Progesterone assays and rectal palpation in pre-service management of a dairy herd.

Fifty-one dairy cows were examined three times at weekly intervals during weeks 5 to 7 after calving. Rectal palpation of the ovaries and plasma progesterone assay were used to determine cyclic ovarian function. Eight of 51 cows exhibited true anoestrus by day 49 after calving. Only 23 of 43 cycling cows were served by day 77, the end of the target period for first service. In 77 per cent of 142 examinations, rectal palpation and progesterone assay gave compatible results. Most incompatibility occurred early or late inthe cycle, or in association with cystic structures in the ovaries. Eleven of the 51 cows had cysts in the ovaries but cyclicity and fertility were not adversely affected.     

Evidence for transmission of bovine leukemia virus by rectal palpation in a commercial dairy herd

The risk of Bovine Leukemia Virus (BLV) transmission by rectal examination was determined over 22 months in a commercial dairy herd. All 167 BLV seronegative cattle, of breeding age or greater, were divided randomly into two groups and identified by neck-chain color. In the treatment group, routine rectal palpation occurred after a BLV infected animal and without a change of sleeve, while in the other group, palpation occurred in a similar manner with the exception that sleeves were changed between animals. When BLV seronegative cattle in either group were palpated after BLV infected cattle, the event and identification of the cattle involved were recorded. Serologic testing was performed eight times during the 22 month study to determine the number of animals that became infected following a palpation (an event). Thirty-one animals seroconverted during the study; 24 in the treatment (no sleeve change) group and seven in the sleeve change group. Sixteen of the animals in the treatment group that seroconverted had been palpated prior to their seroconversion. A hazard ratio (relative risk) for BLV seroconversion was determined between the two groups. Cows palpated with no sleeve change had a 2.8-fold increase in risk (confidence interval 1.1–6.8) of BLV infection. The increased risk of BLV infection associated with rectal palpation may have been affected by the presence of some highly infectious cows in the herd. This study confirms that rectal palpation without a change of sleeve may be a significant risk factor in some herds, and if efforts are made to decrease the spread of BLV in a herd, the potential for rectal sleeve transmission must be considered.     

Investigation into the use of prostaglandin F2 alpha (PGF2 alpha) and oxytocin for the induction of farrowing

This experiment was conducted in order to compare the effects of injecting PGF2 alpha alone, PGF2 alpha with oxytocin and placebo on the induction of farrowing in swine and to compare the relative effects of 3 different dosages of oxytocin (10, 20 and 30 iu per animal) when combined with PGF2 alpha (10 mg). The findings revealed that animals treated with 30 iu oxytocin farrowed within 10.6 h which was similar to those receiving PGF2 alpha only (9.4 h), but shorter than control animals (53.6 h). Animals receiving 20 and 10 iu of oxytocin farrowed within 1.4 and 1.7 h, respectively. Difficult farrowings requiring manual assistance occurred in 30%, 30%, 50% and 10% of sows given 30 iu, 20 iu and 10 iu of oxytocin and in the control group, respectively. Thirteen of 73 sows treated with PGF2 alpha farrowed within 12.6 +/- 5.3 h. Stillbirths were highest (10.2%) in the control animals whilst in the others it was under 7%. Oxytocin at dosages of 20 and 10 iu, seemed most promising in terms of synchronising farrowing following PGF2 alpha treatment in swine. However, farrowing complications were more common in these groups.     

Synchronisation of oestrus in buffaloes (Bubalus bubalis) using prostaglandin F2alpha

Prostaglandin F2alpha (PGF2alpha) was used intramuscularly in two preliminary trials to determine its effect in cycling buffalo cows. In the first trial, animals with corpora lutea in their ovaries responded to either two doses of 15 mg on two consecutive days, or to a single dose of 30 mg, by showing signs of oestrus commencing 31 to 55h after the initial injection. In the second trial two doses of 30 mg PGF2alpha given 11 days apart resulted in oestrus on the third day after the second injection.     

