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PubMed1988

Increase of pregnancy rate in dairy cattle after preovulatory follicle palpation and deep cornual insemination.

A total of 334 first-service lactating cows in natural estrus were used in the study. Semen was deposited into the uterine body of 174 cows and deep into the uterine horn ipsilateral to the side of impending ovulation of 160 cows. In both groups, insemination was performed within the interval of 50 to 100 d postpartum at 8 to 15 h after estrus detection and after preovulatory follicle palpation. Pregnancy rates were determined by palpation per rectum 50 d post insemination. The pregnancy rate was higher (P < 0.05) for deep uterine horn insemination (70.62%) than for uterine body insemination (60.34%).

Journal Article↗
PubMed1996

Relationship of production to reproductive performance in Ontario dairy cows: herd level and individual animal descriptive statistics.

Data were collected on reproductive, health and production events in 45 dairy herds distributed throughout southwestern and eastern Ontario. The data were collected between July 1990 and July 1993. The herds were serviced by 11 different veterinary practices. Herd size ranged from 19 to 231 lactating cows, but 90% of the herds consisted of fewer than 125 milking cows. Mean and median actual milk yields per cow per day were 46.0 and 52.3 lbs, respectively, with a minimum of 21.3 and maximum of 67.8 lbs. Mean and medium adjusted corrected milk yields were 56.0 and 62.3 lbs, reflecting mean and median average days in milk of 199.0 and 198.5 d, respectively. Mean and median days in milk at the first estrus were 85.1 and 83.9 d, respectively, at first service 94.0 and 88.9 d, and at conception 126.3 and 115.5 d. Mean and median percentages of days open > 120 were 27.7 and 23.1%, respectively. The mean estrus detection rate was 48.3%, with a minimum of 28.4% and a maximum of 64.2%. The mean first service conception rate was 48.2%, with a minimum of 27.0% and maximum of 72.1%. The mean overall conception rate was 46.7%, with a minimum of 29.8% and a maximum of 70.7%. Mean and median lactation lengths were 341.1 and 338.5 d and the mean and median average dry days were 62.0 and 67.0, respectively. The mean lactational removal rate was 20.6%, with a range of 4.3 to 40.5%. Reasons for culling were available for 1381 cows. Low production accounted for 23.7 % of the cullings; reproductive reasons, 20.6 %; dairy sales, 13.4%; mammary problems, 12.8%; and lameness, 9.9%. Lactational incidence rates for diseases were lower than previously reported for Ontario dairy herds. The most commonly used therapeutic agents were GnRH (10.5%) and PGF (11.7%).

Journal Article↗
PubMed2003

Effect of oestradiol benzoate given after prostaglandin at two stages of follicle wave development on oestrus synchronisation, the LH surge and ovulation in heifers.

Oestrus synchronization following prostaglandin-induced luteolysis is variable and dependent on follicle wave status in cattle. Oestradiol benzoate (ODB) has been used following prostaglandin to reduce the interval to oestrus and ovulation, but the effect of follicle wave status at the time of ODB administration is not clear. The aim of this study was to characterize the endocrine and follicular responses following ODB after luteolysis at different stages of the follicle wave. Prostaglandin was administered at either emergence or dominance of the second follicle wave. Twenty-four hours later animals received either 0.5mg ODB in oil or a control oil injection. Follicular development was monitored daily by ultrasonography, oestrous behavior was determined and blood samples were collected. In animals treated with ODB at emergence, there was a reduction (P<0.05) in the maximum diameter of the ovulatory follicle (11.7+/-1.2 mm versus 13.1+/-0.1 mm) and in the interval from prostaglandin to oestrus (52.0+/-2.3 h versus 88.0+/-9.6h), to the LH surge (53.3+/-3.5 h versus 89.1+/-6.5 h) and to ovulation (96+/-0.0 h versus 129.6+/-9.6h), compared with controls. In animals treated with ODB at dominance, there was a reduction (P<0.05) in the interval from prostaglandin to the LH surge (54.0+/-3.1 h versus 70.9+/-4.8 h), but not in the interval from prostaglandin to oestrus (53.3+/-2.7 h versus 65.7+/-4.5 h; P=0.11), to ovulation (96.0+/-0.0 h versus 110.4+/-4.8 h; P=0.12) or the maximum diameter of the ovulatory follicle (12.7+/-0.3 mm versus 13.6+/-0.4 mm; P=0.12), compared with controls. Treatment did not affect (P>0.05) the length of the subsequent oestrous cycle or corpus luteum size. In conclusion, the use of ODB advanced, but did not alter the temporal relationships among oestrus, the LH surge and ovulation, regardless of stage of follicle development at treatment.

