Jan Beran

Relationships between milk fatty acids composition in early lactation and subsequent reproductive performance in Czech Fleckvieh cows.

Increase of milk yield after calving causes changes in milk fatty acids (FA) composition and simultaneously corresponds with reproduction performance decrease. The objective of this study was to evaluate the relationships between milk FA group composition (SFA, saturated fatty acids; MUFA, monounsaturated fatty acids; and PUFA, polyunsaturated fatty acids) during the first 5 lactation weeks and subsequent reproductive results (INT, calving to first service interval; NUM, number of services per conception, and DO, days open) in Czech Fleckvieh cows. A total of 1231 individual milk samples from 382 cows were collected and subsequently analyzed. Simultaneously, body condition score (BCS) was weekly evaluated as well. Software SAS 9.1 was used for statistical analysis. Daily milk yields increased whereas BCS, milk fat and protein contents decreased during period observed. The reduction of basic milk components (% of fat, % of protein) was associated with increased SFA and decreased MUFA, respectively PUFA contents. Significant (P<0.01-0.05 days) increase in NUM (+0.15 to +0.29 AI dose) and DO (+8.16 to 15.44 days) were detected in cows with the lowest SFA content. On the contrary, cows with the highest content of MUFA presented significantly (P<0.01-0.05) higher values of NUM (+0.13 to +0.30) and DO (+7.26 to +15.35 days). Milk FA groups composition in early lactation potentially used as NEB indicators, especially SFA and MUFA proportion, affected subsequent reproductive results of Czech Fleckvieh cows. Therefore, its post-partum values could serve as predictors of potential fertility of dairy cows.

Relationship of Udder and Teat Morphology to Milking Characteristics and Udder Health Determined by Ultrasonographic Examinations in Dairy Cows / Związek Między Morfologią Wymienia I Strzyków A Cechami Doju I Zdrowotnością Wymienia W Badaniach Usg Krów Mlecznych

Abstract The aim of this study is to call attention to the possibility of using ultrasonography as a useful tool for the evaluation of morphological characteristics of the udder and teats in dairy cows in relation to milking characteristics and udder health. A total of 26 dairy cows of the Holstein breed in the first (n = 13) and second lactation (n = 13) were investigated with a linear array ultrasound probe. Recovery of the teat internal parameters after milking was determined by ultrasonographic scanning. Teat canal length, teat canal diameter and teat wall thickness of 103 teats were evaluated from 622 measurements before and directly after milking and every 15 minutes until 1 hour after milking (6 measurements). The most significant differences in internal proportions were determined within those values measured before and immediately after milking. The dynamics of changes in the length of the teat canal demonstrated the extension by 27%. A sudden restoration of the initial length by 11% was detected one hour after milking. Differences in teat canal diameter were significant at P<0.01 between the 1st and 4th measurement. The initial extension was 17% immediately after milking and the restoration about 9% one hour after milking. The wall thickness was strengthened during the 2nd measurement immediately after milking in comparison with the 1st measurement before milking (P<0.01). Significant differences in the wall thickness were detected between the 1st and 2nd measurement (+26%; P<0.01) and between the 2nd and 3rd measurement. The ultrasonographic scanning of the teat parameters was a useful tool to study teat changes caused by milking. Streszczenie Celem badań było zwrócenie uwagi na możliwość użycia ultrasonografii jako przydatnego narzędzia w ocenie cech morfologicznych wymienia i strzyków u krów mlecznych, w odniesieniu do cech doju i zdrowotności wymienia. Dwadzieścia sześć krów mlecznych rasy holsztyńskiej, w pierwszej i drugiej laktacji (n = 13), badano za pomocą USG, przy użyciu głowicy liniowej. Powrót parametrów strzyków do poziomu sprzed udoju określano za pomocą skanowania wiązką ultrasonograficzną. Długość i średnicę kanału strzykowego oraz grubość ścian strzyka oceniano na 103 strzykach, podczas 633 pomiarów przeprowadzonych przed udojem, bezpośrednio po udoju oraz do 60 minut po udoju, w odstępach 15-minutowych (6 pomiarów). Najbardziej istotne różnice w wewnętrznych proporcjach określono w obrębie wartości mierzonych przed i bezpośrednio po udoju. W dynamice zmian długości kanału strzykowego stwierdzono wydłużenie o 27%. Nagły powrót do 11% początkowej długości zaobserwowano godzinę po udoju. Różnice w średnicy kanału strzykowego były istotne na poziomie P<0,01, pomiędzy 1. a 4. pomiarem. Powiększenie wyniosło 17% bezpośrednio po udoju i około 9% w godzinę po udoju. Grubość ściany kanału strzykowego uległa zwiększeniu podczas 2. pomiaru zaraz po udoju, w porównaniu do 1. pomiaru przed dojem (P<0,01). Istotne różnice w grubości ściany wykryto między 1. a 2. pomiarem (+26%; P<0,01) oraz między 2. a 3. pomiarem. Badanie USG parametrów strzyków okazało się przydatne w określaniu zmian zachodzących w strzykach na skutek doju.

