Evaluation of Oral Colostrum or an Organic Botanical Preparation on Reproduction in Dairy Cattle
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2009-12-02
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MCKEE, SARA LYNN. Evaluation of Oral Colostrum or an Organic Botanical Preparation on Reproduction in Dairy Cattle. (Under the direction of Dr. Steven P. Washburn).
The two objectives of this research project were: 1) to observe the effects of pooled oral colostrum on reproductive traits including ovarian structures, serum progesterone concentration, and days to estrus in dairy heifers and 2) to evaluate the effects of the botanical, estrogenic compound, Heat Seek on milk progesterone values, days to subsequent estrus, as well as ovarian structures in dairy cows (Rep 1). In the first objective, purebred Holstein, Jersey, and Holstein/Jersey crossbred heifers (n = 29) were ultrasounded for presence of a viable corpus luteum (CL); average CL diameter = 2.9 ± 0.07 cm. Heifers were assigned at random to 1 of 4 treatment groups: 1) untreated control (n = 7); 2) positive control, 25mg Lutalyse (PGF2α) i.m. (n = 7); 3) 1 L oral colostrum (n = 7); or 4) 2 L oral colostrum (n = 8). Ultrasound measurements and blood samples were collected before treatment (d 0) and at 1 and 4 d after treatment to determine changes in CL size and serum P4 concentrations. Heifers received tailhead paint and were observed for estrus twice daily. Exact stages of the estrous cycle were not known, however sizes of CL and serum concentrations of P4 were comparable across treatments at the start of the experiment (d 0). Comparisons of P4 concentrations showed significant differences between Lutalyse vs. all other groups at d 1 (P < 0.01) and d4 (P < 0.05). Based on P4 and ovarian palpation, all 7 PGF2α treated heifers responded with luteal regression as expected. Heifers treated with I L or 2 L of colostrum had higher P4 on d 1 and d 4 (P < 0.05) than the negative control group and had similar sizes of luteal structures on d 4 indicating a lack of effect of luteal regression from treatment with colostrum. All 7 heifers receiving Lutalyse came into estrus within 4 d after treatment (2.8 ± 0.2 d) whereas only 3 heifers from the untreated group, 2 from the 1 L group, and 3 from the 2 L group were detected in estrus within 7 d after treatment. All heifers detected in estrus had P4 >2.0 ng/ml at treatment which declined thereafter. In contrast, the 14 heifers not observed in estrus by 7 d all had concentrations of P4 >2.0 ng/ml at treatment and at 1 and 4 d after treatment. All PGF2α -treated heifers responded with a decline in P4 and subsequent estrus whereas responses among the 15 heifers that received colostrum were similar to that of the 7 untreated heifers. A bioassay conducted determined there was little estrogenic activity in a sample of the pooled colostrum, which was unexpected. It is not known whether the use of colostrum of higher quality or at higher doses would be more effective. In summary, this trial provided no evidence that use of oral colostrum would be effective in facilitating luteal regression and earlier onset of estrus in dairy heifers.
For the second objective, a two-replicate experiment was conducted to determine the effects of the botanical, estrogenic compound, Heat Seek on reproductive traits. Cows in the first trial (n = 24) and second trial (n = 27) were purebred Holstein, Jersey, or various H/J crossbreds. Preliminary milk samples were collected in both trials to determine positive cyclicity (P4 >2ng/ml). In each trial, cows were separated at random into 2 treatment groups (Control or Heat Seek-treated) based on breed group. In the first replicate, ultrasound data was collected on d 1 for initial observation of ovarian structures and then again on d5. Cows received tailhead paint and were monitored twice daily until detection of estrus. Daily milk samples of 5-8mls were also taken from cows for analysis of progesterone concentration. Heat Seek treated cows received a daily 13-g bolus capsule of Heat Seek (Rep 1: 0.10µg/kg; Rep 2: 0.11µg/kg estrogen equivalent given per day) for 6 consecutive days (d1-d6). Lastly, post treatment milk samples were taken on d 10 from all cows for analysis of P4. In Rep 1, average CL diameters for cows in the control group were 2.0 ± 0.7cm (n = 3) for d 1. By d 5, average diameters for this group were 1.8 ± 0.3cm (n = 6). Cows in the treated group had d 1 average diameters of 1.9 ± 0.3cm (n = 8). Heat Seek treated cows had average CL diameters of 1.3 ± 0.1cm by d 5 (n = 7). For both trials, there were no differences in milk progesterone concentrations for all 6 sampling days for both treatment groups. Post-treatment samples also showed no significant differences between the 2 groups (Rep 1 P = 0.86; Rep 2 P = 0.54). In Rep 1, average days to estrus for control cows were 24.0 ± 10.4 d and 24.8 ± 9.2 d for treated cows. For Rep 2, average days to estrus for control cows were 19.2 ± 3.4d and 27.3 ± 8.7d for treated cows. There were no significant effects of low or high d1 progesterone levels in regards to attainment of estrus within 25 d for the combined trial data (P = 0.52 for treatment; P = 0.35 for P4 value on d 1). The percentage of those that conceived to their first subsequent estrus after d1 for Rep 1 was 33% (Control) and 55% (Heat Seek). Rep 2 percentages were 50% (Control) and 69% (Heat Seek). The lack of significant differences in milk progesterone data for cows treated in both replicates suggests that the estrogens present in the Heat Seek capsules may not have been sufficient enough to elicit a response. The variation in responses may have been subject to the timing of treatment and stage of cycle. Low progesterone levels on d1 and during treatment may have also been a result of cows that were not cyclic or because they had regressed a CL.
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Keywords
dairy cattle, reproduction, botanical preparation, colostrum
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Degree
MS
Discipline
Animal Science
