Days Of Lactation Research Articles

MATERNAL FOOD RESTRICTION DURING LACTATION PROMOTES RENAL DYSFUNCTION IN THE MALE OFFSPRING AT ADULTHOOD

The aim of this work is to evaluate the renal function and the morphology of the kidneys inthe offspring, of both sexes, of mothers who underwent a 50% food restriction duringlactation. Pregnant Wistar rats were divided into two experimental groups: Control group(CO) fed with standard diet and Food restriction (FR) fed with standard diet restricted to 50%of the daily food intake of CO mothers. The intervention was carried out from the 1st to the14th day of lactation, after from the 14th to the 21st day of lactation. The offspring of bothgroups were fed with standard diet and water ad libitum until 120-day-old. At the end of theexperimental period 24-hour urine collection was performed. After euthanasia biochemicaland histological analysis were performed. Male and female FR offspring showed no change inbody weight or kidney weight compared to control counterparts. Male FR showed a reductionin the glomerular filtration rate (CO 3.22±0.35 vs FR 2.25±0.12; ml/min) and increased totalurinary protein (CO 82.82±11.79 vs FR 123.8±8.37; mg/dL) compared to the CO offspring.We observed a reduction in glomerular area in the male FR (CO 7259±271.7 vs FR6349±106.3; μm 2 ) in comparison to CO offspring. In conclusion, maternal food restrictioncauses functional and morphological kidney damage in adult males, being a sex-specificresponse since females did not show alterations.

PROTEIN-CALORIC RESTRICTION DURING LACTATION HAS A TRANSGENERATIONAL EFFECT IN GLUCOSE HOMEOSTASIS OF MALE RATS

Experimental and epidemiological studies demonstrated an important association betweeninsults in sensitive stages of development and metabolic syndrome at adulthood.Developmental Origins of Health and Disease (DOHaD) concept indicates that pregnancy andlactation are windows to metabolic programming, once in these phases, occurs a peak ofneuronal development. There is a gap in the study of the transgenerational effect of insultsperformed in programming windows, especially when it comes to malnutrition. FemaleWistar rats were submitted to a protein-caloric restriction during the first 14 days of lactation(LP, low-protein group) or a normal-caloric diet through the lactation (NP, normal-proteingroup). At 70 days old these females were mated with a control male rat. The offspring (F2generation, NP and LP groups) were fed with normal-caloric diet and were euthanized at 21days old to blood collection and biometric analysis. There were no differences betweengroups in body weight at weaning. Also, retroperitoneal, periepididymal and mesenteric fatpads were similar between NP and LP animals. We showed an 11% (P˂0.05) increase inbrown adipose tissue weight in LP group. Fasting glucose was increased by 99% (P˂0.05) inLP groups, without alteration in fasting insulin levels. We conclude that protein-caloricrestriction during lactation has a transgenerational effect in male rats, altering the glucosehomeostasis.

Multi-omics reveals that the host-microbiome metabolism crosstalk of differential rumen bacterial enterotypes can regulate the milk protein synthesis of dairy cows