Animals↗
PubMed1997

Vaginal temperature is not related to the time of ovulation in sows.

The relationship between vaginal temperature and ovulation time was studied in sows. The vaginal temperature was measured continuously between Day 4 and Day 10 after Altrenogest-treatment in 10 sows. Oestrus was checked with a vasectomized boar at 8-h intervals, and during oestrus, ovulation time was checked with transrectal ultrasonography at 2-h intervals between 07:00 h and 23:00 h. Two sows ovulated between 23:00 h and 07:00 h, and these sows were taken out of the experiment. In the eight remaining sows, a clear day/night rhythm in vaginal temperature was found: between 03:00 h and 09:00 h, vaginal temperature (LSM +/- sem, corrected for sow) was on average 38.2 +/- 0.01 degrees C; between 15:00 h and 21:00 h, vaginal temperature was on average 38.5 +/- 0.01 degrees C (P < 0.001). Between 4 days before ovulation and 2 days after ovulation, no changes in temperature could be found that were related to ovulation time in any of the sows. Therefore, in sows, changes in vaginal temperature cannot be used as a predictor for ovulation time, and consequently cannot be used to predict the best time for insemination.

Animals↗
PubMed2000

Synchronization of lactating dairy cows with prostaglandin F2 alpha: insemination on observed oestrus versus timed artificial insemination.

The effect of two insemination policies after synchronization of oestrus on reproductive performance in two groups of cows was investigated. Oestrus was synchronized by two treatments with prostaglandin F2 alpha (PGF2 alpha) at a 14-day interval. Cows in Group 1 (n = 234) were inseminated twice on appointment 66 and 90 h after the second treatment. Cows in Group 2 (n = 222) were intensively watched for signs of oestrus after the synchronization protocol and inseminated on observed oestrus. Cows with abnormal discharge after synchronization were excluded from breeding and inseminated later during the study period. Service rate within 1 week after synchronization was higher in Group 1 than in Group 2 (89.3 versus 67.1%). Conception rates on first service did not differ between groups (33.2 versus 30.0%). Days to first service and days open were shorter in Group 1 (P < 0.05). The number of cows culled for infertility did not differ between the groups. Endometritis 14-20 days post-partum decreased the percentage of cows pregnant at the end of the study period in both groups but did not have a significant effect on conception rates and days open. It is concluded that additional inseminations required in the timed artificial insemination protocol were economically justified by the reduction in days open in comparison with insemination on observed oestrus after synchronization.

Animals↗
PubMedDate not supplied

Prepartum peripherally-induced hyposmia does not reduce postpartum anoestrus duration in nursing goats.

Parturient goats rapidly develop exclusive nursing of their own litter that relies on olfactory recognition of the young. They also show a period of postpartum anoestrus whose duration depends on the presence of the kid. In cattle, maternal selectivity is one of the factors that delays the recovery of sexual activity. To investigate the possible influence of maternal selectivity on the duration of postpartum anoestrus in goats, we compared the recovery of estrus behavior by daily estrus detection with an active buck in intact and selective nursing goats (n = 24) with that of dams rendered non-selective by peripheral hyposmia with ZnSO4 (n = 18). Postpartum anoestrus duration was shorter in intact (68+/-7 days) than in hyposmic mothers (93+/-7 days; P < 0.05). However, the cycles of normal duration were less frequent in intact goats (P = 0.03). We conclude that in nursing goats, preventing the establishment of selective nursing by prepartum peripheral hyposmia does not reduce postpartum anoestrus duration. Our results suggest that daily exposure to the buck may result in an earlier recovery of ovarian activity in intact mothers.

Anestrus↗
PubMed1992

Endocrine and ovarian responses associated with the first-wave dominant follicle in cattle.

