Factors affecting expression of estrus in dairy cows with high milk yields

The objectives of this study were to define the effect of the milk progesterone (P4) concentration on estrus expression in dairy cows with high milk yield and to identify the effect of milk yield and parity on the milk P4 concentration and cow’s pregnancy after artificial insemination (AI). In this study, 48 clinically healthy cows without reproduction disorders, on day 90-100 after calving were used. At the beginning of estrus and 12 hours after the beginning of estrus, the milk P4 concentration in dairy cows with high milk yield (group 3) was higher than in group 2 (33.66; 22.36%) and in group 1 (51.60; 65.26%) (P <0.001). The milk P4 concentration in the ≥3 lactation cows was higher than the second (13.45%; P>0.05) and the first (28.28%; P<0.01) lactation ones (28.28%; P<0.01). The milk P4 concentration at the beginning of estrus and 12 hours after the beginning of estrus in pregnant and non-pregnant cows was 2.58 and 3.32; 4.20 and 5.00 ng/ml, respectively (P<0.001). As a result, it was concluded that high progesterone concentration affected the expression of estrus and pregnancy results in dairy cows, and the measuring of progesterone concentration in milk can be used as a non-invasive method to provide detailed information about fertility in high milk yield cows..

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Post partum suboestrus in dairy cows : comparison of treatment with prostaglandin F2α or GnRH + prostaglandin F2α + GnRH

BSAP Occasional Publication ◽

10.1017/s0263967x00033887 ◽

2001 ◽

Vol 26 (2) ◽

pp. 347-352 ◽

Cited By ~ 1

Author(s):

B. Grimard ◽

G. Laumonnier ◽

C. Ponsart ◽

H. Fauxpoint ◽

E. Barassin ◽

...

Keyword(s):

Dairy Cows ◽

Artificial Insemination ◽

Post Partum ◽

Prostaglandin F2α ◽

Specific Protein ◽

Pregnancy Rates ◽

Progesterone Concentration ◽

Treatment Groups ◽

Group 2 ◽

Group 1

AbstractTwo studies (expt. 1, 185 cows in 1996/97; expt. 2, 168 cows in 1997/98) were conducted with Prim ‘Holstein dairy cows in the Mayenne region (France) to investigate suboestrus. Cows which had not been observed in oestrus since calving were allocated alternately to treatment groups between 60 and 90 days post partum. Expt. 1. Group 1: GnRH (Day 0, 100 μg im), PGF2α (Day 7, 25 mg im), GnRH (Day 9, 100 μg im) with artificial insemination (AI) Day 10. Group 2 : PGF2α (Day 0, 25 mg im), AI at oestrus or if oestrus not observed a second PGF2α injection was given (Day 13) with AI on Day 16 and Day 17. Expt. 2. Group 1 : GnRH (Day 0, 100 /μg im), PGF2α (Day 7, 25 mg im), GnRH (Day 9, 100 μg im) with AI at observed oestrus after Day 0 or at Day 10 if oestrus not observed. Group 2 : PGF2α (Day 0, 25 mg im), AI at oestrus, or if oestrus was not observed a second PGF2α injection was given (Day 13) and AI at observed oestrus. Progesterone was measured in serum at Day 0 and in milk at AI. Pregnancy diagnosis was performed by measuring bovine Pregnancy Specific Protein B (bPSPB) (Day 50 + 3) and confirmed by ultrasonography when the result was doubtful.In expt. 1, farmers observed 47/101 (46.9 %) of group 1 cows in oestrus, 33/91 on Day 10 and 10 before Day 10. The progesterone concentrations were compatible with oestrus in 69/86 (80%) of cows on Day 10. In group 2, 36/83 (43.4 %) of cows were inseminated after the first PGF2α injection. After the second PGF2 α, only 29/43 (67 %) of cows had a low progesterone concentration at AI. The pregnancy rates were 36.1% and 32.5 % for groups 1 and 2, respectively. In expt. 2, oestrus was observed in 31/93 (33.7 %) of group 1 cows. In group 2, 51/75 (66 %) of cows were inseminated after the first injection of PGF2α, 13/75 (17.3 %) after the second and 11/75 (14.7 %) were not seen in oestrus. Pregnancy rates were 53.7% and 53.3% in groups 1 and 2, respectively. In conclusion, it is recommended that suboestrus be treated with PGF2α followed by AI at observed oestrus when oestrus detection is good while, the use of GnRH + PGF2α + GnRH is recommended when oestrus detection is poor.

