{"id":{"repo_id":"sask","oai_identifier":"oai:harvest.usask.ca:10388/15247"},"canonical_url":"https://search.dev.ndltd.org/etd/sask/oai:harvest.usask.ca:10388/15247","repository":{"repo_id":"sask","name":"University of Saskatchewan","base_url":"https://harvest.usask.ca/server/oai/request"},"display":{"title":"FACTORS AFFECTING THE VITAMIN A AND ß-CAROTENE CONTENTS OF MILK","abstract":"The factors affecting the vitamin A and s-carotene contents of milk were investigated. A series of short- and long-term experiments were conducted using the University of Saskatchewan dairy herd and Saskatoon commercial fluid milk, respectively. The vitamin A potency of the milk was significantly influenced by cow-to-cow variations when the experimental cows were receiving high levels (87,600 IU/kg feed) of vitamin A supplementation. The day-to-day variations significantly affected the vitamin A content of milk when early lactation cows received low levels (8,200 IU/kg feed) of vitamin A supplementation. The milk of cows in late lactation contained more vitamin A per 100 ml but the milk of cows in early lactation contained more vitamin A per gm butter fat. Pronounced seasonal variations were observed in Saskatoon market milks. The spring milk contained 28.87%, 20.09%, and 8.33% more vitamin A potency than that of winter, fall and summer milk, respectively. Overall, spring and summer milk had significantly more vitamin A (1.17 times) than that of winter and fall milk. Supplementation of feeds with about 10 times the RDA of vitamin A increased the vitamin A content of the milk by 24% but did not affect either the milk yield or the B.F.% of the milk. Dietary hay suppressed, but dietary silage promoted, the recovery of dietary vitamin A in milk of cows fed the above forages, each supplemented with 250,000 and 600,000 IU vitamin A/cow/day. High levels of vitamin A intake depressed the milk and blood levels of s-carotene. Dietary levels of the vitamin A did not affect the concentration of the vitamin in the blood of the experimental animals. Pasteurization of milk had no deleterious effects on the vitamin A potency of milk. Skimming significantly reduced the vitamin A content of whole milk by 85.0% and 26.5% for skim and 2% B.F. milk, respectively. Fortification, at the processing plant, increased the vitamin A content of the low fat milk to above average levels. Maximal photodegradation of vitamin A occurred between 340 to 440 nm. s-carotene significantly protected vitamin A from photodegradation. Storage stability of vitamin A in processed milks (skim, 2% B.F. and homogenized milk) was found to be much less than that of whole, raw milk. The results from the study indicated that the vitamin A potency of milk can be optimized by fortification of winter feeds, particularly silage, with vitamin A. Once the milk has been produced, the vitamin A levels can be optimized by proper fortification of low fat milk and by proper packaging and storage of processed milk.","abstract_html":"The factors affecting the vitamin A and s-carotene contents of milk were investigated. A series of short- and long-term experiments were conducted using the University of Saskatchewan dairy herd and Saskatoon commercial fluid milk, respectively. The vitamin A potency of the milk was significantly influenced by cow-to-cow variations when the experimental cows were receiving high levels (87,600 IU/kg feed) of vitamin A supplementation. The day-to-day variations significantly affected the vitamin A content of milk when early lactation cows received low levels (8,200 IU/kg feed) of vitamin A supplementation. The milk of cows in late lactation contained more vitamin A per 100 ml but the milk of cows in early lactation contained more vitamin A per gm butter fat. Pronounced seasonal variations were observed in Saskatoon market milks. The spring milk contained 28.87%, 20.09%, and 8.33% more vitamin A potency than that of winter, fall and summer milk, respectively. Overall, spring and summer milk had significantly more vitamin A (1.17 times) than that of winter and fall milk. Supplementation of feeds with about 10 times the RDA of vitamin A increased the vitamin A content of the milk by 24% but did not affect either the milk yield or the B.F.% of the milk. Dietary hay suppressed, but dietary silage promoted, the recovery of dietary vitamin A in milk of cows fed the above forages, each supplemented with 250,000 and 600,000 IU vitamin A/cow/day. High levels of vitamin A intake depressed the milk and blood levels of s-carotene. Dietary levels of the vitamin A did not affect the concentration of the vitamin in the blood of the experimental animals. Pasteurization of milk had no deleterious effects on the vitamin A potency of milk. Skimming significantly reduced the vitamin A content of whole milk by 85.0% and 26.5% for skim and 2% B.F. milk, respectively. Fortification, at the processing plant, increased the vitamin A content of the low fat milk to above average levels. Maximal photodegradation of vitamin A occurred between 340 to 440 nm. s-carotene significantly protected vitamin A from photodegradation. Storage stability of vitamin A in processed milks (skim, 2% B.F. and homogenized milk) was found to be much less than that of whole, raw milk. The results from the study indicated that the vitamin A potency of milk can be optimized by fortification of winter feeds, particularly silage, with vitamin A. Once the milk has been produced, the vitamin A levels can be optimized by proper fortification of low fat milk and by proper packaging and storage of processed milk.","abstract_has_math":false,"creators":["Kakuramatsi-Kikafunda, Joyce"],"institution":"University of Saskatchewan","degree_name":"Master of Science (M.Sc.)","degree_level":"Masters","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":["Angel, J.","Gibson, D.","Humbert, E."],"year":1978,"date_issued":"1978-11","date_published":"1978-11","updated_at":"2026-07-24T04:27:16Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10388/15247","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Angel, J.","Gibson, D.","Humbert, E."]