Određivanje optimalne veličine folikula za dobivanje najkvalitetnijih oocita za in vitro oplodnju

The aim of this study was to determinate optimal follicular size for collection of high quality oocytes, and the subsequent capacity of the oocyte to mature and be fertilized and to develop in vitro. The ovaries of dairy cows were cut out immediately after slaughter and transported within one hour. The follicles were separated and divided into three groups according to diameter, i.e. small (3-5 mm), medium-size (6-9 mm), large (10-20 mm). Quality grading (A, B, C, D) of the oocytes was performed on the basis of cumulus cell development and homogeneity of cytoplasm. A total of 284 COCs were aspirated from 123 ovaries. Among 143 COCs, 236 were grades A and B and 48 were grades C and D. The maturation rate of the oocytes from medium size follicles A and B grade was 56.01% better than C and D grade. Only A and B graded oocytes were fertilized in vitro with 1×106 sperm/mL using Fert-TL, with 0.3% BSA, 22 μg/mL sodium pyruvate, 10 μg/mL heparin. The cleavage rate in the small follicle oocytes was significantly lower (35.89%) than in the medium-size follicle oocytes (56.41%), and a similar trend was observed in the morula development rates, independent of the oocyte grade. Good quality oocytes received from medium size follicles, and oocytes with more than three complete layers of cumulus cells (Grades A and B) have better competence for in vitro maturation and cleavage.Cilj ovoga istraživanja bio je odrediti optimalnu veličinu folikula kako bi se prikupile oocite visoke kvalitete s obzirom na visoki kapacitete za sazrijevanje, oplodnju i razvoj in vitro. Jajnici krava mliječne pasmine izrezani su odmah nakon klanja i prevezeni unutar sat vremena. Folikuli su izdvojeni i podijeljeni u tri skupine s obzirom na njihov promjer: u skupinu malih folikula (3 - 5 mm), skupinu folikula srednje veličine (6 - 9 mm) i skupinu velikih folikula (10 - 20 mm). Stupnjevanje kvalitete oocita (A, B, C, D) učinjeno je na temelju razvoja kumulusnih stanica i homogenosti citoplazme. Aspirirane su ukupno 284 kumulusne oocite iz 123 jajnika. Od ukupno 284 kumulusne oocite njih 236 bilo je A i B-stupnja, a 48 ih je bilo C i D-stupnja. Sazrijevanje oocita iz skupine folikula srednje veličine A i B-stupnja bilo je 56,01 % bolje od onih stupnja C i D. Samo su oocite A i B-stupnja oplođene in vitro s 1×106 sperme po mililitru uz upotrebu Fert-TL-a, s 0,3 % Bovine Serum Albumin-a, 22 μg/mL natrijeva piruvata i 10 μg/mL heparina. Brazdanje oocita dobivenih iz folikula male veličine bilo je znakovito niže (35,89 %) nego u skupini folikula srednje veličine (56,41 %), a slično je uočeno i u razvoju morula, neovisno o kvaliteti oocita. Zaključeno je da oocite dobre kvalitete dobivene u skupini folikula srednje veličine, oocite s više od tri cjelovita sloja kumulusnih stanica (stupnjevi A i B) imaju veće šanse za sazrijevanje in vitro i brazdanje

Superovulacijski odgovor prvog dana liječenja i njegova povezanost s veličinom i položajem jajnika kod visokoproizvodnih mliječnih krava.