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Randomised clinical trial showing the curative effect of bandaging on M2-stage lesions of digital dermatitis in dairy cows

Veterinary Record Open ◽

10.1136/vetreco-2017-000264 ◽

2019 ◽

Vol 6 (1) ◽

pp. e000264 ◽

Cited By ~ 3

Author(s):

Marcus Klawitter ◽

Dörte Döpfer ◽

Theo Broderick Braden ◽

Ermias Amene ◽

Kerstin Elisabeth Mueller

Keyword(s):

Clinical Trial ◽

Dairy Cows ◽

Dairy Herd ◽

Randomised Clinical Trial ◽

Digital Dermatitis ◽

Group 4 ◽

Treatment Type ◽

Group 3 ◽

Group 2 ◽

Group 1

Objectives and designThis trial evaluated the effect of bandaging of acute painful ulcerative bovine digital dermatitis (DD) lesion (stage M2) in dairy cows, tested using two different topical treatments.DesignRandomised clinical trial.SettingThis study was conducted using Holstein-Friesian cows ranging in age from heifers to fourth lactation in a single dairy herd and diagnosed with acute ulcerative DD lesions (stage M2) on the first examination (week 0). Cows were randomly assigned into either a non-bandaged or bandaged group across two treatment conditions: topical chlortetracycline spray (CTC) and Intra Hoof-Fit Gel (IHF). Lesions received standardised bandaging and treatment on a weekly basis. Unhealed lesions could receive up to five repeated treatments, at weekly intervals, within a four-week period. Both M-stage and locomotion were also evaluated and scored weekly. Cows with healthily formed skin (stage M0) were deemed healed and subsequently released from the study.ResultsIn total, 163 M2 lesions were diagnosed at week 0. Bandaged M2 lesions had a significantly higher probability of cure than non-bandaged lesions regardless of treatment type (HR: 4.1; P<0.001; 95 per cent CI: 2.5 to 6.8). Most healing occurred within the first three weeks of trial. Furthermore, bandaged lesions (group 2 and group 4) were significantly less likely to progress into the chronic hyperkeratotic or proliferative stage (M4) than non-bandaged lesions in group 1 and group 3 (HR: 0.10; P<0.001; 95 per cent CI: 0.04 to 0.22). Out of concern for the cow’s wellbeing, this study investigated the effects of bandaging on locomotion. Bandaging had no effect on locomotion for either cows treated with CTC (group 1: median Sprecher score, 2; IQR=1–2; group 2: median Sprecher score, 2; IQR=1–3; P=0.3) or IHF (group 3: median Sprecher score, 2; IQR=1–2; group 4: median Sprecher score, 2; IQR=1–3; P=0.3).

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Milk yield at first lactation, parity, and season of calving affect the reproductive performance of water buffalo cows

Animal Production Science ◽

10.1071/an18420 ◽

2020 ◽

Vol 60 (8) ◽

pp. 1073

Author(s):

Héctor Nava-Trujillo ◽

Robert Valeris-Chacin ◽

Armando Quintero-Moreno ◽

Juan Escalona-Muñoz

Keyword(s):

