Three experiments were designed to test the hypothesis that zinc has a specific effect independent of anorexia during induction of molt. In Experiment 1, hens were fed a low-calcium (.08%) basal molt diet to which was added 0, 110, 620, or 1,120 mg/kg (ppm) zinc as zinc sulfate heptahydrate (ZnSO4.7H2O) for 7 days and 0, 1, 400, 2,800, or 4,200 ppm zinc, respectively, for the following 14 days. In Experiment 2, hens were provided ad libitum access to the low-calcium basal molt diet with 2,800 ppm added zinc for 14 days during which a paired control hen received a similar amount of the low-calcium basal molt diet. In Experiment 3, hens were fed the low-calcium basal molt diet on a restricted basis amended with either 0 or 2,800 ppm zinc on a restricted basis for 10 days. In Experiment 1, all hens that consumed zinc had significantly fewer days to last oviposition as compared with control hens, and this occurred without significant differences in body weight or feed consumption for the lowest zinc group. When compared with the control group, higher levels of zinc did decrease body weight and feed consumption. In Experiment 2, the hens consuming the diet with 2,800 ppm zinc (Zn2800) reached last oviposition significantly sooner than control hens, although the Zn2800 hens actually consumed more feed. In Experiment 3, the Zn2800 hens lost more body weight than control hens due partially to earlier reproductive tract regression. Serum luteinizing hormone was increased in the Zn2800 hens.(ABSTRACT TRUNCATED AT 250 WORDS)

Halofuginone (HAL) and monensin (MON) were effective in controlling coccidiosis in turkey poults when included in the feed at concentrations of 2 and 66 ppm respectively. At 10 and 14 weeks of age, body weight and feed intake were greater in poults given HAL with bambermycins (BAM) than in poults given HAL or MON with bacitracin methylene disalicylate (BAC). Poults given two anticoccidial drugs (MON followed by HAL or HAL followed by MON) weighed more and had a lower feed conversion than poults that received no medication, but no difference was found in the performance of turkeys given one or two anticoccidial drugs. There were no differences in performance whether HAL was used before or after the use of MON. None of the drugs completely suppressed oocyst production. At 11 weeks of age, an increase in the number of oocysts in the droppings was noted following drug withdrawal, but no increase was observed in the number of oocysts in the litter. There was no indication of clinical coccidiosis after drug withdrawal.

The effect of early protein restriction on poult performance and mortality due to spontaneous turkey cardiomyopathy were examined in a facility that historically had a high incidence of the condition. Two thousand male turkey poults were divided into two equal subgroups for the first 4 weeks of life: one received standard commercial rations for the first 4 weeks (high-protein subgroup), and the other received rations with a protein content approximately 70% of the first subgroup (low-protein subgroup). Rations were the same after 4 weeks of age (standard commercial rations). At 16 weeks of age, turkeys in the low-protein subgroup weighed an average of 12.32 kilograms (27.1 pounds), whereas turkeys in the high-protein subgroup weighed an average of 12.73 kilograms (28.0 pounds). Total mortality for the low-protein subgroup was 10.1%, whereas total mortality for the high-protein subgroup was 15.7%. Total mortality due to spontaneous turkey cardiomyopathy in the high-protein subgroup was greater than twice that in the low-protein subgroup (10.4% versus 4.6%). These results show that lowering the protein content of the feed in the first 4 weeks significantly reduces mortality due to spontaneous turkey cardiomyopathy, but body weight gain is also reduced.

The duodenal loop was excised from hens that had been induced to molt by a low-calcium diet containing 2,800 ppm zinc in the form of zinc sulfate heptahydrate. This was compared to that of hens pair-fed a layer diet. In Experiment 1, hens exhibited an increased duodenum weight after receiving the zinc diet for 14 days but no differences remained 14 days later. In Experiment 2, increased duodenum weight was noted after 4 days on the zinc diet and this persisted through 10 days. This greater tissue weight was observed whether expressed on a wet or dry weight basis. Thus, there was a persistency of tissue mass. The duodenum does not regress during a zinc-induced molt as it does during a fast-induced molt.