The aim of this research was to determine the relation between the size of ovaries, their topographic position, ovarian structures (follicles (F) and corpora lutea (CL)) before superovulatory treatment and the superovulatory response and embryo yield. Holsteinized dairy cows (32) were treated for superovulation with Pluset® (Laboratorios Calier, S.A., Barselona, Spain). On Day 1 of the superovulatory treatment and during the procedure to recover the embryos, we examined the ovaries of donors with an ultrasound scanner. The ovaries were divided into 3 groups according to their size. Group 1 ovaries (1112.0 mm2) were 25 % larger than Group 2 ovaries, the area of which varied from 668.0 to 1112.0 mm2 (mean, 890.0 mm2 ± 25 %). After superovulation, the mean area of the right side ovaries (RSO) (3147.61 ± 106.6 mm2) was by 27.3 % (P0.05) compared with the LSO. The most intense response to the superovulatory treatment by ovary size was observed in Group 1 ovaries: the RSO increased by 5.5 times and the LSO by 4.8 times, but according to the absolute measure, the greatest increase was observed in Group 3, where ovaries on both sides increased 2.4 times. According to the number of CL, Group 1 RSO donors showed a 2.3 times (P1112,0 mm2) više od 25 % veći od jajnika skupine 2. Nakon postupka superovulacije, srednja veličina (3147,61 ± 106,6 mm2) desnih jajnika (DJ) bila je 27,3 % (P0,05) u usporedbi sa LJ. Najintenzivniji superovulacijski odgovor s obzirom na veličinu jajnika opažen je u skupini 1: kod DJ povećanje je bilo 5,5, a kod LJ 4,8 puta, ali s obzirom na apsolutne mjere, najveći porast opažen je u skupini 3 u kojoj su jajnici s obje strane povećani 2,4 puta. S obzirom na broj CL, skupina 1 DJ davateljica pokazala je 2,3 puta (P<0,05) slabiji superovulacijski odgovor u usporedbi sa skupinom 3 DJ davateljica. Broj dobivenih embrija (9,8 ± 2,2) bio je 3,6 puta (P<0,05) veći među davateljicama 3 DJ skupine prije superovulacije u usporedbi sa davateljicama skupine 1 DJ (2,7 ± 0.5). Kod krava skupine 3 DJ, broj prenosivih embrija (6,3 ± 0,6) bio je 3,2 puta (P<0,05) veći u usporedbi s kravama davateljicama skupine 1 DJ (2,0 ± 0,3). Žuta tijela u DJ su pokazala signifikantni utjecaj od 85 % (P<0,05) na dobivanje embrija u usporedbi sa samo 30 % (P<0,05) u LJ

Prevalencija kliničkog metritisa i pokazatelji plodnosti u krava liječenih slabijim laserskim zračenjem i antibioticima u postpartalnom razdoblju.

The aim of the study was to compare the efficiency of low-intensity laser (LIL) irradiation, antibiotic injections and a combination of both methods in the prophylaxis and treatment of metritis in cows. Examinations were carried out on 290 freshly calved cows with a rectal temperature on the second day after parturition above 38.9 C. Cows from group I (n = 95) were given an intramuscular injection of ceftiofur hydrochloride (600 mg) for three days, commenced from the second day after parturition. Group II consisted of 55 cows, the sacroiliac area of which was irradiated for 10 days consecutively with LIL. Group III (n = 65) were given an intramuscular 600mg injection of ceftiofur for three days and the sacroiliac area was irradiated 10 times consecutively, once a day with LIL. The control group IV (n = 55) were not given antibiotics or laser irradiation. A number of cows, ranging from 57.1% (group III a) to 65% (group IV), developed clinical metritis, which was treated with antiseptics. The longest recovery time from metritis (21 ± 6.12 d) was found in the IV group. Cows from group III recovered from metritis 11.5 days more quickly than the cows from the IV (negative control) group (P<0.05) and 4 days more quickly than cows from the I (positive control) group. Fertility indices such as: calving-first insemination, service period, conception rate, insemination index and the calving-pregnancy period, were better in cows treated prophylactically with the combined method (antibiotic and LIL physiotherapy) in comparison to the other groups.U radu se uspoređuje učinkovitost slabijeg laserskog zračenja, primjene antibiotika i kombinacije obiju metoda u profilaksi i liječenju metritisa u krava. Istraživanje je bilo provedeno na 290 netom oteljenih krava s rektalnom temperaturom višom od 38,9 °C drugog dana nakon teljenja. Kravama I. skupine (n = 95) intramuskularno je bio primijenjen ceftiofur hidroklorid (600 mg) tijekom tri dana, počevši drugog dana nakon teljenja. U II. skupini bilo je 55 krava koje su bile zračene laserskim zračenjem u sakroilijačnom području tijekom 10 uzastopnih dana. Kravama III. skupine (n = 65) intramuskularno je bio primijenjen ceftiofur hidroklorid (600 mg) tijekom tri dana, a bile su zračene laserskim zračenjem u sakroilijačnom području tijekom 10 uzastopnih dana jedanput dnevno. Kontrolna skupina IV (n = 55) nije dobivala antibiotik niti je bila zračena. U određenog broja krava, od 57,1% (skupina IIIa) do 65% (skupina IV), razvio se klinički metritis, koji je bio liječen antisepticima. Najduže vrijeme oporavka od metritisa (21 ± 6,12 d) ustanovljeno je u skupini IV. Krave skupine III oporavile su se od metritisa za 11,5 dana brže od krava IV. (negativne kontrolne) skupine (P<0,05) i četiri dana brže od krava I. (pozitivne kontrolne) skupine. Pokazatelji plodnosti poput prvoga osjemenjivanja nakon teljenja, servisnog perioda, stope začeća, indeksa osjemenjivanja i razdoblja od teljenja do bređosti bili su bolji u krava kojima je bio profilaktički primijenjen antibiotik u kombinaciji s laserskim zračenjem u usporedbi s drugim skupinama

