Overfeeding copper during rearing affects the liver function and fertility of replacement dairy heifers.

BACKGROUND: Oversupply of dietary copper (Cu) is common among UK dairy herds, but studies on the long-term outcomes of this oversupply are scarce. METHODS: A longitudinal study was undertaken to determine the long-term implications when 80 Holstein‒Friesian heifers with a mean (±standard error) age of 4.1 ± 0.1 months and a mean liveweight of 137 ± 2.4 kg were fed a recommended (R; 16 mg/kg dry matter [DM]) or high (H; 32 mg/kg DM) dietary Cu concentration until 6 weeks prior to calving. RESULTS: Hepatic Cu concentrations in both treatment groups were elevated into the ranges used to diagnose chronic Cu toxicity in cattle at 6.9 months of age (798 ± 46.4 mg/kg DM for H vs. 643 ± 35.4 mg/kg DM for R), with associated evidence of liver damage. Hepatic Cu concentrations then returned to normality but remained higher (p < 0.001) for heifers fed H than for those fed R and were associated with a reduced (p = 0.044) conception rate to first and second services (73.7 ± 8.05% for H vs. 91.2 ± 7.68% for R). LIMITATION: This retrospective analysis identified pre-study liver damage, which may have affected results. CONCLUSIONS: Supplying Cu in excess of requirements resulted in liver damage and reduced conception rates.

Feeding nanoparticles of copper oxide coated with lysine with or without added antagonists affects the copper status but not performance of Holstein dairy cows.

The apparent absorption of copper (Cu) in ruminants is low, with between 0.01 and 0.07 g/g absorbed from sources such as copper oxide (CuO) under typical feeding conditions, resulting in high levels of excretion. Improving the bioavailability of Cu could reduce the supplemental amount required to maintain Cu status and reduce excretion, particularly in the presence of dietary antagonists such as sulfur (S) and molybdenum (Mo). The objective of our study was to determine the Cu status of cows when fed nanoparticle CuO coated with Lys compared with conventional CuO when fed without or in combination with antagonists to Cu absorption (S and Mo) in the diet of dairy cows. Fifty-six multiparous Holstein-Friesian cows that were 48 d ± 17.4 (mean ± SD) post calving and yielding 40.6 ± 6.9 kg milk/d were used in a 2 × 2 factorial design. The 4 treatment groups were; CuO (O-), CuO with added antagonists (O+), nano CuO with a lysine coating (N-), and nano CuO with a Lys coating with added antagonists (N+), fed for 16 wks. We formulated the diets to contain approximately 17 mg Cu/kg dry matter (DM) and diets with antagonists contained an additional 1 g S/kg DM and 6 mg Mo/kg DM, with Lys added to O- and O+ to provide the same daily supply as N- and N+. Blood samples were collected at wk 0, 2, 4, 6, 10 and 16, and liver biopsy samples at wk 0 and 16. We found no effect of dietary treatment on DM intake, milk yield, live weight or body condition score, with mean values of 23.3 kg/d, 40.1 kg/d, 646 kg and 2.68, but milk SCC was higher in cows fed conventional compared with non CuO, or with added antagonist. We also found no effect of treatment on blood activity of gamma glutamyl transferase, superoxide dismutase or ceruloplasmin, hematology profile, or plasma Cu and iron concentration. We found that plasma Mo concentration was increased from 0.36 µmol/L in cows fed O- or N- to 0.80 µmol/L in those receiving O+ or N+. Additional dietary antagonists also decreased the concentration of Cu in the liver of cows fed conventional CuO (C+) over the study period by 1.3 mg/kg DM/d, but in cows fed dietary antagonists and nano CuO coated with Lys (N+), liver Cu concentration was increased by 1.1 mg/kg DM/d. Our study is the first to demonstrate that reducing the particle size of CuO into the nano scale with a lysine coating improves the bioavailability of CuO in the presence of dietary antagonists in dairy cattle, and we did not observe any negative effects on performance or health.

Macromineral and trace element concentrations in milk from Finnish Ayrshire cows fed microalgae (Spirulina platensis) and rapeseed (Brassica napus).

