1066 Effect of GnRH removal at CIDR insertion in the 5 d CO-Synch + CIDR ovulation synchronization protocol on ovarian function in beef cows

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 511-511
Author(s):  
T. M. Grussing ◽  
T. C. Grussing ◽  
P. J. Gunn
Keyword(s):  
Ovarian Function ◽  
Beef Cows ◽  
Synchronization Protocol

EFFECT OF GLUCOSE INFUSION ON METABOLIC AND REPRODUCTIVE FUNCTION IN POSTPARTUM BEEF COWS

1988 ◽  
Vol 68 (4) ◽  
pp. 1079-1087 ◽  
Author(s):  
W. P. McCAUGHEY ◽  
L. M. RUTTER ◽  
J. G. MANNS
Keyword(s):  
Luteinizing Hormone ◽  
Ovarian Function ◽  
Plasma Concentrations ◽  
Reproductive Function ◽  
Beef Cows ◽  
Glucose Infusion ◽  
Ovarian Activity ◽  
Beef Cow ◽  
Constant Rate ◽  
Infusion Period

An experiment was conducted to determine if glucose infusion could alter hypothalamic, pituitary or ovarian function in the postpartum (PP) beef cow. Twenty-six cows were assigned randomly at parturition to one of three infusion treatments. Controls (CON, n = 8) received 0.9% NaCl from days 26 to 32 PP. Glucose-infused animals (GLU, n = 8) received glucose at a constant rate of 4 mg min−1 kg−0.75 from days 26 to 32 PP, while glucose-spiked cows (SPIKE, n = 10) received glucose at rates up to 8 mg min−1 kg−0.75 for 48 h (days 26 and 27 PP), then received 0.9% NaCl as in CON. On day 32 PP 25 μg of gonadotrophin-releasing hormone (GnRH) was injected intravenously and blood samples were taken at 15- to 30-min intervals to evaluate pituitary release of luteinizing hormone (LH). During the entire infusion period, GLU had lower (P < 0.05) daily free fatty acid concentrations than either SPIKE or CON. Plasma concentrations of glucose in cows receiving the SPIKE treatment were elevated (P < 0.05) during the 48-h infusion period when compared to GLU and CON. In addition, glucose concentrations were higher (P < 0.05) in the GLU group than in the CON group during the first 48 h of infusion. For the remaining 4 d of the infusion period, plasma concentrations of glucose were similar between CON and GLU. Plasma insulin values were numerically but not significantly higher in GLU than in CON over the 6-d infusion period. During the 48-h glucose spike treatment insulin levels were elevated (P < 0.05) over preinfusion values and higher (P < 0.05) than both CON and GLU. Glucose infusion did not alter concentrations of plasma LH or the response to exogenous GnRH. The number of cows exhibiting ovarian activity by day 53 PP was similar among treatments. Key words: Beef cattle, glucose, reproduction, energy, luteinizing hormone, metabolism

scholarly journals Effects of bovine somatotrophin (bST) on ovarian function in post-partum beef cows

1996 ◽  
Vol 8 (6) ◽  
pp. 951 ◽  
Author(s):  
LP Andrade ◽  
SM Rhind ◽  
IA Wright ◽  
SR McMillen ◽  
PJ Goddard ◽  
...  
Keyword(s):  
Ovarian Function ◽  
Post Partum ◽  
Ovarian Follicle ◽  
Beef Cows ◽  
Ovarian Follicle Development ◽  
Factor I ◽  
Glucose Injection ◽  
Igf I ◽  
And Function ◽  
Bovine Somatotrophin

The effects of bovine somatotrophin (bST) on ovarian follicle development and function and associated gonadotrophin profiles during the first nine weeks post partum were investigated in beef cows. Thirty-two cows (Shorthorn x Galloway) in moderately low body condition (BC) at calving were fed to maintain BC thereafter. At Weeks 2, 4, 6 and 8 post partum, animals were injected with 320 mg bovine somatotrophin (bST) (T, treated; n = 17) or with the carrier oil only (C, control; n = 15). Ovulation occurred in 4 of 17 T cows and 0 of 15 C cows (P = 0.10) by nine week post partum. Treatment with bST did not affect the numbers of small (3-8 mm in diameter) or large (> 8 mm in diameter) follicles or the granulosa cell populations but enhanced the oestradiol (P < 0.05) and insulin-like growth factor-I (IGF-I) content (P < 0.01) of large follicles by nine weeks post partum. It did not significantly affect the testosterone concentrations of large follicles. Circulating concentrations of growth hormone (GH) and IGF-I were higher in T cows than in C cows (P < 0.001) but were unrelated to gonadotrophin profiles or gonadotrophin receptor concentrations in the follicles. At Week 8, plasma insulin concentrations were higher in T cows than in C cows both before (P < 0.05) and after (P < 0.05) glucose injection. It is concluded that GH may play an important role in mediating the effects of nutritional state on ovarian function during the post-partum period, possibly through alteration of intrafollicular IGF-I concentrations.

