Four double 3×3 latin square experiments were conducted to study the efforts of three concentrate-to-forage ratios (10:30, 40:60 and 70:90), three concentrate types and four forages, on chewing time of steers. Diets were fed for 14 days and chewing was monitored for the last 48 hours. Chewing time was reduced (P<.05) with each increase of concentrate level. Long hay and coarsely cut wheat silage resulted in more chewing time (P<.05) than finely cut sorghum or corn silage. Citrus pulp increased chewing time over ground corn or soybean mill feed. While there was some indication of interaction among forages and concentrate levels, mean values were linear, so we assumed the effect of concentrate and forage dry matter on chewing time was additive. Chewing time for the concentrate and forage was partitioned by regression. Roughage value index (chewing time per kilogram of dry matter) was 68.9 ± 3.2 SE for wheat silage, 67.3 ± 1.2 for corn silage, 59.7 ± 2.4 for sorghum silage, 78.5 ±5.5 for bermudagrass hay, 30.9 ± 15.4 for citrus pulp, 5.1 ± 4.2 for ground corn, and 8.4 ± 2.8 for soybean mill feed.

AbstractA comparison of male sterile and male fertile corn (Zea mays L.) for dry matter production, total available carbohydrates (TAC), silage digestibility, and volatile fatty acid (VFA) production from the silage during rumen dermentation was made at Experiment, Georgia in 1968 to 1969. Dry forage yields were similar for the male literile and male fertile corn in 1968, but the male sterile vielded more than the male fertile in 1969. The male fertile hybrid contained a higher percentage TAC than did the male sterile hybrid. There were no significant percentage differences between the silages in individual VFA production, or digestibility of dry matter, crude protein, crude fiber, cellulose, ether extract, and nitrogen iree extract. The data indicate that at the maturity studied male sterile corn plants (without kernel development) are comparable to male fertile corn plants (with kernel development) for making silage.

Most studies conducted to determine energy requirements of mature cow for maintenance, weight gain and milk production have been with dairy cattle. As increasing emphasis is placed on economical production of beef, it is important for research workers to provide information indicating cost, in terms of total digestible nutrients (TDN),metabolizable energy (ME or net energy (NE), of maintenance, change in body weight and milk production of mature beef cows. Actual energy requirements for maintenance and production are individualistic and change from time to time within cows. A realistic measure of the mean requirements and a knowledge of the range in requirements is needed. Thus, this study was conducted to provide a portion of this information. Trials were conducted in 1967 (Trial 1) and 1968 (Trial 2). In Trial 2, source of forage was changed and slightly higher levels of TDN were used; otherwise, the procedures were the same as for Trial 1.

Four silos of wheat silage were used to measure the influence of stage of maturity at harvest and level of grain feeding on total dry matter and energy intake. Silage 1 (early heading) was fed to milking cows, Silages 2 (early heading), 3 (milk stage), and 4 (dough stage) were fed to dairy heifers. Intake of the early cut silages was superior to the late cut silages when fed as the only feed. This superiority was retained when 20, 35, and 50% of the silage dry matter was replaced with a grain mixture.

While some difficulties were encountered, due to the broadness of the project objectives and the variations in geography and climate of the Southern region, definite progress was made in a difficult but important area of research. Knowledge was gained in the elucidation of forage constituents and properties which influence intake, digestibility and subsequent animal performance. Progress was made in the development of methodology for the estimation of forage nutritive value. The experience encountered during the project indicated the need to concentrate research efforts on fewer areas of endeavor. The revised S—45 project, “Development of Methods for Relating Forage Properties to Intake and Digestibility,” is an attempt in this direction.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffects of Various Factors on Vitamin B12 Content of Cows' MilkJosephine Miller, Jane Wentworth, and M. E. McCulloughCite this: J. Agric. Food Chem. 1966, 14, 3, 218–221Publication Date (Print):May 1, 1966Publication History Published online1 May 2002Published inissue 1 May 1966https://pubs.acs.org/doi/10.1021/jf60145a006https://doi.org/10.1021/jf60145a006research-articleACS PublicationsRequest reuse permissionsArticle Views94Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Three silages with calculated dry matter digestibilities of 56, 63, and 68% were individually fed to dairy heifers to study factors influencing average daily gain. The data were analyzed by least-squares analysis and showed significant influences for digestibility, dry matter intake, and gain/100lb. of feed on average daily gain (R2 = .966). Dry matter intake was influenced by digestibility, body weight, and average daily gain (R2 = .890). The animals fed the 68% digestible silage had an average daily gain which was 207% of the gain of the heifers on the 56% digestible silage. The respective differences in digestible dry matter intake and Nutritive Value Index were 190 and 189%. A suggested program for obtaining reliable information to be used in forage testing programs is outlined.

The persistency of milk production was found not to be related to the initial level of milk production in a 42-day trial, using eight cows with different levels of production, allowed only good pasture. On a within-period basis, the respective correlations between level of actual and 4% FCM and persistency of milk production were −.007 and −.097. On a within-cow basis, the respective repeatabilities for actual and 4% FCM were .373 and .367. When the data were corrected for period effects, the repeatabilities were .810 and .654.

OUR INDUSTRY TODAY 571 tween the leaf content and DDM value of firstgrowth forage is different from that of aftermath forage.Both the amount and digestibility of protein in forages decline as growth approaches maturity.The percentage of apparently digestible protein can be predicted acurately from the concentration of protein in both first-growth and aftermath forages, thus obviating the need for its actual measurement.

Factors affecting weight gains by dairy heifers were studied with 28 heifers on pasture and ten individually fed heifers on either an all hay or grass silage ration. The heifers averaged about 450lb. in weight. The only factor significantly correlated with gains on pasture was forage dry matter digestibility (r=.797). On pasture, the multiple correlation between average daily gains and dry matter digestibility, dry matter intake, and body weight was .831. Over a 56-day feeding period, the correlations between dry matter intake and average daily gains were .711 for silage and .399 for hay. Correlations between body weight and dry matter intake were .932 for silage and .857 for hay. Multiple correlations between average daily gains, body weight, and dry matter intake were .858 for silage and .463 for hay. Respective average daily gains for pasture, silage, and hay were 1.79, .92, and 1.34lb. The error of estimate of weight gains in all groups prevents accurate estimate of response from the factors measured and emphasizes the large number of animals required to show significant differences between rations. On an individually fed hay ration, 82, 14, and four animals per treatment were required to show significant differences in average daily gains of .10, .25, and .50lb. between group means. On silage, 174, 28, and seven animals were required to show the above differences. When the effects of body weight and dry matter intake of silage were removed, the number of animals needed was reduced to 72, 12, and three. The data would appear to indicate that intake was a major factor only on the grass silage.

Agronomy JournalVolume 51, Issue 4 p. 219-222 Article Symposium on Forage Evaluation: III. The Significance of and Techniques Used to Measure Forage Intake and Digestibility1 M. E. McCullough, M. E. McCullough The author acknowledges with thanks the aid of W. E. Neville, Jr. in the statistical analysis used in this paper.Search for more papers by this author M. E. McCullough, M. E. McCullough The author acknowledges with thanks the aid of W. E. Neville, Jr. in the statistical analysis used in this paper.Search for more papers by this author First published: 01 April 1959 https://doi.org/10.2134/agronj1959.00021962005100040011xCitations: 2 1 Georgia Experiment Station, Journal Series No. 338. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume51, Issue4April 1959Pages 219-222 RelatedInformation