Supplementing rumen‐protected methionine to lactating multiparous dairy cows did not improve reproductive performance

Abstract

There is evidence that supplementing methionine has positive effects on uterine environment, oocyte quality and embryo development in cattle. Thus, the objective of this study was to evaluate reproductive traits of cows supplemented with rumen‐protected methionine (RPM) during early to mid‐lactation in comparison with an untreated control group (CON). An additional focus was on the effect of puerperal diseases on reproductive performance parameters in RPM‐supplemented group MET and in CON. A total of 1,709 multiparous Holstein‐Friesian cows were enrolled in this field trial conducted on a commercial dairy farm in Slovakia. Cows were allocated at approximately 12 days post‐partum (dpp) to either CON or MET, the latter supplemented with 25.0 g–27.2 g RPM per cow per day incorporated into the total mixed ration (TMR) until leaving the study pen at approximately 140 dpp. The amount of RPM was calculated based on individual feed ingredients analysis and adjusted during the study period when TMR changed. Cows were monitored during the post‐partum period by vaginal examination (day 5 pp), measuring of beta‐hydroxybutyrate in blood (3, 5, and 8 dpp) and by vaginal examination, uterine cytology and measuring of back fat thickness by ultrasound (all at 31 ± 3 dpp).Compared with CON, cows supplemented with RPM did not show better reproduction performance parameters (first service submission rate, days to first service, conception risk, days open 140). Results from binary logistic regression model for the risk of conception showed that metritis had a significant effect, but the supplementation of methionine had not. Results of Cox regression analysis for the odds of conception within 140 dpp revealed only metritis and clinical endometritis as significant factors. In conclusion, supplementation of RPM had no beneficial effect on reproductive performance in this study farm compared with an untreated control group.

Identification and characterization of dairy cows with different backfat thickness antepartum in relation to postpartum loss of backfat thickness: A cluster analytic approach

“…The current study extends the study by Süss et al (2019) in which the effect of dietary supplementation with rumen-protected methionine (MET) on reproductive performance was tested in 1,709 multiparous Holstein cows. The field trial was conducted from March 2016 to November 2017 on a dairy farm in Slovakia that housed approximately 2,400 Holstein-Friesian cows.…”

“…Each barn consisted of groups of approximately 250 cows and was equipped with concrete floors and cubicles. All animals received the same basal diet as a TMR during pregnancy and lactation as reported previously (Süss et al, 2019). Cows were offered the TMR twice daily and adjusted to achieve refusal rates of 5 to 10%.…”

“…On d 25 ± 10 ap and d 31 ± 3 pp (means ± SD), BFT was assessed by ultrasound (Easi-Scan, IMV Imaging; 7.5-MHz linear probe with wrist display) as previously described (Schröder and Staufenbiel, 2006). Cows were evaluated for metritis at d 5 pp by assessment of vaginal discharge and body temperature, and for endometritis at d 31 ± 3 pp by vaginal examination and uterine cytology (Süss et al, 2019). Reproduction management procedures were defined in dairy farm-specific standard operating procedures.…”

“…Blood samples were collected from a coccygeal vessel using evacuated tubes coated with a clot activator for serum collection (Süss et al, 2019), on the same day as the BFT measurements. In the samples, serum BHB was used to classify cows as normal or hyperketonemia using a BHB threshold of 1.2 mM (Süss et al, 2019).…”

“…With this background, we used a cluster analytic approach to identify clusters of cows based on either antepartum BFT (BFT-ap) or the BFT change during the transition period (BFT loss, ΔBFT), with thresholds that were not arbitrary but derived solely from the data set used. We used data and samples from a previously described feeding trial (Süss et al, 2019). The objectives of the present study were (1) to characterize the interindividual variation in the relationship between BFT-ap (d 25 ± 10 ap, means ± SD) and subsequent BFT loss pp (d 31 ± 3 pp, means ± SD) in a large dairy herd;…”