scholarly journals Effect of bovine somatotropin (growth hormone) treatment on gonadotropin profiles and ovarian follicle populations during the postpartum period in beef cows in low body condition

1993 ◽  
Vol 1993 ◽  
pp. 89-89
Author(s):  
L.P. Andrade ◽  
S.M. Rhind ◽  
I.A. Wright ◽  
S.R. McMillen ◽  
T.K. Whyte
Keyword(s):  
Growth Hormone ◽  
Body Condition ◽  
Growth Hormone Treatment ◽  
Ovarian Function ◽  
Post Partum ◽  
Ovarian Follicle ◽  
Hormone Treatment ◽  
Beef Cows ◽  
Follicle Development ◽  
Ovarian Follicle Development

Cows in low body condition exhibit a prolonged postpartum anoestrous period and a delayed return to normal follicular function (Prado et al 1990). Previous studies have shown that the effects of body condition on gonadotrophin profiles are inconsistent (Wright et al 1990; Rhind et al 1992) indicating that the effects of body condition on ovarian function cannot be explained by changes in gonadotrophin profiles alone. Since nutritional state influences growth hormone profiles which in turn can affect ovarian function (Gong et al 1991), it was postulated that the effects of body condition on the duration of postpartum anoestrus could be mediated through changes in profiles of this hormone.The aim of the present study was to determine the effect of growth hormone on ovarian follicle development and associated gonadotrophin profiles in post-partum beef cows.

Effects of body condition and supplementation on ovarian function, growth factors and response to estrus synchronization in postpartum beef cows in Tamaulipas, Mexico

2018 ◽  
Vol 68 (3) ◽  
pp. 124-133
Author(s):  
Miguel Angel Domínguez-Muñoz ◽  
José Armando Guerra-Puga ◽  
Hossana Guadalupe Berrones-Morales ◽  
Rigoberto López-Zavala ◽  
Jaime Salinas-Chavira
Keyword(s):  
Growth Factors ◽  
Body Condition ◽  
Ovarian Function ◽  
Beef Cows ◽  
Estrus Synchronization

scholarly journals PSXIII-14 The impact of estrus intensity on variables associated with fertility in Bos taurus-influenced beef cows

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 362-363
Author(s):  
Reinaldo F Cooke ◽  
Nicola Oosthuizen ◽  
Kelsey Schubach ◽  
Alice Brandão ◽  
Ramiro Oliveira Filho ◽  
...  
Keyword(s):  
Physical Activity ◽  
Bos Taurus ◽  
Fixed Time ◽  
Beef Cows ◽  
Estrus Synchronization ◽  
Estrus Detection ◽  
Follicle Size ◽  
The Impact ◽  
Ovarian Dynamics ◽  
Synchronization Protocol

Abstract To evaluate the impact of estrus expression and intensity on parameters associated with reproductive performance, 219 lactating, multiparous Bos taurus-influenced beef cows were enrolled in this study. Cows were exposed to an estrus synchronization protocol, where they received a 100-µg injection of GnRH and a CIDR insert on d -10, a 25-mg injection of PGF2a at CIDR removal on d -3, and an injection of GnRH 60–66 h following CIDR removal at fixed-time AI (TAI; d 0). Cows were fitted with a pedometer behind their right shoulder on d -10, and an estrus detection patch was applied to their tail-head on d -3. Estrus expression was defined as removal of &gt; 50% of the rub-off coating from the patch on d 0. Net physical activity during estrus was calculated by subtracting daily activity during the non-estrus period (d -10 to -3) from activity during the expected estrus period (d -3 to 0). Cows were classified into 3 groups: cows that did not express estrus (NOESTR; n = 119), cows that expressed estrus with net physical activity greater than the median (HIESTR; n = 50), and the remaining cows (LWESTR; n = 50). Ultrasonography was performed on d -3, 0, and 7 to determine the presence and size of ovarian structures. Pregnancy diagnosis was performed 29 d after TAI. Net physical activity was greater in HIESTR compared to both LWESTR and NOESTR (P &lt; 0.01). Dominant follicle size was greater in HIESTR compared to both LWESTR and NOESTR (P &lt; 0.01). Furthermore, HIESTR had greater corpus luteum volume on d 7 than LWESTR and NOESTR (P &lt; 0.01). Pregnancy rates to AI (PR/AI) were greater in HIESTR and LWESTR compared to NOESTR (P &lt; 0.01). In conclusion, cows that expressed estrus at a greater intensity had improved ovarian dynamics. Additionally, cows that exhibited estrus had greater PR/AI compared to non-estrual cows.

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