ONITEBSITY OF CALIFORNIA PUBLICATIONS COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA INVESTIGATIONS WITH MILKING MACHINES BY F. W. WOLL BULLETIN No. 311 September, 1919 UNIVERSITY OF CALIFORNIA PRESS BERKELEY 1919 EXPERIMENT STATION STAFF Heads of Divisions Thomas Forsyth Hunt, Dean. Edward J. Wickson, Horticulture (Emeritus). Walter Mulford, Forestry, Director of Resident Instruction. Herbert J. Webber, Director Agricultural Experiment Station. B. H. Crocheron, Director of Agricultural Extension. Hubert E. Van Norman, Vice-Director; Dairy Management. James T. Barrett, Acting Director of Citrus Experiment Station; Plant Pathology. William A. Setchell, Botany. Myer E. Jaffa, Nutrition. Charles W. Woodworth, Entomology. Ralph E. Smith, Plant Pathology. J. Eliot Coit, Citriculture. John W. Gilmore, Agronomy. Charles F. Shaw, Soil Technology. John W. Gregg, Landscape Gardening and Floriculture. Frederic T. Bioletti, Viticulture and Enology. Warren T. Clarke, Agricultural Extension. John S. Burd, Agricultural Chemistry. Charles B. Lipman, Soil Chemistry and Bacteriology. Clarence M. Haring, Veterinary Science and Bacteriology. Ernest B. Babcock, Genetics. Gordon H. True, Animal Husbandry. Fritz W. Woll, Animal Nutrition. W. P. Kelley, Agricultural Chemistry. H. J. Quayle, Entomology. Elwood Mead, Rural Institutions. H. S. Reed, Plant Physiology. J. C. Whitten, Pomology. Frank Adams, Irrigation Investigations. C. L. Roadhouse, Dairy Industry. F. L. Griffin, Agricultural Education. John E. Dougherty, Poultry Husbandry. S. S. Rogers, Olericulture. L. J. Fletcher, Agricultural Engineering. Edwin C. Voorhies, Assistant to the Dean. Division of Animal Husbandry G. H. True F. W. Woll J. I. Thompson J. F. Wilson C. V. Castle P. I. Dougherty G. H. Wilson INVESTIGATIONS WITH MILKING MACHINES F. W. WOLL Milking machines have now been successfully operated in dairy herds in different parts of the country for more than a quarter of a century, and in many dairies several generations of cows have been milked by machines during this period. Owing to the difficulty of securing efficient and reliable milkers in recent years, especially while war conditions prevailed, machine milking has been adopted in a rapidly increasing number of American dairies during this period, and there are now perhaps few dairy sections in the country where milking machines have not been installed and are operated successfully. Practical experience with milking machines and numerous investiga- tions of the work of different makes of machines conducted by experi- ment stations during the last decade or two have fully established the practicability and the economy of modern milking machines by this time; as a result, there is at present a constant and, in many sections, a rather rapid transition from hand to machine milking in American dairy herds. This transition is retarded in some cases by a doubt in the minds of dairy farmers, perhaps especially by owners of valuable pure-bred herds, as to whether the cows will do quite as well when milked by machine as by hand, and whether machine milking will not necessarily have a tendency, at least in the case of some cows, to reduce their milk production for entire lactation periods as compared with hand milking, even if this would not be sufficiently marked to interfere ap- preciably with their future usefulness as dairy producers. Failures of certain milking machines in the case of individual herds, and the fact that conditions and results obtained in other sections are not known, doubtless account for this questioning by some dairy farmers of the practical value of milking machines. The investigations of milking machines in the University dairy herd reported in this bulletin were commenced in the spring of 1915 with a special view to ascertaining the effect of long periods of machine milking on the dairy production of cows. The plan of the investigations especially aimed at furnishing definite evidence on the question of whether or not machine milking involves any risk in regard to the con- tinued efficiency of dairy cows, and the results should be of special 32 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION interest and value to dairymen who may be more or less in doubt with regard to this point. It is believed that the results herewith presented will also be of value to other dairy farmers who have not as yet seriously considered the matter of installing milking machines in their herds, and will clear up various points in connection with the operation of the machines, concerning which there may be a question. At the time this investigation was commenced there were at least three different makes of milking machines on the market in this country that had been found to do satisfactory work when operated in accor- dance with the direction of manufacturers, and that had been more or less thoroughly investigated by American experiment stations. Con- siderable literature on the subject of milking machines had been pub- lished by these stations which, generally speaking, furnished conclusive evidence as to the value of this method of milking. During the last three years the number of different milking machines placed on the market, and the published reports of investigations of these have been further increased (see partial bibliography, pp. 54) ; frequent discussions on the subject of machine milking in our agricultural and dairy press have likewise greatly enlarged our knowledge of different types of milk- ing machines and of their practicability under present conditions of dairying. Two different makes of machines were employed in this investiga- tion, viz., the " Calf- Way" Milker, during the first three years, and the Empire Milking Machine for the past year, operated either alone or along with the " Calf- Way " Milker. The latter machine is an improved type of the Hazelwood milking machine, which was manufactured by a Spokane, Washington, firm and introduced in a number of western dairy herds about a dozen years ago.