Wyniki wyszukiwania - Biblioteka Nauki

1

Ultrasound examination of mammary glands in ruminants

100%

Olechnowicz J. , Jaskowski J.

Medycyna Weterynaryjna

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2009

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tom 65

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nr 03

EN

Machine milking of ruminants has a considerable effect on the length of the teat canal, the width of the teat sinus, the width of the teat end and the thickness of the teat wall. The width of the teat end and the length of the teat canal showed the biggest changes 6 and 2 h, respectively, after the completion of milking. The thickness of the teat wall and the width of the teat sinus returned to the original condition from before milking after 6 and 8 h, respectively. In sheep the thickness of the teat wall in left and right half-udders 4 h after milking increased by 17 and 16% in relation to measurements taken before milking, while for the length of the teat canal it was by 10 and 8%. With progress in lactation the area of milk sinuses in cows decreased significantly. Similarly, in Manchega and Lacune sheep the size of milk sinuses decreased during lactation. The values of correlation coefficients between the size of milk sinuses and milk yield of ewes, depending on the applied ultrasound measurement methods, were 0.53 and 0.48. The area of milk sinuses in goats and the daily milk production, irrespective of the number of milkings per day (one or two), increased linearly with the number of hours between milkings. In healthy mammary glands of cows teat canals were longer and narrower, while in infected glands they were shorter and wider. The length of the teat canal in cows was negatively correlated with the peak and mean values of the milk flow index.

2

Impact of clinical lameness, calving season, parity, and month of lactation of milk, fat, protein, and lactose yields during early lactation of dairy cows

100%

Olechnowicz J. , Jaskowski J.

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2010

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tom 54

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nr 4

EN

The aim of this paper was to investigate the impact of clinical lameness in Polish Holstein-Friesian dairy cows on milk yield as well as on fat, protein, and lactose yields during early lactation (120 d). The dataset includes 312 monthly test-day milk yields and milk composition records from 78 cows, which calved from October 2008 to April 2009. Twice a week, during the first 120 d postpartum, the cows were examined for lameness and they were scored fortnightly according to a 5-point locomotion scoring system. Factors affecting milk yield and milk components included calving season, parity, month of lactation, and degree of lameness. In cows, which were clinically lame for a month and which were clinically lame for more than a month (maximum per 2 months), the total mean reduction in milk yield per 120-d lactation was approximately 308 and 283 kg, respectively, as compared with cows, which were never lame in early lactation.

3

Relation between clinical lameness and reproductive performance in dairy cows

100%

Olechnowicz J. , Jaskowski J.

Medycyna Weterynaryjna

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2011

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tom 67

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nr 01

EN

Lameness of cows is an important factor influencing the longevity and performance of the herd, including milk yield losses. It has a negative impact on reproductive performance and constitutes an increasing risk for early culling. Claw disorders, such as white line diseases, sole ulcers or papillomatous digital dermatitis, are the most frequent causes of clinical lameness in dairy cows. Lameness most often appears within 100 days postpartum, and its incidence was calculated at 54.5 to 65% per 100 cows, whereas the mean prevalence of lameness has been estimated at 20.6%. Lame cows exhibit different oestrus behavior than non-lame cows. Above all, lame cows had a shorter oestrus, and an increased locomotion score was associated with a shorter time of standing and walking as a consequence of a longer time of lying down. A poor oestrus detection rate is likely to be a more important factor in reducing average fertility levels. Hence, the average conception rate and pregnancy rate for lame cows are lower, and the rates of services per conception are higher. Lame cows have a longer interval from calving to conception compared with non-lame cows. In the case of lame cows with lesions and multiple lesions this interval amounted to 140 and 170 days, respectively, as compared with 100 days for healthy cows. Ovarian cysts are observed in about 10-30% of lactating dairy cows and are more likely to occur within the first 80 days postpartum, i.e. during the same period when hoof disorders and lameness occur. Lameness in cows within the first 30 days postpartum was associated with a higher incidence of ovarian cysts, a lower likelihood of pregnancy and lower fertility than in non-lame cows. The effect of lameness on culling within the first 60 DIM was lower, but cows diagnosed in this period seemed to be at a greater risk of being culled between 121 and 240 DIM. Nevertheless, when deciding whether to cull a cow, one should consider such factors as parity, lactation stage, milk yield, reproductive performance, health, season and animal welfare.

4

Quality and number of cumulus-oocyte complexes (COC) and concentrations of leptin and ghrelin in blood and follicular fluid depending on the body condition of cows

80%

Nowak T. , Jaskowski J. , Szczepankiewicz D. , Olechnowicz J.