To examine endocrine and biochemical differences between dominant and subordinate follicles and how the dominant follicle affects the hypothalamic-pituitary-ovarian axis in Holstein cows, the ovary bearing the dominant follicle was unilaterally removed on Day 5 (n = 8), 8 (n = 8), or 12 (n = 8) of synchronized estrous cycles. Follicular development was followed daily by ultrasonography from the day of detected estrus (Day 0) until 5 days after ovariectomy. Aromatase activity and steroid concentrations in first-wave dominant and subordinate follicles were measured. Intact dominant and subordinate follicles were cultured in 4 ml Minimum Essential Medium supplemented with 100 microCi 3H-leucine to evaluate de novo protein synthesis. Five days after unilateral ovariectomy, cows were resynchronized and the experiment was repeated. Follicular growth was characterized by the development of single large dominant follicles, which was associated with suppression of other follicles. Concentrations of estradiol-17 beta (E2) in follicular fluid and aromatase activity of follicular walls were higher in dominant follicles (438.9 +/- 45.5 ng/ml; 875.4 +/- 68.2 pg E2/follicle) compared to subordinate follicles (40.6 +/- 69.4 ng/ml; 99.4 +/- 104.2 pg E2/follicle). Aromatase activity in first-wave dominant follicles was higher at Days 5 (1147.1 +/- 118.1 pg E2/follicle) and 8 (1028.2 +/- 118.1 pg E2/follicle) compared to Day 12 (450.7 +/- 118.1 pg E2/follicle). Concentrations of E2 and androstenedione in first-wave dominant follicles were higher at Day 5 (983.2 +/- 78.2 and 89.5 +/- 15.7 ng/ml) compared to Days 8 (225.1 +/- 78.6 and 5.9 +/- 14.8 ng/ml) and 12 (108.5 +/- 78.6 and 13.0 +/- 14.8 ng/ml). Concentrations of progesterone in subordinate follicles increased linearly between Days 5 and 12 of the estrous cycle. Plasma concentrations of FSH increased from 17.9 +/- 1.4 to 32.5 +/- 1.4 ng/ml between 0 and 32 h following unilateral removal of the ovary with the first-wave dominant follicle. Increases in plasma FSH were associated with increased numbers of class 1 (3-4 mm) follicles in cows that were ovariectomized at Day 5 or 8 of the cycle. Unilateral ovariectomy had no effects on plasma concentrations of LH when a CL was present on the remaining ovary. First-wave dominant follicles incorporated more 3H-leucine into macromolecules and secreted high (90,000-120,000) and low (20,000-23,000) molecular weight proteins that were not as evident for subordinate follicles at Days 8 and 12.(ABSTRACT TRUNCATED AT 400 WORDS)

Androstenedione↗
PubMed1989

Dinoprost 14-day oestrus synchronisation schedule for dairy cows.

Oestrus and ovulation were synchronised in 82 lactating Friesian dairy cows with two injections of dinoprost, and the cows were inseminated 72 and 96 hours after the second injection. Twenty-one of the 41 cows (51 per cent) which had a 14-day interval between the dinoprost injections conceived to the inseminations, compared with 18 of the 41 cows (44 per cent) which had an 11-day interval between the injections.

Animals↗
PubMed2003

Re-serviced females on commercial swine breeding farms.

The objectives of this study were to observe subsequent reproductive performance of re-serviced females by the number of services within a parity, to measure mean days to re-service and culling intervals, to determine lifetime performance in re-serviced gilts, and to investigate re-serviced females across parities on commercial farms. Reproduction records on 539 U.S.A. farms were used to observe re-serviced females by the number of service groups at the herd level. Farrowing rate decreases by approximately 10%, and re-service occurrence increases by approximately 5% for each increase in the number of services increase within a parity group (P<0.05). Only in parity 0 to 2 groups, average pigs born alive at subsequent farrowing in the second or later service groups were greater than in the first service group (P<0.05), but in parity >or=3, the third or later service groups produced fewer pigs born alive than the other service groups (P<0.05). Lifetime performance and re-service events were observed in 39945 individual females on the 149 selected farms that had complete 5-year records. Means of days to re-service, first-mating-to-culling intervals in gilts and weaning-to-culling intervals in sows were 46.3 days, 95.2 days, and 48.2 days, respectively. Re-serviced gilts had longer NPD (>50 days), a lower parity at culling (>0.5) and fewer lifetime pigs born alive (>2 pigs) than non-return gilts (P<0.05), but no difference in average pigs born alive per parity was found between re-serviced gilt groups and non-return gilts. Of 19677 re-serviced females, 35.6% had two or more re-services across parities in pig life, 10.6% had 3 or more re-services, and 1.95% had four or more re-services. Accurate estrus detection with a boar and improved mating techniques on re-serviced females are suggested to improve herd productivity.

