Research on the vitamin A requirements of sheep, and more especially the vitamin A value of carotene, is more limited than that with cattle. The objective of this experiment was to study effects of various levels of vitamin A and carotene supplementation with lambs previously depleted of vitamin A stores. Liver storage and blood levels of vitamin A following repletion were considered the primary measures of the value of the various levels of supplementation

Embry, L. B.

Luther, R. M.

Samuel, D. F.

English

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South Dakota State UniversityOpen PRAIRIE: Open Public Research Access InstitutionalRepository and Information ExchangeSouth Dakota Sheep Field Day Proceedings andResearch Reports, 1981 Animal Science Reports1981Vitamin A and Carotene Nutrition of LambsD. F. SamuelSouth Dakota State UniversityR. M. LutherL. B. EmbryFollow this and additional works at: http://openprairie.sdstate.edu/sd_sheepday_1981This Report is brought to you for free and open access by the Animal Science Reports at Open PRAIRIE: Open Public Research Access InstitutionalRepository and Information Exchange. It has been accepted for inclusion in South Dakota Sheep Field Day Proceedings and Research Reports, 1981 byan authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For moreinformation, please contact michael.biondo@sdstate.edu.Recommended CitationSamuel, D. F.; Luther, R. M.; and Embry, L. B., "Vitamin A and Carotene Nutrition of Lambs" (1981). South Dakota Sheep Field DayProceedings and Research Reports, 1981. Paper 9.http://openprairie.sdstate.edu/sd_sheepday_1981/9SHEEP DAY VITAMIN A AND CAROTENE NUTRITION OF LAMBS D .  F. Sam uel , R .  M. L u t h e r  an d L. B. Embry Depart m e n t  of A n i m al S c i e n c e  E x per i m ent Stat i o n  Summary So u t h  Dakota State U n i vers i ty  S H E E P  81-9 Resu l t s o f  the exper imen t show that lamb s with h igh l iver s torage of v i t amin A r equire a lengthy period for dep let ion to levels  ind icat ive o f  a def icient s t a te as mea su red by low bl ood leve ls  o f  the vi tamin A and d ef i c iency s igns . However , l iver s torage at levels  to g ive b lood v i t amin A c ons idered ad equa te for growth and ab s ence of de f ic i ency s i gns may be dep le ted t o  d e f i c ien t  level s  over a p er iod of as  l i t t le as 2 mon ths . Blood l ev e l s  of vi tamin A r esponded to carotene and vi t amin A sup p l e­ment a t ion promp t ly with levels o f  supp lemen t a t ion as low as 1 mg . carotene from d ehyd rated a l f a l f a  meal or 400 IU of vi t amin A palmi t a te per pound of feed . Levels  o f  1 and 2 mg . o f  carotene or 400 and 800 IU of v i t amin A per pound of rat ion wer e no t enough to have an appr ec iab le ef fect  on l iver s t orage o f  the v i t amin over a per iod  o f  9 1  days  when l iver vi t amin A had been e ssen t i a l ly deple t ed . Car o t ene a t  4 mg . and vi t amin A at 1 600 IU per p ound of rat ion resu l ted in sub s t ant ial l iver s t orage of the v i t amin f o l lowing 91  days o f  sup p lemen t a t ion . Re su l t s  indi cated tha t the connnonly used value o f  400 IU o f  v i t amin A per 1 mg . o f  carotene was an appr opr i a te one at these levels of supplemen t a t ion . The v i t amin A value of c aro tene a t  8 mg . per pound o f  rat i on appeared les s ef fec t ive than 3200  IU o f  vi t amin A per pound o f  rat ion as measured by l iver s t ores with dep leted lambs . At th i s  leve l ,  the vi t amin A va lue o f  c aro tene appeared t o  b e  cons iderably less  than when fed at 4 mg . per  pound o f  rat ion . Introduct ion Pas t  research has indi cated that the need f or and the lev e l  of vi t amin A supp lementat ion to feed l o t  lamb s are rela ted to the feed ing p rogram p rior to en tering the feed lo t .  