-breed (I breeding group). The difference for the first lactation was 11.2; 32.9; 1.5; 1.0 kg respectively. In cows with the second lactation, the pattern remained, the difference was 22.2; 395.8; 15.8; 13.1 kg respectively, and for the third lactation – 31.4; 124.3; 4.8; 4.2 kg. The fat and protein content of milk varied between 3.88–3.89% and 3.33–3.34%, respectively. It should be noted that in cows of both groups there was a decrease in milk milk yield with increasing number of lactations.An evaluation of the productive qualities of the first-born cows of the different lines showed that Marshall's first-borns were better in live weight, milk yield, milk fat and protein, although they were inferior to other lines in terms of fat and protein content. In the firstborn of the Hanover Red line, the estimated values were lower than in animals of other lines, in particular – by live weight by 11.4 kg, milk yield by 1115.2 kg, milk fat by 44.1 kg, milk protein by 37.2 kg (Chif line), by 5.4; 1336.5; 52.7; 45.2 kg (Starbuck line) and 14.7; 1465; 55.1; 48.3 kg (Marshall Line).The effectiveness of breeding for increasing dairy productivity of cows depends on the efficiency of selection and selection of animals, taking into account the phenotypic and genetic correlation between economically beneficial traits. It was found that the highest positive values of correlation coefficients were observed in the cows of the studied groups between milk yield and protein content in the context of all lactations – 1st breeding group (r = 0,12–0,25), 2 nd breeding group (r = 0.19–0.3). In the cows of the first breeding group for the first and second lactations revealed not high but positive correlation of milk yield with live weight (r = 0.33–0.49). In the cows of the second breeding group for the first and second lactation positive correlation with milk fat content was found.The first positive cows of different lines showed the highest positive values of the correlation coefficients between milking and protein content (r = 0.19–0.43). There was also a low positive correlation of milk yield with live weight in the firstborn of all evaluated lines (r = 0.03–0.09), as well as milk fat content in cows of Starbuck and Marshall lines.Conclusions. 1. By live weight, milk yield, milk fat and protein content, two-bovine cows of the Bukovyna factory type of Ukrainian red-speckled dairy breed were better than three-born. The fat and protein content of milk varied between 3.88–3.89% and 3.33–3.34%, respectively. In cows of both groups there was a decrease in milk yield with increasing number of lactations.2. By live weight, milk yield, milk fat and protein content, Marshall Line firsts were better, although they were inferior to other lines in terms of fat and protein content. In the firstborn of the Hanover Red line, the estimates were lower than in other line animals.3. The highest positive values of correlation coefficients were observed between milk yield and protein content in the context of all lactations in the cows of Bukovyna factory type of Ukrainian red-rippled dairy breed. In two breeds of cows for the first and second lactation revealed not high but positive correlation of milk yield with live weight, and in three breeds for the first and second lactation positive correlation of milk yield with fat content.

