The study was carried out to determine the presence and concentration of some heavy metals in the blood of Holstein-Friesian cattle in a private farm in Nasarawa State Nigeria. Blood samples were obtained from 22 Holstein-Friesian cattle consisting of 21 cows and 1 bull, of ages between 3.5 and >3.5 years. The samples were analyzed using Atomic Absorption Spectrophotometer (AAS). The mean lead (Pb), Iron (Fe) and Cadmium (Cd) concentrations were 1.160, 47.681 and 0.051 mg/kg, respectively. There was no significant (P>0.05) effect of age and sex on the concentration of Pb, Fe and Cd. The study found the presence of Pb, Fe and Cd in blood samples collected from Friesian cattle. The FAO/WHO permissible limit of Cd and Pb in blood is 0.5mg/kg. Pb was detected above the maximum limit. The high concentration of these metals recorded could be as a result of prolong use of inorganic agricultural products and likely irrigation water which contaminate the feed. High levels of these metals in Holstein-Friesian can cause decreased milk production, placenta damage, mineral deficiency and respiratory failure among others. Inorganic agriculture should be replaced with organic methods; industrial activities close to pasture yards should be avoided. Sources of irrigation water should be free from heavy metals contamination.

This study was conducted to determine the concentrations of some toxic heavy metals in cattle slaughtered from the three agricultural zones of Nasarawa State, Nigeria. Selected tissues of muscle, intestine, skin, kidney and liver were analyzed for the presence of  Cadmium (Cd), Chromium (Cr), Lead (Pb), Copper (Cu) and Nickel (Ni) using Atomic Absorption Spectrophotometer (AAS). Thirty cattle were used for sampling. Five samples of the tissues were collected from each of the cattle, making a total of one hundred and fifty samples. Values obtained were compared with that of FAO/WHO guidelines. Statistical analysis was done using descriptive statistics, t-test and ANOVA. The mean concentrations (mg/kg) of Ni, Cd, Pb and Cu in all the sampled tissues were generally low and below the codex standards. Cr was detected above permissible limit with mean concentrations (mg/kg) of 1.19±5.94, 1.07±4.42, 3.01±6.65, 1.18±5.56 and 1.35±6.94 in intestine, kidney, liver, muscle and skin respectively. There was a significant (P < 0.05) difference in the level of Ni and Cd across two agricultural zones. Government and private sectors should establish cattle ranch and colonies across Nigeria so  as to reduce pasture contamination. Public enlightenment on the grazing of cattle in heavy metals prone areas such as automobile workshops, construction sites and paint factory premises should be advocated. Measures should be put in place for continuous monitoring of heavy metals in Nasarawa state in order to curtail their potential negative effect in human and animal tissues. Key words: cattle, heavy metals, AAS, Nasarawa state.