* The direct occasion for taking up this study was the fact that no report on the character of the work done with the " Calf- Way" Milker had been published at the time. Gradually, however, the investigation was broadened so as to cover the scope stated above. At first one string of cows in the University dairy herd was milked by machine and the balance by hand, but during the last year and a half nearly all milch cows in the herd were milked by machine throughout the lactation period. *The state agents, with addresses, of these two and other milking machines at present on the market in this state are as follows: Burrell (B-L-K); Baker, Hamilton & Pacific Co., San Francisco. " Calf-Way"; Calf- Way Milker Co., San Francisco. De Laval; De Laval Dairy Supply Co., San Francisco. Empire; J. N. Blair & Co., Sacramento. Hinman, C. F. Daniells, Hughson, Cal. Perfection, H. F. Lingg Co., 1901 Grant Street, Berkeley. Sharpies; The Sharpies Separator Co., San Francisco. Universal; California Hydraulic Engineering Co., San Francisco. INVESTIGATIONS WITH MILKING MACHINES 33 The general plan of the experiments was to continue the cows on the milking machine for one or more complete lactation periods so as to secure accurate data as regards the total milk production and the rate of decrease, if any, in the milk flow during the lactation that may result from machine milking. Data concerning the immediate effect of changes in the method of milking practiced, from hand to machine and vice versa, were also obtained. The milk from each milk- ing for the individual cows was weighed and sampled separately, com- posite samples for each cow being tested regularly once a week for con- tent of solids and butter fat; bacteriological examinations of the milk from individual cows were also made from time to time to determine to what extent milk drawn by machine comes up to modern sanitary standards. During the progress of this investigation a total of 78 cows were machine-milked for periods ranging from a few weeks to three complete lactation periods. The cows included 34 grades (mostly grade Hol- steins), and the following number of pure-breds: 20 Holsteins, 12 Jerseys, 10 Guernseys and 2 Ayrshires. The method of milking adopted for a given period in case of individual cows was at times necessarily deter- mined by other considerations than those coming within the plan of this investigation; with pure-bred cows especially by the chances of their making creditable yearly records; but in the main the original plan was adhered to insofar as cows were generally milked by machine for one or more complete lactation periods. In comparing the results obtained by machine milking with those obtained by hand milking for the cows included in the investigation, data showing the immediate effect of a change from hand to machine milking, and vice versa, will be presented, followed by data for entire lactation periods. Immediate Effect of a Change in the Method of Milking The immediate effect of the method of milking practiced may be traced from the results for the production of milk and butterfat for two weeks prior to and following the period of machine and hand milking, respectively, as shown in Table I. Periods close to the beginning or to the end of a lactation period, when the milk production was either not yet up to normal or was abnormally low because of the cow being dried up, were excluded from the compilations. 34 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION o Ph fe 1—1 a r-J M 3 H s a ^ o OOOOiOOOOWQOMCOOiOOHCOffiffl^ rH Pn OOCOlNOINCDHiOroNCSOOOOONaKNOiHNOO^NOaiiOMINCONN rH 05(M»OC0Hf00000(NHMMOOtDN01iO00ai»COCiH0>C0OFH00WlM'O +» C^©OCOCOCOTt^©TH©^c0^rHCOCOCOCiCNt^C^l>l>^^ r-4 c4 pt< 0"Ol>(Nt^l>OC005i-ii>.05l>OOT-iC5(NiOOOOOCOCOt^OOcOt^GO>OCOOO>0<30 OS rH i— IHi- 1 i—\ r-i i— I i— I CN r- IHr- 1 i— I r- I i— 1 i— I T— I r- 1 l— IH rH>~i TtiO(X)tOT^Ttir^t^i^Oi(X)i>ooi>coT^cocDoo^cic^^OiTticooo»o^ "-C CO "* CO CM CO CM CO (M CO ■* i-i CO »C i-t (M GO +»OOOOOOcOM»>0 00«OOOOH>OiONN»OOOOiOOiO>0000>iON!-N o3 TtHCO'*cOO^t l I>»0001>.COi— ir-H T -©Tt , rtHiOO(X)COCOTtiCOC^050c01>OCOcOCOi^t^(X)^i-ii-iTjH050<|Oo ^ TP©COrt<©©©©©THiOiOr^l>l>00TfriT*rHCOl>00a)LO©l>COCO^uOC005OTCOi-iC^OOOt^COCOC01>OOCOCO>000'*Ci>GO r- £3 HHHN'^(N03tOirOOON'^05iOiMiHCO(N(NCOON(NHOOH(NiOCON05 CO SNHCOiO^GOMO^iOOOJOOlOONCON^iCNOOO^CDMNr-i^OCN ^^CO^^i-li-lC^i-lC^COC^COCOCOOO^C^^COC^COC^COl(^ ■piCOOiOOiCOH^cOOiCiOHNiON^iOHOlNHNiOO^OaiONN o3cOI>O^OOC^CO(^C^^COTtHCOCco^OrHcooi^i-HCO<^cqcoo5oocooiOc^^ooi>oorHcoi-ii^O(Nc^(»crico^c^coo>0(Nooi>ioco COCOCOO^tHC^(^^rHi01^C^OOO^COt^iOTftCOOOCNJl>01^COCX)iOiOrHl>0 COM^^hhnh{OMN^CONOO«5(N»ON(NMW^INCO^h^iON(N^ CO a s * s h rl_» o oq3 co >h3 at •d d d CD CD bfi bfi a a t-t >> rd CO m * 2 cu CD CD H {> _ co d g.S ^ *H CD CO fl d c3 °? b S co rH^ *K rd <*r* i2 co O c3 .3 o 5r! *-• CD o Ph cd rH ^ CO cd bfi | 8 CU d -r3 O CQ CO rH CO Q H INVESTIGATIONS WITH MILKING MACHINES 35 m H M 03 m -1 1 § C h H O 5 a U fa o § h w u y in - in W rfi "5 00(ONffiON05THHiOcDi0iO0iN00^O50H £ ©NCD©^OONOOOH(N(005iOHCOH(X)^0 OOMOHCOHCCOO 05H05CDUJN00O^ M©^NCOcOCOWWiONiOfO(NOMm»ONO O^O5i0N00OOi05He0»0^OON(N05>QTt* NNiOMMmCOOONCOCO^OJNlMNHOiCo© lOOOiOfllNNfOCONCOMOO^aiNOOOto CO i— I (M H H CO i— I H ^ —l NOJiO^^^iOLOcOHO^INOOiOOCOlM CO^iOOOawiMCOOOOieoNiO^OClNOO N'O^'^W'^iOM'^NCOWCO'OM^Tji^si. + oo os o CO^HiOOCOOOOOCOCOtOCONiOOj NOOMOCO^^OOOOH^OOIHNH lOOO^^iOCOiOCOiOcOOi^MCOOliO^iONOO NtOINOlHCOcO'O'OO^tONNCOOfflOlOoOl COMOCOCDNOOOOHOM N^OOO^iOffiOOO(NiO^ COHNHH CO t-I CN l-H T^ 00 »0 i— i O i-H O Oo CO l—l 1— I 1— I -i-h I T -£ H^ooiOO^COONiCiOiO^©0»C^iMif5 g Oi-HOCOi-H^i-HtMf-OfMtMOi^t^-sHCiO'^ (OtOOOCOOHNHiNiOHiOHHNtOO)©Oo T-tOOiiOOfMt^^fi— iCOi-tTjH^OT-H(MOO^- 000'*M^©iOiMGOOO'OMCOM©CONOo ^ ©HOOMCOOOOOOCOOCOOiOCOlNNtONN a t^ i-h oo i-H i-i ci § 00 lO O rH CO CO CO H CO H H HH^^COCD^OO^O\+ COO5NO5N00CDCO^lC!THCS COrH(Ni-l^ CO ^H t— I i— I <3s> o3 o3 ^ 5h ^ TO O OS 52; £ 5 o3 cu ^p^pL,p^^fepq^W £ fl 02 fl T5 CD O O 00 e CO CD & CO o3 |tt" S -^ £_ S v„ 'V ^ SL ^ZZ*- - % K *$-*-& - ^ S Z% ^ *!?>&,- ^ ^ s n2S^ CO ^N^S- ^g ^-^Sw c s ^ *^Sfc _% ^s- -$"2- ^ 20 : ^3fe^ s ^< ^S^Sri^ S S *^2p N. ^^ V l*\£- ""^^ics** _. : v si >5 "^^2^2-2^& w ^ S S2 PB'^2 1 ! y^^^-* --*tz%& &tir^r- ^S^J^Eaiafc**-, ^SSSZS&g*,^ - --=^-^£^^^5|-Sl^ ^^=2 = =.^ iS __^= a ^ s= __ ir __ "—■——. ZLijL _ '5 6 7 FOUR-WEEK PERIODS Fig. 1 *Wis. Station Bulletin 102 and Research Bulletin 26; Geneva (New York) Station Report 1886, p. 21; Kentucky Station Bulletin 106; California Station Bulletin 301. INVESTIGATIONS WITH MILKING MACHINES 39 Complete data bearing on this point are available for about fifty cows in the university dairy herd, for machine and hand milking, respec- tively. The following summary tables show the average daily yields of milk and butter-fat for successive periods of four weeks each, for all cows that gave milk during ten and eleven 4-week periods. Data for the latter cows are included in the second part of the table. The percentage decrease in production by the two groups for successive months are also given. Table III. — Percentage Decrease in Production During Lactation Period for 4- Week Periods Ave. daily Ave. daily mi Ik Decrease butterfat Decrease yield , lbs. in per cent. yield , lbs. in per cent. Mach. Hand Mach. Hand Mach. Hand Mach. Hand No. of cows