scholarly journals Influence of Male to Female Ratio on Hormone Profiles and Reproductive Performance of Anestrus Postpartum Ewes Subjected to the Male Effect

2017 ◽  
Vol 45 (1) ◽  
pp. 8
Author(s):  
José Carlos Ferreira-Silva ◽  
Tracy Anne Burnett ◽  
Paulo Francisco Maciel Póvoas Souto ◽  
Jorge Motta Rocha ◽  
Heder Nunes Ferreira ◽  
...  
Keyword(s):  
Body Condition Score ◽  
Management Practice ◽  
Blood Collection ◽  
Ovarian Activity ◽  
Female Ratio ◽  
Male Effect ◽  
Ovulatory Follicle ◽  
Conception Rates ◽  
Condition Score ◽  
Male To Female

Background: Complete isolation of genders allows intense estrous induction and synchronization once rams are introduced in ewe flocks at the onset of the breeding season (BS). This management practice, defined as the male effect, results from a neuroendocrine process mediated by pheromones. The male effect is a straightforward procedure to induce estrous in noncycling ewes, but conditions for its use have not been fully explored. Thus, this study aimed to evaluate hormone levels and ovarian activity of postpartum ewes in anestrus which are subjected to the male effect under different male to female ratios.Material, Methods & Results: Pospartum females were selected according to body condition score and cyclicity status. Females were kept apart from males during 30 days at a distance of 10 m. Anestrus and ovulation were determined by P4 measures on days 10, 20 and 30 after isolation from males. After P4 concentration diagnosis, anestrus ewe (n = 99) were subjected to male to ewe ratios (MFR) of 1:20 (MFR20), 1:30 (MFR30) and 1:40 (MFR40). Santa Inês rams  (n = 3) of proven fertility were used. Three females of each group were randomly subjected to blood collection for LH concentration analysis. Ovarian activity was performed by ultrasonography after estrus manifestation in six ewe of each group. Estrus events were observed twice a day during the BS of 35 days, and estrus were considered synchronized when it occured within the initial five days of the BS. Pregnancy diagnosis was performed by ultrasonography on days 35 and 60 after the last mating. All ewe were in a non-cycling condition before BS onset, based upon P4 analysis. After initiation of the BS, P4 concentrations increased for all groups. Irrespectively of male to female ratio, male effect induced LH pre-ovulatory peaks within the initial 26 to 86 h of the BS. Synchronization of estrus reached 50% for MFR20, 40% for MFR30 and 20% for MFR40 for all ewe. Moreover, overall estrus incidence was 100% (MFR20), 90% (MFR30) and 65% (MFR40) within the initial 15 days of the BS. However, incidence of ewe that had repeated estrus events was lower for MFR20 than for MFR30. Follicular growth and number of ovulations was similar between groups. Conception rates on first service was higher than that of second service for MFR20 and MFR30, although there was no difference between services for MFR40. In contrast, overall conception rates, delivery type and prolificacy were similar between groups.Discussion: P4 increased to cyclicity levels after contact between genders, demonstrating the potential of the male effect to induce estrus in non-cycling ewes. Most ewe ovulated within three days after the male effect, possibly due to elevated basal LH levels. Moreover, the LH preovulatory peak varied within groups, possibly due to greater interactions between genders, which ultimately may have led to earlier ovulation anticipation under lower MFR. Estrus parameters were similar between groups, suggesting low or negligible effects of MFR. Ovulatory follicle size and growth and the number of ovulations were similar between all groups; previous reports have suggested that this may be due to a strong effect of their genetic background. Conception rates were higher at first than second services, demonstrating the potential of male effect. In conclusion, male to female ratio affects the efficiency of the male effect to induce and synchronize estrus in ewes under postpartum anestrus, but it does not affect conception rates and prolificacy.

scholarly journals Precision Betacarotene Supplementation Enhanced Ovarian Function and the LH Release Pattern in Yearling Crossbred Anestrous Goats

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 659
Author(s):  
Noé M. Lopez-Flores ◽  
César A. Meza-Herrera ◽  
Carlos Perez-Marin ◽  
Dominique Blache ◽  
Gerardo Arellano-Rodríguez ◽  
...  
Keyword(s):  
Ovarian Function ◽  
Body Condition Score ◽  
Area Under The Curve ◽  
Live Weight ◽  
Beta Carotene ◽  
Ovarian Activity ◽  
Release Pattern ◽  
Time Treatment ◽  
Condition Score ◽  
Lh Release