ESTIMATION OF HOLSTEIN BREED BULLS BY DAIRY PRODUCTIVITY OF THEIR DAUGHTERS

The scientific community has shown that the genetic improvement of dairy cattle depends on many genotypic factors, including paternal ancestry and lineage. With this in mind, the purpose of our research was to evaluate the Holstein bulls of black-and-white and red-and-white suits of different lines for the milk productivity of their daughters.&#x0D; The research was carried out on the basis of primary breeding records of 10 breeding herds of Ukrainian Black-and-White Dairy breed, 3 – Ukrainian Red-and-White Dairy breed and one – Ukrainian Red Dairy breed, which are subordinated to NAAS. Cows of the studied breeds has divided into groups according to lineage and paternal origin.&#x0D; Studies have revealed a significant differentiation of milk yield of cows of the first and highest lactation not only of one breed, but also of linear affiliation and paternal origin. It was found that the yield of the first lactation in cows of the Ukrainian Black-and-White Dairy breed varied from 3211 kg (Damir 7100354042) to 7884 kg (Dzhokus 113080315) of milk. Noteworthy are the daughters of Dzhokus 113080315, from which 9143 kg of milk were obtained for higher lactation, Polyarsten 342347941 and Manteno 344222859 – 8248 kg and 8290 kg of milk, respectively. The significant influence of paternal origin on the yield of Ukrainian Black-and-White Dairy breed cows of the first and higher lactation (31.0%; P &gt; 0.999) and 37.3% has been proved; P &gt; 0.999). The influence of genealogical formation on the milk productivity of cows was significant and amounted to 10.8% for the first lactation, higher – 10.2%. Some of the first-born Ukrainian Black-and-White Dairy breed has characterized by high milk productivity, which steadily increased until the third and higher lactation.&#x0D; The yield of cows of the Ukrainian Red-and-White Dairy breed of the first lactation varied from 5414 kg (Dialog 2009) to 6689 kg (Larets 6177), testifying to better homogeneity of herds in terms of milk productivity compared to the Ukrainian Black-and-White dairy breed. The highest yield of the third and highest lactation – 7626 kg, had cows-daughters of the bull Roman 660886883 Starbuck line 352790. The variability of milking cows of Ukrainian Red-and-White Dairy breed of the first and highest lactation by 25.0% and 15.2%, respectively, was due to the influence of the father offspring and to a lesser extent – belonging to the line.&#x0D; A very high (6517–8013 kg) realization potential of milking cows of the Ukrainian Red Dairy breed was established, but it also depended on the paternal origin and linear affiliation. The highest yield of the first lactation were shown by the daughters of the bull Belisar 365235897, Dzhorin 114414759 and Tumpi 112367468, who produced 8013 kg, 7323 kg and 7170 kg of milk, respectively. In cows of this breed it was found that yield increased with increasing serial number of lactation, with the third and higher lactation cows produced more than 8000 kg of milk per lactation, and the daughters of bull Dzhorin 114414759 – more than 9000 kg. The influence of the bull on the milk productivity of the first-born cows of the Ukrainian Red Dairy breed (16.7%; P &gt; 0.999) is almost three times higher than this linear affiliation. Significant phenotypic variability of milk productivity of cows of different breeds of half-sisters by the father is established. The advantage of the daughters of the bull Belisar 365235897 of the Ukrainian Red Dairy breed on milking of the first lactation over the representatives of the Ukrainian Red-and-White Dairy breed was 1932 kg (p &lt; 0.001). The difference in milk yield of the first lactation of the half-sisters by the father, the bull Konbeo 579810507 was 1007 kg (p &lt; 0.01), and Roman 660886883 – 717 kg.&#x0D; Thus, a significant phenotypic variability of milk productivity of cows of different breeds of half-sisters by father was established. At the same time, regardless of the breeder, the cows of the Ukrainian Red Dairy breed were characterized by higher milk yield of the first lactation in comparison with the Ukrainian Red-and-White Dairy breed.

Milk yield and somatic cells in dairy ewes with respect to their mutual relations

The objective of this study was to analyze milk yield and somatic cell count (SCC) expressed as somatic cell sore (SCS) in Lacaune dairy breed. Data from milk performance testing recorded between 2016 and 2018 (farm in West Slovakia) were used. A total, 377 individual milk yield and SCC records of 61 ewes (first, second and third lacation, respectively) were analysed. Mixed model for milk yield included fixed factors: SCC class (lowest, low, middle, high and highest), year of measurement, lactation number, month in milk and interaction between month in milk and SCC class, and random factors of ewe and error. Mixed model for SCS included milk yield class (lowest, low, middle, high, highest), year of measurement, lactation number, month in milk and interaction between month in milk and milk yield class. Random factors of ewe and error were considered as well. Milk yield was significantly affected ( p &lt;0.05 or p &lt;0.01) by all investigated factors. Except for interaction between month in milk and milk yield class, the remaining factors significantly affected (p &lt;0.05 or p &lt;0.01) also SCS. The analyses confirmed that SCC may be used as a useful indicator of udder health. It may help in identifying infected ewes, and thus, avoiding mammary infections to be spread throughout the whole flock.

Potential of milk mid-infrared spectra to predict nitrogen use efficiency of individual dairy cows in early lactation