Effect of tetracosactid on post partum cyclicity in cows after induction of parturition with PGF2 alpha

Parturition and retention of fetal membranes were induced with PGF2 alpha in 3 primiparous dairy cows. Starting on day 12 post partum (PP) the cows were treated with 500 micrograms i.m. of ACTH-analogue (tetracosactid) every 6 h for 6 times. Changes in plasma concentrations of cortisol, progesterone and 15-ketodihydro-PGF2 alpha were evaluated immediately after treatment. The effects on the resumption of ovarian activity were evaluated by clinical and ultrasound examinations and by progesterone and 15-ketodihydro-PGF2 alpha analyses for 56 days after parturition. Treatment was able to induce a statistically significant (p < 0.01) similar increase in cortisol and progesterone after both the 1st and the 6th injections, in all cows. No changes in 15-ketodihydro-PGF2 alpha concentrations were seen after any of the injections of ACTH-analogue. The first corpus luteum (CL) was seen on day 18 PP (cow A), and 28 (cow B) and in both cases it was followed by a normal ovarian cyclicity. No CL was observed during the whole period of study in cow C. Progesterone profiles confirmed these clinical and ultrasonographic findings. The steroid output, especially progesterone, induced by the ACTH-analogue might be a stimulus for the onset of ovarian cyclicity, since 2 of the 3 animals ovulated earlier than expected. These findings point to the fact that interference with the stress system might have a positive effect on ovarian cyclicity. The different pattern of response does however demand further studies.     

Induction of ovulation with GnRH and PGF(2 alpha) at two different stages during the early postpartum period in dairy cows: ovarian response and changes in hormone concentrations

The aims of this study were 1) to determine whether dairy cows can be induced to ovulate by the treatment with gonadotropin releasing hormone (GnRH) followed by prostaglandin F(2 alpha) (PGF(2 alpha)) during the early postpartum period and 2) to describe their ovarian and hormonal responses according to ovarian status. Cows were divided in two groups and received 10 microg of buserelin followed by 500 microg of cloprostenol 7 days apart starting from 21 (GnRH21, n=7) or around 37 days postpartum (GnRH37, n=7). The groups were further classified according to presence (-CL) or absence (-NCL) of functional corpora lutea (CL) on the day of GnRH treatment (d 0): GnRH21-NCL (n=4), GnRH21-CL (n=3) and GnRH37-CL (n=7). Ovarian morphology was monitored and the concentrations of P(4), E(2), FSH and insulin-like growth factor 1 (IGF-1) were measured. All cows ovulated after administration of GnRH. The P(4) levels of the GnRH21-NCL group from d 0 to d 5 were lower than those of the GnRH21-CL (P<0.05) and GnRH37-CL groups (P<0.01). In contrast, the E(2) levels of the GnRH21-NCL group within d 2 to d 6 were higher (P<0.05) than those of the other groups. Compared with the GnRH37-CL group, the GnRH21-NCL group had more small follicles on d 2 (P<0.05), d 3 (P<0.01) and d 4 (P<0.01) and more large follicles on d 5 (P<0.05). The induced CL and new ovulatory follicles were larger in the GnRH21-NCL group compared with the GnRH21-CL (P<0.001 and P<0.01) and GnRH37-CL groups (P<0.001 and P<0.05). IGF-1 did not differ among the groups. The GnRH21-NCL group had higher FSH levels than the GnRH21-CL (P<0.01) and GnRH37-CL groups (P<0.001) on d 0. Low P(4) and high FSH levels may suggest higher gonadotropin support on the enhanced ovarian morphology of the GnRH21-NCL group. PGF(2 alpha) treatment induced CL regression and subsequent ovulation in 3/4 (75%), 3/3 (100%) and 7/7 (100%) cows in the GnRH21-NCL, GnRH21-CL and GnRH37-CL groups, respectively. In conclusion, a 7-day GnRH-PGF(2 alpha) synchronization protocol can effectively induce dairy cows to ovulate as early as 21 days postpartum, regardless of ovarian status.     

Induction of ovulation with GnRH and PGF2alpha in lactating Bos taurus x Bos indicus cows

Induction of ovulation for timed artificial insemination (TAI) with the Ovsynch protocol was evaluated in 49 anoestrous and lactating Bos taurus x Bos indicus cows. Palpation per rectum and transrectal ultrasonography were used on Days -30, -20, -10 and 0 (start of treatment) to confirm anoestrus but with the presence of follicles > or = 10 mm, and every other day during treatment to determine ovarian activity. Cows were randomly assigned to: (1) Ovsynch (n = 24; Day 0, 200 microg GnRH; Day 7, 150 microg PGF2alpha; Day 9, 200 microg GnRH + TAI 16 to 20 h later) and (2) control (n = 25; no treatment). Rates of ovulation for the first GnRH injection, detection of a corpus luteum (CL) at PGF2alpha injection, pregnancy and induction of cyclicity were greater (P < 0.05) with Ovsynch. There was no effect of body condition score (P > 0.05). In conclusion, the Ovsynch protocol was not effective in obtaining acceptable pregnancy rate for TAI, but it was effective for induction of cyclicity in anoestrous and lactating Bos taurus x Bos indicus cows under tropical conditions.     

