Effect of an injectable trace mineral at the initiation of a 14 day CIDR protocol on heifer performance and reproduction1

Abstract Three experiments were conducted at separate locations to determine the effects of a trace mineral injection (TMI), Multimin 90, on heifer performance and reproduction. In Exp. 1, [spring-born, Angus, n = 93, body weight (BW) = 428 ± 45.2 kg], Exp. 2 (spring-born, Angus × Simmental, n = 120, BW = 426 ± 54.0 kg), and Exp. 3 (fall-born, commercial Angus, n = 199, BW = 345 ± 39.7 kg) heifers were stratified by BW within experiment and assigned to 1 of 2 treatments: a control, saline injection, or TMI at a dose of 1 mL/68 kg BW. Free choice mineral, containing Cu, Mn, Se, and Zn formulated to meet or exceed NRC recommendations, was supplemented to heifers. Injections were given 33 d prior to breeding at the initiation of a 14-d controlled internal drug release (CIDR)-prostaglandin protocol. There was no difference (P ≥ 0.37) in BW during Exp. 1. Additionally, there was no difference (P ≥ 0.52) in body condition score (BCS) at initiation or at artificial insemination (AI) and final pregnancy confirmation in Exp. 1; however, a greater (P = 0.03) BCS was noted for control heifers at breeding. Pregnancy rates to timed AI and overall pregnancy rates were also similar (P ≥ 0.74) regardless of treatment. During Exp. 2, BCS and BW did not differ (P ≥ 0.44) across treatments. There was a tendency (P = 0.07) for TMI heifers to have an increased AI pregnancy rate (62 vs. 45%) compared with control heifers despite no difference (P = 0.51) in overall pregnancy rate. In Exp. 3, BW was not different (P ≥ 0.39) across all time points. Also, BCS did not differ (P ≥ 0.45) at initiation, AI, or final pregnancy conformation. Interestingly, there was a tendency (P = 0.10) for TMI heifers to have an increased BCS at the time of breeding compared with control heifers. However, there were no differences (P ≥ 0.50) in AI and overall pregnancy rates. In 1 of 3 experiments, an injectable trace mineral administered 33 d prior to the breeding season in conjunction with a 14-d CIDR protocol, tended to increased AI conception rates of heifers even when adequate trace mineral supplement was provided. The variable response observed across experiments may be caused by differences in breed, calving season, mineral sources, and management strategies.

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29 SHORT-TERM v. LONG-TERM PROGESTERONE PROTOCOL USING CERVICAL OR INTRAUTERINE FIXED-TIME INSEMINATION IN SHEEP

Reproduction Fertility and Development ◽

10.1071/rdv22n1ab29 ◽

2010 ◽

Vol 22 (1) ◽

pp. 172

Author(s):

A. Menchaca ◽

M. Vilariño ◽

E. Rubianes

Keyword(s):

New York ◽

Pregnancy Rate ◽

Body Condition Score ◽

Skim Milk ◽

Prostaglandin F2α ◽

Fixed Time ◽

Short Term ◽

Condition Score ◽

N 93

The short-term protocol with progesterone, prostaglandin F2α (PGF2α), and eCG is used to control follicular dynamics and luteal activity synchronizing the ovulation for fixed-time AI in sheep. The objective of this experiment was to compare the pregnancy rate obtained with short-term protocol (6 d) and long-term protocol (14 d) using cervical or intrauterine fixed-time AI in sheep. Three hundred fifty-two Merino ewes with a body condition score of 2.9 ± 0.3 (mean ± SD; scale 0 to 5) were used during the breeding season (April, 33S, Uruguay). All the females received a CIDR-G (0.3 g of progesterone, InterAg, Hamilton, New Zealand) for 6 d (short-term protocol; n = 178) or 14 d (long-term protocol, n = 174). One imdose of eCG (300 IU, Novormon, Syntex, BA, Argentina) was given at the moment of device withdrawal for the both protocols, and one imdose of PGF2α (10 mg of dinoprost, Lutalyse, Pfizer, New York, NY, USA) was given at the end of the short-term protocol to ensure luteolysis. Cervical AI (short-term protocol, n = 85; long-term protocol, n = 104) or intrauterine AI (short-term protocol, n = 93; long-term protocol, n = 70) was performed 48 or 54 h after device withdrawal, using 200 × 106 or 100 × 106 spermatozoa per ewe, respectively. Fresh semen was extended in UHT skim milk (1000 × 106 spermatozoa mL-1) and used within 1 h of collection. Estrus was recorded twice a day for 4 days after device withdrawal using vasectomized males. Pregnancy diagnosis was performed by transrectal ultrasonography 40 d after AI (5.0 MHz, Aloka, Tokyo, Japan). Logistic regression was used to analyze the effect of the treatment (P < 0.05), the AI technique (P < 0.05), and their interaction (P = NS). Pregnancy rate was higher for the short-term than for the long-term protocol, and for intrauterine than for cervical AI (Table 1). The highest pregnancy rate was achieved with short-term protocol using intrauterine AI (54.8%, 51/93), and the lowest response was obtained with long-term protocol using cervical AI (33.7%, 35/104; P < 0.05). These data were not different from data of short-term protocol using cervical AI or long-term protocol using intrauterine AI (42.4%, 36/85; and 44.3% 31/70, respectively). Ewes in estrus/treated ewes was not different among short-term and long-term protocols (83.7%, 149/178; and 82.8%, 144/174, respectively; P = NS). In summary, regardless of insemination technique, short-term protocol of 6 d enhances pregnancy rate in fixed-time AI programs in sheep. Table 1.Main effects of short-term (6 d) v. long-term (14 d) protocol using cervical or intrauterine fixed-time AI on pregnancy rate in sheep Financially supported by Pfizer, SP, Brazil.