Quality of preimplantation embryos recovered in vivo from dairy cows in relation to their body condition.

This study examined the impact of cow body condition on the quality of bovine preimplantation embryos. The embryos (n = 107) were flushed from dairy cows and classified according to a five-point scale body condition score (BCS2 n = 17; BCS3 n = 31; BCS4 n = 11) on the 7th day after insemination and then analyzed for development, dead cell index (DCI), cell number and actin cytoskeleton quality. The highest embryo recovery rate (P < 0.05) was recorded in the BCS3 group and the lowest in the BCS4 group. More transferable (morula, blastocyst) embryos were obtained from the BCS4 cows (79%), compared with the BCS2 (64%) or BCS3 (63%) animals. However, cell numbers were higher in the BCS2 and BCS3 groups (P < 0.05) compared with the BCS4 embryos. Conversely, the DCI was lowest in the BCS2 (3.88%; P < 0.05) and highest in the BCS4 (6.56%) embryos. The proportion of embryos with the best actin quality (grade I) was higher in the BCS2 and BCS3 cows compared with the BCS4 group. Almost 25% of all embryos showed fragmented morphology and a higher DCI (5.65%) than normal morulas (1.76%). More fragmented embryos were revealed in the BCS2 (28.6%) and BCS4 (31.25%) groups, and less (19.15%) in the BCS3 group. The cell numbers in such embryos were lower in the BCS4 (22.57) than in the BCS2 (46.25) or BCS3 (42.4) groups. In conclusion, the body condition of dairy cows affects the quality of preimplantation embryos. A BCS over 3.0 resulted in a higher incidence of poor (fragmented) embryos.

Influence of selected factors on growth performance of Suffolk lambs and their crossbreds

The monitoring was performed in one year period in selected population of Suffolk sheep (SF, n = 257) and their crossbreds with Merinolandschaf (SF × ML, n = 87). Total of 627 lambs (SF, n = 463; SF × ML, n = 164) were observed in breeding conditions of two semi-extensive flocks. Lambs’ live weight at 100 days of age (LW100); musculus longissimus lumborum et thoracis (MLLT100) depth and backfat thickness (BT100) at the same age were assessed. Effects of breed, ewes’ live weight at mating, litter size, sex of lambs and ewe’s age as linear regression were evaluated using SAS 9.1. Significant differences (P < 0.05) in LW100, MLLT100 and BT100 between SF and SF × ML were observed. All the evaluated traits of growth performance were also influenced (P < 0.05) by ewes’ live weight at mating. The highest lambs’ growth performance traits were detected in lambs of ewes with highest live weight at mating (group of ≥ 80.7 kg). Significant differences (P < 0.05) were observed among singles, twins and triplets lambs as well. Significantly higher LW100 was marked in ram lambs compared to ewe lambs (P < 0.05).

The comparison of milk production and quality in cows from conventional and automatic milking systems

The objective of this study was to evaluate the effects of two different types of milking systems (conventional parlour vs. automatic milking system) and the season of the year on the composition and hygienic quality of milk from Czech Fleckvieh cows. A total of 500 cows were involved; 200 and 300 in conventional and automatic milking systems, respectively. Bulk milk samples were collected for 12 months from July 2010 to June 2011. The following milk components and quality indicators were determined: % of fat, % of protein, % of lactose, % of fat-free dry matter (FFDM), % of casein, urea content, somatic cell count (SSC), total germ count (TGC) and milk freezing point (FP). The data were processed and evaluated with MS Excel and the statistical software SAS 9.1. Significantly higher (P<0.05 – 0.01) contents of fat, protein, FFDM and casein and increased TGC were observed in the automatic milking system, whereas SCC and FP were significantly lower (P<0.01). The highest contents of fat, protein and casein, and the lowest lactose content were found in the winter season. The highest contents of FFDM, urea and SCC were observed in autumn, whereas TGC was highest in summer (P<0.05 – 0.01). Only FP was not influenced by the season.