I t  is  fa i r ly wel l-d ocumen t ed in research li tera ture tha t e ar ly-weaned lamb s may have low l iver vi t amin A s tores and can be dep leted very rap id ly . In contras t ,  lamb s tha t  have been consuming high qua l i ty hay or coming o f f  green pas ture can have h igh l iver vi t amin A s tores and can then c onsume d ie t s  low in vi t amin A a c t iv i ty for ex t ended per iods o f  t ime ( i . e . , 200 days or more ) bef ore exh ibi t ing any s igns of defic iency . In det ermining the level  of v i t amin A supp lemen t a t ion , one mus t  cons ider the source o f  the feed s t u f fs ava i l able  for feed ing . Hay , grain and pas t ure , depend ing on kind and qua l i t y ,  will  contain vary ing amount s  o f  caro teno id p igmen t s , p r imar i ly be ta- carot ene , whi ch have a high degree of vi t amin A ac t ivi ty . Preformed v i t amin A i s  also commercia lly avai l ab l e  to supp lement • • sheep r a t i ons . Therefore , both sources o f  vitamin A should be cons ide red in • d e t e rmining the level o f  supp l emen t a t ion for a given rat i on . Pr epar ed for Sheep Day , June 5 ,  1 98 1 . 4 0  • • • - 2 -Research on the v i t amin A r equi remen ts o f  sheep , and more espe c i a lly the v i t amin A value o f  carotene , is mor e  l im i t ed than tha t with ca t t le . The obj ec t ive of th i s  experiment was to s tudy ef f ec t s  of various lev e l s  of v i t amin A and carot ene sup p lemen t a t ion wi th lambs prev ious ly dep l e t ed of vi t amin A s tores . L iver s torage and b lood levels  of v i t amin A following reple t ion wer e  con s idered the p r imary measu res o f  the value of the various lev e l s  o f  supplemen ta t ion . Vitamin � Depl e t ion Phas e  Experimen t a l  Procedure A gr oup o f  1 60 lamb s of s imi lar background cons i s t ing of an equa l  number o f  ewe s and wethers wa s selec t ed for the expe r imen t .  Af t er we ighing , the 1 0  heavies t lamb s ( f ive ewes and f ive we the r s )  wer e  s laugh t er ed to ob t ain ini t ia l  b lood and l iver levels  of vi t amin A. The remaining lamb s were a l lo t t ed to 1 0  pens of 1 5  each on ba s i s  of sex group and weight . The rat ion during th i s  v i t amin A d ep le t ion was rolled oats  fed to appe t i t e  and top-d re s s ed with . 2  lb . per head da i ly o f  a gr ound oat supp lement con t a ining a calc ium-phospha te sup plemen t ,  trace mineral sal t and aureomyc in . Th i s  rat ion wa s prac t i ca l ly devo id of carot ene . At approxima t ely 2-mon th intervals and af ter we ighing , the 1 0  heav i e s t  lamb s ( f ive ewes and f ive we th er s )  f rom the group were s ent  to s laugh t e r . Blood and l iver s amp l e s  were ob t a ined to det ermine vi t amin A s t ores a t  thes e  periodic  int ervals . The dep let ion per iod wa s terminated af ter 3 3 3  days . A v i tamin A reple t ion pha s e  was ini t ia t ed at thi s  t ime . Final we igh t s  at th i s  t ime wer e  the ini t ial we i gh t s  for t h e  rep let ion pha s e . Liver levels of v i tamin A ob t a ined from the s laughtered group were cons idered to rep r e s en t  the in i t ia l  vi tamin A s t a t us for the rep l e t ion pha se w i th vi t amin A and c a r o t ene sup plemen t a t i on .  