BackgroundDairy cows’ lactation performance is the outcome of the crosstalk between ruminal microbial metabolism and host metabolism. However, it is still unclear to what extent the rumen microbiome and its metabolites, as well as the host metabolism, contribute to regulating the milk protein yield (MPY).MethodsThe rumen fluid, serum and milk of 12 Holstein cows with the same diet (45% coarseness ratio), parity (2–3 fetuses) and lactation days (120–150 d) were used for the microbiome and metabolome analysis. Rumen metabolism (rumen metabolome) and host metabolism (blood and milk metabolome) were connected using a weighted gene co-expression network (WGCNA) and the structural equation model (SEM) analyses.ResultsTwo different ruminal enterotypes, with abundant Prevotella and Ruminococcus, were identified as type1 and type2. Of these, a higher MPY was found in cows with ruminal type2. Interestingly, [Ruminococcus] gauvreauii group and norank_f_Ruminococcaceae (the differential bacteria) were the hub genera of the network. In addition, differential ruminal, serum and milk metabolome between enterotypes were identified, where the cows with type2 had higher L-tyrosine of rumen, ornithine and L-tryptophan of serum, and tetrahydroneopterin, palmitoyl-L-carnitine, S-lactoylglutathione of milk, which could provide more energy and substrate for MPY. Further, based on the identified modules of ruminal microbiome, as well as ruminal serum and milk metabolome using WGCNA, the SEM analysis indicated that the key ruminal microbial module1, which contains the hub genera of the network ([Ruminococcus] gauvreauii group and norank_f_Ruminococcaceae) and high abundance of bacteria (Prevotella and Ruminococcus), could regulate the MPY by module7 of rumen, module2 of blood, and module7 of milk, which contained L-tyrosine and L-tryptophan. Therefore, in order to more clearly reveal the process of rumen bacterial regulation of MPY, we established the path of SEM based on the L-tyrosine, L-tryptophan and related components. The SEM based on the metabolites suggested that [Ruminococcus] gauvreauii group could inhibit the energy supply of serum tryptophan to MPY by milk S-lactoylglutathione, which could enhance pyruvate metabolism. Norank_f_Ruminococcaceae could increase the ruminal L-tyrosine, which could provide the substrate for MPY.ConclusionOur results indicated that the represented enterotype genera of Prevotella and Ruminococcus, and the hub genera of [Ruminococcus] gauvreauii group and norank_f_Ruminococcaceae could regulate milk protein synthesis by affecting the ruminal L-tyrosine and L-tryptophan. Moreover, the combined analysis of enterotype, WGCNA and SEM could be used to connect rumen microbial metabolism with host metabolism, which provides a fundamental understanding of the crosstalk between host and microorganisms in regulating the synthesis of milk composition.

One-step laparoscopy-guided abomasopexy versus omentopexy via right flank laparotomy to treat left displaced abomasum in dairy cows, in relation to return of milk yield

This study compared two surgical techniques for treating left displaced abomasum (LDA) in dairy cows. The two techniques were compared in terms of milk production at different time intervals: before surgery; on the day of the surgery; and at 8, 15 and 30 days after surgery. The surgical techniques used in this study were laparoscopy-guided abomasopexy and right flank laparotomy omentopexy. A total of 126 lactating Holstein-Friesian cows with LDA were included, 63 of which were treated with laparoscopy, and 63 with right flank laparotomy. Cows with retained foetal membranes, metritis or natural delivery (dystocia) were included and registered on field sheets for subsequent statistical analysis. Cows with clinical mastitis were excluded. A blood sample (5 mL) was obtained from the medial coccygeal vein and analyzed for total proteins, total bilirubin, total calcium, glucose, b-hydroxybutyrate, sodium, potassium, and chloride. No differences were found between the two groups of operated cows with respect to the number of lactation days, body condition score (BCS), rectal temperature, heart rate, and respiratory rate before surgery. No differences were observed between groups regarding the biochemical parameters (P > 0.05) analyzed, except for chloride, which presented lower average values in the omentopexy group (P <0.05). Return of milk yield within the study period did not differ significantly between the laparoscopy and laparotomy groups (P > 0.05), although a significant change in post-surgery time was observed. .

Effects of Dietary Probiotics and Acidifiers on the Production Performance, Colostrum Components, Serum Antioxidant Activity and Hormone Levels, and Gene Expression in Mammary Tissue of Lactating Sows.

The aims of this study were to test the effects of dietary probiotics and acidifiers on the production performance, colostrum components, serum antioxidant activity and hormone levels, and gene expression in the mammary tissue of lactating sows. Four treatments were administered with six replicates to 24 lactating sows. The control group (GC) received a basal diet, while the experimental groups received a basal diet with 200 mL/d probiotics (GP), 0.5% acidifiers (GA), and 200 mL/d probiotics + 0.5% acidifiers (GM), respectively. Compared with the GC, (1) the average weight of the piglets on the 21st day of lactation in the GM was higher (p < 0.05); (2) the colostrum fat ratio increased significantly (p < 0.05); (3) the malondialdehyde levels in GP and GM were lower (p < 0.05) on the 11th day; (4) on the 1st, 11th, and 21st days, the prolactin in GP and GM increased (p < 0.05); (5) on the 21st day, the relative expression levels of the prolactin receptor and fatty acid synthase were increased (p < 0.05). In summary, the basal diet mixed with 200 mL/d probiotics + 0.5% acidifiers could improve the production performance, colostrum components, serum antioxidant activity, and hormone levels of lactating sows.

