Records of milk yield, fat percent, body weight, reproduction and health of 506 calvings of 362 cows were used for estimating the efficiency of utilization of tropical grass pastures by lactating cows fed on grazing alone or grazing with various types of supplement. There were seven feeding systems: grazing alone (T1); grazing plus supplement with ground maize (T2); with molasses (T3); with concentrate (T5); or with urea-molasses (T6), at the rate of 1.0 kg per 2.0 kg milk in excess of 10 kg of milk per day and of 2.5 cows per ha; or grazing plus concentrate feeding of 1.0 kg per 2.0 kg milk irrespective of milk yield at a stocking rate either of 2.5 cows (T4) or 5-0 cows (T7) per ha. All supplement systems had significantly higher yields of milk, fat and fat-corrected milk than grazing alone. Level of fat percent paralleled dependence on intake of forage. Supplement also extended days in milk. System of feeding was significant for body weight gain, time to reach peak milk yield, the level of peak yield, persistency of milk yield, days open, time from first breeding to conception, and calving interval. High levels of supplement (T4, T7) increased weight gains, time to reach peak yield, and persistency, but lowered breeding efficiency. On medium levels (T3, T5, T6), the efficiency (Meal/kg dry matter) of utilization of supplement for milk production was satisfactory, but unsatisfactory on high supplement levels (T4, T7). Supplements as high or higher than those in the grass treatments supplemented with non-protein nitrogen (urea-molasses) or crude protein (concentrate) gave a more efficient utilization than either maize or molasses. During the first 150 days of lactation, cows on grazing alone averaged 14.3 kg pasture grass dry matter intake per day, or 2.9% of body weight. Cows on low supplement (T2, T3, T5, T6) averaged 24 to 29% less; and cows on high supplement, nearly 60% less intake. Type of supplement had little influence on pasture grass dry matter (PGDM) intake. When the genetic potential for milk yield of cows exceeds 3,000 kg, supplementary feeding appears economically feasible. Even under the high levels of nitrogen fertilization employed, there was a rise in average milk yield with intakes of protein from the supplementary feed. Supplementary feeding with tropical grass pastures caused a high rate of substitution; hence, the efficiency of use of PGDM is lowered unless stocking rate is carefully adjusted.

No abstract

In two experiments, each employing 200 hybrid chicks, dried stillage levels of 0, 10, 20 and 30% were compared in rations based mainly on ground maize, soybean meal and fishmeal, and theoretically equicaloric and isonitrogenous. In experiment 1, chicks were fed starter rations (20.3-21.9% CP) from 1 day until 4 weeks of age, and then grower rations (15.7-16.6% CP) until marketing age at 9 weeks. The chicks spent the first 2 weeks in a battery brooder and thereafter were in pens of 20 each on a bedded floor. Mean final liveweights for the respective rations were 2446, 2341, 1614 and 1223 g, with 10% stillage not significantly different, but the 20% and 30% stillage treatments inferior to the control (P <.01). Twenty-two chicks died, mostly during the first 2 weeks, but apparently not because of the experimental rations. The respective feed efficiencies (liveweight gain/feed intake) over the 9 weeks of test were .46, .47, .34 and .29. A saving of other feed inputs was achieved without loss of efficiency by using 10% stillage, whereas the higher levels were inefficient. In experiment 2 all the chicks were raised to 5 weeks of age on a ration without stillage. The same grower rations as in experiment 1 were fed from 5 to 9 weeks. Mean finalliveweights were 2106, 2098, 1968 abd 1628 g, with the same significant differences among treatments as previously. The feed efficiencies during the 4 weeks of test were .41, .38, .37 and .25, with only the 30% stillage inferior to the control (P <.01). The saving of other feed due to the use of stillage was less at the 10% level but more at the 20% than in experiment 1. In neither experiment did the inclusion of stillage make the rations unacceptable to the chicks. There was a direct relation between stillage level and daily feed intake as a percentage of liveweight. Sanitary conditions worsened due to black and watery excreta at successive stillage levels. Ten percent dried stillage, or possibly slightly higher in the final stages of growth, could be used in broiler rations as one non-polluting method of stillage disposal with only a minimal reduction in animal productivity.

Different levels of coconut meal in laying diets were compared in three studies using intensity of lay and feed conversion as criteria for comparison. In all studies the production and efficiency of feed utilization decreased as the level of coconut meal was increased in the diet. The best results were obtained when the level of coconut meal did not surpass approximately 20% of the diet. The practical level of coconut meal up to approximately 20% of the diet will be determined by its relative net cost.

Twenty-four grade Holstein cows, which averaged not less than 30 pounds of milk daily during a 30-day preliminary period were subjected to either of two treatments: 1, The control treatment which consisted of grazing properly managed Pangolagrass supplemented with a commercial 20-percent crude protein concentrate mixture; and 2, the experimental treatment which consisted of confining the cows and feeding them ad libitum a 15.3-percent crude protein complete ration containing 22.5- percent ground sugarcane bagasse and 77.5 percent concentrates, minerals, and vitamin supplement. The average milk production of the control and experimental cows was 42.9 and 40.1 pounds, respectively, during the preliminary period. During the comparison period the corresponding figures were 43.8 and 42.0 pounds for the first 30 days (peak lactation), 35.3 and 31.6 pounds for the remaining 175 days (declining lactation), and 36.5 and 33.1 pounds for the entire 205 days. None of these differences between treatments was significant using covariance adjustment for milk production during the preliminary period. The experimental cows consumed an average of 36.1 pounds of complete ration daily and required 1.09 pounds of feed per pound of milk produced. The average protein content of the milk produced by the experimental cows during the comparison period was significantly (P < .01) higher than that of the control cows (3.55 vs. 3.18 g./100 ml.). The average milk-fat percentages were 3.07 and 3.28, and the average milk solids-not-fat percentages were 8.33 and 8.34 under the control and experimental treatments, respectively. The control and experimental cows gained live weight at the average rates of 0.52 and 0.56 pound per day, respectively. Based on costs of $3.58 and $4.41 per 100 pounds for the complete ration and commercial concentrate, respectively, $0.34 per head per grazing day, and $7.80 income per 100 pounds of milk produced, the following economic estimates were made under the control and experimental treatments, respectively: Total daily feed costs per cow, $1.16 and $1.29; gross income from milk produced, $2.85 and $2.58; income from milk above feed costs, $1.69 and $1.29; and feed costs per 100 pounds of milk produced, $3.18 and $3.90. With respect to the productive responses, no evidence was found contrary to the null-hypothesis that the treatment under evaluation was not better than the control. The mean figures for economic return were in favor of the control treatment, though no tests of statistical significance could be made with the data available. The results emphasize the indispensability of obtaining high average milk production (at least 40 pounds per cow daily) in order to make the complete ration economically competitive.