COMPARATIVE INFLUENCE OF HARD AND SOFT WATER ON MILK PRODUCTION OF DAIRY COWS 1

Transcription

1 COMPARATIVE INFLUENCE OF HARD AND SOFT WATER ON MILK PRODUCTION OF DAIRY COWS 1 T. H. BLOSSER AND B. K. SONI Depart~wnt o/dairy Science, State College of Washington, P~dl~nan Confirmatory evidence revealed that there were no differences in the performance and feed consumption of 27 lactating cows consuming either hard or soft. Editor. Several reports have appeared in farm magazines claiming that softened by an ion-exchange process was superior to hard for lactating dairy cows. Until recently, no controlled experiments had been reported on this subject. Graf and Holdaway (1), using six pairs of cows in a reversal type of experiment, observed no differences in performance of cows when hard and soft were the experimental variables. The purpose of the experiment reported herein was to determine the value of softened and aerated, as compared with that of hard, for lactating dairy cows. EXPERI!VIENTAL PROCEDURE Initially, 28 cows (16 Holsteins, 8 Jerseys, and 4 Guernseys) were started on the trial. These cows were divided into two comparable groups, based on level of production, body weight, and stage of lactation and gestation. (One Holstein was removed from the trial because of a foreign body in the reticulum ; therefore, data are available for only 27 cows.) This trial was run concurrently with one on dehydrated forage, in which four treatments were involved. A Latin-square design was used in the dehydrated-forage experiment. The experiment was divided into four, 6-wk. periods with a 1-wk. transition between each two experimental periods. During any given 6-wk. period, one-half of the cows were receiving soft and one-half hard. At the end of 6 wk., the treatments were reversed, as they were at the end of the second and third 6-wk. periods. Thus, the soft- trial was a double-reversal type trial. Each cow on experiment was on hard for a total of 12 experimental weeks. Details of the design are indicated (Table 1). Feeding. Individual feeding was practiced throughout the trial. All feeds were weighed. Average-quality chopped alfalfa hay was supplied ad libitum. Grass silage was fed during the first month of the experiment and pea-vine silage during the last 5 mo., at the rate of 3 lb. per 100 lb. of body weight daily. Grain was fed for a given week at the rate of 1 lb. per 3 lb. of 4% fat-corrected milk (FCM) produced during the preceding week. The grain contained in poundages: ground barley, 230, ground cull peas, 200, ground corn, 100, ground oats, Received for publication October 17, Scientific Paper No. 1537, Washington Agricultural Experiment Project Station, Pullman.

2 1520 T. /~I. BLOSSER AND B. K. SONI TABLE 1 Design of experiment Experimental period Group I II III IV ( s ff 1 A B C D (H-S) (S-H) (H-S) (S-H) 2 D A B C (H-S) (S-H) (H-S) (S-H) 3 C D A B (H-S) (S-]~) (H-S) (S-H) 4 B C D A (H-S) (S-H) (H-S) (S-H) A--Control grain ration; B--30% grain replacement with regular dehydrated, pelleted cereal grass; C--30% grain replacement with regular dehydrated, pelleted alfalfa; D--30% grain replacement with regular dehydrated, chopped cereal grass; H--hard, S---soft. 300, linseed meal, 50, wheat mixed feed, 100, steamed bone meal, 10, and iodized salt, 10. Data collected. The cows were weighed on two consecutive days at the end of each experimental week, and on three consecutive days at the beginning and end of each experimental period. Each milking was weighed and nfilk samples were eomposited and tested for percentage butterfat at the end of each experimental week. Feed weigh-backs were made routinely and were chemically analyzed. Results of chemical analyses of the feeds are presented (Table 2). The TDN content of the feeds was calculated by using appropriate digestion coefficients as listed ill Morrison (2), for all except the dehydrated forages. For these materials, TDN was determined in digestion trials with sheep, following methods described by Murdoek et al. (3). Chemical analyses and standard error of the weigh-backs are given (Table 3). There were no grain or dehydrated-alfalfa weigh-backs. The composition of the small amount of silage weigh-backs was much like that of the silage fed, except for dry matter. Appropriate corrections were made for dry matter in calculating the TDN consumed by the cow. The statistical analyses of the data were made essentially as outlined in Snedeeor (4). TABLE 2 Chemical analyses of the feeds ~lsed on an as-fed basis Samples Nitrogenana- Dry Crude Ether Crude free Feed lyzed matter protein extract fiber Ash extract (lvo.) (Vc) Alfalfa hay Grass-legume silage Pea-vine silage Grain mix Grass, dehydrated, pelleted Grass, dehydrated, chopped O O , Alfalfa, dehydrated, ,21 pelleted

