Increasing milk production requires increasing milking frequency (MF) from two times daily (2X) to three (3X) or more. High milk production leads to negative energy balance (NEB) and homeorhesis, ...characterized by lipolysis, ketogenesis, and endocrinological changes. The relationship among energy balance (EB), lipolysis, and ketogenesis with endocrine and metabolic parameters in blood of cows milked 2X and 3X daily was studied. Holstein Friesian cows milked 2X (n = 45) and 3X (n = 45) were analyzed, with approximately 50% of cows in each group in positive EB (PEB) and 50% in NEB. After determining EB, blood samples were collected from all cows and blood serum was analyzed for non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), glucose (GLU), cholesterol (CHOL), triglycerides (TGC), total bilirubin (TBIL), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), calcium (Ca), inorganic phosphate (P), total protein (TPROT), albumin (ALB), urea, insulin (INS), T3, T4, and cortisol (CORT), and the RQUICKIBHB index of insulin resistance was calculated. Cows milked 3X in NEB represent a special cluster that partially overlaps with cows milked 2X in NEB and has no contact points with cows in PEB. Cows milked 3X had higher levels of NEFA, BHB, AST, GGT, TBIL, and CORT and lower levels of GLU, Ca, INS, and T4. Cows milked 3X in NEB had higher levels of NEFA, BHB, AST, GGT, TBIL, and CORT and lower levels of GLU, CHOL, TGC, TPROT, P, INS, RQUICKIBHB, and T3 compared with cows milked 2X in NEB and cows in PEB. In cows milked 3X, lipolysis and ketogenesis were much more prominent, and EB levels were lower, implying a pronounced shift in homeorhesis. Metabolic and endocrinology parameters were determined mainly by the values of EB, NEFA, and BHB in cows milked 3X in NEB compared with other categories of cows. The results confirm the peculiarity of metabolic adaptation in cows with increased MF, characterized not only by differences in the concentration of metabolites but also in their interactions.
This study aimed to determine blood and milk metabolic parameters and their correlations for the purpose of evaluating metabolic status in dairy cows. Blood and milk samples were collected from 100 ...Holstein dairy cows during morning milking. The cows were allocated to four groups according to the production period, including cows in early (n = 18), full (n = 26), mid (n = 25) and late (n = 31) lactation. The value of non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), glucose, triglycerides (TG), total cholesterol (TChol), total protein (TP), albumin, globulin, urea, total bilirubin (TBil), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), and lactate dexydrogenase (LDH) in the blood were determined. The following milk parameters were measured: fat, protein, lactose, urea, AST, ALT, ALP, GGT, LDH and BHB. Blood serum NEFA, BHB, TBil, AST, ALT, ALP and LDH were higher in early lactation cows, whereas glucose, TP, globulin and urea levels were significantly lower in early lactation cows. Milk fat and lactose levels were lower in early lactation cows, whereas milk protein and the activities of AST, ALT, ALP and LDH in milk were highly greater in early lactation cows. Milk fat was positively correlated with glucose, TP and TG, and negatively correlated with BHB, NEFA, TBil, ALT, LDH and ALP levels in the blood. Enzyme activities in milk were positively correlated with those in blood and with blood NEFA, BHB and TBil levels, and negatively correlated with blood glucose, TChol and TG. A significant positive correlation existed between blood and milk BHB values. Many correlations showed the same slope during all lactation periods. In conclusion, similar changes in blood and milk metabolite concentration during lactation and milk to blood correlations confirm that milk has great potential in predicting of blood metabolites and metabolic status of cows.
Frequent phlebotomies, even when only a small volume of blood is taken for diagnostic purposes, can lead to the development of iron deficiency with hematological and metabolic changes. The study ...aimed to determine the influence of frequent blood loss by phlebotomy on blood iron concentration (Fe), hematology, metabolic and endocrine parameters and their relationships. Blood samples were collected from 30 blood donor rams for 6 consecutive weeks, with approximately 10% of blood collected weekly. Such chronic blood loss resulted in a decrease in Fe. Indicators of iron transport in the bloodstream changed, so the value of total iron-binding capacity (TIBC) and unsaturated iron-binding capacity (UIBC) increased, while the value of transferrin saturation percentage (TS%) decreased. Hematological changes included a decrease in red blood cells, hemoglobin, mean red blood cell volume and hematocrit and a tendency for reticulocyte count and red cell distribution width to increase. Chronic blood loss resulted in a specific metabolic response that included the increase in glucose, cholesterol, triglycerides, aspartate-aminotransferase, and insulin resistance, while thyroxine, triiodothyronine and cortisol decreased and there was a tendency for lactate to increase and BHB to decrease. The mentioned blood parameters correlated with Fe and additionally showed greater changes when Fe was extrapolated to the level of clinical deficit (Fe=9μmol/L). These correlations suggest the need to monitor the metabolic and endocrine status during chronic blood loss, in addition to Fe and erythrocyte indices. Compared with previous results in other animal species, Fe may have a direct influence on metabolic processes in rams.