87 Milk Yield, Vaginal Temperature, and Solar Radiation Exposure in Slick and Wild Type-Haired Puerto Rican Holstein Cows

Abstract As heat stress limits dairy cattle performance in the tropics, selection for heat resistant cattle has been proposed as a possible alternative for these countries. Such cattle should be able to regulate their body temperature efficiently so grazing activity is not compromised by environmental conditions. This is particularly important for Puerto Rico’s dairy industry, which depends on grazing as the principal or unique source of dietary fiber. Even though Puerto Rican slick-haired dairy cattle (SLICK) have been associated with superior thermoregulation, empirical data about their capacity to withstand greater solar radiation exposure while maintaining lower body temperature is scarce. The current study aimed to compare the vaginal temperature, solar radiation exposure, and milk yield between SLICK and wild type-haired (WT) cows. Evaluated groups were balanced for lactation number (P = 0.8101) and days in milk (DIM: P = 0.9619). Eight SLICK (2.00 ± 0.33 lactations and 160.33 ± 11.39 DIM) and 8 WT Holstein cows (1.89 ± 0.31 lactations and 159.44 ± 14.34 DIM) were compared. Initially, experimental groups were selected visually, then a genomic test confirmed each the hair coat type of each cow. Vaginal temperature was recorded by means of a HOBO TidbiT v2 Water Temperature datalogger secured to a blank CIDR. Light intensity exposure was recorded using a HOBO Pendant MX Temperature / Light datalogger secured to the top of a neck collar, as an index of solar radiation exposure (previously validated by our group). Data were recorded in each cow every 15 seconds for 48 consecutive hours (August 4-5, 2022) and averaged by hour for statistical analysis using the GLIMMIX Procedure of SAS. The week before the study SLICK cows showed greater milk yields than their WT counterparts (20.76 ± 0.55 vs.8.60 ± 0.56 kg/d; P = 0.0073). No time by hair coat type interaction was observed for vaginal temperatures (P = 0.1396). However, time (P &amp;lt; 0.0001) and hair coat type (P = 0.0042) affected vaginal temperature. The SLICK cows presented lower vaginal temperatures than their WT counterparts, with daily averages of 39.08 ± 0.09 and 39.45 ± 0.10°C, respectively. A time by hair coat type interaction (P = 0.0293) was observed for the light intensity exposure of the cows. The SLICK cows had greater light intensity exposure than their WT counterparts at 1,000 h (15,467.00 ± 1,584.92 vs.10,057.00 ± 787.35 lx; P &amp;lt; 0.0001), 1,100 h (12,028 ± 1,660 vs. 8,571.11 ± 888.13 lx; P = 0.0078), and 1,200 h (13,191.00 ± 2,188.86 vs.10,923.00 ± 1,904.31 lx; P = 0.0801). No other differences in light intensity exposure were observed. Slick-haired cows were able to maintain a lower daily vaginal temperature, even with a greater exposure to direct solar radiation, further suggesting a superior thermoregulatory capacity. Concurrently, a greater milk production was observed in the slick-haired group. Future studies should evaluate grazing activity under direct solar radiation exposure in both hair coat groups.

Seasonal, physiological and bacteriological risk factors for subclinical mastitis in dairy cows maintained under different farming conditions.

Subclinical mastitis (SCM) is a major health problem of dairy animals in India and across the globe. An identification of potential risk factors of SCM can help for efficient udder health management in dairy animals. In this study, apparently healthy cows (HF crossbred: n = 45; Deoni: n = 43) were screened for SCM during different seasons through milk somatic cell count (SCC: reference test using 200 × 103 cells/ml as cut off value), California mastitis test (CMT) and differential electrical conductivity (DEC) test at an organized research farm. SCM positive milk samples (n = 34) were inoculated in selective media for Coliform sp., Streptococcus sp. and Staphylococcus sp. and DNA was isolated (n = 10) for species confirmation by 16s rRNA method. Both bivariate and multivariate models were used for risk assessment. We found the cumulative prevalence of 31 and 65% SCM in Deoni and crossbred cows, respectively. Screening of 328 crossbred cows under field conditions revealed point prevalence of 55% SCM. Multivariate analysis revealed stage of lactation (SOL), milk yield in previous lactation and test day milk yield in Deoni cows, as well as parity and mastitis treatment history in current lactation in HF crossbred cows as risk factors. SOL was a significant factor under field conditions. Receiver operated characteristic curve analysis revealed better accuracy of CMT than DEC. We found more mixed infections due to Staphylococcus sp. and Streptococcus sp. in culture, while 16s rRNA based molecular method revealed lesser-known pathogens associated with SCM. It is concluded that SCM prevalence rate is higher in crossbred than indigenous cows and these breeds have different risk factors for SCM. HF crossbred cows had similar SCM prevalence rate under different farming conditions, where CMT can be used for SCM diagnosis with excellent accuracy. The 16s rRNA method is useful for specific identification of lesser known and emerging mastitis pathogens.