Animals↗
PubMed2001

Hormonal characterization of the reproductive cycle and pregnancy in the female Mohor gazelle (Gazella dama mhorr).

The oestrous cycles of seven captive Mohor Gazelles (Gazella dama mhorr) were investigated. Hormone profiles obtained from faecal samples collected each day from cyclic females indicated that the mean duration of the oestrous cycle was 18.62 +/- 0.26 days (range 16-22 days; n = 37 oestrous cycles). No inter-individual differences in the concentration of faecal progestagen metabolites excreted were observed, but mean faecal oestrogen excretion during both the luteal and inter-luteal phases of the oestrous cycle varied among females (P < 0.001 and P = 0.070, respectively). Oestrous cycles were synchronized using controlled internal drug release (CIDR) devices, before natural mating with an intact male. Concentrations of faecal progestagen metabolites remained approximately constant for the first 10 weeks of gestation (mean +/- SEM = 4048 +/- 407 ng g(-1) faeces), before increasing to a mean of 23 556 +/- 1176 ng g(-1) faeces. Two of seven female gazelles conceived immediately after removal of the CIDR device, a similar proportion to that conceived at the postpartum oestrus under natural conditions. Life history data for these individuals indicated that the mean time to conception in female gazelles is positively correlated with peak values in the ratio of excreted oestrogen : progestagen during the inter-luteal period of their oestrous cycles (R(2) = 0.58; P < 0.05). This finding indicates that interactions between steroid production and metabolism may influence the likelihood of conception occurring in this species.

Animals↗
PubMed2005

Estrous cycle characterisation and artificial insemination using frozen-thawed spermatozoa in the bottlenose dolphin (Tursiops truncatus).

The reproductive endocrinology of the bottlenose dolphin, Tursiops truncatus, was characterized to facilitate the development of artificial insemination using cryopreserved spermatozoa. Specific objectives were: (i) to determine the excretory dynamics of urinary luteinizing hormone (LH) and ovarian steroid metabolites during the estrous cycle; (ii) to evaluate the effect of an exogenously administered synthetic progesterone analog (altrenogest) on reproductive hormone excretion; (iii) to correlate follicular growth and ovulation (as determined by transabdominal ultrasound) to urinary LH and ovarian steroid metabolites; (iv) examine the in vivo fertilisation capacity of cryopreserved semen, and (v) to develop an intrauterine insemination technique. Based on urinary endocrine monitoring of natural estrous cycles (2 consecutive cycles) and nine post altrenogest cycles in ten females, estrous cycles were found to be 36 days long and comprised of an 8 day and 19 day follicular and luteal phase, respectively. Peak estrogen conjugates (EC; 5.4+/-3.8 ng/mg creatinine (Cr)) occurred 8 h prior to the LH surge (70.9+/-115.7 ng/mg Cr). The time of ovulation, as determined by ultrasonography, occurred 32.1+/-8.9 h and 24.3+/-7.0 h after the onset of the LH surge and LH peak, respectively. Mean preovulatory follicular diameter and circumference were 2.1+/-0.5 cm and 6.5+/-1.5 cm, respectively. Of the 27 estrous synchronisation attempts, 13 resulted in an ovulatory cycle, with ovulation occurring 21 days post-altrenogest treatment. Intrauterine (4 of 5) and intracornual (1 of 3) inseminations conducted across eight estrous cycles resulted in five pregnancies (63%), one pregnancy resulted from the use of liquid stored semen, whereas four were achieved using cryopreserved semen. These data provide new information on female bottlenose dolphin reproductive physiology, and demonstrate that the combination of endocrine monitoring and serial ultrasonography contributed to successful AI using liquid-stored and cryopreserved semen.

