Luděk Stádník

Effect of prepubertal and postpubertal growth and age at first calving on production and reproduction traits during the first 3 lactations in Holstein dairy cattle

The objective of this study was to evaluate the effect of body condition score (BCS), body weight (BW), average daily weight gain (ADG), and age at first calving (AFC) of Holstein heifers on production and reproduction parameters in the 3 subsequent lactations. The data set consisted of 780 Holstein heifers calved at 2 dairy farms in the Czech Republic from 2007 to 2011. Their BW and BCS were measured at monthly intervals during the rearing period (5 to 18 mo of age), and the milk production and reproduction data of the first 3 lactations were collected over an 8-yr period (2005 to 2012). The highest milk yield in the first lactation was found in the group with medium ADG (5 to 14 mo of age; 0.949 to 0.850 kg of ADG). The highest average milk yield over lifetime performance was detected in heifers with the highest total ADG (≥ 0.950 kg/d). The difference in milk yield between the evaluated groups of highest ADG (in total and postpubertal growth ≥ 0.950 kg/d and in prepubertal growth ≥ 0.970 kg/d) and the lowest ADG (≤ 0.849 kg/d) was approximately 1,000 kg/305 d per cow. The highest milk yield in the first lactation was found in the group with the highest AFC ≥ 751 d, for which fat and protein content in the milk was not reduced. Postpubertal growth (11 to 14 mo of age) had the greatest effect on AFC. The group with lowest AFC ≤ 699 d showed a negative effect on milk yield but only in the first 100 d of the first parity. The highest ADG was detrimental to reproduction parameters in the first lactation. The highest BW at 14 mo (≥ 420 kg) led to lower AFC. Groups according to BCS at 14 mo showed no differences in AFC or milk yield in the first lactation or lifetime average production per lactation. We concluded that low AFC ≤ 699 d did not show a negative effect on subsequent production and reproduction parameters. Therefore, a shorter rearing period is recommended for dairy herds with suitable management.

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.

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.

Effects of age and nutritional status at mating on the reproductive and productive traits in Suffolk sheep kept under permanent outdoor management system

Ptáček M., Ducháček J., Stádník L., Fantová M. (2017): Effects of age and nutritional status at mating on the reproductive and productive traits in Suffolk sheep kept under permanent outdoor management system. Czech J. Anim. Sci., 62, 211–218. This study examined the variability of reproductive and productive traits in Suffolk sheep (a commercial flock, n = 316 ewes) with regard to the dams’ age or the nutritional status of sheep at mating under a year-round outdoor management. Data were collected across a 3-year monitoring period (totally 655 observations). The fixed effects of dam’s age (dams grouped as: 2, 3, 4, 5, 6 years and older), ewe’s live weight (LW; ewes grouped as: < 72 kg; 72–83 kg; > 83 kg), and backfat thickness at mating (BT; ewes grouped as: < 7.9 mm; 7.9–10.5 mm; > 10.5 mm) were evaluated. The dam’s age influenced reproductive and productive traits such that 2and 6-year and older ewes reached the lowest values. Ewes with LW > 83 kg had significantly higher lambing rate (11.8%) compared to those with LW < 72 kg. The group of ewes with LW < 72 kg gave birth to a significantly lower number of live lambs in litter (–8.9%) in comparison with LW < 83 kg group. An increase (9.9%; P < 0.01) of total litter weight at birth or an increase (12.5%; P < 0.05) of total litter weight at 100 days of age were detected in LW > 83 kg group compared to LW < 72 kg group. BT > 10.5 mm ewes had by 8.9% lower lambing rate (P < 0.05), by 6.8% lower litter size (P < 0.05), by 14.5% lower number of live lambs in litter (P < 0.01), and by 8.6% lower total litter weight at birth compared to BT < 7.9 mm ewes. A significantly lower total litter weight at 100 days of age (–10.8%) and a significantly lower total litter gain from birth to 100 days of age (–11.5%) were detected in BT > 10.5 mm ewes in comparison to BT 7.9–10.5 mm ewes.