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20 ADMINISTRATION OF FOLLICLE-STIMULATING HORMONE AT CIDR REMOVAL DOES NOT AFFECT THE PREGNANCY RATE IN A CIDR-BASED, COSYNCH PROTOCOL IN LACTATING BEEF COWS

Reproduction Fertility and Development ◽

10.1071/rdv20n1ab20 ◽

2008 ◽

Vol 20 (1) ◽

pp. 90 ◽

Cited By ~ 1

Author(s):

J. Small ◽

F. Dias ◽

L. Pfeifer ◽

K. Lightfoot ◽

M. Colazo ◽

...

Keyword(s):

Logistic Regression ◽

Pregnancy Rate ◽

Bos Taurus ◽

Body Condition Score ◽

Animal Health ◽

Beef Cows ◽

Pregnancy Rates ◽

Condition Score ◽

Secondary Objective ◽

Pfizer Animal Health

In previous studies, giving eCG at CIDR removal significantly increased the pregnancy rate after timed-AI in beef cows. However, eCG is not universally available. Therefore, we tested the hypothesis that giving pFSH at CIDR removal might improve the pregnancy rate in a CIDR-based, Cosynch protocol in postpartum, suckled Bos taurus beef cows; a secondary objective was to compare pregnancy rates when GnRH v. pLH was used to synchronize wave emergence and ovulation. This work was conducted as two experiments (separate locations). All cows were given a CIDR (containing 1.9 g progesterone; Pfizer Animal Health, Montreal, QC, Canada) on Day 0 (without regard to stage of estrous cycle or cyclicity). On Day 7, CIDRs were removed, all cows were concurrently given 25 mg PGF (Lutalyse; Pfizer Animal Health, Groton, CT, USA), half were given 20 mg pFSH (Folltropin-V; Bioniche Animal Health, Belleville, ON, Canada), and all cows were timed-AI 54 h later (Day 9). In Experiment 1, 240 cows [94 � 10.8 days postpartum; body condition score (BCS: 1 = emaciated, 9 = obese; mean � SD): 5.8 � 0.4] were used; at CIDR insertion and AI, cows were allocated to receive either 100 µg GnRH (n = 160; Cystorelin, Merial Canada Inc., Victoriaville, QC, Canada) or 12.5 mg pLH (n = 80; Lutropin-V, Bioniche Animal Health). In Experiment 2, 109 cows (59.2 � 19.5 days postpartum; BCS: 5.6 � 1.1) were used; all received 100 µg GnRH (Cystorelin) at CIDR insertion and AI. In Experiment 1, three cows that lost their CIDR were excluded; pregnancy rates after timed-AI (logistic regression, backward selection: parity, pFSH, synchronizing treatment, and their interactions) were not different between cows given pFSH v. control cows (64.7 v. 65.2%; P > 0.80), nor between cows given GnRH v. pLH (62.7 v. 69.6%; P = 0.91). However, there was an interaction (P < 0.04) between parity and the synchronizing treatment; in primiparous cows, pregnancy rates were significantly lower in those given GnRH v. pLH (59.3 v. 83.3%). In Experiment 2, pregnancy rates after timed-AI (logistic regression, backward selection: parity, pFSH, and their interaction) were not different between cows given pFSH v. control cows (38.2 v. 42.6%; P > 0.6). In conclusion, our hypothesis was not supported; giving pFSH at CIDR removal did not significantly improve the pregnancy rate in a CIDR-based, Cosynch protocol in postpartum, suckled Bos taurus beef cows.