The possible out-of-season effect of beta-carotene supplementation on ovulation rate (OR), antral follicles (AFN), and total ovarian activity (TOA = OR + AFN) as related to the LH release pattern in yearling anestrous goats was evaluated. In late April, Alpine-Saanen-Nubian x Criollo goats (n = 22, 26 N) were randomly allotted to: (1) Beta-carotene (BETA; n = 10, orally supplemented with 50 mg/goat/d; 36.4 ± 1.07 kg live weight (LW), 3.5 ± 0.20 units, body condition score (BCS) or (2) Non-supplemented (CONT; n = 12, 35.2 ± 1.07 kg LW, 3.4 ± 0.2 units BCS). Upon estrus synchronization, an intensive blood sampling (6 h × 15 min) was accomplished in May for LH quantifications; response variables included (pulsatility-PULSE, time to first pulse-TTFP, amplitude-AMPL, nadir-NAD and area under the curve-AUC). Thereafter, an ultrasonography scanning was completed to assess OR and AFN. The Munro algorithm was used to quantify LH pulsatility; if significant effects of time, treatment or interaction were identified, data were compared across time. Neither LW nor BCS (p > 0.05) or even the LH (p > 0.05); PULSE (4.1 ± 0.9 pulses/6 h), NAD (0.47 ± 0.13 ng) and AUC (51.7 ± 18.6 units) differed between treatments. Nonetheless, OR (1.57 vs. 0.87 ± 0.18 units) and TOA (3.44 vs. 1.87 ± 0.45 units) escorted by a reduced TTFP (33 vs. 126 ± 31.9 min) and an increased AMPL (0.55 vs. 0.24 ± 0.9 ng), favored to the BETA supplemented group (p < 0.05), possibly through a GnRH-LH enhanced pathway and(or) a direct effect at ovarian level. Results are relevant to speed-up the out-of-season reproductive outcomes in goats while may embrace translational applications.

8 EFFECT OF SEMEN TYPES (SEXED v. NONSEXED) ON CONCEPTION RATES OF GIROLANDO HEIFERS INSEMINATED IN FIXED-TIME AI

2010 ◽  
Vol 22 (1) ◽  
pp. 162
Author(s):  
J. Almeida ◽  
O. A. Resende ◽  
D. L. Silveira
Keyword(s):  
Body Condition Score ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Sao Paulo ◽  
São Paulo ◽  
Device Removal ◽  
Conception Rates ◽  
Sexed Semen ◽  
Condition Score ◽  
Intravaginal Device

With the goal of optimizing protocols, fixed-time artificial insemination (FTAI) was performed under field conditions in a study to evaluate conception rates in Girolando (5/8) heifers (18 to 24 months of age) treated with estradiol benzoate (BE) to induce ovulation. Forty heifers were allocated to 2 groups with 20 animals each: GI-sexed semen (2 million spermatozoa/dose) and GII-nonsexed semen (20 million spermatozoa/dose), with body condition score (BCS) of 3.0 ± 0.14 (scale of 1 to 5), middleweight of 335 ± 38 kg, so that it was made for reutilization of progesterone device. On Day 0 (morning), the animals received 2.0 mg of BE (RIC-BE®,Tecnopec, São Paulo, Brazil), 0.075 mg of D-cloprostenol (Prolise®, ARSA S.R.L., Buenos Aires, Argentina), and an intravaginal device of 1 g of progesterone (Primer®, Tecnopec). On Day 8 (morning) the device was removed and 0.075 mg of D-cloprostenol was managed in the GI animals, then these animals received 1.0 mg of BE 24 h after device removal. The insemination was in the late afternoon of Day 10 with a 6-hour delay (4 to 6 pm). The GII animals received Primer previously used for 8 days (being used in the GI animals under the same protocol). After pregnancy diagnosis at 60 days, a third group was created (GIII) using the not-pregnant animals of GI and GII. In GIII, Primer from third use [disinfected in solution Kilol®-L 1:250 (Quinabra, São Paulo, Brazil) and rinsed with water, dried, and packed in plastic sacks and kept for 60 days] was used following the GI protocol with sexed semen. There were no significant differences (P > 0.05) in the conception rates of 40, 58, and 65% among groups GI (8/20), GII (11/20), and GIII (13/20). These results indicate very good conception rates for heifers, contrary to recommendations of commercial companies of sexed semen that alert for the conception rate for mated animals to be lower when using FTAI and mating protocols in mass, compared with that of AI after estrus observation.