Effects of dietary linseed and corn supplement on the fatty acid content in the pork loin and backfat tissue

The influence of linseed and corn dietary supplements on the fatty acid (FA) composition of pork was evaluated. The effects of their appropriate use and dosage on pork meat and fat technological quality were also investigated. In total 72 pigs fed complete feed mixtures were divided into 4 groups: control (C), corn- (CD), linseed- (LD), and corn + linseed-supplemented (CLD). After slaughter the lean meat share, intramuscular fat content, meat and fat colour, shear force, drip loss, and malondialdehyde content were determined. Subsequently, the FA content and sum of saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids, the n-6/n-3 fatty acid ratio, and atherogenic and thrombogenic indexes in the loin and backfat tissue were determined. Corn and lineseed supplementation increases the content of myristic, linoleic, α-linolenic, and eicosapentaenoic acids and reduces the amount of palmitic, palmitoleic, oleic, eicosenoic, and arachidonic acids. Therefore it reduces the PUFA/SFA ratio and improves atherogenic and thrombogenic indexes. No negative effects of linseed and corn supplementation on the technological characteristics of pork meat and backfat were registered. Due to the positive effects on indicators related to human health, linseed and maize supplementation can be recommended in pig diet.

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).

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.

The effect of the design of housing systems for calves on the microclimatic conditions of the rearing environment

Abstract. The objective of this study was to compare microclimatic conditions in three different housing systems designed for calf rearing – individual wooden hutches, individual tarpaulin hutches and individual pens under shelter – and to evaluate the thermal comfort of calves reared in these systems. Air temperature, relative air humidity and the rectal temperature of calves (n=324) were measured in the hutches and pens during three consecutive years. The hypothesis that the climatic conditions of different housing system designs used in calf rearing affect the thermal comfort of calves was confirmed, as the design of the individual housing systems affected microclimatic conditions and subsequently the rectal temperature of the housed calves as well. Statistically significant differences (P

Equilibration and freezing interactions affecting bull sperm characteristics after thawing

The objective was to determine effects of equilibration length and freezing curve type as well as their interactions on motility and live spermatozoa proportion in bull sperm after thawing. The ejaculates of 6 sires were repeatedly collected. Fresh semen was diluted with one extender and divided into 3 groups equilibrated for 30, 120, and 240 min. Subsequently, half straws of each group were frozen using standard 3-phase or 2-phase freezing curve differing in the rate of temperature decrease. Th e spermatozoa motility (M) was evaluated immediately after thawing and at 30, 60, 90, and 120 min of thermodynamic test (TDT). Live spermatozoa proportion was evaluated after thawing and at the end of TDT. Average of spermatozoa motility (AM), decrease of spermatozoa motility (MD), average proportion of live spermatozoa (ALS), and decrease of live spermatozoa proportion (DLS) through the TDT were calculated. Significant inter-sire differences in AM (0.45–17.0%; P < 0.05–0.01), MD (0.76–12.57%; P < 0.05–0.01), and ALS (0.99–23.8%; P < 0.01) were detected. The longest equilibration ensured the highest M during TDT and AM (+2.72 and +4.58%; P < 0.05–0.01), however higher MD (+4.06%; P < 0.01) compared to standard length as well. Straws freezed using 2-phase curve achieved higher M through TDT, AM (+7.3%; P < 0.01) as well as ALS (+11.77%; P < 0.01). The 2-phase curve presented higher M compared to the 3-phase freezing curve within all equilibration lengths. Significant differences in AM, MD, and ALS (0.45–6.78%, 0.62–5.35%, and 20.79–21.11%; P < 0.05–0.01) between equilibration length vs freezing curve interactions were determined. Results document the importance of equilibration length, freezing curve, and their interaction effect on live spermatozoa proportion and sperm motility after thawing as well as necessity of individual conditions for bulls semen processing and insemination doses production.