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10 EFFECT OF ESTRADIOL BENZOATE OR hCG ON DAY 22 AFTER TIMED ARTIFICIAL INSEMINATION ON THE CORPUS LUTEUM SIZE, PROGESTERONE CONCENTRATION, AND PREGNANCY RATE IN RESYNCHRONIZED BEEF HEIFERS

Reproduction Fertility and Development ◽

10.1071/rdv28n2ab10 ◽

2016 ◽

Vol 28 (2) ◽

pp. 134

Author(s):

J. B. S. Borges ◽

H. L. D. Neri ◽

M. R. Almeida ◽

E. P. Silva ◽

A. Bilha

Keyword(s):

Corpus Luteum ◽

Pregnancy Rate ◽

Body Condition ◽

Body Condition Score ◽

Pregnancy Rates ◽

Control Group ◽

Beef Heifers ◽

Pregnancy Diagnosis ◽

Condition Score ◽

And Control

This study aimed to compare the effects of 2 inducers of new follicular wave [oestradiol benzoate (EB) or hCG] administrated at onset of resynchronization protocols initiated 22 days after the first timed AI (TAI) of beef heifers. We evaluated the effect of treatments on corpus luteum (CL) development, serum progesterone (P4) concentrations, and pregnancy rates. A total of 467 grazing Brangus heifers, with 24- to 26-months, 320 ± 10 kg of body weight, and 3.2 ± 0.5 body condition score, were utilised. The resynchronization protocol began 22 days after the first TAI (Day 22). Heifers were randomly allocated into 1 of 3 groups: EB (n = 199), hCG (n = 101), or control untreated (n = 167). The EB- and hCG-treated heifers received an intravaginal P4 device (Procliclar, 0.75 g of P4; Hertape, Brazil) and an IM treatment with 1 mg of EB (Benzoato HC, Hertape) or 1000 IU of hCG (Vetecor 5000, Hertape), respectively. On Day 30, P4 device was removed, and the pregnancy diagnosis was performed. At this time heifers had the CL area (cm2) determined by ultrasound and seric P4 concentration evaluated by chemiluminescence assay. The assay sensitivity was 0.1 ng mL–1, and the intra- and interassay coefficients of variation were 7.9 and 10.6%, respectively. Nonpregnant heifers after the first TAI (EB = 97, hCG = 36) received intramuscularly 150 μg of sodium cloprostenol (Veteglan Luteolítico, Hertape) and 1 mg of oestradiol cypionate (Cipionato HC, Hertape). The second TAI was performed 48 to 52 h after the P4 device removal. On Day 62, heifers were submitted to a second pregnancy diagnosis. No effect of the body condition score (P = 0.28) was observed on the first and second pregnancy per AI. Pregnancy rates after the first TAI were higher (P = 0.03) on hCG-treated heifers (64.4%) than EB (51.3%) or the control group (58.7%). The EB group determined greater (P = 0.04) pregnancy rate after the second TAI (49.5%) than the hCG group (22.2%). The cumulative pregnancy rates were similar (P = 0.46) between groups [EB (72.4%) and hCG (68.3%)]; however, both were greater (P < 0.05) than the control group (58.6%). Heifers treated with hCG (3.42 ± 0.76) presented greater CL area at Day 30 (P < 0.05) than the EB (2.44 ± 0.57) and control (2.61 ± 0.61) groups. The treatment with hCG 22 days after TAI determined greater (12.43 ± 3.48; P < 0.05) serum P4 concentrations on Day 30 than the EB (6.92 ± 3.04) and control (7.29 ± 2.45) groups. Therefore, the use of hCG at the beginning of resynchronization protocol 22 days after the TAI increased pregnancy rate following the first TAI. However, the use of 1 mg of EB determined greater pregnancy rate after the second TAI, and no detrimental effects on CL development, P4 concentration, and on first TAI pre-established pregnancy.

