18 research outputs found
Detection of noncyling cows by heatmount decectors and ultrasound before treatment with progesterone
Our objective was to determine accuracy of identifying anovulatory lactating dairy cows before the application of a timed AI protocol [with or without progesterone supplementation via a controlled internal drug release (CIDR) insert and 2 different timings of AI] by using heatmount detectors and a single ovarian ultrasound examination. At 6 Midwest locations, 1,072 cows were enrolled in a Presynch protocol (2 injections of prostaglandin F2α(PGF2α) 14 days apart) with the second injection administered 14 days before initiating the Ovsynch protocol (injection of gonadotropin releasing hormone (GnRH) 7 days before and 48 hours after PGF2αinjection, with timed AI at 0 or 24 hours after the second GnRH injection). Heatmount detectors were applied to cows at the time of the first Presynch injection, assessed 14 days later at the second Presynch injection and again at initiation of the Ovsynch protocol, and ovaries were examined for presence of a visible corpus luteum (CL) by ultrasound before initiation of treatment. Treatments were assigned to cows based on presence or absence of a visible CL: 1) anovulatory (no CL + CIDR insert for 7 d); 2) anovulatory (no CL + no CIDR); and 3) cycling (CL present). Further, every other cow in the 3 treatments was assigned to be inseminated concurrent with the second GnRH injection of Ovsynch (0 hour) or 24 hours later. Pregnancy was diagnosed at 33 and 61 days after the second GnRH injection. Heatmount detectors and a single ultrasound examination both underestimated proportions of cows classified as anovulatory or having no prior luteal activity compared with those classifications determined by concentrations of progesterone in blood serum. Overall accuracy of heatmount detectors and ultrasound was 71 and 84%, respectively. Application of progesterone to cows without a CL at the time of the first injection of GnRH reduced incidence of ovulation but improved pregnancy rates at day 33 or 61 compared with nontreated cows without a CL at the onset of the Ovsynch protocol. Pregnancy rates and pregnancy survival did not differ for cows having a CL before treatment compared with those not having a CL but treated with progesterone. Pregnancy rates were 1.5-fold greater for cows ovulating in response to the first GnRH injection. Timing of AI at 0 or 24 hours after the second GnRH injection did not alter pregnancy rates, but cows having prior luteal activity before treatment had improved pregnancy rates compared with anovulatory cows. We conclude that identifying anovulatory cows by ultrasound was more accurate than by heatmount detectors. Subsequent treatment of potential anovulatory cows with progesterone failed to improve fertility but had benefit for cows with prior estrous cycles at the onset of the timed AI (TAI) protocol, regardless of luteal status before the final luteolytic injection of PGF2α.; Dairy Day, 2007, Kansas State University, Manhattan, KS, 2007; Dairy Research, 2007 is known as Dairy Day, 200
Efeito da sincronização e da indução de estros em novilhas sobre a prenhez e o índice de repetição de crias na segunda estação reprodutiva
Retardo da realização da IATF sobre o desempenho reprodutivo na estação de acasalamento de vacas de corte lactantes
"Modification of Rumen Bacterial Populations for Enhanced Performance and Health," 65th Minnesota Nutrition Conference and Preconference Symposium "On the Cutting Edge of Direct Fed Microbials" Proceedings, September 21-22, 2004. St. Paul MN
338EFFECT OF TRACE MINERAL NUTRITION ON FOLLICULAR RESPONSE, OVULATION, AND EMBRYO PRODUCTION IN SUPEROVULATED ANGUS HEIFERS
Detection of noncyling cows by heatmount decectors and ultrasound before treatment with progesterone
Dairy Research, 2007 is known as Dairy Day, 2007Our objective was to determine accuracy
of identifying anovulatory lactating dairy
cows before the application of a timed AI protocol [with or without progesterone supplementation via a controlled internal drug release (CIDR) insert and 2 different timings of AI] by using heatmount detectors and a single ovarian ultrasound examination. At 6 Midwest locations, 1,072 cows were enrolled in a Presynch protocol (2 injections of prostaglandin F2α (PGF2α) 14 days apart) with the second injection administered 14 days before initiating
the Ovsynch protocol (injection of gonadotropin releasing hormone (GnRH) 7 days before and 48 hours after PGF2α injection, with timed AI at 0 or 24 hours after the second GnRH injection). Heatmount detectors were applied to cows at the time of the first Presynch injection, assessed 14 days later at the second Presynch injection and again at initiation of the Ovsynch protocol, and ovaries were examined for presence of a visible corpus luteum (CL) by ultrasound before initiation of treatment. Treatments were assigned to cows based on presence or absence of a visible CL: 1) anovulatory (no CL + CIDR insert for 7 d); 2) anovulatory (no CL + no CIDR); and 3) cycling (CL present). Further, every other cow in the 3 treatments was assigned to be inseminated concurrent with the second
GnRH injection of Ovsynch (0 hour) or 24
hours later. Pregnancy was diagnosed at 33
and 61 days after the second GnRH injection.
Heatmount detectors and a single ultrasound
examination both underestimated proportions
of cows classified as anovulatory or having no
prior luteal activity compared with those classifications
determined by concentrations of
progesterone in blood serum. Overall accuracy
of heatmount detectors and ultrasound
was 71 and 84%, respectively. Application of
progesterone to cows without a CL at the time
of the first injection of GnRH reduced incidence
of ovulation but improved pregnancy
rates at day 33 or 61 compared with nontreated
cows without a CL at the onset of the
Ovsynch protocol. Pregnancy rates and pregnancy
survival did not differ for cows having
a CL before treatment compared with those
not having a CL but treated with progesterone.
Pregnancy rates were 1.5-fold greater for cows
ovulating in response to the first GnRH injection.
Timing of AI at 0 or 24 hours after the
second GnRH injection did not alter pregnancy
rates, but cows having prior luteal activity
before treatment had improved pregnancy
rates compared with anovulatory cows.
We conclude that identifying anovulatory
cows by ultrasound was more accurate than by
heatmount detectors. Subsequent treatment of potential anovulatory cows with progesterone
failed to improve fertility but had benefit for
cows with prior estrous cycles at the onset of
the timed AI (TAI) protocol, regardless of
luteal status before the final luteolytic injection
of PGF2α