Parenteral Copper Administration at the Beginning of a Fixed-Time Artificial Insemination Protocol in Beef Cattle: Effect on Ovarian Function and Pregnancy Rates.

The aim of this study was to evaluate the association between plasma copper (Cu) concentration and ovarian function during a fixed-time artificial insemination (FTAI) protocol and the effect of parenteral Cu administration (100 mg) at the start of such protocol (day 0) on area of preovulatory follicle (APF); area of corpus luteum (ACL), plasma estradiol (E2), and progesterone (P4) concentrations; CL blood flow (CLBF); and pregnancy rate in beef heifers and cows. In cows, plasma Cu concentration on days 0 and 7 correlated positively with APF. Copper administration increased plasma Cu concentration and decreased APF and plasma E2 concentration (day 9), without modifying ACL, plasma P4 concentration, and CLBF (day 16) in cows. Pregnancy rate was higher in Cu-supplemented cattle on day 41 after FTAI as compared with controls (58.76 and 45.28%, respectively). In conclusion, Cu administration at the beginning of the FTAI protocol increased pregnancy rate in beef heifers and cows, modifying APF and plasma E2 concentration in the latter.

Effects of Parenteral Supplementation with Minerals and Vitamins on Oxidative Stress and Humoral Immune Response of Weaning Calves.

We aimed to evaluate the effects of injectable mineral and vitamin supplementation on weaning calves subjected to a low-stress (fence-line) weaning system. Seven-month-old Aberdeen Angus female calves (n = 40, 152 ± 11 kg body weight) from a selenium-deficient area of extensive cattle production on natural grass were randomly assigned to two groups (n = 20 each). One group received subcutaneous supplementation with copper, zinc, selenium, manganese and vitamins A and E (SG), and the other was given sterile saline solution (CG). The animals were supplemented twice, seven days before weaning (day -7) and on the day of weaning (day 0), and they were evaluated 30 (+30) and 60 (+60) days after weaning. Total antioxidant status (TAS), selenium-dependent glutathione peroxidase (GPx) activity, body weight, and average daily gain (ADG) were evaluated. Additionally, antibody titers were assessed prior to and after each immunization with a vaccine containing bovine herpes virus type 1 (BoHV-1). On day +30, body weight (p = 0.03) was higher in SG, whereas TAS (p = 0.02) and GPx (p = 0.0038) activity were lower in CG and remained constant in SG. Antibody titers increased in SG and CG following immunization, being higher in SG on days +30 and +60 (p < 0.05). In conclusion, parenteral supplementation of minerals and vitamins with antioxidant effects in a low-stress weaning system prevented the decrease in TAS and GPx activity, improved antibody response and had positive effects on body weight.

Effect of cysteine, glutamate and glycine supplementation to in vitro fertilization medium during bovine early embryo development.

Glutathione (GSH) is an antioxidant synthesized from three constitutive amino acids (CAA): cysteine (Cys), glycine (Gly) and glutamate (Glu). Glutathione plays an important role in oocyte maturation, fertilization and early embryo development. This study aimed to investigate the effect of Cys (0.6 mM), Gly (0.6 mM) and Glu (0.9 mM) supplementation during in vitro fertilization (IVF) of cattle oocytes. In a Pilot Experiment, de novo synthesis of GSH in bovine zygote was evaluated using a modified TALP medium prepared without MEM-essential and MEM-non-essential amino acids (mTALP): mTALP + CAA (constitutive amino acids); mTALP + CAA+5 mMBSO (buthionine sulfoximide); mTALP + Cys + Gly; mTALP + Cys + Glu and mTALP + Gly + Glu. This evidence led us to investigate the impact of CAA supplementation to TALP medium (with essential and non-essential amino acids) on zygote viability, lipid peroxidation, total intracellular GSH content (include reduced and oxidized form; GSH-GSSG), pronuclear formation in zygotes and subsequent embryo development. IVF media contained a) TALP; b) TALP + Cys + Gly + Glu (TALP + CAA); c) TALP + Cys + Gly; d) TALP + Cys + Glu; e) TALP + Gly + Glu, were used. Total GSH-GSSG concentration was increased in TALP, TALP + CAA, and TALP + Cys + Gly. The viability of zygote was similar among treatments. Lipid peroxidation was increased in zygote fertilized with TALP + Cys + Gly; TALP + Cys + Glu; TALP + Gly + Glu and TALP + CAA. The percentage of penetrated oocytes decreased in TALP + CAA and TALP + Cys + Gly. The cleavage rate was lower in TALP + CAA and TALP + Gly + Glu. The percentage of embryos developing to the blastocyst stage was lower in TALP + Cys + Glu and TALP + CAA. In conclusion, we have demonstrated the synthesis of GSH during IVF. However, Cys, Gly and Glu supplementation to TALP medium had negative effects on embryonic development.

