Augļa segu aiztures ārstēšanas metožu salīdzinošs vērtējums un to ietekme uz govju turpmāko laktāciju un reprodukciju = Comparative assessment of treatment methods of retained fetal membranes and their effects on the subsequent lactation and reproduction in cows

Retention of the fetal membranes (RFM) comprises a failure of dehiscence and a lack of expulsion of fetal membranes within the duration of the calving's physiological third stage. If the fetal membrane does not separate within 12 to 24 hours after the fetus has been expelled from a cow's birth canal, then it is considered retention of the fetal membranes. The retention of the fetal membrane in the dairy herd should not exceed 10% of cows, but now it reaches 15% and more. The causes of RFM are various ones - from genetics, nutrition, hormonal disorders, high milk yield, sex or number of offspring, stillbirths, micronutrient and vitamin deficiencies, heat, age of the animal and many other factors that can affect the development of RFM. Also, RFM reduces the milk yield of the animal and causes delayed recovery of ovarian function, having an increased time from calving to the first ovulation, missing the first estrus postpartum, prolongs the calving interval and incurs additional costs when treating it. It is important to find and understand which of the proposed RFM treatment methods or approaches would be more economical and less impact on future lactation and reproduction. For the first time in Latvia, three RFM treatment methods have been compared in the doctoral thesis. The study took place over three years - from 2006 to 2009 - in two herds of Zemgale region with the same keeping, feeding, and milking system. The study aimed to find out the most cost-effective and suitable treatment method of retained fetal membranes in Latvian conditions, which would have a positive effect on further lactation and reproduction of cows. The following objectives have been set to achieve the goal: 1. to evaluate uterine involution using rectal and ultrasonographic examination, as well as ovarian functional status, using a rectal, ultrasonographic, and immunohistochemical examination of cows with and without fetal retention; 2. to explore the morphological and biochemical parameters of blood and the dynamics of progesterone levels in the blood serum of cows with and without the retention of fetal membranes; 3. to analyse the bacterial microflora of cows' uterus with and without the fetal membranes' retention; 4. to analyze the histological picture of the uterus endometrium on day 42 after calving in cows with and without retention of the fetal membranes, using histological and immunohistological examination; 5. to evaluate the effect of different treatment methods of retained fetal membranes on further lactation, using milk yield and somatic cell count parameters; 6. to evaluate the effectiveness of different treatment methods for cows with fetal membranes retention, using reproductive indicators; 7. to calculate the economic costs of cows with fetal membrane retention. The cows used in the study were registered, then the general health was tested, thermometry, the rectal and ultrasonographic examination of the genitals, morphological and biochemical analyses of the blood, microbiological analysis of the contents of the uterine cavity were carried out, as well as endometrial biopsy samples for histological, the immunohistochemical examination was taken. The obtained study data were grouped: 1) by days (2, 4, 6, 14, 16, 18, 22, 24, 26, 28, 30, 32 and 42 days delivery); 2) by cow groups (first, second, third and fourth), where Group 1 (n=15) – control group – fetal membranes were expelled during 12-24 h after calving; Group 2 (n=15) – cows with retention of fetal membranes, which were removed manually, and the cows were treated intrauterine (IU); Group 3 (n=15) – cows with retention of fetal membranes, which were not removed, and the cows were treated IU; Group 4 (n=15) – cows with retention of fetal membranes, which were not removed, and the cows were not treated IU; 3) by the vaginal discharge was scored (from 0 to 5, where 0 - no discharge, but 5 - watery, fetid, sanguino-purulent); 4) by uterine tone was scored (atonic, moderate tone, good tone); 5) by uterine size was scored (large, medium, and small); 6) with a sixth-day post partum (PP) after ovarian activity (active, inactive). Data analysis was carried out based on cow groups' categorisation (control cows with physiological postpartum period and cows with retention of the fetal membranes). During the research blood morphological and biochemical parameters were determined by Ltd Central Laboratory, microbiological examinations performed at the Institute of Food Safety, Animal Health and Environment "BIOR". Morphological and immunohistochemical analyses of bovine endometrium were performed in the laboratory of the Institute of Pathology of P. Stradins Clinical University Hospital. The findings of the study In the postpartum period, both control cows and cows with RFM showed a slow decrease in uterine size. Significantly slower uterine involution was observed in cows with RFM. In the control group, complete uterine involution were observed on day 28 PP, but in cows with RFM - only after day 42 PP. Evaluating the ovarian function on day 14 PP, we found that 65% of cows in the RFM group and 80% of cows in the control group had inactive ovaries (oval, small, smooth with small follicles) (p 0.05). However, during the first 100 days of PP, economically significantly higher milk losses were observed in cows, where the retained fetal membranes were removed manually, and the animals were treated IU, and in cows, where the RFM was not separated, and the animals were not treated IU. Also, in terms of SCC, both groups of cows in standard lactation (305 days) had significantly higher SCC than it was in control group cows (p<0.05). Further evaluating the impact of different RFM treatment methods on the study cows' reproductive performance, we found that there are not markedly better or worse RFM treatment methods. Each RFM treatment method has its pros and cons. Consequently, there is no single specific RFM treatment method that would be more economically advantageous and appropriate for Latvian conditions, which would have a positive effect on the future lactation and reproduction of all diseased cows. Each case of RFM should be evaluated individually, and the specific method of RFM treatment should be chosen. The Doctoral Thesis is summarized on 120 pages including 15 Tables and 32 Figures. It consists of annotation, introduction, literature review, materials and methods, research results, discussions, 8 conclusions, 3 recommendations for practice, list of references (270 literature sources), and 3 annexes.