Donkey Colostrum and Milk: How Dietary Probiotics Can Affect Metabolomic Profile, Alkaline Sphingomyelinase and Alkaline Phosphatase Activity

Positive results on animal health, feed efficiency, and milk’s nutritional content have been obtained after oral administration of probiotics. The aim of the present study was therefore to evaluate the effect of dietary supplementation with high numbers of multispecies probiotic formulations on the milk metabolomic profiles of alkaline sphingomyelinase (alk-SMase) and alkaline phosphatase (ALP) in donkeys. Twenty animals were randomly allocated to receive either a normal diet (group B) or a supplemented diet (group A). Colostrum and milk samples were obtained within 48 h, at 15 days (supplementation start), and at 45 days after parturition. Different metabolomic profiles were observed between colostrum and milk, as were the concentrations of 12 metabolites that changed following 30 days of probiotic supplementation. Alk-SMase activity was found to be higher in donkey colostrum (vs. milk at 15 days); this enzyme, together with ALP, increased in milk after 30 days of probiotic supplementation. The results of the present study provide new insight into the complex changes in donkey colostrum and milk composition in the first 45 days of lactation and how the milk metabolome can be modulated by probiotic supplementation.

Effects of pathogen-specific clinical mastitis occurrence in the first 100 days of lactation 1 on future mastitis occurrence in Holstein dairy cows: An observational study

The objective of this observational study was to estimate effects of clinical mastitis (CM) cases caused by different pathogens (Streptococcus spp., Staphylococcus aureus, Staphylococcus spp., Escherichia coli, Klebsiella spp., and CM cases with no growth) occurring in the first 100 d in lactation 1, of a dairy cow on the future rate of occurrence of different types of CM during a cow's full lifetime. The outcomes were occurrence of Streptococcus spp., Staphylococcus aureus, Staphylococcus spp., Escherichia coli, Klebsiella spp., and CM cases with no growth, after the first 100 d of lactation 1, until a cow's removal through death or sale in that or a subsequent lactation. Data, including information on CM cases, milk production, and event dates (including death or sale dates), were collected from 14,440 cows in 5 New York State Holstein herds from January 2004 until February 2014. Generalized linear mixed models with a Poisson distribution and log link function were fit for each pathogen. The individual cow was the unit of analysis. Escherichia coli was a predictor of future occurrence of E. coli, Klebsiella spp., and CM cases with no growth. Early-occurring Klebsiella spp. was a predictor of future cases of Klebsiella spp. Cases with no growth were predictors of future occurrence of Staphylococcus spp., E. coli, Klebsiella spp., and cases with no growth. Thus, E. coli and cases with no growth occurring early in lactation 1 appear to be consistent risk factors for future cases of CM, whether cases with the same pathogen or a different pathogen. In this study, farm effects on later pathogen occurrence differed somewhat, so treatment protocol and culling strategy may play a role in the findings. Nevertheless, the findings may help farmers in managing young cows with CM in early productive life, especially those with E. coli or cases with no growth, in that they may be more susceptible to future CM cases in their later productive life, thus meriting closer attention.

Estimating Excreted Nutrients to Improve Nutrient Management for Grazing System Dairy Farms.