Milk Yield ◽

Reproductive Performance ◽

Water Buffalo ◽

Negative Energy ◽

Calving Interval ◽

Water Buffaloes ◽

Group 4 ◽

Group 3 ◽

Group 2 ◽

Group 1

Context Profitability of water buffalo systems depends on a calving interval (CI) <400 days. Several factors affect the achievement of this target. However, milk yield at first lactation has received little attention. Aims Determine the effect of milk yield at first lactation, parity, season of calving and farm, on the length of CI and the probability of a CI ≤ 400 days in water buffaloes. Methods A retrospective analysis of milk yield at first lactation and reproductive records of 1459 water buffaloes was carried out. Milk yield was categorised as Group 1 (≤1090 kg), Group 2 (1090–1377 kg), Group 3 (1377–1684 kg) and Group 4 (>1684 kg); parity was categorised as parity 1, 2 and ≥ 3; and month of calving was grouped into three seasons: December–March, April–July, and August–November. Data were analysed using linear and logistic mixed models. Key results CI increased from 425.3 days (95% CI: 418.8–431.8 days) in group 1 to 463.3 days (95% CI: 456–470.6 days) in group 4 (P < 0.05), while the probability of having a CI ≤ 400 days decreased from 0.5 (95% CI: 0.46–0.54) to 0.26 (95% CI: 0.22–0.29), respectively (P < 0.05). CI decreased from 466 days (95% CI: 460.8–471.3 days) in parity 1 to 410.5 days (95% CI: 405.2–415.8 days) in parity ≥3, whereas the probability of a CI ≤ 400 days increased from 0.26 (95% CI: 0.24–0.29) to 0.51 (95% CI: 0.47–0.54) respectively (P < 0.05). Water buffaloes calving in August–November showed significantly shorter CI and, along with those calving between December–March, showed the highest probability of a CI ≤ 400 days. An interaction between milk yield at first lactation and parity on both outcomes was observed. Conclusions Shorter CI and higher probability of a CI <400 days were associated with lower milk yields at first lactation, higher parity and calving between August–November. Higher milk yield at first lactation affected negatively the reproductive performance of water buffaloes, especially at parity 1 and 2. Implications These results highlight the importance of adequate nutritional management to allow water buffaloes to cope with the challenge of the postpartum negative energy balance and have a calving interval less than 400 days.

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350 EFFECT OF DIFFERENT SUB-DOSES OF EQUINE CHORIONIC GONADOTROPIN ON PREGNANCY AND TWINNING RATES OF CYCLIC ZEBU COWS SUBMITTED TO FIXED-TIME ARTIFICIAL INSEMINATION

Reproduction Fertility and Development ◽

10.1071/rdv27n1ab350 ◽

2015 ◽

Vol 27 (1) ◽

pp. 263 ◽

Cited By ~ 1

Author(s):

R. H. Alvarez ◽

F. L. N. Natal ◽

R. M. L. Pires ◽

K. M. R. Duarte ◽

C. A. Oliveira

Keyword(s):