COMPARISON OF DIFFERENT SORTING OF FATTY ACID IN BOVINE MILK IN RELATION TO BODY CONDITION OF CZECH FLECKVIEH DAIRY COWS

Fatty acids in milk are one of the most important components of milk. The aim of this study was to determinate relationships between groups of fatty acids and body condition score change in Czech Fleckvieh cows. Fatty acids were classification along its length of chain and its source of creation. To analysis was included total of 50 Czech Fleckvieh cows with different order of lactation. During the first 4 weeks of lactation, milk samples were collected at a weekly interval and body condition score was assessed. Statistical analyses were performed using Microsoft Office Excel and the procedures MEANS and GLM of SAS 9.1. During the first four week of lactation, the proportions of short- and medium-chain fatty acids as well as de novo synthesised fatty acids increased. Moreover the cows with a greater body condition score change mobilized storage depot fat more intensively, which resulted in higher proportions of dietary and depot fatty acids since week 1 of lactation, and long-chain fatty acids since week 2 of lactation. On the contrary, the animals with only a small body condition score change exhibited high proportions of short- and medium-fatty acids as well as de novo synthesised fatty acids in the most part of the period analysed. This indicates abut negative energy balance in early part of lactation and its compensation. The results also confirm the relationships between different groups of fatty acids, body condition score and negative energy balance. As more accurate for evaluation of intensity of negative energy balance was confirmed rather classification along source of creation. These results further emphasize importance the monitoring of body condition, milk composition and good herd management in first part of lactation.

The relationship between fatty acid and citric acid concentrations in milk from Holstein cows uring the period of negative energy balance

The objective of this study was to determine the relationship between body condition score changes and the dynamics of energy balance indicators - fatty acid and citric acid contents - in milk during a early part of lactation. In addition, the relationship between these two indicators was also evaluated. A total of 27 Holstein cows that calved within three consecutive weeks were included in the analysis. During the first 17 weeks of lactation, milk samples were collected at a weekly interval and body condition score was assessed once a month. Statistical analyses were performed using Microsoft Office Excel and the procedures MEANS and CORR of SAS 9.1. Trend functions describing the development of fatty acid and citric acid contents explained 67.67 to 92.19 % of their variability. Similar relationships between fatty acid and citric acid contents and the changes in body condition score during the first three months of lactation were observed. In addition, a similar decreasing tendency was also determined for the contents of both the dependent variables in this period. Significant correlations (P0.01 – 0.001) were calculated (r = 0.51 – 0.74) for lactation weeks 6 and 7, thus before the subsequent decrease of body condition score by 0.2 points between weeks 8 and 12 after parturition. The results indicate the possibility of using the contents of fatty acids and citric acid as indicators of energy balance in dairy cows. The results also confirm the relationships between these indicators and emphasise the importance of proper herd management with respect to body condition score changes and the contents of fatty acids and citric acid in milk.

Effect of low-density lipoprotein addition to soybean lecithin-based extenders on bull spermatozoa following freezing-thawing – preliminary results

Soybean lecithin-based extenders represent an alternative to extenders containing egg yolk, but there has been discussion about their cryoprotective efficacy. Low-density lipoprotein (LDL) was proved as a cryoprotective agent, which can replace egg yolk in extenders. The aim of this study was to investigate the effects of LDL addition to the soybean extenders on their cryoprotective properties. The effect of the LDL of our production was verified using commercial egg yolk extender BULLXcell®, 6%, 8%, and 10% LDL (v/v) as an egg yolk replacement. The effects of LDL addition to the soybean lecithin-based extenders in concentrations of 4%, 6%, and 8% (v/v) were tested using extenders AndroMed® and Bioxcell®. In total, 64 samples from eight bulls were evaluated. Kinematic parameters of spermatozoa, resulting from Computer Assisted Sperm Analysis, and their viability, evaluated by fluorescent technique, were assessed immediately after thawing and after 2 hours. The quality of LDL compared to other studies was confirmed, and the beneficial effects of egg yolk replacement by LDL were proved in extender BULLXcell®. 8% LDL provided the best values for the majority of kinematic parameters (P < 0.05), without effect on total motility (P > 0.05). Furthermore, addition of 4%, 6%, and 8% LDL to the soybean lecithin-based extender Bioxcell® showed a positive effect on the majority of kinematic parameters of spermatozoa (P < 0.05) at both times of incubation. However there was no significant influence on total motility (P > 0.05). Viability was higher after thawing in the case of 8% LDL (P < 0.05). However, there was no consistent effect of LDL addition to the AndroMed® extender. In conclusion, cryoprotective properties of the semen extenders based on a soybean lecithin can be improved by the addition of LDL.