Improving nutrient management in grazing system dairy farms requires determining nutrient flows through animals, the placement of cows within farms and potential for collection, and the re-use and loss of nutrients. We applied a model incorporating data collected at a range of temporal and spatial scales to quantify nutrient excretion in all locations that lactating herds visited on five days over a year on 43 conventional and organic grazing system dairy farms. The calculated nutrient loads excreted by cows in different places were highly skewed; while N, P and K deposited loads were consistent across the year, S, Ca and Mg loads varied between sampling times and seasons. The greatest mean and range in nutrient loads were deposited in paddocks, with the smallest amounts deposited in dairy sheds. All excreted nutrient loads increased with farm and herd sizes and milk production. Mean daily loads of 112, 15, 85, 11, 22 and 13 kg of N, P, K, S, Ca and Mg were deposited by the herds which, when standardised to a 305-day lactation, amounted to 24, 4, 20, 3, 5 and 3 t excreted annually, respectively. In addition to routine manure collection in dairy sheds, ensuring collection and recycling of nutrients excreted on feed pads and holding areas would decrease potential nutrient losses by 29% on average. Non-collected, recycled nutrients were disproportionately returned to paddocks in which cows spent time overnight, and except for S and Ca, nutrient loading rates were greater than rates applied as fertilisers. These data demonstrate the extent of excreted nutrients in grazing dairy systems and indicate the need to account for these nutrients in nutrient management plans for Australian dairy farms. We propose incorporating excretion data in current budgeting tools using data currently collected on most Australian grazing system dairy farms.

Association of precalving serum NEFA concentrations with postpartum diseases and reproductive performance in multiparous Holstein cows: Cut-off values.

High concentrations of NEFA relative to a defined reference or 'cut-point' values before calving can predict the risk of specific or collective periparturient disease events. A field-based cohort study was conducted to evaluate the value and critical points of serum nonesterified fatty acids (NEFA) at the precalving time to predict the occurrence of postpartum diseases and reproductive performance in dairy cows. Blood samples were taken from 521 high-yielding dairy cows at 1 week (±3days) before calving and NEFA levels were measured. Health and reproduction information of each cow includes dystocia, retained placenta, milk fever, metritis, mastitis, pregnancy in the first insemination and pregnancy in the first two inseminations, and culling in the first 60 days of lactation and milk production. Our results show that there are significant relationships between precalving NEFA with the probability of pregnancy at the first and the first two inseminations after calving. The cows that had NEFA concentrations less than 0.5mmol/L at the last week of pregnancy were 3.51 and 3.15 times more likely to be pregnant at first insemination and the first two inseminations, respectively. Also, our results showed that there are significant relationships between precalving NEFA concentration and the likelihood of dystocia and milk fever. The probability of dystocia and milk fever occurrence were 2.56 and 1.91 times greater in those cows that had NEFA concentrations more than 0.3mmol/L, respectively. The present results indicated that Increasing NEFA during the prepartum period could adversely affect the reproductive efficiency of dairy cows.

Dairy productivity of cows of different genealogical lines and the quality of the cheese

Providing the population of the country with high-quality food products of its own production is one of the most important tasks facing the employees of the agro-industrial complex of the country. Milk is such product. It also acts as a raw material for the processing industry, which produces a large range of dairy products, including cheeses. Special requirements are imposed on the milk used for the production of cheeses. Three groups of cows were formed: the 1st without taking into account the belonging to genealogical line (n=60), the 2nd cows belonging to the line Reflection Sovereign 198998 (n=15), the 3rd cows belonging to the line Wes Back Ideal 1013415 (n=15). The groups were formed taking into account age, live weight and milk productivity according to previous lactation by the method of balanced groups. All cows were on the third lactation. According to milk yield for lactation, the cows of the line Refl ection Sovereign 198998 turned out to be the best, according to milk yield for 305 days of lactation, cows of the 1st group (excluding line belonging). According to physic and chemical indicators, milk from cows of the line Refl ection Sovereign 198998 was inferior to milk from herdmates from other groups. Thus, in the milk of cows without taking into account the origin of the genealogical line, high indicators of nonfat milk solids and dry matter were observed, and in the milk of cows of the line Wes Back Ideal 1013415, a high content of fat, protein and lactose was noted. From the point of view of the fat : protein ratio, milk obtained from cows of the 2nd and 3rd groups was more valuable. During the production of Kostroma cheese, milk obtained from cows of the line Wes Back Ideal 1013415 turned out to be more stable, and cheese from this milk also received a high score according to an organoleptic assessment. In order to increase the production of high-quality cheese, it is necessary to pay attention to the breeding of cows of the genealogical line Wes Back Ideal 1013415.

