Effect of progesterone infused controlled internal drug releasing (CIDR) device and timing of gonadotropin stimulation using P.G. 600 on reproductive success in ewes bred out of season.

Objectives of this study were to determine effects of exogenous progesterone (via controlled internal drug releasing devices; CIDR) in combination with exogenous gonadotropins (PMSG/hCG) use either at CIDR removal or 1 d before CIDR removal to induce estrus and cyclicity and subsequently enhance the proportion of ewes lambing, lambing rate, prolificacy, and days to lambing in ewes bred out of season. Multiparous ewes ( = 414) were randomly assigned to one of four treatments: untreated (, = 122), 7 d CIDR (, = 97), 7 d CIDR plus P.G.

Maternal nutrition and stage of early pregnancy in beef heifers: impacts on hexose and AA concentrations in maternal and fetal fluids1.

We examined the hypothesis that maternal nutrition and day of gestation would affect the concentrations of AAs and hexoses in bovine utero-placental fluids and maternal serum from days 16 to 50 of gestation. Forty-nine cross-bred Angus heifers were bred via artificial insemination and fed a control diet (CON = 100% of requirements for growth) or a restricted diet (RES = 60% of CON) and ovariohysterectomized on days 16, 34, or 50 of gestation; nonpregnant controls were not bred and ovariohysterectomized on day 16 of the synchronized estrous cycle. The resulting design was a completely randomized design with a 2 × 3 factorial + 1 arrangement of treatments.

The effects of nutrient restriction on mRNA expression of endogenous retroviruses, interferon-tau, and pregnancy-specific protein-B during the establishment of pregnancy in beef heifers.

We hypothesize that syncytin-Rum1, bovine endogenous retrovirus-K1 (BERV-K1), pregnancy-specific protein-B (PSP-B), and interferon-τ (IFN-τ) will be influenced by maternal nutrient restriction and be differentially expressed during key stages (day 16, 34, and 50) of the establishment of gestation when fed to meet industry standards. Commercial crossbred heifers (n = 49) were maintained on a total mixed ration and supplemented with dried distillers grains with solubles. All heifers were subjected to 5-d CO-Synch + CIDR estrus synchronization protocol.