Medycyna Weterynaryjna

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2011

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tom 67

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nr 02

EN

The aim of our study was to investigate the effect of body condition on the number of ovarian follicles, the number and quality of COC-complexes and/or concentration of leptin (LEP), total and active ghrelin (TGHR and AGHR) in blood plasma and follicular fluids. Before slaughter all cows were divided into five classes according to their body condition scores (BCS). Body condition had no significant influence on the number of follicles and aspirated oocytes. The mean number of oocytes of a very good quality (Grade 1 and Grade 2) was 0.79 and 1.14 in cows with BCS 2.50 and 2.51-3.0, and was lower than 2.69, 2.66 and 2.0, respectively, aspirated from follicles in cows from group 3.01-3.5, 3.51-4.0 and > 4.0. Body condition influenced the number of COCs of a very good quality (Grade 1, P < 0.05). There was no relation between body condition and the number of oocytes grades 2 and 4. We found an interrelation between blood leptin concentration and its concentration in the follicular fluid (P < 0.01). No significant relationship exists between the BCS of cows and concentrations of leptin and active ghrelin in blood plasma and the follicular fluid.

5

Effect of cows' body condition during the periparturient period and early lactation on fertility and culling rate

80%

Nowak T. , Jaskowski J. , Olechnowicz J. , Bukowska D.

Medycyna Weterynaryjna

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2009

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tom 65

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nr 09

EN

The aim of the study was to determine the effect of body condition score (BCS) of cows during the last weeks of pregnancy and in the first months of lactation on the incidence of postpartum complications. A total of 528 cows were included in the study. No significant effect was found of BCS of cows ap on the incidence of dystocia, corpus luteum pseudograviditatis, ovarian cysts, repeat breeders, infertility and the service period (SP). In turn, BCS before calving had an effect on the incidence of the retention of the placenta, puerperal metritis and clinical endometritis (MET), ovarian afunction (OA), the first service conception rate (FCR) and pregnancy rate (PR). The pregnancy rate was 2.67 in the group of lean cows and this was higher (p ≤ 0.05) than in the other groups of cows. The highest FCR of 46.3% was recorded in fat cows before calving (BCS > 4.0). It was higher than in cows with BCS of 3.0 and 2.5 ap (p ≤ 0.01 and p ≤ 0.05, respectively). The lowest FCR of 11.1% was recorded in the group with BCS of 2.0. The mean BCS of cows after calving was 2.52 and its loss amounted to 0.74 points, i.e. 22%. Body condition loss did not have an effect on the frequency of ovarian afunction, ovarian cysts, the percentage of repeat breeders and the length of service period. The frequency of MET in the HBCL group was 29.5% and it differed significantly (p ≤ 0.05) from the frequency of this complication in MBCL and LBCL groups. In the HBCL group OA was significantly more frequent (at p ≤ 0.05) than in LBCL cows (8.7 vs. 2.1%), similarly as it was for corpus luteum pseudograviditatis (14.7 vs. 4.1%), while higher values were recorded both for FCR (41.4 vs. 37.3 in group II at p ≤ 0.05 and 32.6 in group III at p ≤ 0.01) and pregnancy rate (2.24 vs. 2.05 at p ≤ 0.05 in group III and 2.06 at p ≤ 0.05 in group II). In the analyzed population a total of 24.2% cows were culled. The higher the antepartum BCS of cows and the higher its postpartum loss, the higher the risk of culling due to infertility and the total culling risk, as well as the risk of death.

6

Effect of hind limb conformation on claw disorders in dairy primiparous cows

80%

Olechnowicz J. , Jaskowski J. , Nowak W.

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2010

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tom 54

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nr 3

EN

The objective of this study was to determine the effect of hind limb conformation on claw disorders and locomotion in primiparous cows. The cows, housed in tie stalls (n=68) and in free stalls (n=74), calved throughout the year 2008. Rear legs set rear view, rear legs set side view, and foot angle scores were given in a scale from 1 to 9. Locomotion scores were defined in a scale from 1 to 5. Cows with healthy hooves had straight rear legs in rear view and lower scores for rear legs side view than cows with hoof disorders in hind limbs.

7

Effect of cows' body condition during periparturient period and early lactation on post parturient development of ovarian follicles and size of corpus luteum

80%

Nowak T. , Jaskowski J. , Olechnowicz J. , Bukowska D.

Medycyna Weterynaryjna

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2009

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tom 65

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nr 11

EN

The aim of the study was to establish the effect of body condition in the period before parturition on the dynamics of follicular waves, the appearance of the first dominant follicle and the corpus luteum and on the number of ovarian follicles during the first 36 days after calving. In the study the analysis was conducted on 23 cows, which were divided into three groups depending on their body condition before calving. Groups I, II and III included cows with body condition scores ≤ 3.0, 3.01-3.5 and > 3.5 points, respectively. In all cows, starting from days 14-16 post partum up to days 34-38 post partum thorough ultrasound examinations (USF) of ovarian surface were performed at 2-3-day intervals. No significant effect of BCS before calving was found on the cumulative number of ovarian follicles detected in the first 36-38 days after calving, although in cows from group III this number was slightly higher than in cows from group I. No effect of the body condition of cows before calving on the date and frequency of FDF and FCL was found in this study. However, the dominant follicle and the corpus luteum in cows from group I were detected later than in cows with body condition scores corresponding to groups II and III.

