Successful management of lactating dairy cows needs to integrate the programs of herd reproduction and health. The objectives of this study was to determine the relationship of dystocia, stillbirths, and the prevalence of mastitis in dairy cow herds. A total of 559 304 Lithuanian Black and White dairy cows were evaluated in relation to calving ease and stillbirths. Moreover, 1498 cows from the aforementioned group were tested for the milk somatic cell count and the presence of udder microbiota in the post partum period. The majority of extremely difficult births were estimated in primiparous and multiparous cows of lactations 6-8 (3.8-4.2% births) (P < 0.0001). Repeatability of dystocia was determined in 82.7% of cows in the following lactation (P < 0.0001). The stillbirth parturition rate was estimated to be 5.37% and shown to be the most important problem in the first calving compared to the second and subsequent calvings (P < 0.0001). Stillbirth was 11.2 × higher in cows with severely difficult calving compared to cows having no calving difficulties or slight calving difficulties (P < 0.0001). Dystocia significantly increased the somatic cell count (P < 0.05) and incidence of mastitis (P < 0.001), in particular mastitis caused by Streptococcus agalactiae and Staphylococcus aureus.
In this study, we hypothesized that differences of automatic milking systems (AMS) variables in dairy cows during estrus and through diverse stages of lactation can be suggested as alternative indicators to support the pregnancy in dairy farms using automatic milking systems. The key objectives were: (1) to determine the variation of automatic milking system indicators during lactation and to estimate the relationship with reproduction status in dairy cows; (2) to test the hypothesis that milking traits of cows can be influenced by estrus and conceiving, and can be used as a predictor of the likelihood of reproductive success in dairy herds. Estrus synchronization was performed in 368 healthy Lithuanian Black and White cows. All cows (n = 368) were synchronized and inseminated for the first time on the 91st day in milk (DIM). Cows not pregnant (17.39%) were synchronized and inseminated again at 132 DIM. After the first insemination pregnant (n = 304) cows were identified as group 1, after the second insemination pregnant (n = 58) cows – as group 2. Overall, 12 01 713 records of udder quarters in cows from 5 to 305 DIM were evaluated. The results revealed the reduction in milk yield during estrus 11.05% on 91 DIM and 13.89% on 132 DIM (P < 0.001) and an increment in milk flow traits in cows after 91 DIM (P < 0.05), also a slight decline in milk flow traits on 132 DIM. Furthermore, milking frequency (MF) of cows decreased significantly (P < 0.001) after conceiving. The interval between milkings (MI) increased (40.30%) during estrus of cows in group 1 (P < 0.001), and thereafter gradually increased, however in group 2 there was a temporary increment (6.06%) on the 91 DIM and steady rise (42.13%) on 132 DIM was noticed. The results highlight that changes in AMS indicators of cows may be considered as an additional tool for improvement of reproductive management in dairy herds, but further research-based studies are necessary before practical application.
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 <0.001). The milk P4 concentration in the ≥3 lactation cows was higher than the second (13.45%; 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 aim of this study was to analyse the influence of dairy cows' diet on electrical conductivity (EC) of milk during pasturable and stall periods and to assess EC relationship with milk yield and somatic cell count (SCC). The experiments were carried out during 2009-2013 with 421 dairy cows which were milked using an automated voluntary milking system "DeLaval VMS" ("DeLaval", Sweden). All year round the cows were kept untied indoors and fed on farm-made grass silage forage, during pasturable period the diet was supplemented with a fresh legume/ grass mixture. The data consisted of 462582 milking records. The average EC of milk (4.92 ± 0.001 mS cm -1 ) met zootechnical standards. The average milk yield was 25.12 ± 0.020 kg, milk SCC -188.95 ± 1.032 thousand ml -1 . Milk yield during pasturable period was in average 1.4% lower and SCC was 7.9% higher than during the stall period. The average EC during pasturable period of the experiment was 3.6% higher than during the stall period in all lactations (p < 0.001). The higher (23.03 g) cows' ruminal N-balance (RNB) during pasturable period had no positive effect on milk yield as SCC increased during that period. The correlation between milk yield and EC of milk during pasturable and stall periods was negative (r = −0.124-−0.226, p < 0.001). The observed SCC was lower than 200 thousand ml -1 in the milk samples where EC was in the range of 4.6 to 5.8 mS cm -1 . As EC increased, SCC had a statistically significant (p < 0.001) rise both in pasturable and stall periods (r = 0.356-0.403). EC of milk could provide an alternative way for early diagnosis of mastitis.
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: less than 30 kg (n=20) and e”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 less than 0.001), whereas it was negatively correlated with milk protein (P less than 0.05-P less than 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 less than 0.001), higher milk fat (P less than 0.05) and milk protein content (P less than 0.001). These cows had 1.90 times lower prevalence of the signs of subclinical ketosis (P less than 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.
The aim of this study was to evaluate the possibility to predict outcomes of artificial insemination (AI) in dairy cows based on in-line milk progesterone (P4) concentration. The research was carried out on the herd of loose housing 245 dairy cows of 2-4 lactations, with average milk yielding 11.000 kg per cow. Milk sampling, measuring, and recording of milk P4 concentration was carried out using the Herd Navigator (HN). The grouping was performed according to the following three indices: the first by reproductive condition -pregnant or not pregnant after AI, the second by P4 concentration from day 20 before AI to day 20 after AI, and the third by P4 concentration at AI time. There was a significant difference in P4 concentration in the group of pregnant cows from day 15 to day 9 before AI, and it was by 18.3% higher compared to that in the group of non-pregnant cows in the said period (p<0.01). The milk P4 concentrations began to differ mostly from day 10 after AI. At that time, the average P4 concentration in the group of pregnant dairy cows was by 36.8% higher compared to that in the group of non-pregnant cows (p<0.01). A statistically significant difference between the ratio of the cows with high, medium, and low P4 concentration on days 20-16 before AI (p<0.01) was determined. The highest number of cows with up to 2-3 ng/ml P4 concentration became pregnant at the AI time.In-line milk P4 records captured on day 10-15 before AI can be used to predict the proper for reproduction period. By P4 concentrations on day10 after AI, the ratio of pregnant cows in herd can be assessed.
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