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dc.contributor.advisorVan der Merwe, H. J.
dc.contributor.advisorHayes, J. P.
dc.contributor.authorMoreki, John Cassius
dc.date.accessioned2015-11-24T09:02:40Z
dc.date.available2015-11-24T09:02:40Z
dc.date.copyright2005-07-31
dc.date.issued2005-07-31
dc.date.submitted2005-07-31
dc.identifier.urihttp://hdl.handle.net/11660/1822
dc.description.abstractEnglish: 1. A study was conducted to investigate the effects of dietary Ca levels and feed restriction on the bone development of broiler breeder pullets up to 18 weeks of age. Six hundred and forty one-day-old Ross breeder pullets were randomly assigned to 4 treatment groups; namely 1.0% Ca (0.45% Pi), 1.5% Ca (0.7% Pi), 2.0% Ca (0.9% Pi) and 1.0% Ca (0.45% Pi). The first three treatments were feed restricted while the last treatment was fed ad lib. At 6, 12 and 18 weeks of age 20 pullets were randomly selected from each treatment and killed. Treatment effects on bone dimensions (length, width and weight), bone ash, Ca and P contents of tibia, mechanical properties (bone strength and stress) were investigated. Increasing dieta ry Ca levels had no significant (P>0.05) effect on bone measurements. As expected, all the bone measurements significantly (P<0.05) increased with age. Feed restriction significantly (P<0.05) reduced all the bone characteristics. The results suggested that 1.0% Ca (average 0.7 g/hen/day) is sufficient to support bone development and growth for feed restricted broiler breeder pullets up to 18 weeks of age. 2. One hundred and ninety eight Ross broiler breeder pullets were reared on restricted diets with 1.0, 1.5 and 2.0% Ca up to 22 weeks of age. The pullets in each experimental diet were further randomly divided into three treatments with 1.5, 2.5 and 3.5% dietary Ca (66 birds per treatment) fed from 23 to 60 weeks. At 35 and 60 weeks of age, 12 pullets per treatment were randomly selected and killed to obtain tibiae and humeri. Treatment effects on bone dimensions, bone ash, Ca and P content of tibia, mechanical properties, true cortical area (TCA) and percent bone were investigated. The 1.5% Ca diet resulte d in lower (P<.05) feed intake and body weight. Calcium level had no effect on bone dimensions, bone stress, ash content, Ca content of ash, TCA and percent bone. These results suggest that the 2.5% dietary Ca (4 g/hen/day) may be adequate to support bone development and growth of feed restricted broiler breeder pullets. 3. The broiler breeder pullets described in paragraph 2 were used to investigate the effects of three levels of dietary Ca (1.5, 2.5 and 3.5%) during the early lay period (23 to 35 weeks) on egg production and eggshell quality. Increasing dietary Ca level from 1.5 to 3.5% had no significant effect (P>.05) on egg production, egg weight, egg mass, egg surface area and egg contents. Increasing the level of Ca from 1.5 to 2.5% increased shell weight, shell weight per unit surface area, shell percentage and shell thickness. As anticipated, egg weight increased with age. The converse was true for egg production and eggshell parameters. It was concluded that a dietary Ca level of 2.5% and Ca intakes of 3.8, 3.9, and 3.5 g at weeks 27, 30 and 33, respectively were sufficient to sustain good eggshell quality of feed restricted broiler breeder hens. 4. The mentioned broiler breeder hens in paragraph 3 were fed three dietary Ca levels, 1.5, 2.5 and 3.5% from week 36 to 60. Regression analysis suggested that Ca level during the rearing period could positively influence eggshell quality during the