V i t amin � Reple t ion Phas e  Eighty lamb s ( 4 0  ewe s and 4 0  we ther s )  from the vi t amin A-d ep le t ed group were used in the vi tamin A r ep l e t ion pha se o f  the exp er iment . They were a l l o t t ed int o  16 pens of fiv e  each on ba s is o f  we ight wi th ewes and wethers f ed separa tely . Ra t ions wer e  rolled oats supp lemen t ed w i th a dehyd rat ed a lf a l f a  supp l ement or a vitamin A supplement . Two p en s  of f ive lambs each were f ed one o f  e igh t r a t ions during the rep let ion pha s e . Fou r ra t ions p rovided c arot ene f rom d ehyd r a t ed alfalf a mea l  at 1 ,  2 ,  3 o r  4 mg . p er pound o f  f eed . Ano ther four rat ions provided vi t amin A a s  the p almi ta t e  a t  400 , 800 , 1 600 and 3 200 I U  per p ound o f  rat ion . The carotene and vi t amin A supplement s  were mixed with rolled oats  to p rovide mixed rat ions approxi­ma t e ly equal in a l l  nu tr ients excep t for levels  of vi t amin A and caro t ene . The dehyd r a t ed alfalfa  meal  and the v i t amin A pr imary premix were a s s ay ed for carotene and vi t amin A each t ime sup p lemen t s  were mixed and approp r i a t e  amoun t s  were used to ob t a in trea tment levels  of carot ene and vi t amin A .  The lamb s were we ighed and b lood samp l e s  ob t a ined for vi t amin A analys is ini t i a l ly and a t  4-week int ervals  dur ing th is pha s e  o f  the exper iment . The rep le t ion pha s e  was terminated a t  91 days . The lamb s were s l augh t ered and l iver samp les ob t a ined to det ermine l iver s t orage o f  v i t amin A .  4 1  - 3 -All b lood and l iver samp l e s  were also analyzed f or car o t ene d ur ing the d ep l e t ion and reple t ion pha s e s  o f  the exper iment . Low levels of c ar o t ene were ob served which have b een shown to be c harac t er is t ic f or sheep . Therefore ,  caro t ene values are not r eport ed . Vitamin ! Deple t ion Resu l t s  and Discuss ion Feed lo t per formanc e  data and b lood and liver values f or v i t amin A a t  periodic int ervals during the dep l e t ion phas e of  the experiment a r e  shown in table 1 .  Feed consump t ion was at  a reasonable level for the oat rat ion throughout the 3 3 3  day s of v i tamin A dep le t ion . There wer e  no maj or var i a tions during thi s  t ime . Wei gh t  gain was also at a reasonable level f or the rati on through the f ir s t 1 8 0  days . Af ter  th i s  t ime , there was a marked reduct ion in rate o f  ga in . The rat e  o f  gain remained a t  a low level f o r  the remainder o f  the dep le t i on per iod .  At 1 8 0  day s , the average wei gh t  of the lamb s  was about 120 pounds . Thi s  wei gh t  and the degree o f  f inish wer e likely impor tant f ac tors af f e c t ing ra t e  of ga in a f t er thi s  t ime . Blood serum v i tamin A showed no maj or decreas e  in values unt il a f t er 2 2 8  days . The value at  thi s  t ime i s  connnonly cons idered to  represent levels  adequat e  f or normal growth with absence o f  def ic i ency s igns . Liver v i tamin A was qui te high ini t ially . Ther e wer e  marked reductions at each samp l ing through 1 80 days . The levels