8 Evaluation of puberty induction protocol in peripubertal beef heifers prior to fixed-time AI programs

2019 ◽  
Vol 31 (1) ◽  
pp. 129
Author(s):  
J. B. S. Borges ◽  
D. S. V. Luiz ◽  
P. R. L. Aguiar ◽  
C. G. B. Berlitz ◽  
G. S. Velho ◽  
...  
Keyword(s):  
Breeding Season ◽  
Body Condition ◽  
Body Condition Score ◽  
Animal Health ◽  
Hormonal Treatment ◽  
Fixed Time ◽  
P Value ◽  
Ovarian Activity ◽  
Beef Heifers ◽  
Condition Score

Beef heifers that conceive early during their first breeding season calve earlier, wean heavier calves, and tend to continue doing so throughout the rest of their reproductive lives. Otherwise, under extensively managed systems in Southern Brazil, only a variable proportion of 2-year-old beef heifers reach puberty before the start of the breeding season. The aim of this study was to evaluate a protocol to induce puberty in peripubertal beef heifers using injectable progesterone (P4) and oestradiol cypionate (EC) to improve pregnancy per AI (P/AI) in fixed-time AI (FTAI) programs. A total of 311 Angus heifers, 24±3 months of age, 3.1±0.3 body condition score (1=emaciated; 5=obese), and 328±41kg of body weight (BW), were examined before FTAI protocol (Day −24) by transrectal ultrasonography to determine reproductive tract score (RTS; 1=prepubertal; 5=pubertal). Prepubertal heifers (RTS 1; 12.8%, 40/311) were excluded from the study. Heifers with RTS=2 (n=271) were assigned to 2 groups: P4 (RTS 2 or 3, n=100) and cyclic (RTS 4 and 5, n=171). Peripubertal heifers were treated on Day −24 with 150mg of injectable P4 IM (Sincrogest® injectable, Ourofino Animal Health, Cravinhos, Brazil) and on Day −12 received 1mg of EC IM (Sincro CP®, Ourofino Animal Health). Cyclic heifers received no hormonal treatment before FTAI protocol. On Day 0, heifers in the P4 group were evaluated again to determine RTS, body condition score, and BW. Induction of puberty was defined by the presence of a follicle &gt;8.5mm (RTS=4) or a corpus luteum (RTS=5). All heifers received an FTAI protocol consisting of 2mg of oestradiol benzoate IM (Sincrodiol®, Ourofino Animal Health) and an intravaginal progesterone implant (1 g; Sincrogest®, Ourofino Animal Health). On Day 8, heifers had implants removed and were injected with 1mg of EC and 500µg of sodium cloprostenol IM (Sincrocio®, Ourofino Animal Health). After 48h, all heifers received an FTAI. Thirty days after AI, the diagnosis of gestation was performed by ultrasonography. Statistics included chi-square and linear regression with coefficients analysed as independent variables, considering a significant P-value of 0.05. On Day 0, percentages of RTS 5, 4, and 3 in the P4 heifers were 37, 27, and 36%, respectively, resulting in 64% of puberty induction. The P/AI was similar (P=0.14) in P4-treated and cyclic heifers (59v. 50.3%, respectively). The regression analysis presented a linear and positive effect of BW on P/AI (P&lt;0.001) in cyclic heifers and a positive influence of BW on RTS (P=0.05) and RTS on P/AI (P=0.008) in P4-treated heifers. The application of RTS system associated with P4 treatment of peripubertal heifers before FTAI protocol improved ovarian activity and might have contributed to higher P/AI, comparable with that achieved in cyclic heifers.

scholarly journals Distribution of dominant follicles in postpartum dairy cows

2017 ◽  
Vol 33 (2) ◽  
pp. 181-191
Author(s):  
Benjamin Cengic ◽  
Nazif Varatanovic ◽  
Tarik Mutevelic ◽  
Amel Cutuk ◽  
Ermin Saljic
Keyword(s):  
Dairy Cows ◽  
Corpus Luteum ◽  
Milk Production ◽  
Milk Yield ◽  
Body Condition ◽  
Body Condition Score ◽  
Diagnostic Ultrasound ◽  
Ovarian Activity ◽  
Pathological Effect ◽  
Condition Score