included 54 52 54 52 1st 4-week period 31.9 34.7 1.17 1.42 2nd 4-week period 29.2 33.7 8 3 1.05 1.34 10 6 3rd 4-week period 26.5 31.3 9 7 .97 1.25 8 7 4th 4-week period 23.9 28.7 10 8 .90 1.16 7 7 5th 4-week period 22.5 26.6 6 7 .84 1.08 7 7 6th 4-week period 20.8 24.7 8 7 .79 1.01 6 6 7th 4-week period 19.4 22.8 7 8 .74 .93 6 8 8th 4-week period 17.8 20.4 8 11 .70 .85 5 9 9th 4-week period 16.1 18.2 10 11 .64 .76 9 11 10th 4-week period 14.1 15.3 11 16 .57 .66 11 14 Difference, l-5th mo. 29.5 23.3 28.2 23.9 l-10th mo 54.9 55.9 48.7 53.5 No. of cows included 43 41 43 41 1st 4-week period 31.3 35.9 1.18 1.46 2nd 4-week period 29.0 35.2 7 2 1.05 1.39 11 5 3rd 4-week period 26.4 32.4 9 8 .98 1.28 7 8 4th 4-week period 24.1 29.8 9 8 .91 1.19 7 7 5th 4-week period 23.0 27.4 5 8 .86 1.11 5 7 6th 4-week period 21.3 25.0 7 9 .81 1.04 6 6 7th 4-week period 19.8 23.6 7 6 .76 .95 6 9 8th 4-week period 18.0 21.2 9 10 .71 .88 7 7 9th 4-week period 16.4 19.2 9 9 .66 .80 7 9 10th 4-week period 15.0 16.5 9 14 .60 .71 9 11 11th 4-week period 12.7 13.7 15 17 .52 .61 13 15 Difference, l-5th mo. 26.5 23.7 27.1 24.0 1-1 1th mo. 59.4 61.8 55.9 58.2 The data for the percentage decrease in production presented in Table III suggest that the production of both milk and butter fat by the machine-milked cows decreased, on the average, somewhat more rapidly than that of the hand-milked cows during the early months of the lactation period, and that it was somewhat lower during the latter part of the same. Between the first and the fifth monthly period the 40 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION milk production went down 29.5% for the machine-milked cows that gave milk during ten complete 4-week periods, against 23 . 3% for the corresponding hand-milked group ; the decrease in production of butter fat for this period was 28 . 2% for the machine-milked cows against 23.9% for the hand-milked cows. On the other hand, if the yields during the first and the tenth monthly periods be compared, it will be seen that the machine-milked cows decreased on the average 54.9% in milk and 48.7% in butter fat, against 55.9% and 53.5%, respectively, for the hand-milked cows. Results agreeing closely with these were obtained for the cows in milk for eleven complete 4-week periods. It will be noted that the average daily yields of milk and butter-fat for hand milking given in the table are always somewhat higher than those for machine milking, the reason being that, when milked by hand, the cows were in many cases fed more liberal rations, and therefore produced more heavily than when machine milked, as will be seen presently. Data for the same cows were included in both groups in many cases, but the two groups were not composed of the same cows; all available records obtained on machine milking were included in the compilations given in Tables III and IV and a similar number of records for hand-milked cows in the herd were selected at random for comparison from the herd records. The average quality of the milk produced by the two groups of cows will be seen from Table IV. Table IV. — Average Per Cent, of Fat in Milk During Successive Periods Machine No. of cows included 54 1st 4-week period 3.67 2nd 4-week period 3 . 60 3rd 4-week period 3.66 4th 4-week period 3.77 5th 4-week period 3.73 6th 4-week period 3.80 7th 4-week period 3.81 8th 4-week period 3.93 9th 4-week period 3.98 10th 4-week period 3.96 11th 4-week period 1-5 increase in % of fat +.06 —.03 1-10 increase in % of fat +.29 +.22 1-5 increase in % of fat —.03 —.02 1-11 increase in % of fat +.32 +.31 Hand Machine Hand 52 43 41 4.09 3.77 4.07 3.98 3.62 3.98 3.99 3.71 3.95 4.04 3.78 3.99 4.06 3.74 4.05 4.09 3.80 4.06 4.08 3.84 4.03 4.17 3.94 4.15 4.18 4.03 4.17 4.31 4.00 4.31 4.09 4.38 INVESTIGATIONS WITH MILKING MACHINES 41 It will be noted from Table IV that the changes in the average quality of milk during the progress of lactation periods are fully normal and quite similar in the case of both machine and hand-milked cows; they are apparently independent of the special method of milking prac- tised (see figs. 1 and 2). 4.5 4.0 3.5 /\ Ig. 4 j jf[ i— A'ilwu} = ^ c #- -.5 7 n _ fric'iLie -)titki% 5 FOUR- Fig. 6 7 WEEK PERIODS 2 It is of interest to compare the results given in Table III for the rate of decrease in production with the progress of the lactation period with similar data obtained in dairy herds in this and other states. We select as typical the average data secured for cows entered in the Cali- fornia State Dairy Cow Competition and similar findings for cows in the dairy herd of the Wisconsin Experiment Station, and in pure-bred herds owned by Wisconsin farmers.* Table V shows the results secured in these investigations. The figures for the average decrease in pro- duction of milk and butter fat during successive 4-week periods of the lactation for the herds included in these investigations have been cal- culated and are given in the last two columns of the table. Table V. — Average Decrease in Production During Progress of Lactation Period Cal. Dairy Cow Comp'tion Milk Ave. yield 1st mo., lbs 46.4 Decrease in per cent.: 2nd 4 weeks + 1 3rd 4 weeks 9 4th 4 weeks 7 5th 4 weeks 7 6th 4 weeks 7 7th 4 weeks 9 8th 4 weeks 11 9th 4 weeks 9 10th 4 weeks 11 Total decrease, l-5th mo 20.7 l-10thmo 51.1 Butter- fat 1.95 + 1 9 5 6 6 7 9 8 11 16.9 45.1 Wisconsin Station Herds Milk 31.0 6 7 8 5 4 7 10 11 24.2 54.5 Butter- fat 1.34 10 8 7 5 2 8 6 6 26.9 50.8 Wisconsin Dairy Herds Milk 43.9 5 7 6 5 5 6 10 13 20 21.2 56.3 Butter- fat 1.76 7 5 5 5 5 9 11 15 21.0 50.6 Averages Milk 7 6 5 7 10 11 16 22.0 54.0 Butter- fat 13 21. 48. *Cal. Station Bulletin 301 letin 26. Wisconsin Station Bulletin 102 and Research Bui- 42 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION The figures given in Table V were in practically all cases obtained by hand milking and are therefore directly comparable to the results previously given that were obtained by this method of milking with cows in the university dairy herd. In the majority of cases they were obtained with pure-bred cows and represent the best modern dairy practice as adopted by leading dairymen. Comparing the average data given in the last two columns of the table with the results presented in Table III, it will be seen that the latter figures for the decrease in production with advancing lactation, as well as between the first and the last period of the lactation periods, were in most cases slightly higher than the former, in the case of both methods of milking. This is only what might be expected from the conditions under which the milking was done, in the case of the investigations quoted in