The reproductive efficiency of the cows was monitored after two resynchronization protocols: Ovsynch (OVS) and Double Ovsynch (DOS). The research initially included 70 HF cows who entered the first ...synchronization protocol – Presynch. Cows that did not conceive after the first synchronization were divided into two groups and introduced to two resynchronization protocols. In the first group of cows (n=35), the DOS protocol began with the application of GnRH on day 22 after the Presynch TAI (Timed Artificial Insemination), and seven days later pregnancy check-up was done and PGF
was applied only to non-pregnant cows (n=23), which remained in the study. In the second group of cows, the OVS protocol started on day 32 after Presynch TAI only in non-pregnant animals (n=20). Progesterone (P4) concentration was determined at the time of application of GnRH1, PGF
and GnRH2 in both groups of cows, and then 30 days after Resynch TAI, ultrasound pregnancy diagnosis was done. A higher percentage of pregnant cows were recorded in the OVS group compared to the DOS group (45% and 35%, respectively). The concentration of P4 in the serum of cows in the DOS group during the first measurement (GnRH1) was significantly higher than the value in cows that did not conceive (p<0.05), while in the third measurement (GnRH2) the average concentration of P4 in conceiving cows was significantly lower (p<0.001) compared to cows that did not coincive. The open days period was significantly longer in pregnant cows that were resynchronized using the DOS protocol compared to cows from the OVS protocol. In conclusion, the OVS protocol of estrus resynchronization in dairy cows proved to be more successful than the DOS protocol. However, considering the advantages the OVS, it is needed to determine which day of the sexual cycle is the best to start resynchronization.
The Total Bacterial Count (TBC) and the Somatic Cells Count (SCC) in the milk are important indicators of its hygiene and quality. Hygienic conditions in barns, milking procedures, udder hygiene ...before, during and after milking, milking machine hygiene, as well as milk cooling procedures immediately after milking, have direct or indirect influences on milk hygiene indicators. Poor results of milk hygiene quality, when it comes to SCC and TBC, which are often seen in dairy cattle farms in our country, indicate numerous omissions before and during milking. To determine the possibility of improving milk hygiene quality, training of extension service professionals and farmers was conducted, corrective and preventive measures were determined and the achieved state was monitored on 128 dairy farms where SCC and TBC were observed at regular monthly intervals for 6 months. The results showed a continuous statistically very significant improvement in hygienic conditions in barns, milking procedures, udder hygiene before, during and after milking, milking machine hygiene, as well as milk cooling procedures. This has contributed to a statistically very significant improvement in the hygienic quality of milk, both in SCC and TBC indicators, continuously from month to month, with a visible improvement at the end related to the beginning of the study period. At the begining and the end of survey 19.7% and 50.0% of milk samples belong to 1
class of milk quality, respectively, indicating a significant improvement after implementation of corrective measurements.
The main subject of the research is the assessment of the knowledge, attitudes and behaviors of veterinarians regarding the use of antibiotics (AMU) and antimicrobial resistance (AMR) through a ...questionnaire conducted among veterinarians in the northern region of Serbia. A total of 62 respondents completed the questionnaire, which represents a response rate of 44.3%. Male veterinarians are less likely to be in the group of veterinarians with insufficient knowledge (p < 0.05). Veterinarians engaged in mixed practice (small and large animals) (p < 0.001) and veterinarians who have over 100 patients per month (p < 0.005) are also less likely to be in the group with insufficient knowledge of antimicrobial resistance. The proportion of those with insufficient knowledge is growing among veterinarians whose source is the Internet (p < 0.01), while the proportion of those with insufficient knowledge about antimicrobial resistance is declining among veterinarians whose source of information is continuous education (p < 0.05). The majority of the respondents (n = 59, 95.2%) completely agreed that AMR is a very big issue in the global health sector right now. Unfortunately, there are crucial gaps in the knowledge and attitudes of the surveyed participants. They do not appear to be aware of the importance of AMU in veterinary medicine and its influence on overall AMR, or the crucial part that non-prescribed antibiotics have in all of it. Positively, many veterinarians use good practice AMU guidelines in their everyday practice and in line with the global trend of AMU reduction, respondents have also decreased their AMU compared to the previous year.