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9THE USE OF ECG TO INCREASE PREGNANCY RATES IN POSTPARTUM BEEF COWS FOLLOWING TREATMENT WITH PROGESTERONE VAGINAL DEVICES AND ESTRADIOL BENZOATE AND FIXED-TIME AI

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab9 ◽

2004 ◽

Vol 16 (2) ◽

pp. 127 ◽

Cited By ~ 7

Author(s):

G.A Bo ◽

L. Cutaia ◽

P. Chesta ◽

D. Moreno

Keyword(s):

Body Condition Score ◽

Fixed Time ◽

Beef Cows ◽

Estradiol Benzoate ◽

Pregnancy Rates ◽

Control Group ◽

Treatment Groups ◽

Condition Score ◽

N 93 ◽

Rectal Palpation

Treatments with progesterone (P4) releasing devices and estradiol benzoate (EB) have been extensively used in fixed-time AI (FTAI) programs in beef cattle. However, pregnancy rates in postpartum cows kept on pasture often have been lower than expected because of poor body condition score (BCS) and a high incidence of anestrous. A recent study (Cutaia L et al., 2003 Theriogenology 59, 216) suggested that the addition of eCG to a P4/EB FTAI program may improve pregnancy rates in cows with fair to poor BCS, but results were not conclusive. Therefore, this experiment was designed to further investigate the effect of eCG treatment on pregnancy rates in postpartum beef cows in those conditions. The experiment was performed at 2 locations with lactating Angus cows (n=93), 60 to 90d postpartum with a BCS 1.9 (1 to 5 scale; Location 1), and crossbred Zebu cows (n=290), 60 to 90d postpartum with a BCS 2.0 (Location 2). In each Location, cows were randomly allocated to 1 of the following treatment groups: Control, eCG Day6, or eCG Day8. All cows received a P4 intravaginal device (DIB, Syntex, Argentina) and 2mg EB i.m. (Syntex) on Day0, 500mg cloprostenol (Estroplan, Syntex) at the time of DIB removal (Day8), 1mg EB i.m. on Day9 and FTAI 52 to 56h after DIB removal. Cows in the Control group received no further treatment, whereas cows in the eCG-treated groups received 400 IU eCG (Novormon 5000, Syntex) on Day6 or Day8. Cows were examined on Day0 by rectal palpation (Location 1) or by ultrasonography (US; Location 2) and were classified as those with a CL or without a CL, with either large (>8mm) or small (<8mm)small follicles. Pregnancy was determined by US 45d after FTAI. Data were analyzed by logistic regression and the effects of location, treatment, ovarian status, AI technician and semen were considered in the model. There was no effect of location (P=0.3), AI technician (P=0.2) or semen (P=0.8) on pregnancy rates. However, there was an effect of treatment (P=0.02), attributed to higher pregnancy rates in the eCG Groups than in the Control Group (Table). Furthermore, cows with a CL or without a CL but with large follicles on Day 0 had higher pregnancy rates than those with small follicles (P=0.04). It was concluded that the use of eCG in a P4/EB FTAI program improved pregnancy rates in postpartum beef cows that were in fair topoor BCS.

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8 COMBINATION OF OESTRUS DETECTION AND FIXED-TIME ARTIFICIAL INSEMINATION IN BEEF HEIFERS FOLLOWING A SHORTENED OESTRADIOL-BASED PROTOCOL THAT PROVIDES FOR A LENGTHENED PROESTRUS

Reproduction Fertility and Development ◽

10.1071/rdv27n1ab8 ◽

2015 ◽

Vol 27 (1) ◽

pp. 96 ◽

Cited By ~ 2

Author(s):

J. J. de la Mata ◽

M. Ré ◽

G. A. Bó

Keyword(s):