Table V, and in our own milking-machine trials. As above suggested, careful milking was doubtless, as a rule, practised in most of the former herds, the cows being milked by the owners themselves or by interested help who fully appreciated the importance of their work for the development of ex- cellent dairy qualities in cattle, and for the maintenance of a large dairy production. On the other hand, the milking in the university dairy herd was, as a rule, done by help similar to that available in other dairy districts in the state, — a class of men who are frequently none too interested in their work and who in the large majority of cases do not remain a long time in the same place. This class of laborers are not, as a rule, likely to make good milking-machine operators, but especially during the war conditions of the past year one was glad to be able to secure any kind of help. Reference to the problem of the milker is made here in order to show that the conditions under which the investigations reported in this bulletin were conducted were, in general, similar to those that prevail in most of the dairies in the state. The results secured are, therefore, as a rule, no better than those that may be obtained by California dairy farmers in general; in fact, it may be safely stated that they are not as good as those which a dairyman of fair intelligence and resourcefulness, who milks his own cows or who has competent reliable help may count on by machine milking. We have seen that both in the case of the cows in the university herd giving milk during ten complete 4-week periods and those in milk for eleven such periods, the percentage decrease in milk production as well as in average yield of butter-fat during the entire lactation period was slightly higher for the hand-milked cows than for those milked by machine, an average difference of two to five per cent, occurring in the production of butter fat and of one to two per cent, in the production of INVESTIGATIONS WITH MILKING MACHINES 43 milk, both in favor of machine milking. These figures refer to the decrease in production from the first to the tenth or eleventh month of the lactation period, respectively. In view of this result, it becomes of special interest to investigate how the total production of the cows for the entire lactation period compares when the cows were machine- milked and when they .were milked by hand. The available data on this point are presented and discussed below. Comparison of Yields for Entire Lactation Periods In order to ascertain the effect of the special method of milking practised on the total production of the cows, the data for all complete lactation periods when the cows were machine milked have been com- piled, and the average production for a corresponding number of lacta- tion periods for hand-milked cows has been computed from the records of the university dairy herd, either for the same cows when data for complete normal lactations were available, or for other cows taken at random from the herd record book. The cows included in these com- pilations were milked by one or the other method during entire lactation periods, with only a few exceptions, as noted in a subsequent table. Table VI shows the average data obtained in these compilations for machine-milked and for hand-milked cows. Table VI. — Comparisons of Yields for Entire Lactation Periods Machine- Hand- Milking Milking No. of lactation periods 56 56 No. of different cows 45 40 Ave. age, years-months 3-7 5-0 Ave. length of lactation, days 351 355 Ave. production of milk, lbs 7385.5 7800.3 Ave. per cent, fat 3.84 4.14 Ave. production of butterfat, lbs 283.56 322.91 Corrected for difference in age 326.09 322.91 Highest production of milk, lbs 12722.5 13443.0 Lowest production of milk, lbs 3961.9 2670.1 Highest production of butterfat, lbs 588.16 558.75 Lowest production of butterfat, lbs 156.22 121.44 Longest lactation period, days 507 462 Shortest lactation period, days 284 254 It will be seen from the figures in Table VI that during fifty-six lactation periods (for forty-five different cows), when machine-milking was practised, the cows produced an average of 7,385.5 lbs. milk and 44 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 283.56 lbs. butter fat (average fat content, 3.84%). Similar data for fifty-six lactation periods (forty different cows) in the same herd on hand milking gave an average production of 7,800.3 lbs. milk and 322.91 lbs. butter fat, (average fat content 4.14%). Since the two groups of cows were not made up exactly of the same animals it cannot be safely assumed that the differences in average production noted were due to the difference in the method of milking practiced. There are a number of other factors that would tend to influence the production of the cows, the most important doubtless being the age of the animals making up the two groups. The machine-milked group included about 30 young heifers, mostly grades, which have been milked by machine ever since they were added to the herd in 1916 and 1917, while less than a dozen heifers were included in the hand-milked group. This factor would, of course, tend to favor the production of the group of hand-milk- ed cows. The average age of the cows in the machine-milked group was slightly over 33^ years, against five years for the hand-milked cows. It is known from the results of advanced-registry tests of cows of different ages belonging to the various dairy breed associations that cows will increase, on the average, about 15% in production from V/i to 5 years old.* It may be assumed, therefore, that if the machine-milked cows had been of the same average age as those included in the hand-milked group, they would have had an average production of 326 . 