Animals↗
PubMed2005

Evaluation of factors that affect embryonic loss in dairy cattle.

OBJECTIVE: To identify potential risk factors for embryonic loss before 35 to 42 days of gestation in dairy cattle. DESIGN: Prospective observational study. ANIMALS: 381 cows. PROCEDURE: Body condition score was determined at the time of artificial insemination (AI; day 0) and on days 20, 23, and 27 and between days 35 and 41; serum progesterone concentration was measured on days 0; 20 or 21; and 23, 24, or 25. Cows were excluded from analyses if day 0 serum progesterone concentration was > or = 1.0 ng/mL and classified as pregnant on day 23 if serum progesterone was > 1.5 ng/mL on day 20 or 21 and day 23, 24, or 25. Cows were examined via transrectal ultrasonography on day 27 or 28 and rectally palpated for pregnancy on days 35 to 41. RESULTS: 39% of cows that were pregnant on day 23 lost their embryo by day 27, and 18% of cows that were pregnant on day 27 or 28 were not pregnant on days 35 to 41. Breeding a pregnant cow posed the greatest risk for embryonic loss at both time periods. Mean serum progesterone concentrations on day 21 or 22 and day 23, 24, or 25 were lowest for cows that lost an embryo between days 24 and 28. Cows with a linear somatic cell count score > 4.5 before AI were twice as likely to lose the embryo by 35 to 41 days, compared with cows with a score < 4.5. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that embryonic loss could be reduced by more accurate estrus detection, reducing mastitis, and strategies to improve progesterone concentration after breeding.

Abortion, Veterinary↗
PubMed1990

Effect of cohabitation with white-faced ewes on estrous activity of Hampshire and Suffolk ewes exposed to rams in June.

Two groups of 24 Hampshire and 26 Suffolk purebred ewes each were used to study effects of cohabitation with cyclic white-faced (WF) ewes on estrous activity in June. Ewes lambed in January, February and March and had been isolated from mature rams since the previous fall breeding. From June 1 to July 2, treated (T) ewes were exposed to vasectomized rams and to 65 WF ewes; control (C) ewes were exposed only to vasectomized rams. Ovulation was assessed with biweekly serum progesterone assays; crayon marks were used to detect estrus. Daily observations of ram behavior were conducted to assess sexual activity of rams joined with T and C ewes. Cohabitation with WF ewes increased (P less than .01) ovulation percentages from 46% in C (42% for Hampshires and 50% for Suffolks) to 76% in T ewes (79% for Hampshires and 73% for Suffolks). Mating percentage also was increased (P less than .05) by cohabitation with WF ewes from 14% for C ewes to 30% for T ewes. Rams with T + WF ewes spent more (P less than .05) time checking ewes for estrus than did rams with C ewes. Hence, cohabitation with cycling WF ewes increased ovulation and mating percentages. Many acyclic T ewes first ovulated after 10 or more days of teasing, possibly due to increased ram contact in the presence of WF ewes.

Animals↗
PubMed1996

Effects of dietary fat and season on steroid hormonal profiles before parturition and on hormonal, cholesterol, triglycerides, follicular patterns, and postpartum reproduction in Brahman cows.

