Growth, haematological and biochemical responses of growing lambs injected

Physiological and productive responses to recombinant bovine somatotropin (rbST) injection and calcium soap of fatty acids (CSFA) supplementation were studied in post-weaning male Rahmani lambs. Male lambs (n = 20) of similar initial body weight (27.9 kg) and age (162 d) were divided randomly into four equal groups. The first was fed the injected with 100 mg of rbST biweekly; the third (basal diet and served as control; the second (GH) was CSFA) was supplemented with 50 g/d of CSFA and the fourth (GH + CSFA) was injected with 100 mg of rbST biweekly plus 50 g/d of CSFA. Treatments increased the average daily gain and final body weight. Concentration of insulin-like growth factor-1 (IGF-1) in lambs treated with (GH) and (GH + CSFA) was higher than that of CSFA and control groups. Haematological parameters (RBC, WBC, and haemoglobin concentrations) did not change. Animals injected with rbST had higher serum total protein than other treated groups and controls. Control lambs showed the least serum albumin concentration. Injection of rbST and supplementation of CSFA increased serum glucose in treated lambs compared to controls. Serum urea concentration was not affected by injection of GH, while CSFA supplementation decreased serum urea concentration compared to the control. Serum triglycerides concentration decreased in rbST-injected lambs than other treatment groups. Lambs supplemented with CSFA only or combined with rbST had higher concentration of serum cholesterol than control or rbST-injected lambs. The results of the present study suggest that rbST and CSFA may increase the average daily gain and improve the physiological status of growing lambs

Estrus synchronization of replacement beef heifers by using GnRH, prostaglandin F2α (PGF), and progesterone (CIDR): a multi-location study

Our objectives were to determine whether a fixed-timed artificial insemination (TAI) protocol could yield similar fertility rates to a protocol requiring detection of estrus and whether an injection of gonadotropin hormone-releasing hormone (GnRH) at CIDR (vaginal insert containing progesterone) insertion enhances pregnancy rates. Replacement beef heifers (n=2,077) from 12 locations were assigned randomly to each of four estrussynchronization protocols. All heifers received a CIDR for 7 days, and an injection of prostaglandin F2α (PGF) on the day of CIDR removal. For treatment EAI, heifers were observed for estrus for 84 hours after PGF administration and were inseminated 6 to 12 hours after observed estrus. Any heifer not detected in estrus was injected with GnRH, followed by TAI. For treatment GnRH+EAI, heifers were treated as those for EAI, but also received GnRH at the time of CIDR insertion. For treatment TAI, heifers received a single TAI at 60 hours after PGF administration. For treatment GnRH+TAI, heifers were treated as those for TAI, but also received GnRH at CIDR insertion. The percentage of heifers cycling at the initiation of estrus-synchronization was 91%; the percentage of cycling heifers among locations ranged from 78 to 100%. Overall pregnancy rates among locations ranged from 38 to 74%. Pregnancy rates were 57.3, 54.5, 53.1, and 49.1% for GnRH+EAI, EAI, GnRH+TAI, and TAI, respectively. Although no statistically significant differences in pregnancy rates among treatments were observed, the GnRH+EAI treatment achieved the numerically greatest pregnancy rates. In addition, the GnRH+TAI protocol provides an alternative that allows producers to synchronize heifers without detection of estrus

Estrus synchronization of suckled beef cows by using GnRH, prostaglandin F2α (PGF), and progesterone (CIDR): a multi-location study

Our objectives were to determine whether a fixed-time artificial insemination (TAI) protocol could yield pregnancy rates similar to a protocol requiring detection of estrus and whether inclusion of a CIDR (a vaginal insert containing progesterone) in protocols using gonadotropin-releasing hormone (GnRH) and prostaglandin F2α (PGF) would enhance fertility. Postpartum suckled beef cows (n = 2,630) from 14 locations were assigned randomly to each of five estrus-synchronization protocols using PGF with GnRH and(or) a CIDR. Protocols were Control, CO-Synch, COSynch+ CIDR, Hybrid-Synch, and Hybrid-Synch+CIDR. The percentage of cows cycling at the initiation of estrus synchronization was 66.8%, the percentage of cycling cows ranging from 38 to 90% among locations. Overall pregnancy among locations ranged from 39% to 67%. Pregnancy rates were greatest for the Hybrid-Synch+CIDR (57.9%) treatment, although not significantly different from the CO-Synch+CIDR (53.6%) and Hybrid-Synch (53.0%) treatments, but greater than the Control (52.3%) and CO-Synch (43.4%), which yielded the poorest pregnancy rates. Overall, the Hybrid-Synch+CIDR protocol (AI after detected estrus for 3 days, and then a clean-up TAI) achieved the greatest pregnancy rates, but CO-Synch+CIDR is a reliable, fixed-time AI protocol that gives producers the option to eliminat