Artificial Insemination ◽

Ovarian Response ◽

Fixed Time ◽

Sao Paulo ◽

São Paulo ◽

Chi Square ◽

Group 3 ◽

Group 2 ◽

Twin Pregnancies ◽

Group 1

The injection of a low dose of eCG has the potential to induce multiple ovulation and pregnancies in cattle. The present study aimed to evaluate the ovarian response, conception rate and incidence of twin pregnancies of cyclic cows receiving 1 of 2 low doses of eCG. Multiparous Nellore (Bos t. indicus) cows with plasma progesterone levels >1 ng∙mL–1 on at least one of 2 blood samples collected at 10-day intervals (Day –10 and Day 0) received an intramuscular (IM) injection of 2 mg of oestradiol benzoate (EB; Estrogin®, AUSA, São Paulo, Brazil) and a vaginal device (DIP) containing 1 g of progesterone (Primer®, Tecnopec, São Paulo, SP, Brazil) on Day 0. On Day 8, the DIP was removed and cows received an IM injection of 150 μg of cloprostenol (Veteglan®, Hertape Calier, Juatuba, MG, Brazil). At this time, the animals were randomly distributed into 3 groups. Group 1 (n = 30) received an IM injection of 2 mL of saline, whereas groups 2 (n = 41) and 3 (n = 23) received 600 IU and 900 IU of eCG (Novormon® MSD Saude Animal, São Paulo, Brazil), respectively. Twenty-four hours later (Day 9), all groups received 1 mg of EB and were submitted to fixed-time artificial insemination (FTAI) 30 h later (i.e. 54 h after DIP removal). Oestrus observation was performed daily from the time of the withdrawal of the DIP until the day of FTAI. Ovaries were examined ultrasonically at the time of FTAI, the following day and 7 days after FTAI. Pregnancy diagnosis was done by ultrasonography 30 days after FTAI and the incidence of twin or single calves was recorded at birth. Data were analysed by chi-square test. The rate of expression of oestrus was 70.0% (group 1), 82.9% (group 2), and 78.2% (group 3; P = 0.25). Cows that had 2 or more large follicles at the time of FTAI was 0% (group 1), 14.6% (group 2), and 34.8% (group 3; P < 0.05). The ovulation rate of cows in group 1 (80.0%) was higher than cows in groups 2 (48.8%) and 3 (52.2%; P < 0.05). The conception rates for groups 1, 2, and 3 were 50.0, 26.8, and 39.1%, respectively (P < 0.05). Two animals in group 3, one in group 2, and none of group 1 had twin pregnancies on Day 30 after FTAI. Only one of these cows (group 3) had a twin calving. It was concluded that the injection of 600 or 900 IU eCG, in an oestradiol/progestogen FTAI protocol does not result in an increase in the rate of twin calvings, but may negatively affect pregnancy rates of cyclic Nellore cows.Financial support was provided by FAPESP (proc. 2011/13096–0).

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Socioeconomic Status and COVID-19 Related Outcomes in India: Hospital Based Study

10.1101/2021.05.17.21257364 ◽

2021 ◽

Author(s):

Arvind K Sharma ◽

Rajeev Gupta ◽

Vaseem N Baig ◽

Tejaveer Singh ◽

Surabhi Chakraborty ◽

...

Keyword(s):

Socioeconomic Status ◽

Tobacco Use ◽

Educational Status ◽

Invasive Ventilation ◽

Non Invasive ◽

Non Invasive Ventilation ◽

High Flow Oxygen ◽

Group 3 ◽

Group 2 ◽

Group 1

ABSTRACT Background & Objective: COVID-19 infection has disproportionately affected ethnic minorities and deprived populations in Europe and North America. Influence of socioeconomic status on COVID-19 related outcomes has not been studied in India. To determine association of educational status, as marker of socioeconomic status, with COVID-19 related outcomes we performed a study. Methods: Clinically and virologically confirmed successive patients of COVID-19 presenting at a government hospital in India were recruited. Demographic and clinical details were recorded. The cohort was classified according to educational status into Group 1- illiterate or < primary, Group 2- higher secondary, and Group 3- some college. To compare outcomes among groups we performed univariate and multivariate logistic regression and odds ratios (OR) and 95% confidence intervals (CI) were calculated. Results: From March-September 2020 we recruited 4645 patients (men 3386, women 1259) with laboratory confirmed COVID-19. Mean age was 46+18y, most lived in moderate or large households and 30.5% had low educational status. Smoking or tobacco use was in 29.5%, co-morbidities in 28.6% and low oxygen concentration (SpO2 <95%) at admission in 30%. Average length of hospital stay was 6.8+3.7 days, supplemental oxygen was provided in 18.4%, high flow oxygen or non-invasive ventilation 7.1%, and mechanical ventilation in 3.6%. 340 patients (7.3%) died. Group 1 patients were younger, more women, larger households, higher tobacco use and were more hypoxic at admission with lower lymphocyte counts, elevated liver enzymes and greater kidney dysfunction. In Group 1 vs Groups 2 and 3 requirement of oxygen (21.6 vs 16.7 and 17.0%), non-invasive ventilation (8.0 vs 5.9 and 7.1%), invasive ventilation (4.6 vs 3.5 and 3.1%) and deaths (10.0 vs 6.8 and 5.5%) were significantly greater (p<0.05). Compared to Group 3, OR for deaths were significantly higher in Group 1 (1.91, 1.46-2.51) and Group 2 (1.24, 0.93-1.66). Adjustment for age, sex, household size, risk factors and comorbidities led to attenuation in OR in Groups 1 (1.44, 1.07-1.93) and 2 (1.38, 1.02-1.85) that remained with adjustments for clinical and laboratory parameters and oxygen support in Groups 1 (1.38, 0.99-1.93) and 2 (1.52, 1.01-2.11). Conclusion: Illiterate and less educational (socioeconomic) status patients with COVID-19 in India have significantly greater adverse in-hospital outcomes and mortality. This is related to more severe disease at presentation.