09 lbs. butter fat to their credit, or within one per cent the same production as the average for the hand-milked lot, indicating that the dairy production of the cows was not appreciably influenced by the special method of milking practised. If the production of the individual cows that were below full-age be corrected on basis of an average increase of from 30 to 5%, for cows two to four and a half years old, respectively, (loc. cit.), and the cal- culated yields of butter fat per lactation for mature cows thus obtained, it will be seen that the average production for the machine-milked cows was 337.94 pounds and for the hand-milked ones 352.89 pounds. The standard deviation in the production of the former cows was 90.1, and of the latter 114.2, making the probable error of the mean of the annual yeilds of butter fat for machine-milked cows 8.12, and for the hand-milked cows 10.3. The difference between the probable error of the two means (obtained by extracting the square root of the sum of the two probable errors raised to the second power) is 13.1, which is but slightly less than the difference between the mean production of the two groups of cows. The difference between the mean production divided by the probable error is 14.95-13.1, or 1.14. The probability *California Station Bulletin 301, p. 163. INVESTIGATIONS WITH MILKING MACHINES 45 of the occurrence of a deviation of this magnitude is 44.2. There is, therefore a very slight deviation from an even chance that the difference in the yields on the two methods of milking is not caused by the special method of milking practised, but is practically within the limits of the natural variations in the production of cows kept under conditions similar to those present in the University Dairy herd. It may be noted incidentally that the probable error of the mean in the case of the hand-milked cows was greater than that of machine- milked cows, viz., 10.3 against 8.12. The explanation of this is doubt- less to be sought in the more intensive feeding practiced in the case of several of the hand-milked cows during the lactation periods when they were on Advanced-Registry tests (p. 45). Further evidence as to the effect of machine-milkjng on the milk secretion may be obtained from a study of the production of the cows in the dairy herd that were milked by both methods during different lactation periods. Such data are available for thirteen cows in all, covering eighteen complete lactation periods for machine milking and twenty-one lactation periods when the cows were milked by hand. The main data relating to the production of these cows are included in Table VII, the last two lines of which show the average production per cow and per lactation periods for both methods of milking. Owing to a variety of causes beyond our control, the number of lactation periods for the two methods differ in the case of the individual cows, and the milking-machine periods sometimes preceded and sometimes followed periods when the cows were milked by hand. Only with four cows did the machine-milking periods come within the hand-milked periods, or vice versa, and three of these yielded, on the average, more milk and butter fat t>n hand-milking than on machine-milking. The explanation of this result and of other differences in the production of the cows on the two methods of milking lies in the natural variations in the dairy production of cows from year to year. These variations are due to various causes, some of which are well understood and others but imperfectly so. The most important factor in the case of good dairy cows is doubtless the intensity of the system of feeding practised. In this respect marked differences occurred with the cows whose records are presented in the table. Pure-bred cows in the university dairy herd, as in the case of practically all dairy herds, have generally received special treatment when tested for advanced-registry records, in the way of liberal allowances of concentrates and green or succulent feed, three or even four times a day milking, etc. They were also placed in separate box stalls, which under the conditions present in our dairy necessitated their being milked by hand. Several of the cows (most of them included 46 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 00 lO O O CM >-s (N lO N(- Tjl Tfl Vh Tin CO "<* ^* ^*- CO CO Go OS !>- 00 -* OS CO £3 CC 6 £ I2; ^3 o «3 S •*H O -h 00 OS CO "^ Oi 00 >o ^t- lo o OS GO CO £2 ^ GO i-l O to 01 co 5 CO ^ LO LO Lq, ^t 1 OS 00 O OS CO 00 CO 00 o lO N Co b- io to 00 LO b- CM Lq, lO CM IQ IO O CM TtH CO CM GO 00 CD lO CM OS CD »0 OS CM O OS LO ©4 h ^ O CO N CM OS to CMCO LO CM Go CO N *0 0000 CO ^ ^0, 00 CM O H- LO co r >H -r r- to Ol o to -r © © CO 03 > CO CO Ol CO t> i-H © < CM o < CO CO CO CO CM iO CO rH tF CO 25 CO GO ^ oo b- rH CM CO *H GO CO CO OS 00 CM CM 7 7 00 OS o bC a > CO -# 7 7 CO I> 7 7 o bjj c3 u CD CM CM T^ OS < b- LQ *< CO OS o 00 i-H O CM lQ rH lq lo os oo to O i-H CM CO Sx* Tj" CO CO CO G0 ^ CD CO CO CO GO CO o ^ co o iO N Q GO CD OS i—l OS CD Os O rH i-l CM >-< CO CD CO i-i LO CM O CD CM CM CM CO « OS LO Ol CO 80 i—< on CO »o in OS HH OS OS C) rH 1—1 *H LO co" o on CO on to OS ft CO" S OS o (M >-< 01 co CO CO «0 CM cp CO LO cC t- 03 CJG OS co4 1 co g OSOO}»OO^CMOSOi-H GO Qrj PQ Tt-H (N >-H -0 co >~H t^ OJ Oi CO os <— 1 *«H »o •O <^> Ol »Q vh t^ ^ ^ i—l >-l i-H 1— I >-s «iONO)HOOOJO^NNCO>Q 1-1 >■ H CO Oj 00 H v}-0 N N N O N 1>- .S^IMGOCOW^COM^NW^ CO ■J-Sg 2 CO 00 & CO CO o3 I I ft b- CO > C^ M £ ' »o co op ,— I ,— I ft >0 r-l CM 13 - - 12* M CD ^ >> 73 CD G d O &J0 W <1 03 IO CO fcUO , — 1 , — 1 I I lO * OS CO O U5 -— 1 O •**■ CO O 00 <* OS ^Q GO CO CM GO GO t^ to >H O 00 r^ *"* ^~ co OS ©4 »h ~v 00 5* GO CO t^ 00 OO I- CO 00 lO oa *o> to CO CO GO GO r^ t^ ^T 1 r ~ l H yll i-H (M 10 CM 3^ ***- -t Tf ffi J* *4 *Q 00 £ : >-H * — ' "« : c^ 3 : C3 : ft- GO S J~ : — *■! O ft^ 8 Z £ t3 ^•3 C = n-i - 4 » a £ ^ ^ 48 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION in the hand-milked group) were able to produce more milk on account of these favorable conditions, especially the heavier system of feeding, than if they had been kept in the milking barn with the regular string and milked by machine. The feed records for the cows whose production is given in Table VII have been compiled. None of these cows were pastured during their milking periods. In order to arrive at a definite figure for the total feed consumption of the cows during the lactation period, the number of feed units contained in the rations fed has been calculated and sum- marized. The equivalents of the various feeding stuffs fed were obtained according to the feed-unit system, the following amounts of the dif- ferent feeds being considered one feed unit: — 2 . 2 lbs. alfalfa hay 6 lbs. Indian corn or sorghum silage 7 lbs. green alfalfa 8 lbs. green barley, oats or corn 10 lbs. beets 12.5 lbs. pumpkins 1 . 1 lbs. wheat, bran, oats, or dried beet pulp 1 lb. barley or cocoanut meal . 9 lbs. linseed meal . 