Investigation of electrical conductivity of milk in robotic milking system and its relationship with milk somatic cell count and other quality traits

The scientific research was carried out at Lithuanian University of Health Sciences, Veterinary Academy, state enterprise “Pieno tyrimai”, as well as in dairy farms running automatic voluntary (robotic) milking systems in Lithuania. A total data set of 462574 cow milking records was assessed in the research. The objectives of this investigation were to evaluate the milk electrical conductivity indicator from robotic milking system and to assess the genetic correlation with the indices collected in a database of Lithuanian dairy cattle, to estimate heritability coefficient using multiple traits mixed linear model with permanent environment effects. The research has shown, that the electrical conductivity of milk ranged from 4.6 to 5.8 ms/cm in milk samples where somatic cell count did not exceed 200 thousand/ml and variation in electric conductivity of milk can be treated as one of the main parameters for cows’ health monitoring system. A high coefficient of heritability of electrical conductivity of milk (h2 = 0.512 ± 0.028; p < 0.001) and a very low coefficient of heritability of somatic cell count (h2 = 0.032 ± 0.014; p < 0.001) was determined. The results of the research have also revealed a positive genetic correlation of electrical conductivity with milk somatic cell count (rg = 0.332 ± 0.016; p < 0.001). Electrical conductivity of milk from robotic milking system can be introduced as an indicator of mastitis prevention in dairy cows and genetic selection based on this trait may be possible

The relationship between milk progesterone and milk traits during estrus in dairy cows

The aim of this study was to evaluate relationship between milk progesterone concentration (P4) and milk traits at the start of estrus time and 12h after start of the estrus in dairy cows. The 96 milk samples of 48 Lithuanian dairy cows without reproduction disorders and 90–100 days after calving were evaluated. Cows were classified into two groups based on milk yield per day: <30 kg (n=20) and ?30 kg (n=28). Data were categorized by milk fat and protein content at the start estrus and 12h after start of estrus to evaluate relationship between P4 and milk traits examined. P4 at estrus time in dairy cows was significantly positively correlated with milk yield (P<0.001), whereas it was negatively correlated with milk protein (P<0.05-P<0.01) and fat at 12h after start of estrus. Dairy cows with F/P from 1.0 to 1.5 had the lowest P4 in milk. Results of the pregnancy in dairy cows were related with lower P4 and milk yield level (P<0.001), higher milk fat (P<0.05) and milk protein content (P<0.001). These cows had 1.90 times lower prevalence of the signs of subclinical ketosis (P<0.05) at estrus time when compared with non-pregnant cows. As a result, it was clearly demonstrated that P4 in dairy cows can help to evaluate and improve the reproductive properties of cows