8

Development of ovarian follicles, quality of oocytes and fertility of cows in view of a negative energy balance in the transition period

70%

Wlodarek J. , Jaskowski J. , Nowak W. , Mikula J. , Olechnowicz J.

Medycyna Weterynaryjna

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2011

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tom 67

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nr 04

EN

Energy metabolism in cows during the first three weeks after calving has a decisive effect on the incidence of the first estrus postpartum, the length of the voluntary waiting period and interpregnancy period. Additionally, the negative energy balance (NEB) is usually promoted by the relatively one-sided selection of cows towards high production - accepting the occurrence of NEB after calving as well as excessive body condition of cows before calving. In case of a rapid body condition loss in cows after calving, connected with fat mobilization, characteristic of cows in excessive body condition during drying off, ovarian follicles are not properly formed. Disorders of the ovulation process as well as a lower secretion of progesterone are more frequently recorded in those cows. As a result of an energy deficit at the beginning of lactation, the frequency of GnRH pulses from the hypothalamus is lower in high-producing cows. A lack of pulsation secretion of LH as an effect of the prolonged lack of adaptation of a sufficient amount of energy to the needs of the female was found both in beef and dairy cows. The recurrence of LH pulses, stimulating the onset of ovarian activity and the pre-ovulatory development of ovarian follicles, is crucail to the return of cyclical activity in the postpartum period in cows suffering from NEB. An energy deficit causes the incidence of a dysfunction of the reproductive system in the form of persistent ovarian failure, a delayed onset of normal ovarian activity, and the appearance of the first corpus luteum postpartum. The number of estrus cycles occurring before effective insemination is also reduced and both the voluntary waiting period and interpregnancy period are longer. An energy deficit in the postpartum period results in disorders in the functioning of the endometrium. Disturbed energy-consuming processes of endometrium remodeling lead to delays in uterine involution. Reduced uterine contractility and changes in its environment constitute causes for the retention of the placenta and postpartum metritis; in cows with NEB it was a reduced mitogen response of lymphocytes to cytohaema gglutinin. Moreover, a reduced phagocytic activity of macrophages was found in the milk of cows, in which high contents of ketone compounds were found in their plasma. Similarly, the activity of lymphocytes and neutrophiles was reduced in the environment with an addition of β-hydroxybutyric and acetoacetic acids, as well as elevated PUFA levels and a reduced blood leptin concentration.

9

Effects of different starch sources on metabolic profile, production and fertility parameters in dairy cows

70%

Mikula R. , Nowak W. , Jaskowski J. , Mackowiak P. , Pruszynska Oszmalek E.

Polish Journal of Veterinary Sciences

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2011

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tom 14

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nr 1

EN

The objective of the study was to determine the effect of replacing triticale (high rumen degradable starch) with maize grain (low rumen degradable starch) during the transition period and the first 120 days of lactation on metabolic and hormonal profile indices, milk production and fertility performance in cows. Forty-eight Holstein-Friesian dairy cows were divided into 4 groups: TT (2.5 kg triticale grain/cow per day supplemented from 14 days prepartum to day 120 postpartum), TM (2.5 kg triticale grain/cow per day supplemented from day 14 before parturition to calving, and then 2.5 kg maize grain to 120 days of lactation), MT (2.5 kg maize grain/cow per day supplemented from day 14 before parturition to calving, and then 2.5 kg triticale grain to 120 days of lactation), MM (2.5 kg maize grain/cow per day supplemented from 14 days prepartum to day 120 postpartum). Blood samples were collected 3 weeks and 1 week before calving and on days 14, 56 and 70 of lactation, and they were analyzed in terms of concentrations of glucose, insulin, leptin, insulin-like growth factor I, nonesterified fatty acids, triglycerides, cholesterol, blood urea nitrogen and activities of aspartate aminotransferase and gamma glutamyl transpeptidase. Milk samples were collected twice a day at weekly intervals and analyzed for fat, protein and lactose. Milk yield and individual dry mater intake were recorded at weekly intervals. Body condition was estimated 3 weeks before calving, on parturition day and on days 14, 56 and 120 of lactation. Replacing triticale grain with maize grain in the transition period and during lactation positively affected fertility of lactating cows. An increased first service conception rate and shortening of the days open period was observed in MM and TM groups in comparison to those found in group MT (P ≤ 0.05). The lowest number of services per conception was recorded in groups MM and TM (P ≤ 0.05). Although the impact of milk production and the most of the blood indices were not significantly affected by this treatment, the results of the study suggest that maize grain in the transition period and lactation might be a more effective energy source for dairy cows than triticale grain.