Given the lack of research regarding the effect of microalgal supplementation in dairy cows on milk mineral concentrations, this study investigated the effect of feeding different protein supplements in dairy cow diets on milk, feces, and blood plasma mineral concentrations, associated milk and blood plasma transfer efficiencies, and apparent digestibility. Lactating Finnish Ayrshire cows (n = 8) were allocated at the start of the trial to 4 diets used in a replicated 4 × 4 Latin square design experiment: (1) control diet (CON), (2) a pelleted rapeseed supplement (RSS; 2,550 g/d), (3) a mixture of rapeseed and Spirulina platensis (RSAL; 1,280 g of RSS + 570 g of S. platensis per day), and (4) S. platensis (ALG; 1,130 g of S. platensis per day). In each of the 4 experimental periods, a 2-wk adaptation to the experimental diets was followed by a 7-d sampling and measurement period. Feed samples were composited per measurement period, milk, and feed samples (4 consecutive days; d 17-20), and blood plasma samples (d 21) were composited for each cow period (n = 32). Data were statistically analyzed using a linear mixed effects model with diet, period within square, square and their interaction as fixed factors, and cow within square as a random factor. Cows fed ALG were not significantly different in their milk or blood plasma mineral concentrations compared with CON, although feeding ALG increased fecal concentrations of macrominerals (Ca and Mg) and trace elements (Co, Cu, Fe, I, Mn, and Zn), and reduced their apparent digestibility, compared with CON. When compared with CON and ALG, milk from cows fed RSAL and RSS had lower milk I concentrations (-69.6 and -102.7 µg/kg of milk, respectively), but total plasma I concentrations were not affected significantly. Feeding S. platensis to dairy cows did not affect mineral concentrations in cows' blood or milk, but care should be taken when rapeseed is fed to avoid reducing milk I concentrations which may in turn reduce consumers' I intake from milk and dairy products.

Polyunsaturated fatty acid supplementation during pregnancy alters neonatal behavior in sheep.

The objectives of the study were to determine whether supplementation of pregnant ewes with long-chain (n-3) fatty acids present in fish oil, in combination with dietary vitamin E, would alter neonatal behavior in sheep. Twin- (n=36) and triplet- (n=12) bearing ewes were allocated at d 103 of gestation to 1 of 4 dietary treatments containing 1 of 2 fat sources [Megalac, a calcium soap of palm fatty acid distillate or a fish oil mixture, high in 20:5(n-3) and 22:6(n-3)] and 1 of 2 dietary vitamin E concentrations (50 or 500 mg/kg) in a 2 x 2 factorial design. Feeding fish oil increased gestation length by 2 d and increased the proportion of 22:6(n-3) within neonatal plasma by 5.1-fold and brain by 10%, whereas brain 20:5(n-3) was increased 5-fold. Supranutritional dietary vitamin E concentrations decreased the latency of lambs to stand in ewes fed fish oil but not Megalac, whereas latency to suckle was decreased from 43 to 34 min by fish oil supplementation. Supplementation with fish oil also substantially decreased the secretion rate (mL/h) of colostrum and the yield (g/h) of fat and protein. We conclude that supplementation of ewes with fish oil decreases the latency to suckle, increases gestation length and the 22:6(n-3):20:4(n-6) ratio in the neonatal brain, and may improve lamb survival rate. However, further work is required to determine how to mitigate the negative effects of fish oil on colostrum production.

The effect of dietary vitamin E and fatty acid supplementation of pregnant and lactating ewes on placental and mammary transfer of vitamin E to the lamb.

The present study investigated the effect of maternal vitamin E and fatty acid supplementation on lamb antioxidant status. Forty-eight ewes were fed one of four concentrate diets supplemented with a basal (50 mg/kg) or supranutritional (500 mg/kg) level of vitamin E plus a source of either saturated fat (Megalac; Volac Ltd, Royston, Hertfordshire, UK) or long-chain PUFA (fish oil) from 6 weeks prepartum until 4 weeks postpartum. Blood samples were taken from ewes and lambs at intervals throughout the experiment and, at parturition, muscle, brain and blood samples were obtained from twelve lambs (three per treatment). Colostrum and milk samples were obtained at 12 h and 21 d after parturition, respectively. Supranutritional vitamin E supplementation of the ewe significantly increased concentrations of vitamin E in neonatal lamb tissues although plasma concentrations were undetectable. A significant increase in lamb birth weight resulted from increasing the dietary vitamin E supply to the ewe. Furthermore, maternal plasma, colostrum and milk vitamin E concentrations were increased by vitamin E supplementation, as were lamb plasma concentrations at 14 d of age. Neonatal vitamin E status was not significantly affected by fat source although plasma vitamin E concentrations in both ewes and suckling lambs were reduced by fish oil supplementation of the ewe. Fish oil supplementation reduced vitamin E concentrations in colostrum and milk and the activity of glutathione peroxidase in suckling lambs. The data suggest that the vitamin E status of the neonatal and suckling lamb may be manipulated by vitamin E supplementation of the ewe during pregnancy and lactation.