Factors affecting expression of estrus in dairy cows with high milk yields

The objectives of this study were to define the effect of the milk progesterone (P4) concentration on estrus expression in dairy cows with high milk yield and to identify the effect of milk yield and parity on the milk P4 concentration and cow’s pregnancy after artificial insemination (AI). In this study, 48 clinically healthy cows without reproduction disorders, on day 90-100 after calving were used. At the beginning of estrus and 12 hours after the beginning of estrus, the milk P4 concentration in dairy cows with high milk yield (group 3) was higher than in group 2 (33.66; 22.36%) and in group 1 (51.60; 65.26%) (P 0.05) and the first (28.28%; P < 0.01) lactation ones (28.28%; P < 0.01). The milk P4 concentration at the beginning of estrus and 12 hours after the beginning of estrus in pregnant and non-pregnant cows was 2.58 and 3.32; 4.20 and 5.00 ng/ml, respectively (P < 0.001). As a result, it was concluded that high progesterone concentration affected the expression of estrus and pregnancy results in dairy cows, and the measuring of progesterone concentration in milk can be used as a non-invasive method to provide detailed information about fertility in high milk yield cows

The Association between Charolais Cows’ Age at First Calving, Parity, Breeding Seasonality, and Calf Growing Performance

The objective of this study was to evaluate the impact of cows’ calving ages and newborn calf body weight on the pre-weaning growth rates of calves under the farming conditions of a northeastern European country. The females were purebred Charolais cows that calved between 2019 and 2022. A total of 130 calves (bulls = 76; heifers = 54) were observed during the evaluation. The investigation showed that, based on gender, bulls had a 4.28% higher birth weight than heifers (p p p p p p p p < 0.05)

The Effect of Supplementation of Rumen-Protected Choline on Reproductive and Productive Performances of Dairy Cows

We aimed to evaluate the effects of organic herbal preparations containing rumen-protected choline (RPC) in dairy cow milk&rsquo;s BHB and progesterone (P4) concentration changes, reproduction, and production performances. Cows were divided into the following two groups: The CHOL (n = 60) cow diet was supplemented with 10 g/day RPC from 20 days pre-calving to 20 days post-calving, and CONT (n = 60) were fed a conventional diet. BHB and P4 concentrations were measured at 5&ndash;64 DIM and 21&ndash;64 DIM, respectively, with DelPro 4.2. BHB was lower in the CHOL group at 5&ndash;64 DIM than CONT p &gt; 0.05. The first post-calving P4 peak, p &lt; 0.001, was determined earlier in the CHOL group, and the P4 profile during 21&ndash;64 DIM was similar, p &gt; 0.05. The insemination rate was lower, and the interval between calvings was shorter. The first insemination time was earlier in the CHOL group, p &lt; 0.05. Milk yield was higher in the CHOL group at 21&ndash;64 DIM, p &gt; 0.05. The CHOL group had more fat in their milk at 31&ndash;60 DIM, p &lt; 0.05. There were no significant differences in protein and SCC between the groups, p &gt; 0.05. Based on our results, we concluded that the supplementation of RPC pre- and post-calving had statistically significant effects on the first peak of P4, and benefited the reproduction performances, milk yield, and milk fat during the early postpartum period

Electrical conductivity of milk in different milking phases and relationship with subclinical mastitis and mastitis pathogens of cows

The aim of the study was to investigate the relationships between the electrical conductivity of milk in different milking phases with subclinical mastitis and productivity of cows. Three hundred fourteen Lithuanian Black and White cows in 2-4 lactation months were evaluated with Lactocorder®. We found on average 6.28 mS/cm and 7.17 mS/cm, for respectively electrical conductivity at highest milk flow (ELHMF) and electrical conductivity during the initial time (ELAP). The average was 6.66 mS/cm for the maximum electrical conductivity after reaching the highest milking speed (ELMAX) and 0.79 mS/cm for (beginning peak difference of the electrical conductivity (ELAD). The somatic cell count (r=0.196) and milk yield (r=-0.222) showed the strongest unfavorable correlation (P<0.01) with ELHMF. Higher ELHMF was related to a greater frequency of mastitis. Pathogens of intramammary gland were found by 39 % of cows in group of ELHMF<6 mS/cm and 52% - in group of ELHMF≥6 mS/cm (P=0.002). The milk from cows infected subclinically with Staphylococcus aureus had 0.55 - 0.68 mS/cm higher ELHMF, than with subclinically Streptococcus agalactiae, Streptococcus uberis, Streptococcus dysgalaetia (P<0.001)Lietuvos sveikatos mokslų universitetas. Veterinarijos akademijaVytauto Didžiojo universitetasŠvietimo akademij