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Diagnostic importance of the concentration of milk amyloid A in quarter milk samples from dairy cows with mastitis

Acta Veterinaria Brno ◽

10.2754/avb201281020133 ◽

2012 ◽

Vol 81 (2) ◽

pp. 133-138 ◽

Cited By ~ 1

Author(s):

Milan Vasiľ ◽

Juraj Elečko ◽

Zuzana Farkašová ◽

František Zigo

Keyword(s):

Dairy Cows ◽

Acute Phase Proteins ◽

Subclinical Mastitis ◽

Amyloid A ◽

Milk Samples ◽

Group 4 ◽

Group 3 ◽

Group 2 ◽

Diagnostic Importance ◽

Group 1

Acute phase proteins have been used as biomarkers of inflammation. Their concentrations increase in milk from cows with latent and subclinical mastitis. The aim of our study was to evaluate milk amyloid A (MAA) as indicator of udder inflammation. We used 24 dairy cows from a herd with 120 Slovak Pied cattle. In addition to bacteriological examination, the following indicators were determined in all quarter milk samples. On the basis of results of clinical examination, Californian mastitis test (CMT), and number of Somatic cell count (SCC), four groups of quarter milk samples were formed. The levels of MAA in both subgroups of Group 1 (healthy cows), divided by the number of SCC - IA (n = 10), IB (n = 15), determined at repeated samplings, differed significantly from the initial levels (P < 0.01). Highly significant correlation (R2 = 0.272), was detected between SCC, and MAA in Group 2 (n = 27) at individual collections (P < 0.01), while in the Group 3 (n = 25) the level of both indicators decreased by the end of the experiment despite higher initial concentrations (P < 0.01). No significant differences in MAA were observed between individual collections in Group 4 (n = 6). No positive correlation (R2 = 0.525) was detected between SCC and MAA in this group. The obtained results allowed us to conclude that MAA in milk can act as a marker of inflammation of the udder only in the initial, asymptomatic stages of dairy cow mastitis. The experiment was one of first studies with MAA in Slovak Pied cattle.

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Different estrus induction protocols and fixed time artificial insemination during the anoestrous period in non-lactating Kivircik ewes

Journal of the Hellenic Veterinary Medical Society ◽

10.12681/jhvms.16429 ◽

2018 ◽

Vol 69 (1) ◽

pp. 801 ◽

Cited By ~ 4

Author(s):

I. DOGAN ◽

Z. NUR ◽

B. KILINC

Keyword(s):

Artificial Insemination ◽

Fixed Time ◽

Breeding Period ◽

Detection Rates ◽

Mean Values ◽

Group 3 ◽

Group 2 ◽

Equine Chorionic Gonadotropin ◽

Fresh Semen ◽

Group 1

The efficiency of medroxyprogesterone acetate (MAP) sponges or norgestomet ear implants (half or entire) for synchronizing and inducing the estrous cycle in non-lactating Kivircik ewes was investigated during the natural non-breeding period. Ewes were treated for 11 days either with 60 mg MAP sponges (group 1, n=27) or with 1.5 mg norgestomet (group 2, n=25) or with 3 mg norgestomet (group 3, n=27) ear implants. In addition, each ewe received an intramuscular injection of 500 IU of equine chorionic gonadotropin (eCG) and 125 μg cloprostenol (PGF2α), 48 h prior to progestagen removal. Double Cervical Artificial Insemination (AI) with diluted fresh semen was performed at a fixed time (36 and 48 h) following progestagen withdrawal. Mean values for estrous detection rates at the first 12 ± 6 h and within 72 h, the time from progestagen removal to the onset of estrous, the duration of the induced estrous and pregnancy rate were found to be 46.8%, 86.1%, 26.1 ± 7.3 h, 27.0 ± 10.7 h and 27.8%, respectively. There were significant differences between groups 2 and 3 in the time of induced estrous onset (P<0.05). These results indicate that, each of the three protocols was equally efficient in inducing and synchronizing estrus in non-lactating Kivircik ewes during the natural non-breeding period.