later stages of lay (36 to 60 weeks). Increasing dietary Ca level from 1.5 to 2.5% during the laying period significantly (P<.05) increased egg production, egg weight, egg mass, shell weight, egg contents, egg surface area, shell percentage, shell weight per unit surface area and shell thickness. As anticipated, egg weight, shell weight, egg contents and egg surface area increased with age while egg production, egg mass, shell percentage and shell thickness declined. These results suggest that the 2.5% Ca (3.8 g/hen/day) is adequate to support egg production and to improve eggshell quality in feed restricted broiler breeder hens. 5. The effect of dietary Ca intake (1.5, 2.5 and 3.5% dietary Ca) on Ca retention of broiler breeder hens (30 per treatment) and the relationship between Ca retention and egg characteristics was investigated. Shell (r=0.27) and faecal (r=0.50) Ca excretions were significantly (P<.05) positively related to Ca intake of broiler breeders. Proportionally less of the Ca intake was used for eggshell formation as the intake of broiler breeders increased. It seems that a higher Ca intake was mainly accompanied by a higher Ca excretion through the faeces. The net effect of Ca intake and total Ca excretion was that the 2.5% Ca level (3.8 g Ca /hen/day) exhibit a significant (P<.05) higher Ca retention compared to 1.5% Ca. It was concluded from the results that 1.0% dietary Ca (0.7 g /pullet/day) is needed during the rearing period up to 22 weeks. Thereafter 2.5% Ca (3.5 to 4.0 g /hen/day) should be included in broiler breeder diets up to 60 weeks. The possible effect of Ca levels during the rearing period on eggshell quality needs further investigation.en_ZA
dc.description.abstractAfrikaans: 1. ’n Studie is uitgevoer om die effek van kalsiumpeile en voerbeperking op beenontwikkeling van jong braaikuikenhenne tot 18 weke na te gaan. Seshonderd een- en veertig dagoud Ross braaikuikenhenne is ewekansig aan vier behandelings toegeken naamlik: 1.0% Ca (0.45% P), 1.5% Ca (0.7% P), 2.0% Ca (0.9% P) en 1.0% Ca (0.45% P). Die eerste drie behandelings is beperk gevoer en die laaste groep ad lib . Op 6, 12 en 18 weke is 20 henne ewekansig per behandeling geselekteer en geslag. Behandelingseffekte op beenafmetings (lengte, wydte en gewig), beenas, Caen P-inhoud van tibia, beenbreeksterkte, beenspanning en porositeit is ondersoek. ’n Verhoogde dieet Ca-peil het beenafmetings nie betekenisvol (P>0.05) beïnvloed nie. Soos verwag het alle beenmetings betekenisvol (P<0.05) met ouderdom toegeneem. Volgens die resultate is 1.0% dieet Ca (gemiddeld 0.7 g/hen/dag) voldoende vir beenontwikkeling en groei van voerbeperkte braaikuikenhenne tot op 18 weke ouderdom. 2. Eenhonderd agt-en negentig Ross braaikuikenhenne is op innamebeperkte diete met 1.0, 1.5 en 2.0% Ca tot op 22 weke grootgemaak. Die jonghenne van elke eksperimentele dieet is verder ewekansig in drie behandelings met 1.5, 2.5 en 3.5% dieet Ca (66 henne per behandeling) ingedeel en vanaf 23 tot 60 weke gevoer. Op 35 en 60 weke is 12 jonghenne ewekansig per behandeling geslag om die tibia en humerus te verkry. Behandelingseffekte op beenafmetings (lengte, wydte en gewig), beenas, Ca en P-inhoud van tibia, meganiese-eienskappe (beensterkte en-spanning), ware skorsoppervlakte en persentasie been is ondersoek. Die 1.5% Ca-dieet het voerinname en liggaamsgewig verlaag (P<0.05). Ca-peil het geen invloed op beenafmetings, been sterkte, asinhoud, Ca-inhoud van as, skorsoppervlakte en persentasie been uitgeoefen nie. Volgens die resultate is 2.5% dieet Ca (4 g/hen/dag) nodig om beenontwikkeling en groei van voerbeperkte braaikuikenhenne te ondersteun. 