Pregnancy Rate ◽

Body Condition Score ◽

Fixed Time ◽

Beef Cows ◽

Gonadotropin Releasing Hormone ◽

Pregnancy Rates ◽

Group V ◽

Releasing Hormone ◽

Treatment Groups ◽

Condition Score

Studies have shown that gonadotropin-releasing hormone-based protocols that reduce the period of progestin insertion and prolong the period from progestin removal to gonadotropin-releasing hormone and fixed-time AI (FTAI; named 5-day Co-Synch) results in similar or higher pregnancy rates than the conventional 7-day Co-Synch protocol in beef cows and heifers (Bridges et al. 2008 Theriogenology 69, 843–851). Similar findings have been reported following the use of an oestradiol-based protocol that also provides for a longer period of proestrus (named J-Synch; de la Mata and Bó 2012 Taurus 55, 17–23). An experiment was designed to compare the J-Synch protocol for synchronization of ovulation that allows for a prolonged proestrus with a conventional 7-day oestradiol-based protocol for FTAI in heifers. Cycling 18-month old Angus and Hereford heifers (n = 208) with a body condition score of 6 to 7 (scale of 1 to 9) were randomly allocated to 1 of 2 treatment groups. Heifers in the 7-day EB group (n = 105) received a progesterone (P4) device (DIB 0.5 g of P4, Syntex SA, Buenos Aires, Argentina) and 2 mg of oestradiol benzoate (EB, Syntex SA) on Day 0 and 500 μg of cloprostenol (PGF; Ciclase DL, Syntex SA) and 0.5 mg oestradiol cypionate (Cipiosyn, Syntex SA) on the day of DIB removal (Day 7). Heifers were also tail painted at the time of DIB removal and observed for signs of oestrus (i.e. tail paint rubbed off). Those with the tail paint rubbed off by 36 h after DIB removal were inseminated 12 h later, whereas those not showing oestrus by 36 h were FTAI at 54 h. Heifers in the J-Synch group (n = 103) received DIB and 2 mg of EB on Day 0 and PGF on the day of DIB removal (Day 6). Heifers in this group were also tail painted at DIB removal, and those with their tail paint rubbed off by 48 h were inseminated 12 h later; those not showing oestrus by 60 h received 100 μg of gonadorelin acetate (gonadotropin-releasing hormone, Gonasyn gdr, Syntex SA) and were FTAI at 72 h after DIB removal. Pregnancy was diagnosed by ultrasonography at 55 days after FTAI (Honda 101V, 5.0-MHz transducer). Data were analysed by logistic regression. Oestrus detection rate and pregnancy rate to FTAI did not differ (P > 0.1) between groups (38.8%, 40/103 and 60.3%, 38/ 63 for heifers in the J-Synch group v. 28.5%, 30/105 and 45.3%, 34/75 for those in the 7-day EB group). However, pregnancy rates to observed oestrus tended (P < 0.09) to be higher and the overall pregnancy rate was significantly higher (P < 0.01) in heifers in the J-Synch group (80.0%, 32/40 and 67.9%, 70 /103) compared with those in 7-day EB group (50%, 15/30 and 46.6%, 49/105). Furthermore, heifers within the J-Synch group that had their tail paint rubbed off by 48 h after DIB removal and were AI 12 h later (i.e. 60 h) had higher (P < 0.05) pregnancy rate than those in the same group that were FTAI. In conclusion, reducing the time of progestin device insertion and lengthening the proestrus period, as in the J-Synch protocol, results in higher pregnancy rates than with the conventional oestradiol-based protocol. Furthermore, the combination of oestrus detection and FTAI would appear to improve the pregnancy outcome even more.

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PSXIII-19 Effects of injectable trace mineral supplements at the initiation of estrus synchronization on pregnancy rates in beef cows

Journal of Animal Science ◽

10.1093/jas/skz258.740 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 371-372

Author(s):

Carl Dahlen ◽

Kacie L McCarthy ◽

Sarah Underdahl ◽

Mellissa Crosswhite ◽

Bryan Neville

Keyword(s):

Pregnancy Rate ◽

Body Condition Score ◽

Transrectal Ultrasound ◽

Beef Cows ◽

Pregnancy Rates ◽

Estrus Synchronization ◽

Negative Effects ◽

Trace Mineral ◽

Mineral Supplements ◽

Red Angus

Abstract The objective of this experiment was to evaluate effects of administering injectable trace mineral supplements to beef cows at the initiation of estrus synchronization on pregnancy rates to AI. Four hundred seventeen Angus and Red Angus-based beef cows at two locations were stratified by parity, body condition score, and days postpartum, then randomly assigned to one of 2 treatments; 1) untreated controls (CON; n = 208); or 2) received 90 mg Cu, 60 mg Mn, 30 mg Se, and 360 mg Zn as an injectable TM supplement initiation of synchronization (6 ml Multimin 90 s.q.; ITM; n = 209). All cows received a controlled internal drug release insert (CIDR; 1.38g progesterone) and 100 µg gonadotropin-releasing hormone (GnRH) im, followed in 7 d by CIDR removal and 25 mg prostaglandin F2alpha, followed in 60 to 66 hours with AI and 100 µg GnRH i.m. Cows received an Estrotech heat detection patch on their tailhead at CIDR removal, which was assigned an activation status at AI (yes = ≥50% of patch activated; no = < 50%). Pregnancy status was determined via transrectal ultrasound on day 35 to 40 after AI to determine pregnancy rates to AI in response to treatments. No location × treatment interaction was present (P = 0.66), but pregnancy rate was greater (P < 0.01) for Location 1 (76.9%; 70 of 91) than for Location 2 (58.0%; 189 of 326). However, no differences (P = 0.50) in pregnancy rates were observed among CON (123/208; 63.5%) and ITM (127/209; 60.8%). Overall, 56.6% of cows had activated estrus detection patches at AI, and more cows with activated patches became pregnant (169/236; 71.6%) compared with cows having unactivated patches (90/181; 49.7%). In this experiment, ITM administration at the initiation of estrus synchronization had no negative effects on pregnancy rate to AI.