8 lbs. cottonseed meal Table VIII gives the results of these compilations for the thirteen cows whose records of production are given in the preceding table. Table VIII. — Total Number of Feed Units Supplied in Rations Machine-Milked Hand-Milked Concen- Concen- Roughage trates Total Roughage trates Total Atlantis 3869 1941 5810 3810 2959 6769 Santa 4652 4199 8851 4264 2120 6384 Willowmoor 4527 3620 8147 4648 3521 8169 Colantha 3926 2214 6140 3948 1563 5511 Fayne 5547 19 5566 5026 5026 F. R. Pearl 3981 2471 6452 3815 3402 7217 Marigold 3646 1395 5041 4457 2532 6989 Hannah 3950 2409 6359 3459 1745 5204 Korndyke 4177 2624 6801 4123 3420 7543 Agnes 5372 4236 9608 4008 5631 9639 Jap 5956 5956 5006 5 5011 Begonia 4241 4241 4118 4118 Julie 4520 2349 6869 4209 2638 6847 Average 4489 2114 6603 4222 2272 6494 INVESTIGATIONS WITH MILKING MACHINES 49 If the data for the total feed consumption in Table VIII be compared with the production of the respective cows when milked by machine or hand, it will be seen that, with but few exceptions, the production of milk and butter fat during machine or hand-milked periods follows the feed consumption; wherever the higher production occurs for a given animal, the larger amount of feed eaten will be found, as shown by the total number of feed units consumed during the lactation period. Fig. 3. — Interested Jap's Santa, 296928, owned by the University of California. This is of course what one would expect and is only referred to here for the sake of the comparison that it affords of the amount of feed eaten by machine-milked and hand-milked cows. Attention may be called in this connection to the production of the pure-bred Jersey cow Santa (Interested Jap's Santa, 296928) for the lactation period beginning September 12, 1915, when she was milked by machine. She produced during this lactation period, as a three-year old, 9052.5 lbs. of milk and 588.16 lbs. butter fat (average fat content 6.50%). During the following lactation period, beginning March 13, 1917, she produced on hand milking, 13308.5 lbs. of milk and 805.72 lbs. fat (6.05% fat), which was the highest record of pro- 50 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION duction for a Jersey cow in the state until the next lactation period, just completed, when she produced 15,569.4 lbs. milk and 940.72 lbs. butter fat. Evidently the fact that this cow was milked with machine for an entire lactation period as a heifer did not interfere with her capacity for an even larger dairy production during the following years (see fig. 3) ; on the other hand, however, it cannot be stated definitely, that the increase might not have been still greater if she had not been machine-milked at all. It will be noted from Table VII that the average figures for the pro- duction of the cows for the period they were machine milked were 8,424 lbs. milk and 350.00 lbs. fat (average per cent., 4.15), against 7,946.9 lbs. milk and 336.28 lbs. butter fat (average per cent., 4.23) for periods of hand-milking, — a difference of 5 . 6% in the production of milk and 3 . 9% in the production of butter fat in favor of machine-milking. If the data for the separate lactation periods included be averaged, it will be found that these differences between the two groups are reduced to 4.3% and 1.8% for the production of milk and butter fat, res- pectively. The average age of the cows during the periods of hand- milking was somewhat below that for the periods of machine-milking, but, on the other hand, a number of the cows were fed heavier rations when hand-milked than when milked by machine in the regular string, for the reason previously stated. The extent to which these two factors influenced the production of the cows cannot be determined with certainty, but it would seem that they were of nearly equal import- ance in the case of the two groups of cows. A study of the data pre- sented in the table by the statistical method will show that the natural variations in yearly production by the cows are far greater than the difference between their average production when machine-milked and when hand-milked. The same conclusion may therefore be war- ranted from a consideration of the data presented in Table VII as in the case of those in Table VI, that the special method of milking prac- tised does not, on the whole, affect appreciably the dairy production of the cows, provided the milking is done with equal care in either case. This result is fully corroborated by investigations of the efficiency of milking machines conducted by other experiment stations, notably those of the Wisconsin and Geneva (N.Y.) stations. According the the latter station,* "the only conclusion possible to draw, from trials extending over five years and including a large number of lactation periods, is that machine-milking, if properly done, does not influence the flow of milk to any extent capable of measurement." ♦Bulletin 353, Nov. 1912. INVESTIGATIONS WITH MILKING MACHINES 51 The fluctuations in milk flow that frequently occur during different lactation periods in the case of individual cows are determined by a variety of factors, as previously suggested; of these, the intensity of the system of feeding adopted, the age, and the " condition" of the cow, are of marked influence. Evidently the method of milking practised is not an important factor in determining the amount of milk or butter fat obtained during the lactation period, when the milking is carefully done. Nearly all cows take readily to machine milking, especially young heifers, and under similar conditions they will, as a general rule, yield as much milk when milked by machine as by hand if they are always promptly stripped by hand after the machine is removed. Cases in which cows do not do well on machine-milking are very exceptional, being mostly those of old cows of a nervous disposition. Such cows, and cows that cannot very well be milked by machine on account of unusual size or shape of teats or uneven udders are preferably milked by hand or disposed of when a change to machine milking is made in a herd. Summary The modern milking-machine is a practical and safe labor-saving- device. This has been proved by the results of carefully conducted experiments at our own and other experiment stations, and is also borne out by the experience of practical dairy farmers in all parts of the country during the past dozen years or more. At the present time there are eight different makes of milking machines on the market in this state, any one of which may be confidently expected to do satisfactory work in the hands of a careful operator. Failures in machine-milking have been rather numerous in the past, from a variety of causes, chief among them being perhaps the fact that the owner did not fully understand the mechanics of the machines or appreciate the necessity of care in operating and keeping them clean, or of following up the machine-milk- ing promptly by careful stripping. Of late years the failures have, however, greatly decreased in number, as the machines have been further improved in simplicity and efficiency, and the conditions for their suc- cessful operation are better understood. It is safe to say that a dairy- man who introduces machine-milking into his herd with any standard make of machine on the market is now as much on trial himself as is the machine. The best remedy for failures in machine-milking is to become thoroughly familiar with the machine adopted, its adaptation to in- dividual cows, and the requirements for keeping it in a mechanically perfect and sanitary condition. 