Improving nitrogen use efficiency (NUE) at both the individual cow and the herd level has become a key target in dairy production systems, for both environmental and economic reasons. Cost-effective and large-scale phenotyping methods are required to improve NUE through genetic selection and by feeding and management strategies. The aim of this study was to evaluate the possibility of using mid-infrared (MIR) spectra of milk to predict individual dairy cow NUE during early lactation. Data were collected from 129 Holstein cows, from calving until 50 d in milk, in 3 research herds (Denmark, Ireland, and the UK). In 2 of the herds, diets were designed to challenge cows metabolically, whereas a diet reflecting local management practices was offered in the third herd. Nitrogen intake (kg/d) and nitrogen excreted in milk (kg/d) were calculated daily. Nitrogen use efficiency was calculated as the ratio between nitrogen in milk and nitrogen intake, and expressed as a percentage. Individual daily values for NUE ranged from 9.7 to 81.7%, with an average of 36.9% and standard deviation of 10.4%. Milk MIR spectra were recorded twice weekly and were standardized into a common format to avoid bias between apparatus or sampling periods. Regression models predicting NUE using milk MIR spectra were developed on 1,034 observations using partial least squares or support vector machines regression methods. The models were then evaluated through (1) a cross-validation using 10 subsets, (2) a cow validation excluding 25% of the cows to be used as a validation set, and (3) a diet validation excluding each of the diets one by one to be used as validation sets. The best statistical performances were obtained when using the support vector machines method. Inclusion of milk yield and lactation number as predictors, in combination with the spectra, also improved the calibration. In cross-validation, the best model predicted NUE with a coefficient of determination of cross-validation of 0.74 and a relative error of 14%, which is suitable to discriminate between low- and high-NUE cows. When performing the cow validation, the relative error remained at 14%, and during the diet validation the relative error ranged from 12 to 34%. In the diet validation, the models showed a lack of robustness, demonstrating difficulties in predicting NUE for diets and for samples that were not represented in the calibration data set. Hence, a need exists to integrate more data in the models to cover a maximum of variability regarding breeds, diets, lactation stages, management practices, seasons, MIR instruments, and geographic regions. Although the model needs to be validated and improved for use in routine conditions, these preliminary results showed that it was possible to obtain information on NUE through milk MIR spectra. This could potentially allow large-scale predictions to aid both further genetic and genomic studies, and the development of farm management tools.

Investigating various performance traits of Karakul sheep

Karakul sheep in Turkey is an endangered breed according to the total number of ewes. Two herds of Karakul sheep in Tokat Province, reared similar environmental conditions, kept in situ in vivo conservation as a gene resource. This study aimed to determine various performance traits of Karakul sheep reared in breeder conditions as a gene resource. Least squares means for lambing rate (LR), litter size (LS) and lamb production (LP) were found 95.8±0.60%, 1.04±0.01 and 100.0±0.80%, respectively. It was determined that farm and age had significant effect on LR and LP, while farm and year had significant impact on LS. Survival rate in lambs were found 95.2 and 94.1%, respectively on 90th and 180th days. Means of least squares for live weights of lambs at birth and on 90th and 180th days were identified as 3.35±0.02, 21.52±0.27 and 30.34±0.32 kg, respectively. Live weight after shearing and greasy fleece weight values were 40.73±0.12 and 2.04±0.01 kg for females and 62.65±0.53 and 3.48±0.06 kg for males. Lactation milk yield (LMY) was 104.85±3.73 kg in ewes and lactation duration was 159.01±1.70 days. LMY was affected by the lactation number and farm while lactation duration was affected by lactation number. Results revealed that various performance traits of Karakul sheep conserved in breeder conditions were similar to or better than those previously reported for this breed. Also, the breed is similar to medium size native sheep breeds in terms of growth and mature live weight.

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.

Effect of Calving Season, Calving Year and Lactation Number on the Milk Yield Traits in Holstein Cows Raising in Şanlıurfa

The aim of the present study is to investigate the impact of some environmental factors on the descriptive values of milk yield characteristics in Holstein cows. For this purpose, a total of 241 lactations belonging to 62 Holstein cows had been kept as breeders in a private establishment were evaluated for 7 years in terms of milk yield. When the recording system of the establishment was examined, the average values of lactation yield (LY), corrected 305 day milk yield (305-dMY), average daily milk yield (ADMY) and lactation length (LL) were 9356.2±126.1 kg, 8549.2±105.8 kg, 28.0±0.3 kg and 315.0±2.3 days, respectively. The least mean squares (LMS) of LY was calculated as 9324.9 kg. It was found that the effect of the calving season on the LY was statistically significant (P

Milk productivity of cows of different ages under the conditions of the dairy complex «Ryzhovo»