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Effects of management system on beef heifer growth and reproductive performance

Translational Animal Science ◽

10.1093/tas/txaa209 ◽

2020 ◽

Author(s):

Parker A Henley ◽

Frank A Ireland ◽

Igor F Canisso ◽

J Lannett Edwards ◽

Daniel W Shike

Keyword(s):

Development Strategy ◽

Breeding Season ◽

Reproductive Performance ◽

Body Condition Score ◽

Pregnancy Rates ◽

Fescue Toxicosis ◽

Soybean Hulls ◽

Randomized Design ◽

Condition Score ◽

Calf Performance

Abstract This study evaluated the effect of heifer development system on body weight (BW), body condition score (BCS), fescue toxicosis symptoms, reproductive performance, and subsequent calf growth of fall-calving beef heifers. Angus × Simmental heifers [n = 399; 240 ± 20.0 kg initial BW; age = 252 ± 20 d] were stratified by BW and BCS and assigned to 1 of 12 groups in each of the 2 production years. The study utilized a stratified randomized design. Pens were randomly assigned to 4 treatments: drylot (DL) development (fed ad-libitum diet consisting of 90% hay and 10% DDGS on a dry matter basis), grazing endophyte-infected fescue supplemented daily (2.3 kg as-fed/heifer/d; 50:50 mix of soybean hulls and DDGS; E+/S), grazing endophyte-infected fescue and supplemented from the midpoint of treatment period until breeding (4.5 kg as-fed/heifer/d; 50:50 mix of soybean hulls and DDGS; E+/LS), and grazing novel endophyte-infected fescue with no supplement (NE+/NS). Treatments ceased on d 168 [time of artificial insemination (AI)] and heifers were commingled and managed as a group through second breeding season. Heifers in DL had greatest (P ≤ 0.05) BW and BCS from d 28 until d 254. Furthermore, E+/S heifers had greater (P ≤ 0.05) BW and BCS than both E+/LS and NE+/NS from d 28 until d 168. On d 56 and 84, E+/LS heifers had lower (P ≤ 0.05) BW and BCS compared to NE+/NS, but on d 148 treatments reranked and E+/LS remained at a greater (P ≤ 0.05) BW and BCS compared to NE+/NS through the first breeding season. Drylot heifers had greatest (P ≤ 0.05) percentage cycling and percentage of mature BW at AI (66.6%) and had greater (P ≤ 0.05) AI and overall pregnancy rates compared to E+/LS and NE+/NS. The E+/S (55%) and E+/LS (53.7%) heifers were developed to a greater (P < 0.01) percentage of mature BW than NE+/NS (49.3%). A greater (P ≤ 0.02) percentage of DL and E+/S heifers were pregnant at the end of the first breeding season (89.3 and 85.1%; respectively) compared to NE+/NS (61.5%). In summary, DL heifers had the greatest BW and BCS at AI, percentage cycling, and AI pregnancy rate. However, this strategy did not result in differing overall pregnancy rates between DL, E+/S, and E+/LS and there were no differences in milk production, rebreeding reproductive performance, and calf performance between all treatments. Finally, the poorest AI and overall pregnancy rates of the NE+/NS heifers suggests this is not a viable development strategy for fall-born heifers.