Effect of body condition loss in early lactation Holstein cows on plasma IGF-I, prolactin and NEFA during breeding period and its association with some reproductive indices.

The associations between early lactation changes of the body condition score (BCS) and mid-lactation levels of blood insulin like Growth Factor-I (IGF-1), prolactin, insulin, non-esterified fatty acids (NEFA), milk production and some reproductive indices were investigated. Monthly milk yield and BCS were recorded. Blood samples were collected on days 60, 90 and 120 (±5 days) of lactation. Twelve and 17 cows showed BCS losses ≤0.75 and >0.75 on day 60, respectively. BCS losses ≤0.75 till d60 after calving enhanced the IGF-I concentration on d90 (57.8±10.7 vs 35.6±17.8 ng/ml; P=0.001). The differences of blood metabolites were prominent on d90. Trends of insulin changes between d60 BCS (P=0.04) groups were different. Inverse correlations were detected between IGF-I and NEFA (-0.6, P=0.001), IGF-I and milk production (-0.4, P=0.05), NEFA and prolactin (-0.8, P<0.001) on d90. Higher percentages of cows with BCS loss >0.75 (d60) showed their first heat after d40 postpartum. In conclusion, irrespective of BCS at the time of breeding, the level of BCS loss during the first 60 days of lactation may affect further reproductive performance due to prolonged alterations of IGF-I, NEFA, prolactin and insulin levels. The extent of postpartum BCS loss may be a predictor of metabolic status of cows during mid-lactation.

Effect of Prepartum Magnesium Butyrate Supplementation on Rumination Time, Milk Yield and Composition, and Blood Parameters in Dairy Cows.

Magnesium butyrate (MgB) supplementation of dairy cows during the three-week close-up period was tested for its effects on blood energy analytes, rumination time, inflammation, and lactation performance. Daily milk yield was recorded and weekly milk samples collected for the first 70 days of lactation from MgB supplemented (MgB, n = 34), and unsupplemented (Control, n = 31) multiparous Holstein-Friesian cows. During a period from week 3 to week 10 postpartum, blood samples were taken and analyzed for various parameters, and ruminant activity was measured. The MgB group yielded 25.2% more milk than the Control during week 1, and had increased milk fat and protein concentrations over a longer duration. Somatic cell counts (SCC) were decreased in the MgB group independent of days in milk. No differences were observed between groups in terms of plasma non-esterified fatty acids, β-hydroxybutyrate, glucose, or blood iCa levels. The MgB group had lower haptoglobin (Hp) levels during lactation relative to the Control group. Time spent ruminating increased after calving with MgB due to a shorter post calving rumination delay relative to the Control group. Prepartum MgB supplementation improved lactation performance without affecting blood energy analytes. The basis by which MgB also improved rumination activity remains to be determined, as DMI could not be assessed. As MgB lowered SCC and Hp concentrations, it is speculated that MgB may help minimize postpartum inflammatory processes.

Clinical and sonographic changes in the uterus of repeatedly over -walking cows with subclinical endometritis

The research was carried out at a modern high-tech dairy enterprise using robotic milking (GEA DairyProQ JV "Donskoye" of the Volgograd region with the productivity of cows over 15,000 kg for 305 days of lactation. Rectal palpation of the uterus in cows with subclinical endometritis showed the presence of a pronounced cavity, which was 2.78 times higher than that in clinically healthy animals of the same study period, and the thickness of the uterine wall in subclinical endometritis averaged 9.23± 0.21 mm, which was 1.41 times higher than similar data in healthy animals. According to sonography data, the endometrium acquired an echoneodnomogeneous structure, which is caused by the ongoing inflammatory process. Dilated blood vessels are visualized in the myometrium. The revealed zone of reduced density at the border of the muscular and mucous layers is characterized by hyperechogenicity, which indicates signs of developing edema. The study of the perimeter revealed no structural changes. The detailed sonographic signs of subclinical endometritis in repeatedly overworking highly productive cows showed that the endometrial condition did not correspond to normal echographic criteria in more than half of cases in sick cows during estrus. The presence of variable in shape and size areas of increased echogenicity in the horns of the uterus of the M-echo during the hunting period is noted. Hyperechogenic formations in the basal layer of the endometrium were found in every fifth sick cow with signs of subclinical endometritis who repeatedly overdo it, and in every second, with the manifestation of hunting, a clinically healthy animal. The endometrial echostructure was found to be inconsistent with the stage of sexual cycle arousal in cows with subclinical endometritis in comparison with repeatedly over-walking animals without symptoms of uterine pathology. When comparing the obtained linear parameters of the uterus by rectal palpation of its anatomical structures with the parameters of the sonographic data, their correspondence was noted in both study groups. Ultrasound diagnostics provides an objective assessment of the state of the uterus and allows you to differentiate the nature of the pathological process.