at  1 8 0  and 2 2 8  day s , whi le represent ing marked dep let ion of  ini t ial s tores , appeared adequate to ma int a in p lasma A above levels assoc i at ed with def ic i ency s igns . Liver s to rage at 284 days was low and blood values wer e  at a level as sociated wi th v i tamin A def i c iency . S i gns of def i c iency ( trembl ing and uns teady gai t )  were ob served in 3 6% o f  the lamb s at  thi s  t ime . The data show that a leng thy dep le t ion per iod i s  requ i r ed when ini t ial l iver vi t amin A valu e s  are h i gh as wi th thes e  lamb s . However , dep let ion could b e  qui te rap id wi th apparent adequate  blood values but low l iver s t orage as shown a t  the 2 2 8-day per iod . I t  i s  evid ent tha t the level of  l iver s t orage rather than b lood values wou ld b e  the maj or fac tor in dep l e t ion t ime on ration dev o id or low in carot ene and vitamin A.  Replet ion Phas e  wi th Carot ene and Vitamin A Feed consump t ion and weight ga in data for v i tamin A rep let ion phase  o f  the exper iment are shown i n  tab le 2 .  Feed intake was at  a h i gher level than during the dep l e t ion phas e .  The lambs wer e  larger and would b e  exp ec ted to  have mor e feed c apac i ty .  Over the 9 1 -d ay exp eriment ,  rates o f  gain were low . Weight gain would no t be a useful measure o f  treatments  with the s e  lamb s in v i ew of an ini t ial wei gh t  o f  nearly 1 4 0  pounds . The ma in measures for ef f e c t s  o f  carot ene and vi tamin A supplementation would b e  t h e  blood and liver value s f or vi tamin A.  4 2  • • • • • • - 4 -Table 1 .  Feed lot  Performance , Blood and Liver Dat a  During Vitamin A D ep le tion o f  Lambsa Daily Dai ly Blood s er um Liver Time gain f eed vitamin A vi tamin A per iod lb . lb . mcg . / 100 ml . mcg . /g. Ini t ia l  60 . 0  lb . ( init . wt . )  28 . 10 1 7 3 . 33 0-6 1 d ays . 3 1 0  2 . 25 2 4 . 4 1 86 . 94 6 2- 1 1 7  . 30 1  2 . 65 2 3 . 29  39 . 02 1 1 8- 1 80 . 3 55 2 . 88 1 7 . 44 1 0 . 3 1  18 1 - 2 2 8  . 1 96  2 . 90 20 . 9 1 1 1 . 23 2 2 9 - 28 4  . 1 2 8  2 . 64 1 1 . 2 0 2 . 9 1 2 85-3 33 . 2 1 2  2 . 80 1 3 . 98 1 .  43 0-333 . 266  2 . 66 a One hundred s ixty lambs ini t ially for the experimen t al group . Ten removed at p er iods ind icated and s laugh tered for blood and liver vitamin A analyses . Weight gain and f eed data on bas i s  o f  the decreas ing numbers with a f ew death los se s  t erminat ing the deplet ion phas e  with 91  lamb s . Blood serum v i t amin A a t  the various periods during r ep letion and the f inal liver value s  are shown in t able 3 .  It wil l  b e  no t ed from this t ab le tha t ther e was a mar ked rise  in b lood vit amin A a f t e� only 2 9  day s o f  supplemen t a t ion . This  wa s accomp l i shed wi th as  li t t le as 1 mg . o f  c ar o t ene f rom d ehyd ra ted alfalfa  meal or 400 IU of vitamin A palmi t a t e . Caro tene at 2 mg . per p ound o f  f eed or vitamin A a t  800 IU d i d  not o f f e r  any cons ist en t  advantage over t h e  1 mg . and 4 0 0  IU level during t h e  9 1  days o f  replet ion . Higher levels o f  carot ene ( 4  and 8 g .  