The effect of alfalfa hay substitution with Kochia on milk production and composition, nutrient digestibility and rumen fermentation characteristic of Saanen dairy goats

(Kafi et al. 2010). The weather characteristics of these areas are hot and dry with scarcity of water resources. This crop can produce acceptable forage with much lower water requirement in comparison with the traditional forage crop such as alfalfa. In these areas this forage crop can be fed to ruminant animals instead of alfalfa hay. Therefore, this study was aimed to measure the feeding value of Kochia forage in both forms of dry or ensiled and utilize it instead of alfalfa hay in feeding of Saanen dairy goats. The Kochia forage was harvested from a farm in Mashkan area of Sabzevar city, lokated in west of Khorasan Razavi province of Iran. The harvested Kochia forage was dried under sun light or ensiled with or without 10% waste date in the ground silos for 60 days. In this experiment, 24 lactating dairy goats with average age and live weight of 3 years and 38.4 kg were allocated to 4 experimental diets baed on a completely randomized design. Each dietary treatment was replicated 6 time (6 goats alocated to each diet). Ratio of forage to concentrate part was 50:50 in dry basis. The experimental dietary treatments were as follows: 1) the control or traditional diet including concentrate (50%) plus alfalfa hay (50%) without Kochia, 2) diet with kochia hay instead of alfalfa hay (100% of the alfalfa hay was substituted with the Kochia hay) 3) diet with kochia silage instead of alfalfa hay (100% of the alfalfa hay was substituted with the Kochia silage) and 4) diet with kochia silage supplemented with 10% wasted date (100% of the alfalfa hay was substituted with Kochia silage). The goats were adapted to the experimental diets for 14 days and then, fed with the whole experimental diets for 6 weeks. Goats were milked daily at 6 and 18 hours with a portable milking machine. Diets, ruminal fluid, the produced milk, and blood of the experimental goats were sampled and analyzed according to the standard procedures (AOAC 2000). The experimental diets had no effects on dry matter intake which allocated to goats. The goat fed by the diet including kochia silage supplemented with 10% wasted date produced more milk (P<0.05) in comparison with the goats allocated to other experimental diets, but there were no difference in milk constituents. Dry matter, organic matter, crude protein and neutral detergent fiber digestibilities were not significantly (P>0.05) different among the experimental diets. Total amounts of VFAs measured for the diets 1, 2, 3, and 4 were 71.87, 73.62, 72.75 and 74.95 milimol per liter, respectively. The concentration of propionic acid was highest in kochia silage supplemented with 10% wasted date. Mean value (percentage) of this acid (propionic) for the experimental diets were 20.23, 20.48, 21.05, and 21.65, respectively. Ratio of acetic acid to propionic acid for the repective diets were 3.07, 3.01, 2.91, and 2.83 respectively. The expermential diets had no effects on other ruminal fermentation as well as blood biochemical parameters. Ruminal pH of the goats allocated to experimental diets 1, 2, 3 and 4 were; 6.15, 6.13, 6.12, and 5.99, respectively. There were also no significant (P>0.05) difference between these factors as well. Ruminal NH3-N obtained from the allocated goats to diets 1, 2, 3, and 4 were 16.17, 16.19, 16.85,
and 17.01 (mg/dl), respectively. The measured amounts of boold golucose were within the normal levels for this type of animal (57.60, 60.83, 62.75, and 62.90 mg/dl for diets, 1, 2, 3 and 4, respectively). Water shortage and low rainfall are the top characteristics of Iranian agriculture industry. This environmental scenario must be regarded in any developmental project mainly for forage production as animal feeds. Feeding value and performance of the Kochia forage mainly in the form of supplemented silage with waste dates were comparable to the the locally produced alfalfa hay in this study. Therefore, this resistant forage crop to water sacrcity can be well cultivated instead of alfala forge which needs abadant amount of fresh water. Conservation of this crop in form of supplented forage with a golucogenic feed waste such as wast dates leads to a better result and performance. However, more studies are required for the implenentation of this recommendation. Unfortunatly the most of Iranian farmers are not well acostomized to croping this forage crop. It means more extentional works are needed along with the research activities.