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Rational Decision On the Use of Antibiotics During the Dry Period in Dairy Cows

10.1101/667873 ◽

2019 ◽

Author(s):

Luis O. Lopes ◽

Anna M. C. Lima

Keyword(s):

Dairy Cows ◽

Somatic Cell ◽

Statistical Difference ◽

Coagulase Negative Staphylococcus ◽

Dry Period ◽

Microbiological Culture ◽

Group 3 ◽

Group 2 ◽

Sealant Group ◽

Group 1

ABSTRACTThe aim of this study was to evaluate the use of antibiotics in cows during the dry period. The survey was performed on 148 teats during the dry period, with sample collection in the period D-70 (70 days before delivery) and D14 (14 days after delivery). The milk samples were collected for the Strip Cup Test (SCT), California Mastitis Test (CMT), Microbiological Culture, Somatic Cell Count (SCC), Somatic Cell Score (SCS) and Hyperkeratosis (HK). The groups in which there were no microorganisms grow were divided into two groups, in the first group only the internal sealant in the teat was used (Group 1) and there was another group with the intramammary antibiotic use associated with the internal sealant (Group 2). Teats which were considered positive, with microbiological growth, were treated with the intramammary antibiotic associated with the internal sealant (Group 3). In the comparison of the results of the CMT test between D-70 and D14, a statistical difference was observed in Groups 2 and 3. Group 3, which comprises the positive teats in D-70 presented a reduction of 83.87% and 32.26% in the CMT test between D-70 and D14. Regarding HK, group 1 and 2 had a statistical difference in relation to group 3 in D-70 and D14. As for the numbers of bacteria isolated in D-70 and D14, there was no difference comparing Group 1 and Group 2, unlike Group 3, which had a difference. Group 1 and Group 2 were all negative teats in D-70, showing that the intramammary antibiotic did not influence the outcome of D14. In group 3 there was a reduction of isolates from 62 to 15 in D14. The most prevalent microorganism was Streptococcus agalactiae with 43.37% of the total isolates, followed by Staphylococcus aureus (16.87%) and Corynebacterium spp. (13.25%) and Coagulase negative Staphylococcus (SCN) (10.84%). The selective treatment of teats in dry dairy cows has advantages over Blanket Dry Cow Therapy by reducing the indiscriminate use of antibiotics, avoiding bacterial resistance, ensuring better milk quality and greater food safety. Antibiotics should only be used for teats with subclinical mastitis, with the microbiological culture at the end of lactation performed by fourth individual mammary.

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Effect of an inhibitor of 3β-hydroxysteroid dehydrogenase on progesterone concentrations and embryo survival in sheep

Journal of Endocrinology ◽

10.1677/joe.0.1120205 ◽

1987 ◽

Vol 112 (2) ◽

pp. 205-213 ◽

Cited By ~ 6

Author(s):

C. J. Ashworth ◽

I. Wilmut ◽

A. J. Springbett ◽

R. Webb

Keyword(s):