When production of milk in industrial volumes it is necessary to monitor all processes aff ecting its quantity and quality: animal feeding, breeding, mode and method of milking, herd reproduction, labour organization in the dairy complex, creating favorable conditions for cows that correspond to physiological characteristics. The dairy industry continues to impose higher and higher demands on milk, so in addition to improving the milk productivity of cows, we must not forget about the quality of the product. The issues of milk yield of cows, fat and protein, yield of milk fat and protein, somatic cells in milk of cows of Black-and-White breed for a number of lactations in terms of the dairy complex “Ryzhovo” have been considered in the article. It has been noted be researches that in the 1st and 2nd lactations milk yield of animals was 10 621 and 10 553 kg, respectively. The highest productivity of the cows has reached in the 3rd and 4th lactations 11 365 and 11 655 kg, respectively, after which, in the 5th lactation there was a decrease in milk yield to 10 592 kg. When considering fat content for diff erent lactations, positive dynamics up to the 4th lactation inclusive has been revealed. Thus, the fat content in milk for the 1st lactation was 3,61 %, for 2nd – 3,68 %, for 3rd – 3,93 % and 4th – 4,00 %. In the 5th lactation fat content decreased to 3,78 %. It has been found when calculating the yield of milk fat in experimental cows for lactation that up to the 4th lactation inclusive the indicator increases: for the 1st lactation received 383 kg of milk fat, 2nd – 388 kg, 3rd – 447 kg, 4th – 466 kg, and for the 5th lactation, the decrease in the index to 400 kg. At the same time the yield of milk fat for the 5th lactation exceeds the 1st and 2nd. The protein content in the milk of cows of diff erent ages during the fi rst four lactations increases from 3,18 to 3,43 %. Then, in the 5th lactation there is the decrease in protein content to 3,35 %, however, this fi gure is second only to the highest the 4th lactation. It has been established that before the 3rd lactation the number of somatic cells in milk increases, then in the 4th lactation this indicator decreases (151,25 thousand/cm3 ) and in the 5th lactation reaches a maximum (242,27 thousand/cm3).

Lactoferrin concentration and expression in New Zealand cows milked once or twice a day.

This study evaluated the concentration and expression of lactoferrin (LF) in cows selected for once a day (OAD) milking compared to twice a day (TAD) milking. Milk samples were collected from the Massey University TAD and OAD herds. Milk traits and expression of LF and insulin-like growth factor 1 (IGF-1) were analyzed with a general linear model that included the fixed effects of milking frequency, lactation number, interaction between milking frequency and lactation number, and as covariates proportion of F, heterosis F×J and deviation from the herd median calving date. Cows milked OAD produced milk with higher (p<.01) concentrations of protein and lactose than TAD milked cows. Compared to TAD cows, cows milked OAD had higher expression of the LF gene (1.40 vs. 1.29 folds, p=.03) and the IGF-1 gene (1.69 vs. 1.48 folds, p=.007). The correlation between the expression of LF gene and the concentration of LF in milk was strong (r=.66 p<.001), but the correlation between the expression of the IGF-1 gene and LF concentration was stronger (r=.94, p<.001). These results suggest that milking frequency affects the milk composition and expression of milk composition genes at early lactation.

Effect of test year, parity number and days in milk on somatic cell count in dairy cows of Los Ríos region in Chile

In Chile, most dairy cattle are located in the southern region of the country, where the largest volume of milk is produced. This study aimed to quantify changes of somatic cell count (SCC) over 20 years in 11 herds of the Los Rios region and to assess the effect of parity number, days in milk, milk yield, and milk fat and protein content on SCC. A database of approximately 277,709 observations based on 10,363 cows from 11 herds of the area was used. Data were gathered from 1998 to 2018. Outliers and inconsistent observations were eliminated. Multiple linear regression was used to model SCC on fixed variables such as test year, parity number, test season, and stage of lactation; covariables included in the model were milk yield, milk fat and protein yields, and milk urea concentration. There were statistically significant associations among SCC and all independent variables included in the model. Regarding parity number and stage of lactation, they increased along with SCC. SCC was higher in warmer months and, as SCC increased, the yield decreased. It was concluded that as test year increased, SCC decreased, indicating that the mammary gland health improved and the quality of the milk was better.

Forecasting the milk yield of cows on farms equipped with automatic milking system with the use of decision trees.