A study on claw disorders" infl uence on milk production was performed during one year on 226 Simmental loose-reared cows. The first trial group included 42, the second 37, and the third 34 cows, ...with claw changes observed in the first hundred days of lactation, between days 101 and 200, between days 201 and 305, respectively. The control group included 113 cows with no observed changes. Lameness intensity was assessed once a week. Milk yield data were collected three weeks before, in the week of treatment of claws and three weeks afterwards. There were significantly more cows with lameness in the third group than in the other two groups, as well as the most cows with one aff ected limb in the first hundred days of the lactation (P<0.05). Significantly fewer cows with two aff ected limbs were present in the first group. In the second group, more cows were observed with two aff ected limbs than in the first group (P<0.05). In the third group, more cows with three or four aff ected limbs were noticed than in the other groups. The most common claw disorders were: solar ulcer, laminitis, dermatitis digitalis and overgrown claws. Cows whose claws were aff ected between days 101 and 200 of lactation period produced 231 kg less milk than those of the control group; cows whose claws were aff ected in the last third of lactation produced 26 kg less milk. Nevertheless, no significant diff erences were found between milk yields of the control and trial groups (P>0.05). Cows aff ected in the first third of lactation produced less milk (324 kg) than both healthy and cows with claw changes manifested in later stages of lactation. Obtained data confirm that claw disorders may aff ect dairy production.
Summary The purpose of this paper is to determine the reference ranges for hematological, biochemical and endocrinological parameters in the blood of the commercial F1 Landrace x Yorkshire and ...Yorkshire x Landrace piglets aged 1 and 21 days. A total of 72 animals were enrolled in this study. The following reference ranges were determined for the blood parameters considered (day 1 vs. day 21): WBC 10.0-12.4 vs. 11.5-13.7 × 10 9 /L; RBC 3.72-4.06 vs. 5.25-5.73 × 10 12 /L; HGB 71.4-79.0 vs. 100-110 g/L; HCT 24.4-26.5 vs. 35.7-39.1 %; MCV 64.4-66.0 vs. 72.7-74.8 fL; MCH 20.9-21.7 vs. 24.7-25.6 pg; MCHC 321-329 vs. 367-378 g/L; AST 78.5-98.9 vs. 51.8-66 U/L; ALT 72.5-84.5 vs. 65.9-76.5 U/L; CHOL 2.41-2.71 vs. 3.81-4.27 mmol/L; TGC 1.55-1.93 vs. 1.85-2.25 mmol/L; GLU 5.58-6.24 vs. 5.97-6.67 mmol/L; TPROT 55.2-59.4 vs. 65-69.9 g/L; ALB 13.4-15.1 vs. 27.8-30.9 g/L, GLOB 41.3-44.8 vs. 35.3-40.9 g/L; UREA mmol/L; TBIL 36.6-44.5 vs. 29.4-40.8 μmol/L; ALFAAMYLASE 897-998 vs. 851-949 U/L; LIPASE 74.1-79.7 vs. 88.3-98.1 U/L; CORT 140-196 vs. 41.4-63.8 ng/mL; INSUL 4.04-5.68 vs. 1.71-2.41 μU/L. The RBC, HGB, HCT, MCV, MCH, and MCHC values recorded were found to be higher in the piglets aged 21 days than those in the piglets aged 1 day. The total leukocyte count did not differ between the experimental groups. Lower AST, ALT, globulin, cortisol and insulin values were detected in the piglets aged 21 days than those in the piglets aged 1 day. However, the values of triglycerides, cholesterol, total protein, albumin and lipase were found to be higher in the piglets aged 21 days than those in the piglets aged 1 day. The glucose, alpha amylase and total bilirubin (TBIL) values did not differ significantly between the experimental groups. The Kolmogorov-Smirnov test conducted shows that there are significant differences in the frequency distribution of most of the blood parameters tested in the pigs aged 1 and 21 days, which confirms that a separate reference interval must be determined and applied to the respective piglet ages considered. The establishment of reference values for different age categories can facilitate the assessment of health status and productive performance of farm piglets.
The climatic conditions in Serbia are suitable for the development of heat stress in cows. The values of the bioclimatic THI indicator point to a positive trend in increase in the number of days ...during which the conditions for the occurrence of heat stress are present. In cows, a change in body temperature is noted, activation of the cooling mechanisms, along with reduced milk production and reproductive efficiency. The behavioral changes of cows occur on farms, and the level of welfare decreases slightly when measured according to animal-based criteria. Changes in productivity are mainly related to metabolic, hematological and inflammatory adaptations. The metabolic adaptation that leads to a decrease in milk production is related to an increase in sensitivity to insulin with reduced lipolysis, an increase in TNF-a in cows, as well as to metabolic rearrangements of the mammary gland. Reproductive efficiency is reduced and is characterized by reduced expression of estrus and reduced response to estrus induction procedures. High ambient temperatures, in in vitro conditions, can affect the stability of laboratory parameters in the blood serum of cows. Cows exhibit different profiles of resilience to heat stress, and the study of resilience curves, for productive and blood parameters, represents the starting point for selecting cows that will tolerate heat stress better. For this purpose, the cumulative effects of heat stress expressed in the area under the resilience curve can be used. Certain precautionary measures such as providing shade, cooling by using fans and sprinklers or some other advanced technological methods, can reduce losses during heat stress. All of the above indicate that it is necessary to pay extra attention to all aspects of health care and production on cow farms in Serbia during late spring and summer when the animals are exposed to heat stress.
PDF