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86 Factors affecting beef calf vigor at birth: Dam peripartum body condition score, calving season, and calf size

Journal of Animal Science ◽

10.1093/jas/skaa054.003 ◽

2020 ◽

Vol 98 (Supplement_3) ◽

pp. 3-3

Author(s):

Lindsey G Wichman ◽

Colby A Redifer ◽

Natalie B Duncan ◽

Craig A Payne ◽

Allison M Meyer

Keyword(s):

Mixed Model ◽

Body Condition Score ◽

Negative Relationship ◽

Beef Cows ◽

Abdominal Girth ◽

Factors Affecting ◽

Condition Score ◽

Calving Season ◽

Relationship Of ◽

The Relationship

Abstract To determine effects of cow BCS and calving season on calf vigor and size and the relationship of calf size with vigor, 310 multiparous and primiparous beef cows (age: 4.6 ± 2.2 yr; BW: 663 ± 86 kg; BCS: 5.3 ± 0.6) from 3 spring (2015, 2016, 2017) and 4 fall (2015, 2017, 2018, 2019) calving seasons were observed during parturition. Time to stand (n = 191) was determined as minutes from birth to standing successfully for 5 sec. Within 24 h, calf BW (n = 187) and size [shoulder to tailhead length (STL), heart girth (HG), and abdominal girth (AG; n = 154)] were recorded. Data were analyzed using a mixed model containing effects of calving season (spring and fall), BCS category (< 5, =5, ≥6), and their interaction. Correlations were determined between time to stand and calf measurements separately for spring (n = 79) versus fall (n = 111). Cows with BCS < 5 gave birth to lighter (P = 0.02) calves that tended to have a faster (P ≤ 0.13) time to stand than =5 and ≥6. Calves from cows with BCS ≥6 tended to have greater (P ≤ 0.09) STL than =5 and < 5. Calves from cows with BCS < 5 had smaller (P = 0.13) HG than =5. Fall-born calves tended to have smaller (P ≤ 0.06) BW, HG, and AG than spring-born calves. Within fall calves, there tended to be a positive relationship (r = 0.16; P = 0.09) between time to stand and calf BW. Despite this, spring calves had a negative relationship (r = -0.26; P = 0.02) between time to stand and calf BW. In conclusion, cow BCS and calving season affect calf size and may affect calf vigor. These data suggest that calving season may dictate the relationship between calf vigor and size.

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Comparison of the effects of Presynch-Ovsynch, Presynch- Ovsynch+CIDR, and G6G protocols on the reproductive performance of lactating Holstein cows in the postpartum period

Veterinarska stanica ◽

10.46419/vs.53.4.6 ◽

2021 ◽

Vol 53 (4) ◽

Author(s):

Hesam Kohsari ◽

Khatereh Berenjian

Keyword(s):

Serum Concentration ◽

Pregnancy Rate ◽

Reproductive Performance ◽

Body Condition Score ◽

Dairy Farm ◽

Fixed Time ◽

Pregnancy Rates ◽

Holstein Cows ◽

Treatment Protocols ◽

Ovulatory Follicle

This study was performed on an industrial dairy farm near Tehran province, Iran, on 666 lactating Holstein cows from September 2019 to June 2020 in order to eliminate the harmful effects of heat stress on the reproductive performance of the cows. The hypothesis of the recent study was that by increasing the serum concentration of progesterone (P4) in the luteal phase before insemination in the form of Presynch-Ovsynch+CIDR (POC) and G6G protocols, the pregnancy rate of cows would be increased compared to the Presynch-Ovsynch (PO) protocol. The aim of the present study was to evaluate the effects of Presynch-Ovsynch (PGF2α-14d- PGF2α-12d-Ovsynch (OVS: GnRH(GnRH1)- 7d-PGF2α(PG)-2d-GnRH)-18h-Fixed-time artificial insemination (FTAI), n=212), Presynch-Ovsynch+CIDR (similar to the PO protocol, plus the use of a CIDR for 7 days, from the start of the OVS+FTAI protocol to the time of PG injection, n=230), and G6G (PGF2α- 2d-GnRH-6d-OVS+FTAI, n=224) protocols on the reproductive performance and pregnancy rate of lactating Holstein cows. The average body condition score (BCS) for the cows was about 2.5 at the time of the onset of the OVS+FTAI program. The average daily milk production for cows at the time of the start of the OVS+FTAI program was 38.3 kg/day. On average, the studied cows were inseminated 86 days postpartum. Implementation of the G6G protocol in comparison to the PO and POC protocols increased the serum concentration of P4 at GnRH1 (P=0.04). The cows that received the G6G protocol had a greater number of corpuses luteum (CL) on their ovaries at PG in comparison to the cows in the PO and POC protocols (P=0.03 and P=0.05, respectively). For all treatment protocols, the pregnancy rate of cows with >2 CLs on their ovaries at PG was significantly higher than for cows with ≤2 CLs on their ovaries at this time. The overall pregnancy rate for all cows studied was 42%. Separately, pregnancy rates for cows in PO, POC, and G6G protocols were calculated at 36.7%, 41.7%, and 47.3% respectively. The highest and the lowest pregnancy rates were obtained in the G6G and PO protocols, respectively (P=0.03). It can be concluded that the G6G protocol increased the pregnancy rate of cows in comparison to the PO but not to the POC protocol. This result can be attributed to the increase in serum concentration of P4 at GnRH1 and the greater number of CLs at PG following implementation of the G6G compared to the PO protocol. Although CIDR administration in the POC protocol led to an increase in the pregnancy rate of cows compared to the PO protocol, possibly by increasing the synchrony rate and the quality of the ovulatory follicle, this increase was not statistically significant (P=0.09).