3 HARD AND SOFT WATEI~ FOR ~IILK PRODUCTION 1521 TABLE 3 Chemical analyses and standard errors of hay weigh-backs for treatments, as-fed basis Dry Crude Ether Crude The consumed in the experiment was measured by means of an individual taken. The was softened for one-half the cows on experiment by means of The lactation decline for 4% FCM of cows on hard and soft, when fat, milk and FCM produced, total consumed per cow daily, and consumed per cow on hard for the entire experiment was 1.12 lb., as compared with 1.08 lb. per cow on soft. Since, in the process of softening, the composition of is changed, one might expect to find some differences between consumption of cows on hard and on soft. However, data presented (Table 4) show that cows on hard did not differ greatly from cows on soft, in amounts of drunk. Average pounds of consumed per cow daily for the entire experiment were : hard, 102.1; soft, , ~illc and fat-corrected mil~ prod.~wed, fat prod.~ced, t~nd consumed Tree consumed Free consumed/lb 4% FCM produced

4 HARD AND SOFT WATEI~ FOR ~IILK PRODUCTION 1521 TABLE 3 Chemical analyses and standard errors of hay weigh-backs for treatments, as-fed basis Dry Crude Ether Crude The consumed in the experiment was measured by means of an individual taken. The was softened for one-half the cows on experiment by means of The lactation decline for 4% FCM of cows on hard and soft, when fat, milk and FCM produced, total consumed per cow daily, and consumed per cow on hard for the entire experiment was 1.12 lb., as compared with 1.08 lb. per cow on soft. Since, in the process of softening, the composition of is changed, one might expect to find some differences between consumption of cows on hard and on soft. However, data presented (Table 4) show that cows on hard did not differ greatly from cows on soft, in amounts of drunk. Average pounds of consumed per cow daily for the entire experiment were : hard, 102.1; soft, , ~illc and fat-corrected mil~ prod.~wed, fat prod.~ced, t~nd consumed Tree consumed Free consumed/lb 4% FCM produced

5 HARD AND SOFT WATEI~ FOR ~IILK PRODUCTION 1521 TABLE 3 Chemical analyses and standard errors of hay weigh-backs for treatments, as-fed basis Dry Crude Ether Crude The consumed in the experiment was measured by means of an individual taken. The was softened for one-half the cows on experiment by means of The lactation decline for 4% FCM of cows on hard and soft, when fat, milk and FCM produced, total consumed per cow daily, and consumed per cow on hard for the entire experiment was 1.12 lb., as compared with 1.08 lb. per cow on soft. Since, in the process of softening, the composition of is changed, one might expect to find some differences between consumption of cows on hard and on soft. However, data presented (Table 4) show that cows on hard did not differ greatly from cows on soft, in amounts of drunk. Average pounds of consumed per cow daily for the entire experiment were : hard, 102.1; soft, , ~illc and fat-corrected mil~ prod.~wed, fat prod.~ced, t~nd consumed Tree consumed Free consumed/lb 4% FCM produced

6 Dry Crude Ether Crude The consumed in the experiment was measured by means of an individual taken. The was softened for one-half the cows on experiment by means of The lactation decline for 4% FCM of cows on hard and soft, when fat, milk and FCM produced, total consumed per cow daily, and consumed per cow on hard for the entire experiment was 1.12 lb., as compared with 1.08 lb. per cow on soft. Since, in the process of softening, the composition of is changed, one might expect to find some differences between consumption of cows on hard and on soft. However, data presented (Table 4) show that cows on hard did not differ greatly from cows on soft, in amounts of drunk. Average pounds of consumed per cow daily for the entire experiment were : hard, 102.1; soft, , ~illc and fat-corrected mil~ prod.~wed, fat prod.~ced, t~nd consumed Tree consumed Free consumed/lb 4% FCM produced