per lb . o f  feed ) and vi t amin A ( 1 600 and 3 200 IU per lb . of feed ) r esu l t ed in higher b lood vitamin A bu t wi th no maj or or cons i s t en t  dif f er ences b etween carot ene or v i t amin A a t  thes e  levels . Value s for l iver vitamin A indicat e tha t 1 and 2 mg . o f  carotene p er pound of f eed or 400 and 800 IU of vitamin A wer e  no t adequate levels to increase liver s to rage apprec iably above the dep le t ed levels  during the 9 1 -day rep l e t ion phase . Car o t ene at 4 mg . or vitamin A a t  1 600 IU per p ound o f  r a tion resu l ted in elevated liver s to rage along with rather h igh plasma values . At thi s  level o f  carotene , t h e  value o f  4 0 0  I U  p e r  1 mg . o f  car o t ene connnonly used f or the vi t amin A value o f  c ar o t ene would appear t o  b e  an appropriate  one . Caro tene a t  8 mg . per p ound o f  f eed app ea r ed t o  hav e  somewhat les s ac t ivi ty per uni t o f  weigh t  than the 4 mg . level on basis  o f  liver v i t amin A .  Vitamin A a t  3 200 I U  per pound o f  f eed resu l ted i n  a sub s tan t i al increas e in l iver s to rage over the 1 600 IU l evel bu t with no maj or or cons is t en t  increase in b lood valu e s  • 4 3  Tab le 2 .  Average We i ght s ,  Feed Consump t ion and Da i ly Gains - Supplement a t i on Pha s e  Fol lowing Dep le t ion (Decembe r  1 3 , 1 97 6 ,  t o  Mar ch 1 4 , 1 97 7 -- 9 1  Days ) Caro t ene t rea tment s  V i t amin A treatmen t s  (mg . / lb .  o f  f eed ) ( IU / lb .  o f  feed ) 1 2 4 8 4 00 800 1 6 00 3 200 No . o f  lambs 1 0  1 0  1 0  1 0  1 0  1 0  1 0  1 0  Avg .  ini t i a l  wt . , lb . 1 3 7 .  0 1 3 6 . 8 1 3 4 .  8 1 3 7 . 7 1 33 . 1  1 3 3 . 8 1 3 7  . o  1 35 . 7  Avg .  f inal w t . , lb . 1 4 9 . 7 1 53 . 7  1 53 . 2  1 57 . 6  1 4 7 . 8  1 47 . 2  1 4 7 . 4  1 46 . 6  .i::-- Avg .  daily f eed consump t ion , lb . a .i::--0- 2 9  days 2 . 99 2 . 86 3 . 1 1 3 . 26 2 . 58 2 . 42 2 . 3 7 2 . 40 ln 30-57  days 3 . 26 3 . 3 0 3 . 09 3 . 4 9 3 . 02 3 . 1 9 2 . 80 2 . 7 0 58-91  days 2 .  7 4  2 . 9 1 3 . 0 1 3 . 30 2 . 6 6 3 . 0 1 2 . 95 2 . 9 4 0-9 1 d ays 2 . 98 3 . 01 3 . 07 3 . 3 5 2 . 7 5 2 . 88 2 . 7 0 2 . 7 0 Avg .  da i ly ga in , lb . a 0- 2 9  days . 23 6  . 1 4 7  . 25 9  . 2 3 0  . 1 4 3  . 1 1 2  . 0 2 3  . 03 8  30-57  day s - . 1 6 5  - . 05 7  . 043 - . 020  - . 0 5 4  - . 0 1 8  . 08 0  . 02 9  5 8- 9 1  days . 308 . 4 1 8  . 285  . 40 6  . 35 5  . 3 1 2  . 2 2 1  . 26 3  0-9 1 days . 1 40 . 1 85  . 20 2  . 21 9  . 1 6 2  . 14 7  . 1 1 4  . 1 1 9  a Average da i ly feed consump t ion and averag e  da ily ga in ba s ed on sheep days per period . • e ' • .p... V1 • Tab le 3 .  Blood and L iver D a t a  o f  Lambs Fed Var ious Lev els o f  Car o t ene or Vi t amin A -Supp lementat ion Pha s e  Fo l lowing Dep l e t ion Caro tene trea tment V i t amin A trea tment (mg .  / lb .  f eed ) ( IU / lb . f eed ) 1 2 4 8 400 800 1 600 No . of l amb sa 1 0  1 0  1 0  1 0  1 0  1 0  1 0  Blood serum v i t amin A (mc g . / 1 00 ml . )  I n i t i a l  1 2 . 1 7 1 0 . 7 3  1 1 . 93 1 3 .  2 3  1 0 .  7 4  1 1 . 0 1 1 2 . 4 0 2 9  days 2 5 . 24 2 7 . 97 45 . 7 9 45 . 75 3 2 . 1 9 3 1 . 86 39 . 05 5 7  days 24 . 4 6  24 . 7 8 38 . 66 48 . 50 26 . 3 5 29 . 0 9 38 . 9 4 9 1  days 22 . 79  1 7 . 5 4 30 . 82 33 . 6 4 20 . 3 3 20 . 58 3 1 . 00 Liver v i t amin A (mc g . / gram) 9 1  days 5 . 29 2 . 63 1 2 . 2 8 1 5 . 90 3 . 90 3 . 64 1 0 . 4 8 a Five ewes and f ive we thers . • 3 2 00 1 0  1 3 . 84 3 9 . 6 9 46 . 4 7 °' 3 7 . 7 7  3 1 . 3 8 

Vitamin A and Carotene Nutrition of Lambs

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Vitamin A and Carotene Nutrition of Lambs

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