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AVALIAÇÃO DO DESEMPENHO REPRODUTIVO DE VACAS NA REGIÃO DO PANTANAL SUL-MATO-GROSSENSE SUBMETIDAS A IATF Com Aplicação De GnRH

Nativa ◽

10.31413/nativa.v9i3.11184 ◽

2021 ◽

Vol 9 (3) ◽

pp. 281-285

Author(s):

Gabriel Rodrigo Hass Perucchi ◽

Gabriela de Souza Sartori ◽

Richarlla Aparecida Buscariol Silva ◽

Murilo da Silva Garcia ◽

Rodrigo José Delgado Jardim ◽

...

Keyword(s):

Beef Cattle ◽

Pregnancy Rate ◽

Reproductive Performance ◽

Artificial Insemination ◽

Body Condition Score ◽

The Body ◽

Mato Grosso ◽

Condition Score ◽

Timed Artificial Insemination ◽

Mato Grosso Do Sul

A Inseminação artificial em tempo fixo (IATF) está se difundindo no Brasil, pois contribui para o aumento da produtividade. O objetivo neste trabalho foi avaliar o uso do GnRH em protocolos de IATF de vacas criadas no pantanal Sul-mato-grossense. Participaram da pesquisa 531 vacas paridas da raça Nelore, que foram avaliadas de acordo com o escore de condição corporal (ECC), submetidas a três tipos de protocolos de IATF (lote 1, 2 e 3). Após 40 dias da inseminação artificial foi realizado diagnóstico de gestação. As matrizes que não receberam GnRH no lote 1 (estro aparente), lote 2 (estro parcial) e lote 3 (sem apresentação de estro) apresentaram, respectivamente 55,4%, 19,2% e 25,9% de prenhez, enquanto as que receberam o fármaco apresentaram 48,6%, 37,2% e 38,8%. Relacionado ao ECC, pode-se observar que a maior taxa de prenhez ocorreu em animais com ECC 3. Primíparas apresentaram melhor taxa de prenhez quando receberam GnRH independente do ECC. Concluiu-se que o uso de GnRH mostrou-se eficiente para melhoria da taxa de prenhez principalmente em primíparas, assim como nos animais que não apresentaram estro ou apresentaram estro parcial, e que matrizes com ECC 3 apresentaram melhores taxas de prenhez que vacas com escore inferior. Palavras-chave: bovino de corte; inseminação artificial em tempo fixo; produtividade; GnRH; Nelore. Evaluation of cow reproductive performance in the region of Mato Grosso do Sul swamp submitted to TAI with GnRH application ABSTRACT: The technique of timed artificial insemination (TAI) is spreading in Brazil, as it contributes to the increase of productivity. The objective of this work was to evaluate the use of GnRH in TAI protocols of cows raised in the swamp of Mato Grosso do Sul. 531 Nelore breed calved cows participate in the survey, which were evaluated according to the body condition score (BCS), and then performed three types of TAI protocols (batch 1, 2 and 3). After 40 days of the insemination, a pregnancy diagnosis was made. The matrices that did not receive GnRH in batch 1 (apparent oestrus), batch 2 (partial oestrus) and batch 3 (no oestrus presentation) presented respectively 55.4%, 19.2% and 25.9% of pregnancy, while those receiving the drug showed 48.6%, 37.2% and 38.8%. Related to BCS, it can be observed that the highest pregnancy rate occurred in animals with BCS 3. Primiparous had a better pregnancy rate when receiving GnRH regardless of BCS. It was concluded that the use of GnRH was efficient to improve the pregnancy rate mainly in primiparous as well as animals that showed no oestrus or partial oestrus, and matrices with BCS 3 had better pregnancy rates than cows with lower scores. Keywords: beef cattle; timed artificial insemination; productivity; GnRH; Nelore.

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