Clinical and subclinical disorders and diseases cause reproductive failures and decline in milk production. Etiology of disorders is mainly because of pathological effect of microorganisms, lapses in nutrition and lodging, as well as in management. After partrition, body is under stress and milk yield is highest, which favors appearance of metabolic and infective diseases. Status of puerperium, number of lactation, body condition score and season of parturition, have highest effect to cyclic ovarian activity. Regular development of dominant follicles, ovulation, formation of corpus luteum and luteolysis is necessary for establishment of regular cyclic ovarian activity, which leads to better fertility. Experiment had included 50 cows during first 52 days of lactation. Cows were separated in two main groups, those with normal puerperium - NP (n=32) and abnormal puerperium - AP (n=18). Examinations have been performed during period of 6 to 52 days postpartum. Ovarian dominant follicles have been observed using diagnostic ultrasound linear scanner. The highest number of dominant follicles are present during first two examinations, then their number declines and later in last two examinations rise again. Decrease in number of dominant follicles in both groups is most expressed in period of 14-30 days. During first examination, left ovaries have more dominant follicles, compared with right ovaries, while during later examinations, it is changed in favor of right ovaries. Increased number of vital dominant follicles from period 38-45 days postpartum and absence of abnormal uterine content in lumen in same period postpartum is sign of upcoming fertile estrus.

scholarly journals The Opuntia effect and the Reactivation of Ovarian Function and Blood Metabolite Concentrations of Anestrous Goats Exposed to Active Males

Animals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 550 ◽  
Author(s):  
Cesar A. Meza-Herrera ◽  
Carlos A. Romero-Rodríguez ◽  
Adrian Nevárez-Dominguez ◽  
Arnoldo Flores-Hernández ◽  
Omag Cano-Villegas ◽  
...  
Keyword(s):  
Body Condition ◽  
Ovarian Function ◽  
Body Condition Score ◽  
Live Weight ◽  
Blood Metabolites ◽  
Serum Total Protein ◽  
Time Interaction ◽  
Male Effect ◽  
Metabolite Concentrations ◽  
Condition Score

The effect of protein enriched Opuntia cladodes supplementation upon changes of serum total protein, urea, cholesterol, glucose as related to estrus induction (EI%), estrus latency (EL, h), and ovulation rate (OR, units) in adult anestrous goats exposed to the male effect was evaluated. In late April, anestrus goats (n = 45, 25° N) homogeneous regarding live weight (LE; 43.8 ± 1.6 kg) and body condition score (BCS; 2.3 ± 0.1 units) were randomly assigned to: (1). Protein-enriched Opuntia (PEO; n = 15; 29.8% CP, 2.2 Mcal ME kg−1), (2). Non-enriched Opuntia (NEO; n = 15; 6.4% CP, 2.1 Mcal ME kg−1), and (3). Control (CON; n = 15). NEO and PEO goats were individually supplemented with cladodes (160 g d−1; 0900–1000 h), thereafter all groups grazed in a marginal rangeland (1000–1800 h). Neither LW (p > 0.05) nor BCS (p > 0.05) differed among groups, yet an increased (p < 0.05) EI % (100, 57, 42 ± 0.16%), EL h (62, 60, 32 ± 4.2 h), and OR (1.33, 0.71, 0.43 ± 0.23 units) occurred in PEO and NEO vs. CONT, respectively. However, neither blood metabolites differed among groups nor a treatment x time interaction occurred. Peri-breeding protein enriched Opuntia cladodes supplementation of anestrous goats exposed to active males increased (p < 0.01) reproductive outcomes during the non-breeding season.