52 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Milking-machines have not as yet been as generally adopted in the dairy districts of our country as, for instance, in Australia and New Zealand. According to reliable reports received, there are but few dairies of over thirty cows in these countries that are not milking by mechanical means, and many smaller dairies are likewise using milking-machines. With the present scarcity of reliable, efficient milkers, and the high cost of labor, feed, and dairy supplies, the neces- sity of reducing the cost of milk production becomes greater than ever before. It is possible to do this by either or both of the following methods : By increasing the production of the dairy herd through culling, use of good pure-bred sires and modern methods of feeding and manage- ment, or by reducing the operating expenses of the dairy. The milking- machine is an important aid in reducing these expenses. The days of hand-skimming of milk are long gone by, and everything points to the fact that we have now entered upon an era of machine-milking. It is the next step in the economical, efficient management of fair-sized or large dairies, and the experience of other dairy countries in regard to milking-machines will undoubtedly be duplicated in this country. The investigations of this and other experiment stations have shown that milking-machines properly operated do not injure the udders of cows, or cause garget or other udder diseases. Udder troubles are often due to causes that are not in any way associated with the method of milking practiced; they will occur at times in machine-milked, as well as in hand-milked herds, although less frequently when ordinary care is taken in operating the machine. The best way to avoid troubles of this kind in case of machine-milking is to remove the machine as soon as no more milk comes down, and to finish the milking by hand without unnecessary delay. Prompt and careful hand stripping is a most important factor in successful machine-milking, even though the machine used leaves only very small amounts of milk to be stripped out. In the selection of the particular make of machine, a number of points should receive consideration, besides first cost and nearness to service agency, such as cost of up-keep, depreciation, simplicity of mechanism and of cleaning. The various machines on the market differ considerably with regard to these points, and it is evident that no one machine stands out above the others in all respects; also that any farmer with a fair degree of intelligence and resourcefulness need not hesitate to install a milking-machine in his dairy if he keeps twenty or more cows. In many cases it may prove advantageous to adopt machine-milking also in dairies of twelve to fifteen cows, as it will make the owner less dependent upon or entirely independent of hired help. The actual saving in the cost of milking by machine over hand-milking is, INVESTIGATIONS WITH MILKING MACHINES 53 however, greater in the case of large herds than with small ones and will, in general, be in proportion to the size of the herd. It has been shown that with proper care, and with careful, prompt hand-stripping, milking-machines will have no appreciable effect one way or the other on the dairy production of the cows or on the general welfare of the herd, but they will not long render satisfactory service with careless handling and lack of cleanliness. For this reason, milking-machines are most likely to prove successful when operated by the owner himself or by help directly interested in their success. 54 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION PARTIAL BIBLIOGRAPHY ON MILKING MACHINES 1903— Woll, "Methods of Milking," Penn. Dept. of Agriculture, Bulletin 113, pp. 84-96. 1906— Erf, "Milking Machines," Kansas Station Bulletin 140. 1907 — Beach, Stocking and Mason, "Milking Machines: effect upon quality and yield of milk," Conn. (Storrs) Station Bulletin 47. Lane and Stocking, "The Milking Machine as a Factor in Dairying," U. S. Dept. of Agriculture, Bureau of Animal Industry, Bulletin 92. Dean and Edwards, "Milking Machines," Ontario Dept. of Agriculture Bulletin 159. 1908— Haecker and Little, "Milking Machines," Neb. Station Bulletin 108. Mairs, "Test of a Mechanical Cow Milker," Penn. Station Bulletin 85. Price, "Home-grown rations in Economical Production of Milk and Butter," Tenn. Station Bulletin 80. 1909— Harding, Wilson and Smith, "Milking Machines: effect of Methods of Milk- ing on the Germ Content of the Milk," Geneva (N.Y.) Experiment Station Bulletin 317. Woll and Humphrey, "Milking Machine Experiments," Wis. Station Bul- letin 173. Woll and Humphrey, "The Efficiency, Economy and Physiological Effect of Machine Milking," Wis. Station Research Bulletin No. 3. 1912— Smith and Harding, "Milking Machines: Effect of Machine Method of Milk- ing on Milk Flow," Geneva (New York) Station Bulletin 353. 1913 — Wing, "Milking Machines: Their sterilization and their efficiency in produc- ing Clean Milk," Cornell (New York) Station Circular 18. Van Norman, "Sharpies Milking Machine"; Report, Penn. State College 1912-1913, pp. 163-164. Larsen, White and Fuller, "Preliminary Report on the Milking Machine," South Dakota Station Bulletin 144. 1914 — Hooper and Nutter, "Experiments with the Sharpies Mechanical Milker," Kentucky Bulletin 186. 1915 — Archibald, "Milking Machines"; Experimental Farms, Ottawa, Report 1915, Vol. 1, pp. 406-410. 1916 — Robertson and Gilbert, "Milking Machines: A Study of the Practical Opera- tion of 108 Milking Machines," Jefferson Co. (New York) Farm Bureau Bulletin 7. Larsen, "Important Factors affecting Machine Milking," S. Dakota Bulletin 166. Humphrey, "Labor Requirements of Dairy Farms as influenced by Milking Machines," U. S. Dept. of Agriculture, Bulletin 423. 1918 — Ruehle et al, "Control of Bacteria in Milking Machines," Geneva (New York) Bulletin 415. Ruehle et al, "Milking Machines: III. As a Source of Bacteria in Milk; IV. Methods of Maintaining in a Bacteria-free Condition," Geneva (New York) Bulletin 450. 1919— Riddell, "Machine vs. Hand-Milking," Mich. Quart. Bulletin, Vol. I, No. 4. Hart, "Importance of Sterilization in the Successful Operation of Milking Machines," Pac. Dairy Review, Vol. 23, No. 26, pp. 12-15. STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION No. 168. 