Effect of Injectable Copper and Zinc Supplementation on Weight, Hematological Parameters, and Immune Response in Pre-weaning Beef Calves.

Copper (Cu) and zinc (Zn) deficiency may cause poor weight gain, hematological changes, and immune failure in extensive beef cattle breeding systems. Diagnosis of the deficiency is based on plasma Cu and Zn concentrations; however, there are discrepancies regarding data interpretation. Here, plasma Cu and Zn concentrations are discussed as risk markers. We evaluated the effect of parenteral Cu and Zn supplementation on their plasma concentrations, weight gain, hematological parameters, and antibody titers to bovine herpes virus 1 (BoHV-1). Pre-weaning calves (n = 40; 99 ± 8 kg bw) from a typical breeding area of Argentina with background Cu and Zn deficiency were used. They were assigned to two homogeneous groups in a completely randomized design. Calves were subcutaneously injected with 0.3 mg/kg Cu and 1 mg/kg Zn (supplemented group), or saline solution (control), every 40 days during 120 days. Plasma Cu and Zn concentrations, hematological parameters, and weight were recorded. On days 40 and 80 of the trial, calves were vaccinated with inactivated BoHV-1. Antibody immune response was measured on days 80 and 120. Data were analyzed with a mixed model for repeated measures over time. Before treatment, plasma Cu was low and Zn was adequate in both groups. After treatment, plasma Cu increased and remained within a normal range, whereas plasma Zn remained constant. Supplemented animals had higher weight gain (p < 0.01); higher hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin levels (p < 0.05); and higher immune response to BoHV-1 (p < 0.05). Our results suggest that Cu and Zn supplementation improved daily weight gain and the immune response of pre-weaning calves.

Effects of Copper and Zinc Supplementation on Weight Gain and Hematological Parameters in Pre-weaning Calves.

Cow-calf operations may be affected by trace mineral deficiencies, particularly copper (Cu) and zinc (Zn) deficiency, which may decrease the calf daily weight gain and alter hematological parameters. We evaluated the effect of Cu and Zn supplementation on pre-weaning calves (n = 40; 92 ± 6 kg initial body weight) from the Salado River basin, Buenos Aires, Argentina. Calves were divided into four groups (n = 10 each) and subcutaneously administered 0.3 mg/kg Cu (Cu group), 1 mg/kg Zn (Zn group), Cu and Zn together (Cu + Zn group), and sterile saline solution (control group) every 40 days for 120 days. Plasma Cu and Zn concentrations, hematological parameters, and weight were recorded every 40 days. A completely randomized 2 × 2 factorial treatment design was used and data were analyzed with a mixed model for repeated measures over time. Cu and Zn were detected in plasma after the second sampling. Cu × Zn interaction was significant (p = 0.09), being Cu concentration higher in the Cu + Zn than in the Cu group. Differences in weight gain (Zn × time interaction; p < 0.01) were observed in the Zn but not in the Cu group (p > 0.1). On the other hand, none of the treatments altered any of the hematological parameters assessed (p > 0.1). Our results show the risk of lower weight gain due to Zn deficiency in pre-weaning calves raised in the Salado River basin.