Association of pathogen-specific clinical mastitis in the first 100 days of first lactation with productive lifetime: An observational study comparing competing risks models for death and sale with the Cox model.

The objective of this observational study was to study the association between clinical mastitis (CM) (Streptococcus spp., Staphylococcus aureus, Staphylococcus spp., Escherichia coli, Klebsiella spp., cases with other treated or other not treated organisms, CM without growth) occurring in a dairy cow's first 100 days (d) of her first lactation and her total productive lifetime, ending in death or sale (for slaughter). Data were collected from 24,831 cows in 5 New York Holstein herds from 2004 to 2014. Two analytical approaches were compared. First, removals (death, sale) were treated as competing events in separate survival analyses, in proportional subdistribution hazards models. In one, death was coded as the event of interest and sale as the competing event; in another, sale was the event of interest and death the competing event. Second, traditional survival analysis (Cox proportional hazards) was conducted. In all models, the time variable was number of days from date of first calving until event (death or sale) date; if the cow was alive at study end, she was censored. Models were stratified by herd. Ten percent of cows died; 48.4 % were sold. In the competing risks analysis, E. coli and CM without growth were associated with death; the former with an increased hazard rate of death, the latter with a lower one. Streptococcus spp., Staph. aureus, Klebsiella spp., cases with other treated or untreated organisms, and CM without growth were associated with higher hazard rates of sale. The Cox proportional hazards model's hazard rates were higher than those in the competing risks model in which death was the event of interest, and resembled those in the model in which sale was the event of interest. Four additional Cox models, omitting dead or sold cows, or censoring each, were also fitted; hazard ratios were similar to the above models. Proportional subdistribution hazards models were appropriate due to competing risks (death, sale); they produce less-biased estimates. A study limitation is that while proportional subdistribution hazards models were appropriate, they have the illogical feature of keeping subjects at risk for the event of interest even after experiencing the competing event. This is, however, necessary in estimating cumulative incidence functions. Another limitation concerns pathogen variability among study farms, implying that CM decisions are farm-specific. Misclassification of 'dead' vs. 'sold' cows was also possible. Nevertheless, the findings may help in optimizing management of cows contracting specific types of CM early in productive lifetime.

EVALUATION OF LACTATIONAL EXCRETION OF UREA AND AMMONIA IN DAIRY CATTLE HERDS

The aim of the study was to evaluate the lactational unit production of urea and ammonia emissions from cows kept in eastern Poland. The study covered 1089 lactations of Polish Holstein-Friesian cows born between 1992 and 2018 in 15 cattle herds located in the Mazovia and Podlasie voivodships. The amount of urea excreted in urine and nitrogen compounds in cow feces was calculated based on the following regression equations: (y = 15.46 urea concentration in milk (g/L) + 193.4); y = 11.42 urea concentration in milk (g/L) + 41.93); y = 4.05 urea concentration in milk (g/L) + 151.47). Several factors affecting the total production of urea were examined. Four groups of animals were distinguished according to their milk yield from a 305-day lactation (&lt;6000; 6001-8000; 8001-10000; &gt;10000 kg); three groups based on year of birth (1992-2000; 2001-2010; 2011-2018); four age groups (first lactation; second lactation; third lactation; fourth to twelfth lactation); and three groups according to urea content in milk (1-150; 151-250; &gt;250 mg/L). The results of the study showed that the average concentration of urea in cow urine was 78.6 kg and the ammonia emission from a lactating cow was 44.6 kg. The study demonstrated a large variation in the amount of nitrogen compounds excreted in feces and the degree of ammonia emission risk among animals. The main factors differentiating the amount of nitrogen compounds in urine and feces and the level of ammonia emission into the atmosphere included the cow's production level, year of birth, and urea content in milk.