The purpose of this paper was to utilize the decision trees technique to determine the factors responsible for high monthly milk yield in Polish Holstein-Friesian cows from 27 herds equipped with milking robots. The applied statistical method-the decision tree technique-showed that the most important factors responsible for monthly milk yield of dairy cows using robots were, in descending order of importance: milking frequency, lactation number, month of milking, and type of lying stall. At the same time, it has been ascertained that the highest monthly milk yield (47.24kg) can be expected from multiparous cows kept in barns with a deep bedding that were milked more frequently than three times per day. On the other hand, the lowest milk production (13.56kg) was observed among dairy cows milked less frequently than two times a day, with an average number of milked quarters lower than 3.97. The application of the decision trees technique allows a breeder to select appropriate levels of environmental factors and parameters that will help to ensure maximized milk production.

The relationships between udder-quarter somatic-cell counts and milk and milking parameters in cows managed with an automatic milking system

Context Some milking parameters such as milk yield, milk flow, milking duration, milk conductivity and somatic-cell count can all be listed as economically important traits in dairy practice. Aims The aim of the study was to investigate the relationships among lactation stage, lactation number, milking season and milk-performance traits at an udder-quarter level, including somatic-cell count (SCC), milk yield (MY), milking duration (MD), time in box (TB), milk flow (MF) and milk conductivity (MC). An additional aim was to analyse milking-parameter levels in milkings with a SCC lower and higher than 400000 cells/mL. Methods The study included an analysis of 1621582 successful milkings obtained from six herds of dairy cattle equipped with milking robots (AMS). Key results The study confirmed that MD and MY differed greatly between front and rear quarters. Rear quarters took longer to be milked but produced more milk. During the first 100 days of lactation, the primiparous cows spent more time in the robot than did multiparous cows; however, in the second and third lactations, older cows were spending more time in the AMS. For primiparous cows, MF increased with time, being the highest at the end of lactation (&amp;gt;200 days in milk). A different trend has been found in the group of multiparous cows, where a steady decrease in MF was observed with subsequent lactation stages. A lower MC was recorded for cows in their first lactation than for multiparous cows. Data obtained from primiparous cows showed the highest MC to occur between 100 and 200 days of lactation. In the group of multiparous cows, MC increased with the lactation stage. It was also shown that the mean values obtained for MY, MD and TB were higher for cows with a lower SCC (&amp;lt;400000). Correlations between lnSCC (the natural logarithm of SCC) and MY and between lnSCC and MD were negative and low, while those between lnSCC and MC and lnSCC and MF were positive. Moderate correlations were found between lnSCC and total MC. Conclusions The study confirmed the differences in the performance of different udder quarters in relation to MY, MD, TB, MF, MS and SCC. Implications AMS provides farmers with vast data on milk and milking parameters. By monitoring changes in these parameters, farmer may be able to predict the level of production of their herd and the health of cows.

Financial and economic analyses of the impact of cattle mastitis on the profitability of Egyptian dairy farms.

Aim:This study aimed to evaluate and quantify the different factors affecting the costs of mastitis in cattle, to quantify the annual and monthly financial losses attributed to mastitis, and to estimate production losses using average linear scores found on The Dairy Herd Improvement Association somatic cell count (SCC) sheets and bulk tank SCC per lactation number.Materials and Methods:All data (bovine mastitis-associated costs and expenditures in Egyptian dairy herds) were analyzed using SPSS/PCT, 2001. A partial budget technique using spreadsheet software and the general linear model procedure was used to analyze the productive and financial measures.Results:Mastitis was present in 57.1% of cows (240/420), while clinical mastitis (CM) was present in 19% of them (80/420). The geometric mean of SCC/ml in bulk tank milk samples of 150 cattle dairy farms was 556.3×103. The annual subclinical mastitis (SCM)-related economic loss was 21,933,258.6 LE, and the two most important cost components were the subsequent decrease in milk production and quality premium losses (93% and 7% of SCM costs, respectively). The quality premium loss was 1,369,602.1 LE. On the other hand, the annual economic loss due to decreased milk production as a result of SCM was 20,563,656.5 LE. The total cost of 80 CM cases, including the failure and preventive costs, was 1,196,871.4 LE, including 1,169,150.4 LE failure costs (106,336.0 LE in direct costs and 1,062,814.4 LE in indirect costs) and 27,721.0 LE preventive costs. The average cost per CM case was 28,760.9 LE, including veterinary time and consultation fees of 250.0 LE (1%), labor 562.5 LE (2%), premature culling 736,000.0 LE (77%), decreased milk production 4085.18 LE (13.7%), discarded milk 185.3 LE (1%), and drugs and treatments 328.9 LE (1%). The total costs of CM (expenditures) extra control and preventive measures, including the diagnosis of CM for 80 cows annually in 20 Egyptian dairy farms were 27,721.0 LE, representing 346.5 LE or 1% of the total cost of CM cases. The cost of monitoring and diagnostic measures was 8635.2 LE, representing 107.9 LE or 1% of the total cost of a case of CM.Conclusion:The method used for cost estimation, in this study, is highly adaptable to individual cattle farms and had a major role in assessing specific control and management measures. The concepts described in this paper help to improve our understanding of the full economic impact of clinical and subclinical mastitis in cattle in Egypt. Assessing the economic losses from mastitis to determine the economic costs and losses occurring in Egyptian dairy farms is critical for encouraging farmers to acknowledge the scale of the problem and implement effective management practices aimed at improving mastitis control and reducing the associated costs.