169. 174. 185. 208. 216. 230. 242. 250. 251. 252. 253. 255. 257. 261. 262. 263. 264. 266. 267. 268. 270. 271. 272. 273. 274. 275. 276. 277. No. 50. 65. Observations on Some Vine Diseases in Sonoma County. Tolerance of the Sugar Beet for Alkali. A New Wine Cooling Machine. Report of Progress in Cereal Investi- gations. The Late Blight of Celery. A Progress Report upon Soil and Cli- matic Factors Influencing the Com- position of Wheat. Enological Investigations. Humus in California Soils. The Loquat. Utilization of the Nitrogen and Organio Matter in Septic and Imhoff Tank Sludges. Deterioration of Lumber. Irrigation and Soil Conditions in the Sierra Nevada Foothills, California. The Citricola Scale. New Dosage Tables^ Melaxuma of the Walnut, "Juglans regia." Citrus Diseases of Florida and Cuba Compared with Those of California. Size Grades for Ripe Olives. The Calibration of the Leakage Meter. A Spotting of Citrus Fruits Due to the Action of Oil Liberated from the Rind. Experiments with Stocks for Citrus. Growing and Grafting Olive Seedlings. A Comparison of Annual Cropping, Bi- ennial Cropping, and Green Manures on the Yield of Wheat. Feeding Dairy Calves in California. Commercial Fertilizers. Preliminary Report on Kearney Vine- yard Experimental Drain. The Common Honey Bee as an Agent in Prune Pollination. The Cultivation of Belladonna in Cali- fornia. The Pomegranate. Sudan Grass. BULLETINS No. 278. 279. 280. 281. 282. 283. 284. 285. 286. 288. 290. 292. 293. 296. 297. 298. 299. 300. 301. 302. 303. 304. 305. 306. 307. 308. 309. 310. 311. 312. CIRCULARS 70. 76. 82. 87. 107. 109. 110. 111. 113. 114. 115. 117. 124. 126. 127. 128. 129. 130. 131. 133. 135. Fumigation Scheduling. The California Insecticide Law. The Extermination of Morning-Glory. Observations on the Status of Corn Growing in California. Hot Room Callusing. The Common Ground Squirrels of California. Alfalfa. Spraying Walnut Trees for Blight and Aphis Control. Community or Local Extension Work by the High School Agricultural De- partment. Green Manuring in California. The Use of Lime and Gypsum on Cali- fornia Soils. Correspondence Courses in Agriculture. Increasing the Duty of Water. Grafting Vinifera Vineyards. The Selection and Cost of a Small Pumping Plant. Alfalfa Silage for Fattening Steers. Spraying for the Grape Leaf Hopper. House Fumigation. Insecticide Formulas. The Control of Citrus Insects. Cabbage Growing in California. Spraying for Control of Walnut Aphis. County Farm Adviser. Official Tests of Dairy Cows. No. 136. 137. 138. 139. 140. 142. 143. 144. 147. 148. 151. 152. 153. 154. 155. 156. 157. 158. 160. 162. 164. Grain Sorghums. Irrigation of Rice in California. Irrigation of Alfalfa in the Sacramento Valley. Control of the Pocket Gopher in Cali- fornia. Trials with California Silage Crops for Dairy Cows. The Olive Insects of California. Irrigation of Alfalfa in Imperial Valley. The Milch Goat in California. Commercial Fertilizers. Potash from Tule and the Fertilizer Value of Certain Marsh Plants. The June Drop of Washington Navel Oranges. Green Manure Crops in Southern Cali- fornia. Sweet Sorghums for Forage. Topping and Pinching Vines. The Almond in California. Seedless Raisin Grapes. The Use of Lumber on California Farms. Commercial Fertilizers. California State Dairy Cow Competi- tion, 1916-18. Control of Ground Squirrels by the Fumigation Method. Grape Syrup. A Study on the Effects of Freezes on Citrus in California. The Influence of Barley on the Milk Secretion of Cows. Almond Pollination. Pollination of the Bartlett Pear. I. Fumigation with Liquid Hydrocianic Acid. II. Physical and Chemical Properties of Liquid Hydrocianic Acid. I. The Carob in California. II. Nutri- tive Value of the Carob Bean. Plum Pollination. Investigations with Milking Machines. Mariout Barley. Melilotus Indica. Wood Decay in Orchard Trees. The Silo in California Agriculture. The Generation of Hydrocyanic Acid Gas in Fumigation by Portable Machines. The Practical Application of Improved Methods of Fermentation in Califor- nia Wineries during 1913 and 1914. Practical and Inexpensive Poultry Appliances. Control of Grasshoppers in Imperial Valley. Oidium or Powdery Mildew of the Vine. Tomato Growing in California. "Lungworms". Feeding and Management of Hogs. Some Observations on the Bulk Hand- ling of Grain in California. Announcement of the California State Dairy Cow Competition, 1916-18. Irrigation Practice in Growing Small Fruits in California. Bovine Tuberculosis. How to Operate an Incubator. Control of the Pear Scab. Home and Farm Canning. Lettuce Growing in California. White Diarrhoea and Coccidiosis of Chicks. Small Fruit Culture in California. CIRCULARS — Continued No. No. 165. Fundamentals of Sugar Beet Culture 189. under California Conditions. 190. 166. The County Farm Bureau. 191. 167. Feeding Stuffs of Minor Importance. 193. 168. Spraying for the Control of Wild 195. Morning-Glory within the Fog Belt. 169. The 1918 Grain Crop. 197. 170. Fertilizing California Soils for the 1918 Crop. 198. 172. Wheat Culture. 199. 173. The Construction of the Wood-Hoop 200. Silo. 174. Farm Drainage Methods. 201. 175. Progress Report on the Marketing and 202. Distribution of Milk. 176. Hog Cholera Prevention and the Serum 203. Treatment. 204. 177. Grain Sorghums. 178. The Packing of Apples in California. 205. 179. Factors of Importance in Producing 206. Milk of Low Bacterial Count. 207. 181. Control of the California Ground 208. Squirrel. 182. Extending the Area of Irrigated Wheat 209. in California for 1918. 210. 183. Infectious Abortion in Cows. 211, 184. A Flock of Sheep on the Farm. 212. 185. Beekeeping for the Fruit-grower and 213. Small Rancher or Amateur. 214. 187. Utilizing the Sorghums. 188. Lambing Sheds. 215. Winter Forage Crops. Agriculture Clubs in California. Pruning the Seedless Grapes. A Study of Farm Labor in California. Revised Compatibility Chart of Insecti- cides and Fungicides. Suggestions for Increasing Egg Produc- tion in a Time of High-Feed Prices. Syrup from Sweet Sorghum. Onion Growing in California. Growing the Fall or Second Crop of Potatoes in California. Helpful Hints to Hog Raisers. County Organization for Rural Fire Control. Peat as a Manure Substitute. Handbook of Plant Diseases and Pest Control. Blackleg. Jack Cheese. Neufchatel Cheese. Summary of the Annual Reports of the Farm Advisors of California. The Function of the Farm Bureau. Suggestions to the Settler in California. Saving Raisins by Sulfuring. Salvaging Rain-Damaged Prunes. Evaporators for Prune Drying. Seed Treatment for the Prevention of Cereal Smuts. Feeding Dairy Cows in California.