Spring-calving Brahman cows (S) artificially inseminated to Brahman, Angus, or Tuli sires and fall-calving Brahman cows (F) naturally bred to Brahman were allotted randomly to receive 3.74% (LF; n = 9 S and 6 F), 5.20% (MF; n = 8 S and 6 F), or 6.55% dietary fat (HF; n = 8 S). Diets were formulated to contain differing fatty acid concentrations and to be isocaloric and isonitrogenous. Cows were bled and fed twice daily from 2 wk before expected calving date through d 21 after calving. Ultrasonography was performed on d 14 and 21 after calving. From d 21 to 90 after calving a sterile bull equipped with a chin-ball marker was placed with the cows to aid in estrus detection. In both seasons progesterone decreased (P < .01) and estradiol-17 beta increased (P < .01) as parturition approached. Cows receiving MF and HF had increased (P < .01) total numbers of follicles compared to LF cows, and cows receiving MF had larger (P < .01) follicles. During the spring, cows receiving HF and cows bred to Brahman or Tuli sires had longer (P < .01) gestation lengths. Progesterone concentrations before calving were affected (P < .01) by treatment x sire and estradiol-17 beta by a time x treatment interaction (P < .01). Cholesterol after calving was higher (P < .01) in HF cows than in LF or MF cows. In the fall, LF cows had heavier (P < .01) calves than cows receiving MF. Birth weight was also affected (P < .01) by treatment x sex of calf. Progesterone was affected (P < .01) by treatment x sex of calf. Estradiol-17 beta was affected (P < .01) by sex of calf and treatment x sex of calf. Across seasons, by d 90 after calving, 9 of 15 (60%) LF and 11 of 15 (73.3%) MF cows showed estrual behavior. Cows in the spring had increased (P < .01) numbers and larger follicles compared to the fall. In conclusion, dietary fat may influence steroid hormone concentrations before calving, calf birth weight and postpartum follicular populations; furthermore, follicular populations may also be influenced by season.

Animals↗
PubMed1998

Fat supplementation influences postpartum reproductive performance in Brahman cows.

Multiparous Brahman cows (n = 40) in excellent body condition (6.5+/-.1) were randomly assigned to receive either 5.2 (rice bran) or 3.7% (control) dietary fat after calving. The experimental diets were formulated to be isocaloric and isonitrogenous. The experimental diets were fed twice daily from d 1 after calving through the first normal estrous cycle. Cows were weighed, scored for body condition, and bled at weekly intervals from d 1 through 50 after calving. Weekly bleedings continued until the first detectable estrus. Blood samples were collected daily throughout the first normal estrous cycle. All cows were exposed to a fertile bull at the estrus following the first normal estrous cycle and for a 60-d breeding season. Ovarian follicular populations were recorded weekly by transrectal ultrasonography from d 15 to 50 after calving. Calf weights were recorded at 14-d intervals from d 1 to 43 after birth and at weaning (205 d). Cows receiving rice bran gained more body condition (P < .05) than cows receiving the control supplement. The numbers of small (< 4.0 mm, P < .05), medium (4.0 to 7.9 mm, P < .05) and total follicles (P < .05) were greater in the rice bran than in the control group from 15 to 29 d after calving, and large follicles ( > or = 8.0 mm) increased in number (P < .05) and the largest follicle increased in size (P < .001) over time regardless of the level of dietary fat. Fat supplementation increased the numbers of medium (P < .01), large (P < .05), and total (P < .01) follicles and size of the largest follicle (P < .05) during the 3 wk before the first normal estrous cycle. The intervals from parturition to reproductively important end points were similar (P > .10) between dietary treatments as well as the percentage of cows showing normal or abnormal estrous cyclic activity. Treatment did not affect (P > .10) daily serum progesterone (P4) concentrations. However, there was a tendency (P = .09) for more rice bran-supplemented cows to be pregnant (94.1 vs 71.4%) after being exposed to a fertile bull for 60 d. Calf weight gain tended to be higher (P = .08) in calves nursing rice bran-supplemented dams. In conclusion, using rice bran, with high concentrations of oleic and linoleic acids, as a fat supplement for postpartum cows enhanced ovarian follicular growth before normal estrous cycles resumed and increased body condition scores and pregnancy rates without altering postpartum interval or serum P4 concentrations.

Animal Feed↗
PubMed2002

Relationship between postpartum changes in 13, 14-dihydro-15-keto-PGF2alpha concentrations in Holstein cows and their susceptibility to endometritis.