3. Die jong braaikuikenhenne soos beskryf in paragraaf 2 is gebruik om die effek van dieet Ca (1.5, 2.5 en 3.5%) gedurende die lêperiode (week 23 tot 35) op eierproduksie en eierdopkwaliteit te ondersoek. ’n Toenemende Ca-peil vanaf 1.5 tot 3.5% het geen betekenisvolle (P>0.05) invloed op eie rproduksie, eiergewig, eiermassa, eieroppervlakte, eiervolume en eierinhoud uitgeoefen nie. ’n Verhoging van Ca-peil vanaf 1.5 tot 2.5% het eierdopgewig, dopgewig per eenheidsoppervlakte, persentasie dop en eierdopdikte verhoog. Soos verwag het eiergewig met toenemende ouderdom verhoog. Die teenoorgestelde het gegeld vir eierproduksie en eierdop parameters. Daar is tot die slotsom gekom dat ’n dieet Ca-peil van 2.5% en Cainname van 3.8, 3.9 en 3.5 g gedurende onderskeidelik weke 27, 30 en 33 voldoende sal wees vir goeie eierdopkwaliteit van voerbeperkte braaikuikenhenne. 4. Die genoemde braaikuikenhenne in paragraaf 3 is aan drie dieet Ca-peile, naamlik 1.5, 2.5 en 3.5% vanaf weke 36 tot 60 onderwerp. Regressie ontledings dui daarop dat Ca-peile gedurende die grootmaakperiode, eierdopkwaliteit gedurende die latere stadiums van die lêperiode (36 tot 60 weke) positief kan beinvloed. ’n Verhoging van Ca-peil vanaf 1.5 tot 2.5% gedurende die lêperiode het eierproduksie, eiergewig, eiermassa, dopgewig, eierinhoud, eieroppervlakte, persentasie dop, dopgewig per eenheids oppervlakte en dopdikte betekenisvol (P<0.05) verhoog. Soos verwag het eiergewig, dopgewig, eierinhoud en eieroppervlakte met ouderdom toegeneem terwyl eierproduksie, eiermassa, persentasie dop- en dopdikte verlaag het. Die resultate dui daarop dat 2.5% Ca (3.8 g/hen/dag) benodig word om eierproduksie te ondersteun en eierdopkwalitiet van braaikuikenhenne te verhoog. 5. Die effek van dieet Ca-inname (1.5, 2.5 en 3.5% dieet Ca) op Ca-retensie van braaikuikenhenne (30 per behandeling) en die verwantskap tussen Ca-retensie en eiereienskappe is ondersoek. Dop- (r = 0.27) en mis (r = 0.50) Ca-ekskresie was betekenisvol (P<0.05) positief gekorreleerd met Ca-inname van braaikuikenhenne. Proporsionee l is minder van die Ca-inname vir eierdopvorming gebruik soos Cainname van henne verhoog het. Dit blyk dat ’n hoër Ca-inname hoofsaaklik met ’n groter Ca-uitskeiding in die mis gepaard gegaan het. Die netto effek van Ca-inname en totale Ca-ekskresie was dat die 2.5% Ca-peil (3.8 g Ca/hen/dag) ’n betekenisvol (P<0.05) hoër Ca-retensie in vergelyking met 1.5% Ca getoon het. Daar is tot die slotsom gekom dat 1.0% dieet Ca (gemiddeld 0.7 g/hen/dag) benodig word gedurende die grootmaakperiode tot 22 weke. Daarna moet 2.5% Ca (3.5 tot 4.0 g/hen/dag) in diete vir braaikuikenhenne tot 60 weke ingesluit word. Die moontlike invloed van Ca-peile gedurende die grootmaakperiode op eierdopkwaliteit vereis verdere ondersoek.af
dc.description.sponsorshipUniversity of the Free State (Department of Animal, Wildlife and Grassland Sciences)en_ZA
dc.description.sponsorshipW.L. Kellogg Foundationen_ZA
dc.language.isoenW.K. Kellogg Foundation
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectThesis (Ph.D. (Animal, Wildlife and Grassland Sciences))--University of the Free State, 2005en_ZA
dc.subjectCalcium in animal nutritionen_ZA
dc.subjectPoultry -- Feeding and feedsen_ZA
dc.subjectBroilers (Poultry) -- Nutritionen_ZA
dc.titleThe influence of calcium intake by broiler breeders on bone development and egg characteristicsen_ZA
dc.typeThesisen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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