Relationship Between Some Traits Used As Mastitis Indicators in Holstein Cows’ Milk

This study was carried out in order to identify the relations between Somatic cell count (SCC), milk temperature, milk pH and milk density in mastitic and non-mastitic Holstein Friesian cows. The animal material of the study was mastitic and non-mastitic Black and White cows which similar age and lactation number. At the end of the study, it was defined that the mastitic milk was highly corelated with SCC and pH of milk (r=0,633; r=0,570 respectively). While in healthy group (non-mastitic), there wasn’t any correlation between the SCC and the other parameters; but in the mastitic group, it was found that there was significant correlations statistically between SCC and other parameters. Keywords: SCC, cows, Milk temperature, pH, electrical conductivty, density DOI : 10.7176/ISDE/11-1-03 Publication date: January 31 st 2020

Association between age at first calving and milk production in first lactation on longevity traits in Holstein cows

The objective of this research was to determine the association between age at first calving (AFC) and milk production in the first lactation of longevity traits for Holstein cows. The research was conducted on 2307 cows raised on 4 farms in AP Vojvodina. The cows were culled in the period from 2017 to 2018. The cows belonged to the group of Holstein Friesian breed of cattle. Cow longevity was observed using three parameters: number of lactations (NL), lifetime milk yield (LMY) and length of productive life (LPL). The research involved the influence of the farm on which the animals realized their production, the season of first calving. A mean value obtained for the length of productive life in the analysed population was 1207 days (3.30 years on average). During this period the animals on average realized 2.45 lactations and produced on average 18798 kg milk. All studied traits showed a high level of variability. From these data, the study sought to determine the influence of factors on the traits of longevity, our research present that studied factors showed high statistical significance on these traits except in the case of the season of first calving where a statistical significance effect wasn?t observed. The season of first calving did not affect the animal traits for longevity and, generally, didn?t affect the calving interval. Regarding the obtained correlation data between age at first calving and length of productive life, it can be concluded that belated AFC leads to reduced reproductive performance.

Daily rumination time of lactating dairy cows under heat stress conditions.

The dairy industry in regions with moderate climates, such as Central Europe, will be increasingly challenged in the future by climate change. The problem of heat stress will especially affect dairy husbandry in naturally ventilated barns (NVB). The approach of the study was to determine a heat stress threshold of the average daily temperature-humidity index (THI) that results in changes in the daily rumination time (RT) of lactating, high-yielding cows. The data set was composed of a high sample size of 183 cows and long-duration measurements of 21240 daily observations over two years from June 2015 to May 2017, which were collected in an NVB in Groβ Kreutz, Germany. The THI was calculated in 5-min intervals by data from several sensors in different positions inside the barn. Additionally, every cow from the herd of an average of 53 cows in the experimental procedure was wearing a neck collar with a Lely Qwes HR system that provided the RT 24h a day (12 2-h recordings were summarized). The study showed that heat stress also negatively influenced RT in moderate climates. The heat stress threshold of 52 THI was determined by broken-stick regression and indicated changes of RT of lactating dairy cows in Germany. During the experimental period, the heat stress threshold for RT was reached from April to September for up to 720h per month. The changes in RT to the heat stress threshold will be affected by cows' characteristics. Therefore, we considered several cow-related factors, such as milk yield (MY), lactation number (LN), lactation stage (days in milk, or DIM) and pregnancy stage (P) to better understand cows' individual reactions to heat stress. Multiparous, high-yielding cows in later lactation stages are potentially more strongly affected than other cows.