Synchronization of ovulation (OVSYNCH) in high producing dairy cattle herds. Part II: Milk yield, diseases and cost-benefit-analysis

A method for synchronization of ovulation (OVSYNCH) was evaluated for its practical use in seven North German dairy cattle herds. The original procedure of PURSLEY et al. (1995) was applied, i. e. cows were treated with Gonadotropin Releasing Hormone (GnRH) at a random stage of the estrous cycle, followed by an injection of a prostaglandin F2alpha (PGF2alpha)-analog seven days later and another injection of GnRH two days after PGF2alpha. Cows were inseminated 24 h after the last injection by artificial insemination. Control animals were assigned by corresponding lactation number and month of lactation. Cows from the OVSYNCH group returned to the conventional reproductive management after the OVSYNCH treatment, which was the same management as that for the control group. The parameters of fertility and correlations between body condition score (BCS) as well as concentrations of serum progesterone and the success of OVSYNCH were presented in the first report. For the OVSYNCH group, the 100-day-duction during the time period from calving until a pregnancy was established differed markedly from healthy cows in a variety of parameters. Healthy cows had a greater FSC (65.22%) than sick cows (35.90%) (P < 0.05). Furthermore, mean days open were less in healthy cows than in sick cows (85.48 +/- 30.56 days vs 110.85 +/- 46.40 days) (P < 0.05). Cows showing a disease had a higher number of lactation (4.00 +/- 2.26 vs. 2.80 +/- 1.35; P < 0.01) and a decreased BCS (2.72 +/- 0.23 vs. 2.91 +/- 0.23; P < 0.05). Sick and healthy cows from the OVSYNCH group did not differ with regard to 100-day-milk-yield (milk kg, relative and absolute milk fat and protein content). The cost-benefit-analysis revealed higher total cost, and cost per pregnancy (16,408.07 euros and 278.10 euros, respectively) in the control group than in the OVSYNCH group (11,015.69 euros and 196.71 euros, respectively).     

Synchronising oestrus with oestradiol benzoate after using a two-dose prostaglandin treatment to synchronise luteolysis in dairy heifers

OBJECTIVE: To compare the reproductive performance and pattern of onset of oestrus in dairy heifers in which oestrous cycles were synchronised with two doses of prostaglandin (PG) F2alpha and oestrus was synchronised with oestradiol benzoate (ODB). PROCEDURE: Dairy heifers in two herds (herd A, n = 192; herd B, n = 267) were treated with two doses of an analogue of PGF2alpha (cloprostenol, 375 microg, IM) 12 days apart. Heifers not detected in oestrus 48 h after the last dose of PGF2alpha were either left untreated (No ODB, n = 147) or treated with ODB (0.75 mg IM, n = 126). Onset of oestrus was monitored at 0, 24, 48, 80, 96 and 120 h after the last dose of PGF2alpha Heifers were inseminated on detection of oestrus. RESULTS: After the last dose of PGF2alpha, oestrous detection rates at 80 h (43.5 vs 72.6%, P < 0.001), 96 h (74.1 vs 84.9%, P =0.025) and 120 h (78.2 vs 86.3%, P = 0.082) were less in the No ODB compared to the ODB heifers, respectively. Conception rates (percentage pregnant that were inseminated) were greater in the No ODB compared to the ODB heifers (64.3% vs 47.6%, respectively; P = 0.006), while pregnancy rates (percentage pregnant that were treated) were also greater in the No ODB compared to the ODB heifers, but differences were not significant (50.3% vs 41.1%, respectively; P = 0.068). CONCLUSION: Administration of ODB to heifers not in oestrus 48 h after a two-dose PGF2alpha treatment increases the percentage of heifers detected in oestrus by 80 h, 96 h and 120 h after treatment, by an estimated 29%, 11% and 8%, respectively. However, administration of ODB decreases conception rates by an estimated 17%, and may decrease pregnancy rates (estimated 9% difference). Results are consistent with the hypothesis that ODB can increase submission rates but reduce conception rates following a two dose treatment with PGF2alpha.     

