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In late pregnancy and early lactation, ewe's demand increases for zinc (Zn), and selenium (Se) for scavenging of free radicals and due to transfer via placenta, colostrum or milk to lamb.This experiment was conducted to study the effect of slow-release bolus of Zn and Se on performance, and some blood parameters of pregnant ewes in the last third of pregnancy, and early lactation as well as their lambs. Twenty-one ewes were estrus synchronized in the breeding season by intra vaginal insertion of sponge containing medroxyprogesterone acetate. Forty-five days before the expected date of parturition, the pregnant ewes (3–4 years old and 55±5.2 kg in weight) were randomly assigned to one of the three groups: 1) control, 2) slow-release glass bolus with mean release of 20 mg Zn and 0.2 mg Se per day (Bolus), and 3) 20 mg Zn and 0.2 mg Se per day as sulfate and selenite, respectively via Daily feeding (Daily). Blood samples were obtained from ewes at 105th and 135th days of pregnancy, at parturition and 15th day postpartum and from lambs at 15 days of age. The results indicated that total feed intake of ewes increased (P = 0.03) in the Bolus and Daily groups than control. Supplementation of Zn and Se in both methodssignificantly increased Total Antioxidant Capacity (TAC) in the ewesand their lambs than the control group. Compared with the control, there was higher triiodothyronine (T 3) in ewes and their lambs and lower tetraiodothyronine (T 4) only in lambs in Bolus and Dailygroups. Increased T 3 to T 4 ratio in ewes (at days 135 of pregnancy and at parturition) and their lambs was recorded in Bolus and Daily than the control group. An increased level of alkalinephosphatase (ALP) in ewes was observed in the Bolus and Daily groups compared with the control. Alanine amino transferase (ALT) activity on day 135 of pregnancy was significantly reduced by Zn and Se supplementation in both methods. Bolus and Daily groups of ewes had lower creatinephosphokinase (CPK), and their lambs had lower aspartate amino transferase (AST), ALT, CPK, and gamma-glutamyltransferase (GGT) than the control group. Regardless of the supplementation method, Zn and Se increased glucose (P = 0.02) and decreased triglyceride (P = 0.06) in ewes. In the ewes supplemented with Zn and Se, creatinine concentration significantly decreased in parturition day compared to control. Total protein, albumin, globulin and ratio of albumin to globulin in ewes and their lambs were not different between treatments. As a result, Zn and Se improved antioxidant status and some blood parameters in ewes and their lambs. Efficacy of slow-release bolus of Zn and Se was similar with daily feeding of these elements. • Supplementation of Zn and Se improved performance of ewes and their lambs. • Efficacy of slow-release bolus of Zn and Se was similar with daily feeding method. • There Was no difference between the use of zinc oxide and zinc sulfate on parameters of ewes and their lambs. • Boluses would be recommended when animals are not fed especially in extensive grazing situations. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to follow the time-course changes of the milk fatty acids (FA) and particularly conjugated linoleic acid (CLA), n-3, and n-6 FA in response to feeding whole rolled safflower seed (SS). Eighteen cows were blocked by milk production, days in milk, and parity, and randomly assigned to 1 of 3 diets by replacing whole cottonseed with SS. The control diet contained no SS (SS0), whereas the other diets contained 3% of dry matter as SS (SS3) or 6% SS (SS6). The study was conducted for 8 wk. Cows fed SS produced more milk than SS0, with SS3 producing more milk than SS6, but without a change in milk fat yield or milk fat %. Except for C8:0 FA, changes in milk FA were not observed until the third week of SS feeding. The C8:0 began decreasing during wk 1 of SS feeding and continued to decline to wk 8. Short-chain FA (C6:0 to C11:0) and medium-chain FA (C12:0 to C16:1) concentrations decreased in milk when cows were fed SS, whereas long-chain FA (C18:0 and higher) increased after wk 3. The milk long-chain FA increased from wk 3 until wk 5 and then reached a plateau with little difference between SS3 and SS6, whereas the short-chain FA decreased more in milk from cows fed SS6 than SS3. Total CLA increased slightly less than 5x in milk from cows fed SS compared with SS0. Over the same time frame, n-3 FA declined and n-6 FA increased in the milk from cows fed SS, with no difference between SS3 and SS6. This study indicated that SS fed at 3 and 6% of DM had the potential to increase milk production and the CLA in milk, but with a corresponding increase in n-6 FA. [ABSTRACT FROM AUTHOR]