},{"key":"dc:creator","label":"Author","values":["Kakuramatsi-Kikafunda, Joyce"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2023-11-16T16:31:59Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2023-11-16T16:31:59Z"]},{"key":"dc:date.issued","label":"Date","values":["1978-11"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (M.Sc.)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Saskatchewan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10388/15247"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The factors affecting the vitamin A and s-carotene contents of milk were investigated. A series of short- and long-term experiments were conducted using the University of Saskatchewan dairy herd and Saskatoon commercial fluid milk, respectively. The vitamin A potency of the milk was significantly influenced by cow-to-cow variations when the experimental cows were receiving high levels (87,600 IU/kg feed) of vitamin A supplementation. The day-to-day variations significantly affected the vitamin A content of milk when early lactation cows received low levels (8,200 IU/kg feed) of vitamin A supplementation. The milk of cows in late lactation contained more vitamin A per 100 ml but the milk of cows in early lactation contained more vitamin A per gm butter fat. Pronounced seasonal variations were observed in Saskatoon market milks. The spring milk contained 28.87%, 20.09%, and 8.33% more vitamin A potency than that of winter, fall and summer milk, respectively. Overall, spring and summer milk had significantly more vitamin A (1.17 times) than that of winter and fall milk. Supplementation of feeds with about 10 times the RDA of vitamin A increased the vitamin A content of the milk by 24% but did not affect either the milk yield or the B.F.% of the milk. Dietary hay suppressed, but dietary silage promoted, the recovery of dietary vitamin A in milk of cows fed the above forages, each supplemented with 250,000 and 600,000 IU vitamin A/cow/day. High levels of vitamin A intake depressed the milk and blood levels of s-carotene. Dietary levels of the vitamin A did not affect the concentration of the vitamin in the blood of the experimental animals. Pasteurization of milk had no deleterious effects on the vitamin A potency of milk. Skimming significantly reduced the vitamin A content of whole milk by 85.0% and 26.5% for skim and 2% B.F. milk, respectively. Fortification, at the processing plant, increased the vitamin A content of the low fat milk to above average levels. Maximal photodegradation of vitamin A occurred between 340 to 440 nm. s-carotene significantly protected vitamin A from photodegradation. Storage stability of vitamin A in processed milks (skim, 2% B.F. and homogenized milk) was found to be much less than that of whole, raw milk. The results from the study indicated that the vitamin A potency of milk can be optimized by fortification of winter feeds, particularly silage, with vitamin A. Once the milk has been produced, the vitamin A levels can be optimized by proper fortification of low fat milk and by proper packaging and storage of processed milk."]},{"key":"dc:title","label":"Title","values":["FACTORS AFFECTING THE VITAMIN A AND ß-CAROTENE CONTENTS OF MILK"]}]}],"canonical_facts":{"dc:contributor.committeemember":["Angel, J.","Gibson, D.","Humbert, E."],"dc:creator":["Kakuramatsi-Kikafunda, Joyce"],"dc:date.accessioned":["2023-11-16T16:31:59Z"],"dc:date.available":["2023-11-16T16:31:59Z"],"dc:date.issued":["1978-11"],"dc:description.abstract":["The factors affecting the vitamin A and s-carotene contents of milk were investigated. A series of short- and long-term experiments were conducted using the University of Saskatchewan dairy herd and Saskatoon commercial fluid milk, respectively. The vitamin A potency of the milk was significantly influenced by cow-to-cow variations when the experimental cows were receiving high levels (87,600 IU/kg feed) of vitamin A supplementation. The day-to-day variations significantly affected the vitamin A content of milk when early lactation cows received low levels (8,200 IU/kg feed) of vitamin A supplementation. The milk of cows in late lactation contained more vitamin A per 100 ml but the milk of cows in early lactation contained more vitamin A per gm butter fat. Pronounced seasonal variations were observed in Saskatoon market milks. The spring milk contained 28.87%, 20.09%, and 8.33% more vitamin A potency than that of winter, fall and summer milk, respectively. Overall, spring and summer milk had significantly more vitamin A (1.17 times) than that of winter and fall milk. Supplementation of feeds with about 10 times the RDA of vitamin A increased the vitamin A content of the milk by 24% but did not affect either the milk yield or the B.F.% of the milk. Dietary hay suppressed, but dietary silage promoted, the recovery of dietary vitamin A in milk of cows fed the above forages, each supplemented with 250,000 and 600,000 IU vitamin A/cow/day. High levels of vitamin A intake depressed the milk and blood levels of s-carotene. Dietary levels of the vitamin A did not affect the concentration of the vitamin in the blood of the experimental animals. Pasteurization of milk had no deleterious effects on the vitamin A potency of milk. Skimming significantly reduced the vitamin A content of whole milk by 85.0% and 26.5% for skim and 2% B.F. milk, respectively. Fortification, at the processing plant, increased the vitamin A content of the low fat milk to above average levels. Maximal photodegradation of vitamin A occurred between 340 to 440 nm. s-carotene significantly protected vitamin A from photodegradation. Storage stability of vitamin A in processed milks (skim, 2% B.F. and homogenized milk) was found to be much less than that of whole, raw milk. The results from the study indicated that the vitamin A potency of milk can be optimized by fortification of winter feeds, particularly silage, with vitamin A. Once the milk has been produced, the vitamin A levels can be optimized by proper fortification of low fat milk and by proper packaging and storage of processed milk."],"dc:identifier.uri":["https://hdl.handle.net/10388/15247"],"dc:title":["FACTORS AFFECTING THE VITAMIN A AND ß-CAROTENE CONTENTS OF MILK"],"thesis:degree_level":["Masters"],"thesis:degree_name":["Master of Science (M.Sc.)"],"thesis:institution_name":["University of Saskatchewan"]},"updated_at":"2026-07-24T04:27:16Z"}