Lactational exposure to Deoxynivalenol causes mammary gland injury via inducing inflammatory response and impairing blood-milk barrier integrity in mice

Lactation is a unique physiological process to produce and secrete milk. Deoxynivalenol (DON) exposure during lactation has been demonstrated to affect adversely the growth development of offspring. However, the effects and potential mechanism of DON on maternal mammary glands remain largely unknown. In this study, we found the length and area of mammary glands were significantly reduced after DON exposure on lactation day (LD) 7 and LD 21. RNA-seq analysis results showed that the differentially expressed genes (DEGs) were significantly enriched in acute inflammatory response and HIF-1 signaling pathway, which led to an increase of myeloperoxidase activity and inflammatory cytokines. Furthermore, lactational DON exposure increased blood-milk barrier permeability by reducing the expression of ZO-1 and Occludin, promoted cell apoptosis by upregulating the expression of Bax and cleaved Caspase-3 and downregulating the expression of Bcl-2 and PCNA. Additionally, lactational DON exposure significantly decreased serum concentration of prolactin, estrogen, progesterone. All these alterations eventually resulted in a decrease of β-casein expression on LD 7 and LD 21. In summary, our findings indicated that lactational exposure to DON caused lactation-related hormone disorder and mammary gland injury induced by inflammatory response and blood-milk barrier integrity impairment, ultimately resulting in lower production of β-casein.

Dynamics of clinical symptoms of damage to the shin of newborn Ukraini-an red dairy breed under industrial exploitation conditions

The analysis of the data of the 5-year monitoring of the visual (in points) examination of the firstborns (n = 1113) of the newly created Ukrainian red milk (URD) breed for the assessment of the clinical condition of the lateral surface of the lower leg under the conditions of unharnessed keeping on rubber mats is presented. An increase in the number of cows with damage to the epithelium of the leg skin (“gateway of infection”) along the chronological axis (2018–22), namely: from 33.88 ± 3.97 % to 55.95 ± 5.94 % (P &lt; 0.01). Pronounced inflammatory phenomena (purulent-necrotic) in the area of the tibial joint increased by 15.05 % (P &lt; 0.01), and symptoms of severe damage to all tissues of the tibial area with signs of lameness increased from 0.96 ± 0.96 % to 4.11 ± 0.95 % (P &lt; 0.05). The dynamics of the increase in the symptom complex of shin pathologies in firstborns showed a positive correlative relationship with the growth of milk productivity (in 2018, the average milk yield for 305 days of lactation was 6999.13 kg, and in 2020 – 8947.25 kg). Still, the trend of increasing clinical damage to firstborns' shins remained even after the drop in productivity in 2021 to 7995.00 kilograms of milk. The analysis of the results of the study showed a tendency to decrease the adaptive properties of young cows of the URD breed, which probably can be connected with a high degree of Holsteinization of the population of the newly created breed, during which the negative microevolutionary consequences of the rapid transformation of the genotype were manifested, which require further research.

Plant raw materials for correction of reproductive function of cows

The article presents data on the study of the effect of the supplement Lamarin Saldonum on the reproductive ability of highly productive cows. The experiment was conducted in the APC collective farm "Iskra" (Kotelnichsky district, Kirov region). The experiment involved cows of a black-and-white Holstein breed aged 2-5 lactation, with a milk yield of 7,500 kg for 305 days of the previous completed lactation, divided according to the principle of analogues into experimental groups O1, O2, O3 and control K4 (n=5). The additive was introduced into the ration of cows in groups O1, O2 and O3 30 days before the expected date of calving for 2 months (60 days) daily in doses of 0.3, 0.4 and 0.5 g/kg live weight per day respectively. It was found that the use of dietary supplements in these doses does not affect the duration of pregnancy of females and the timing of their arrival in the hunt after calving. However, it reduces the number of spermodoses spent per fruitful insemination by 7,69; 46,15 (p?0,01) and 23,08 % (p?0,05), the number of days from calving to fruitful insemination by 19, 65 (p?0,01), 38,24 (p?0,001) and 27,27 % (p?0,001), and period of infertility by 32,81 (p?0,01), 63,84 (p?0,001) and 45,54 % (p?0,001) respectively relative to group K4 (intact animals). According to the conducted studies, the most optimal dose for correcting the reproductive function of cows is an additive dose of 0,4 g per 1 kg of live weight.