10

Buhaje o ponadprzeciętnej płodności własnej (SCR)

70%

Jaskowski J. , Blaszak B. , Wyrebski M.

Bydło

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2010

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nr 08-09

11

Analizy funkcjonalne i molekularne plemników w ocenie zdolności rozrodczej samców ssaków

51%

Bukowska D. , Kempisty B. , Sikora J. , Wozna M. , Jackowska M. , Zaorska K. , Antosik P. , Jaskowski J.

Medycyna Weterynaryjna

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2011

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tom 67

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nr 01

EN

The development of assisted reproduction methods requires the application of techniques for the assessment of sperm quality of animals kept for breeding purposes. At present there are a number of methods for the parametric evaluation of spermatozoa, used to determine the reproductive potential of males. Owing to the large number of factors inf1uencing the maturation and capacitation of sperm and the complexity of the fertilisation process, it is difficult to accurately estimate fertilising potential. None of the presently used methods is fully reliable. Conventional laboratory methods, such as the microscopic analysis of the number, mobility, morphology and vitality of spermatozoa or the computer-assisted CASA method, do not provide reliable results as to the functional properties of semen. Most of these methods make it possible to analyse only a single determinant of sperm fertilization potential. High heterogeneity in sperm population makes semen analysis even more difficult. In order to achieve more reliable results, a number of functional analyses are applied, such as flow cytometry, sperm-zona binding tests, HZA and SPA tests. Other such methods include the evaluation of apoptosis and DNA damage as well as acrosome reaction assessment and the use of the molecular marker of spermatozoa. All the above methods make it possible to observe a number of influences and transformations occurring in spermatozoa prior to fertilization. A detailed analysis of the stages by which sperm acquires the ability to fertilize an egg is not only essential for the evaluation of sperm quality, but it is also a source of valuable information on molecular and cellular mechanisms of the fertilization process, some aspects of which still remain elusive.

12

Mechanizmy regulujące oogenezę, folikulogenezę oraz zapłodnienie u świń

51%

Kempisty B. , Jackowska M. , Bukowska D. , Antosik P. , Wozna M. , Piotrowska H. , Swierczewska M. , Jaskowski J.

Medycyna Weterynaryjna

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2011

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tom 67

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nr 05

EN

This review presents the molecular basis of mechanisms regulating oogenesis and folliculogenesis, as well as the species specificity of these mechanisms and genetic determinants of successful fertilization in pigs. Oogenesis and folliculogenesis are species-specific processes, although several features are common to all mammals. These features are especially visible in the molecular basis of these processes. The most important genetic factors regulating normal oogenesis and folliculogenesis include the transforming growth factor beta (TGFβ) and several other proteins from the TGFβ family. Several experiments have indicated the influence of this gene’s expression on the ability of oocytes to mature, be successfully fertilized, and form a zygote and a blastocyst. However, the regulation of this gene’s expression shows a considerable species specificity. Similarly, mechanisms regulating the fertilization process have several features common to all mammalian species, which is especially conspicuous in the structure of genes that are responsible for fertilization. Two important determinants of fertilization ability are oocyte morphology and follicular size.

13

Systemy oceny kompetencji rozwojowej oocytów oraz zarodków ssaków oparte na technologii mikrofluidycznej typu Lab-on-Chip

51%

Kempisty B. , Walczak R. , Antosik P. , Szczepanska P. , Wozna M. , Bukowska D. , Zaorska K. , Dziuban J. , Jaskowski J.

Medycyna Weterynaryjna

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2011

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tom 67

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nr 01

EN

This review presents basic criteria for evaluating the developmental competence of oocytes and embryos, and contains a detailed description of the microfluidic-technology-based Lab-on-Chip. The developmental competence of oocytes is acquired through a complex process associated with oocyte growth and maturation, the storage of large amounts of mRNA and proteins, and with the formation of proper cell morphology. The full maturation of oocytes is required for successful monospermic fertilization and embryonic preimplantation development. The morphology of the gamete is one of the most important factors influencing the developmental competence of the cell. There are several indicators for the assessment of oocyte morphology, most of them including the color and granularity of the cytoplasm. Intensive research is under way to develop and introduce new non-invasive methods of oocyte and embryo quality assessment as a major factor in the improvement of assisted reproductive techniques. The Lab-on-Chip technology, as an independent micro-cytometric device, is a combination of reproductive biology techniques and micro-optic electronics. In the future, Lab-on-Chip systems may be used as an important diagnostic instrument for evaluating the quality of mammalian oocytes and embryos.