12 OVARIAN STRUCTURES, ESTRUS EXPRESSION, AND PREGNANCY RATE IN BEEF HEIFERS USING ESTRADIOL CYPIONATE OR GnRH AS OVULATION INDUCTORS IN TIMED AI PROTOCOL

2017 ◽  
Vol 29 (1) ◽  
pp. 113 ◽  
Author(s):  
E. Pradebon da Silva ◽  
A. B. Machado ◽  
L. S. Gambin ◽  
A. V. Gonsioroski ◽  
M. da Silva ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Body Condition Score ◽  
Device Removal ◽  
Treatment Groups ◽  
Follicle Diameter ◽  
Ovulatory Follicle ◽  
Condition Score ◽  
In The Beginning ◽  
Angus Heifers ◽  
Intravaginal Device

The aim of this study was to evaluate the effect of presence of corpus luteum (CL) at the onset of timed AI (TAI) protocol, size of ovulatory follicle and oestrus expression on pregnancy rate using E2 cypionate (EC) or GnRH as ovulation inductor in Angus heifers. On day 0, heifers [n = 414; 317 ± 23 kg; 3.08 ± 0.21 body condition score (1 to 5 scale) and 22–24 months of age] received a 1-g progesterone intravaginal device (Primer®, Agener União, Brazil) and 2 mg of oestradiol benzoate, IM, (RIC-BE®, Agener União, Brazil). On day 8, the device was removed, were administered 500 μg of sodium cloprostenol, IM, (Estron®, Agener União, Brazil) and heifers were divided in 2 groups: EC [n = 213; 0.5mg EC, IM, (SincroCP®, Ouro Fino, Brazil) on day 8] and GnRH [n = 201; 25 μg of Licerelin, IM, (GestranPlus®, Agener União, Brazil) at TAI] TAI was performed 50 h after device removal. Heifers were tail painted (Tell Tail®, GEA, New Zealand) to control oestrus expression from device removal to TAI. Heifers were scanned (7.5-MHz linear transducer MediSono® P3V, USA) to determine presence of CL (Day 0), ovulatory follicle diameter (OFD; Day 10) and ovulation (Day 11). Pregnancy was diagnosed 30 days after TAI. Oestrus expression was confirmed when marking ink was removed on day 10. Data were analysed using logistic regression and ANOVA. Oestrus expression was higher (P < 0.05) in EC (93.90%, 200/213) compared to GnRH group (67.66%, 136/201). The OFD differed (P < 0.05) according to presence of CL on Day 0 (10.3 mm) or not (9.6 mm), but was similar in treatment groups. Ovulation rate did not differ in EC (85%, 17/20) and GnRH (95%, 19/20) groups. Pregnancy rates were similar (P > 0.05) between EC (52.58%, 112/213) and GnRH (59.20%, 119/201) groups; however, in heifers that expressed oestrus, rates were higher (P < 0.05) (EC = 56%, 112/200; GnRH = 71.3%, 97/136) than in those did not show (EC = 0%, 0/13; GnRH = 33.8%, 22/65). Presence of CL at onset of TAI protocol was associated with higher pregnancy (P < 0.05) in GnRH group (68%, 68/100) compared with EC (54.46%, 61/112) group, but in heifers without CL, pregnancy were similar for GnRH (50.5%, 51/101) and EC (50.5%, 51/101) groups. Heifers were also classified in 3 groups according OFD: small (≤9.5 mm), medium (9.6–11.5 mm), and large (≥11.6 mm) to verify its effect on oestrus expression and pregnancy. Medium and large OFD were implicated in higher (P < 0.05) oestrus expression [(EC = 100%, 51/51; 96.97%, 32/33) and (GnRH = 83.02%, 44/53; 97.44%, 38/39)] than small OFD [(EC = 85%, 51/60) and (GnRH = 23.8%, 15/63)]. Pregnancy was lower (P < 0.05) in small OFD groups (EC = 28.3%, 17/60; GnRH = 25.4%, 16/63). In medium and large OFD, pregnancy was similar in EC (72.55%, 37/51; 54.55%, 18/33) groups, but differed (P < 0.05) between GnRH large (82.05%, 32/39) and medium (62.26%, 33/53). Higher pregnancy was achieved in heifers with CL in the beginning of TAI protocol treated with GnRH. Size of ovulatory follicle was associated with higher oestrus behaviour and pregnancy rate in EC and GnRH treatments.

