holstein

Population growth requires extending agriculture and ranching to meet food demand and optimizing water use is necessary for a sustainable agriculture and ranching activities. To water use optimization in livestock production procedure, Amount of water utilized in diet ingredient producing and livestock drinking and servicing water should be noted. This amount of water used to produce livestock production called virtual water of production. The aim of this paper is computing virtual water of Holstein milk production in East Azerbaijan considering three irrigation efficiency 33, 60 and 90 percent. Average virtual water content of wheat, barley, corn, soybean, beet and alfalfa were 1.2, 1.5, 0.13, 3.8, 2.2 and 2.4 cubic meters per a kilogram production by considering 33 percent irrigation efficiency. According to 33 percent of irrigation efficiency the virtual water of milk for after parturition, high yielding, average yielding and low yielding durations were 1.5, 1.4, 2.4 and 3.3 cubic meters per a kilogram production. If percentage of irrigation efficiency increased by 60 and 90, virtual water of milk would decrease 43 and 60 percent respectively.

This research was carried out to investigate the heterogeneity of milk yield variance components in different production levels of holstein cattles. The first lactation milk yield records of 95945 Holstein cattles, which had calved in 651 herds through years 1991 to 2000, were used in this research. Data was collected by the Animal Breeding Center of Iran and adjusted for two-time milking per day. Records were classified into three classes: low (less than 5275 kg), average (5275-6874 kg), and high (more than 6874 kg) based on the level of production. Variance components and genetic parameters were estimated using single and three-trait animal models for each class and three classes with Derivative Free Restricted Maximum Likelihood methods (DF-REML). Bartlett test showed significant differences for variance components between classes. Milk yield heritability was estimated as 0.205, 0.276, and 0.196 for low, average, and high class, respectively, in both single and three-trait analysis. The gentic correlation coefficient between classes ranged from 0.80 to 0.85, Phenotypic correlation coefficients between classes were low and ranged from 0.17 to 0.19. The highest rank correlation coefficient between estimated breeding value by single and three-trait model was obtained in average class. The average changes in the rank of common animals in the top 1% of cows were greather than the top 5% of bulls. Adjustment for heterogeneity of variance components suggested selecting more top cows from herds with high level of production.

To compare the relative value of the fish meal and the cottonseed meal in highly fermentable diets (40% forage and 60% concentrate with), eight cows were assigned randomly to diets with 0, 1.5, 3 and 4.5 percent of the fish meal. In the first experiment, the degradability of dry matter and crude protein of the fish meal, the cottonseed meal and concentrate in diets was estimated with different incubation times (0, 4, 8, 12 and 24 h) with fistulated Ghezel sheep fed at maintenance level. The effective degradability of dry matter and the crude protein of fish meal was significantly lower than cottonseed meal (p<0.05). In different concentrates, there was no significant difference in effective degradability of dry matter but with the increase of fish meal the effective degradability of crude protein decreased significantly. In the second experiment, the eight multiparous Holstein cows with the similar milk production (25.37 ± 0.85) were examined in a replicated 4 × 4 Latin square design with the 21-day period. There were no significant differences between the treatments in digestibility of OM, OM and CP, the dry matter intake, 3.2 % FCM, milk fat (%), milk lactose (%), milk total solid (%), and the yield of the milk fat, feed efficiency and body weights. Diets containing fish meal, compared to the control group, significantly higher milk production, milk protein (%), the yield of milk protein and lactose (p < 0.1), but the different levels of fish meal had no significant effect on these factors. The urea pH decreased significantly with the increase of the fish meal but rumen pH and fecal pH were unaffected. The results of the experiment indicated that diets with the 1.5 or 3% fish meal in cows with less than 30 kg milk is recommended.