Uterine infections (i.e., endometritis) can have a major economic impact on dairy production. Identifying cows that are susceptible to endometritis and improving the diagnosis of endometritis could lead to a reduction in the impact of such infections. Thus, we used Holstein cows to determine whether postpartum changes in 13, 14-dihydro-15-keto-PGF2alpha (PGFM), a metabolite of PGF2alpha, could be used to identify cows that are susceptible to endometritis and to improve the diagnosis of endometritis. Cows were assigned to three treatments. 1) Control (n = 10) had no clinical or bacteriological signs of endometritis during the study. 2) Treated (n = 11) developed endometritis spontaneously and were treated i.m. with 25 mg of PGF2alpha immediately after clinical diagnosis (d 17.6 +/- 0.8 postpartum; mean +/- SEM). 3) Untreated (n = 10) developed endometritis spontaneously and were not treated after diagnosis (d 20.0 +/- 0.5). Examinations of external and internal genitalia and bacteriological data were used to diagnose endometritis. From d 0 (calving) until approximately d 63 postpartum, jugular blood was collected three times weekly. Progesterone and PGFM were quantified in plasma. For PGFM, the treatment x day interaction was significant (P < 0.01). Overall PGFM profiles for Control and Treated differed (P < 0.05), but the Untreated profile did not differ from either Control or Treated. To better understand the interaction, PGFM data from d 0 to 35 postpartum were partitioned into consecutive 7-d periods, and d-36 and greater data were partitioned into one period. Effects of treatment, day, and the treatment x day interaction were then evaluated within period. Except for the d-15 to -21 period, PGFM was greater (P < 0.03) in Control than in Treated and Untreated. In Treated and Untreated, PGFM increased during the d-15 to -21 period. For progesterone, treatment did not affect the profiles, but day was significant (P < 0.001). Progesterone concentrations were basal from d 0 until approximately d 12, and they generally increased after d 12. Onset of endometritis was associated with increased progesterone concentrations. Treatment did not affect the interval from calving to first detected estrus (29.5 +/- 4.9 d) or from calving to AI (73.3 +/- 8.7 d). We conclude that PGFM measures have the potential to be used to identify cows that are more likely to develop endometritis and that PGFM may aid in the diagnosis of endometritis.

Animals↗
PubMed2003

Effect of supplemental nutrition around lambing on hair sheep ewes and lambs during the dry and wet seasons in the U.S. Virgin Islands.

Pregnant St. Croix White and Barbados Blackbelly hair sheep ewes were used to evaluate the effect of supplemental nutrition around the time of lambing on ewe and lamb performance during the dry and wet seasons on St. Croix. Beginning 14 d before expected day of lambing (d 0) and for 21 d postpartum, one group of ewes was fed a pelleted supplement in addition to grazing guinea grass pasture (FEED). Other ewes in the flock grazed pasture only (CONTROL). This study was conducted during the dry season (June through September; FEED n = 14 and CONTROL n = 15) and during the wet season the next year (October through January; FEED n = 11 and CONTROL n = 12). The 24-h milk production of each ewe was measured on d 7, 21, 35, 49, and 63. Ewes were exposed to sterile rams equipped with marking harnesses to detect estrus during the postpartum period. The FEED ewes lost less weight postpartum during both seasons (P < 0.0001) and had higher milk production (P < 0.009) than CONTROL ewes during the dry season. During the dry season, the time to the first postpartum estrus did not differ (P > 0.10) between FEED and CONTROL ewes (46.9 +/- 2.7 vs 52.9 +/- 2.6 d, respectively). During the wet season, the time to first postpartum estrus was less (P < 0.07) in FEED than in CONTROL ewes (33.0 +/- 3.1 vs 41.1 +/- 2.9 d, respectively). The FEED ewes had higher lamb birth weight (P < 0.04) and weaning weight (P < 0.05) than CONTROL ewes (3.2 +/- 0.1 and 12.2 +/- 0.5 vs 2.9 +/- 0.1 and 10.9 +/- 0.5 kg, respectively) during the dry season. In the wet season, lamb birth weight and weaning weight were similar (P > 0.10) between FEED and CONTROL (3.2 +/- 0.1 and 15.5 +/- 0.7 vs 3.1 +/- 0.1 and 15.3 +/- 0.6 kg, respectively). Lambs born during the wet season had higher (P < 0.0001) ADG than lambs born during the dry season (194.4 +/- 5.9 vs 127.7 +/- 4.7 g/d, respectively). Strategic nutritional supplementation of hair sheep ewes may provide a method for increasing the weight of lambs produced during the dry season in the tropics, but it does not seem to be beneficial during the wet season.

Animal Feed↗