Risk assessment of postpartum uterine disease and consequences of puerperal metritis for subsequent metabolic status, reproduction and milk yield in dairy cows

2009 ◽  
Vol 57 (1) ◽  
pp. 155-169 ◽  
Author(s):  
László Könyves ◽  
Ottó Szenci ◽  
Viktor Jurkovich ◽  
Lászlóné Tegzes ◽  
Attila Tirián ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Milk Fat ◽  
Body Condition Score ◽  
Metabolic Status ◽  
Nonesterified Fatty Acid ◽  
Uterine Disease ◽  
Ovarian Activity ◽  
Condition Score ◽  
Uterine Diseases

The objective of this study was to determine some metabolic and other factors predicting the risk of postpartum uterine disease (PUD), and the effects of puerperal metritis (PM) on metabolic status, reproduction and milk yield were analysed. A total of 105 Holstein-Friesian cows were included, and sampled on day < −14 prepartum and days 4, 10–14, 28–35 and 56–63 postpartum for metabolic tests. From day 4 the development of PUD, and from days 28–35 the ovarian activity was monitored. When grade ≥ 1 + ketonuria was present on day 4 postpartum, this indicated a higher probability of PUD [odds ratio (OR) 2.64; P < 0.05] including PM occurring on days 10–14 (OR: 2.65; P < 0.05). Plasma nonesterified fatty acid (NEFA) concentrations > 0.200 mmol/l on days < −14 prepartum indicated a higher risk of uterine diseases (OR: 3.44; P < 0.05). The odds of PUD increased, depending on whether a body condition score (BCS) loss of ≥ 1.0 occurred between days < −14 and 28–35 (OR: 2.82; P < 0.05), between days < −14 and 10–14 (OR: 4.79; P < 0.01) or between days 10–14 and 28–35 (OR: 10.81; P < 0.01). PM was more probable (OR: 27.3; P < 0.001) in cows with retained placenta. The risk of uterine diseases was lower in multiparous than in primiparous cows (OR: 0.29; P < 0.01). PM increased the risk of ovarian inactivity between days 28 and 35 (OR: 2.83; P < 0.05). Cows affected with PM (PM+ cows) showed lower milk production on day 4 (kg; P < 0.05) and lower milk production (P < 0.05), milk fat and milk protein production (kg; P < 0.01; P < 0.01) in the first 100 days of lactation than did PM− cows.

scholarly journals Ovarian activity in Fleckvieh, Brown Swiss and two strains of Holstein-Friesian cows in pasture-based, seasonal calving dairy systems

2011 ◽  
Vol 78 (4) ◽  
pp. 464-470 ◽  
Author(s):  
Valérie Piccand ◽  
Susanne Meier ◽  
Erwan Cutullic ◽  
Sara Weilenmann ◽  
Peter Thomet ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Body Condition Score ◽  
Post Partum ◽  
Oestrous Cycle ◽  
The Other ◽  
Breeding Period ◽  
Ovarian Activity ◽  
Brown Swiss ◽  
Holstein Friesian ◽  
Condition Score

The objectives of the study were to compare the ovarian activity of Holstein-Friesian (CH HF), Fleckvieh (CH FV) and Brown Swiss (CH BS) dairy cows of Swiss origin with that of Holstein-Friesian (NZ HF) dairy cows of New Zealand origin, the latter being used as a reference for reproductive performance in pasture-based seasonal calving systems. Fifty, second-lactation NZ HF cows were each paired with a second-lactation Swiss cow (17, 15 and 18 CH HF, CH FV and CH BS respectively) in 13 pasture-based, seasonal-calving commercial dairy farms in Switzerland. Ovarian activity was monitored by progesterone profiling from calving to first breeding service. CH BS cows produced less energy-corrected milk (mean 22·8 kg/d) than the other breeds (26·0–26·5 kg/d) during the first 100 d of lactation. CH HF cows had the lowest body condition score (BCS) at calving and the greatest BCS loss from calving to 30 d post partum. Commencement of luteal activity (CLA) was later for NZ HF than for CH FV (51·5 v. 29·2 d; P <0·01), with CH HF and CH BS intermediate (43 d). On average, NZ HF and CH HF cows had one oestrous cycle before the onset of the seasonal breeding period; this was less (P<0·01) than either CH FV (1·7) or CH BS (1·6). There was a low prevalence of luteal persistency (3%) among the studied cows. First and second oestrous cycle inter-ovulatory intervals did not differ between breeds (20·5–22·6 d). The luteal phase length of CH BS during the second cycle was shorter (10·6 d) than that of the other breeds (13·8–16·0 d), but the inter-luteal interval was longer (9·8 d v. 7·0–8·0 d). The results suggest that the Swiss breeds investigated have a shorter interval from calving to CLA than NZ HF cows.

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