Luteal Phase ◽

Hydroxysteroid Dehydrogenase ◽

Oestrous Cycle ◽

Silicone Elastomer ◽

Progesterone Concentration ◽

Embryo Survival ◽

Progesterone Production ◽

Group 3 ◽

Group 2 ◽

Group 1

ABSTRACT The effect of an inhibitor of 3β-hydroxysteroid dehydrogenase on peripheral progesterone concentration during the luteal phase of the oestrous cycle and on embryo survival was determined in sheep. Following administration of 10, 50, 100 or 250 mg epostane (4,5-epoxy-17-hydroxy-4,17,dimethyl-3-oxo-androstane-2-carbonitrile) progesterone concentrations were significantly lower than control levels 4 h after injection, from 2·5 to 22 h, 1·5 to 24 h and 1 to 24 h after injection respectively. There appeared to be no effect on peripheral oestradiol concentrations. Adrenal progesterone production was small and not influenced by epostane treatment. Epostane was administered on day 9 of the oestrous cycle to cause a reduction in progesterone concentrations for approximately 12-18 h on day 9 only (group 1, 250 mg epostane on day 9), or a series of such reductions on 3 consecutive days (group 2, 50 mg epostane on days 9, 10 and 11) or a continuous reduction for 3 days (group 3, 250 mg epostane on days 9, 10 and 11). The proportion of ewes that were pregnant was significantly (P<0·05) lower in ewes treated to give a continuously low progesterone concentration for 3 days than in either controls or ewes in which progesterone concentration was reduced for less than 24 h (in controls and groups 1, 2 and 3 the proportion was 85, 92, 54 and 18% of ewes treated respectively). Embryo survival was not affected by administration of 250 mg epostane on days 9, 10 and 11 if luteal phase levels of progesterone were maintained by insertion of a silicone elastomer implant of the steroid. The proportion of embryos surviving was 72% in controls compared with 78% in the treated animals. J. Endocr. (1987) 112, 205–213

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Comparison of Single, Fixed-Time Artificial Insemination in Gilts Using Two Different Protocols to Synchronize Ovulation

Animals ◽

10.3390/ani10020306 ◽

2020 ◽

Vol 10 (2) ◽

pp. 306 ◽

Cited By ~ 1

Author(s):

Lima Rodrigues ◽

Rocio Amezcua ◽

Glen Cassar ◽

Terri L O’Sullivan ◽

Robert Friendship

Keyword(s):

Artificial Insemination ◽

Fixed Time ◽

Treatment Groups ◽

Gonadotropin Releasing Hormone Agonist ◽

Group 3 ◽

Group 2 ◽

Equine Chorionic Gonadotropin ◽

Triptorelin Acetate ◽

Timing Of Estrus ◽

Group 1

In order to efficiently have a consistent supply of service-ready gilts available to incorporate into each batch of breeding sows, it is necessary to manipulate the timing of estrus and possibly the timing of ovulation of gilts. Estrus can be synchronized by the withdrawal of altrenogest after at least 14 days of treatment. It is possible that protocols developed to induce ovulation, and therefore allow fixed-time artificial insemination (FTAI), can improve the predictability of gilt breeding. This study investigated the effect of two FTAI protocols in gilts on reproductive performance and timing of farrowing and piglet weaning weight compared to gilts bred based on signs of estrus after cessation of altrenogest. Puberty was induced in gilts, followed by treatment with altrenogest. Following altrenogest withdrawal, 180 gilts were assigned to one of three treatment groups. Group 1 gilts (LUT, n = 62) were treated with 600 IU equine chorionic gonadotropin 24 h after altrenogest withdrawal and 5 mg porcine luteinizing hormone (pLH) 80 h later, followed by a single FTAI 36 h after pLH. Group 2 gilts (TRI, n= 61) received 2 mL of a gonadotropin-releasing hormone agonist, triptorelin acetate, intravaginally 6 d after altrenogest withdrawal and were bred by a single FTAI 24 h later. Group 3 gilts (CON, n = 57) were observed for estrus and bred twice by AI, 24 h apart. LUT and TRI gilts farrowed closer together (2.4 ± 1.6 and 2.9 ± 1.2 d(days), respectively) compared to CON gilts (4.5 ± 3.3 d). Piglets in LUT were 80 g (p < 0.001) heavier and piglets in TRI were 64 g (p < 0.05) heavier at weaning than CON piglets, when controlling for birth weight. Results indicate that FTAI might be useful as a means of minimizing the time from the first to the last gilt farrowing in a breeding batch of gilts. However, modifications of the protocols may be required to ensure optimum farrowing rates and litter size.

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