Postparturient hemoglobinuria in a Quebec dairy herd (author''s transl)

Postparturient hemoglobinuria in a Quebec dairy herd     

Hemoglobinuria in a dairy herd. (A short report)

This paper reports about the occurrence of hemoglobinuria in a herd of grazing dairy cows. Laboratory findings of serum, liver, pasture and soil showed hypocuprosis in this herd. Copper supplementation results in clinical recovery. Possible pathogenetic relations between copper deficiency and hemolytic anaemia are discussed.     

Clinical signs and hormonal changes in dairy heifers after induction of parturition with prostaglandin F2 alpha

Parturition was induced in 12 dairy heifers with prostaglandin (PG) F2 alpha about 2 weeks before the expected time of calving. Eight animals gave birth after two injections (group 1), three animals needed more than two injections (group 2) and one animal (cow no. 740) required one injection. All animals in groups 1 and 2 had retained foetal membranes and the time needed to induce parturition was 59 +/- 7 and 149 +/- 10 h, respectively. As cow no. 740 did not have retained foetal membranes and calved 24 h after one PGF2 alpha injection, it was excluded from the results. Udder distension and relaxation of the pelvic ligaments could predict the calving to within 12 h. Furthermore, the pre-calving drop of body temperature could predict the time of parturition to within 16 h. The total white blood cells and polymorphonuclear cells were at their highest values on the day preceding parturition whereas mononuclear cells had a tendency to increase 3 days after calving. Increased levels of haemoglobin were found at the time of parturition, whereas, plasma-calcium levels significantly decreased after parturition (P < 0.001). Progesterone levels markedly decreased after the first PGF2 alpha injection and reached 2 nmol/l at the time of parturition. Plasma levels of oestradiol-17 beta reached the peak at the time of parturition, whereas, the highest levels of the PGF2 alpha metabolite and cortisol were recorded 16 h after calving.     

Synchronization of ovulation (OVSYNCH) in high-producing dairy cattle herds. I. Fertility parameters, body condition score and plama progesterone contration

A method for synchronization of ovulation (OVSYNCH) was evaluated for its practical use in seven North German dairy cattle herds. The original procedure of PURSLEY et al. (1995) was applied, i.e. cows were injected Gonadotropin Releasing Hormone (GnRH) at a random stage of the estrous cycle, followed by an injection of a prostaglandin F2 alpha (PGF2 alpha)-analogon seven days later and another injection of GnRH two days after PGF2 alpha. Cows were inseminated 24 h after the last injection by artificial insemination. Control animals were assigned by corresponding lactation number and stage of lactation (month of partus). Cows from the OVSYNCH group returned to the conventional reproductive management after the OVSYNCH treatment, which was the same management as that for the control group. The average milk yield in 1997 and 1998 was 8128.6 +/- 637.0 kg and 8688.3 +/- 665.0 kg per year, respectively. First service conception rate (FSC) in the OVSYNCH group (n = 187) (39.77%) was lower than in the controls (n = 175) (54.34%; P < 0.01). In 1997, FSC for the OVSYNCH group did not differ from controls (48.94% vs. 55.45%; P > 0.05), whereas in 1998, FSC for the OVSYNCH group (29.27%) was significantly lower than in the control group (29.27% vs. 52.78%) and the OVSYNCH group in 1997 (each time P < 0.01). First service conception rate of first lactation cows in the OVSYNCH group was significantly lower than in the control group (37.84% vs. 71.05%; P < 0.01), whereas no difference was found for the other lactation groups. The mean interval calving to first service was shortened in the OVSYNCH group by about 14 d as compared with the controls (P < 0.01). However, mean days open only differed by 2.92 d (P > 0.05). Proportion of cows in each class of lactation number (1., 2. and > 2. lactation number) with days open < or = 115 d in the OVSYNCH group were similar to controls (P > 0.05). There was a great influence of body condition on the success of OVSYNCH. Cows with a body condition score (BCS) of 3.00 had a significant better FSC than cows with a BCS < 3.00 (P < 0.05). First service conception rate was lower for cows with a BCS > 3.25 and < 2.75 (cows in good and poor condition taken together) than for cows with a BCS of 3.00 (P < 0.05). A positive effect of OVSYNCH was found in acyclic cows as determined by progesterone concentration in blood plasma. Nine out of eleven cows reacted with the resumption of ovarian activity. Two cows became pregnant after first insemination.