Effect of curd suppression in a milk replacer on physiological parameters in calves. I. Digestibility of nutrients and body mass-gain

Abstract

Two trials were conducted to determine the effect of coagulation suppression of milk and milk replacers on apparent  digestibility coefficients and body mass-gain of calves. In Experiment 1, two groups of five Holstein bull calves, two to four days of age, were given a milk replacer in which casein coagulation either was normal (CM), or was prevented by the  precipitation of Ca++ with an oxalic acid - sodium hydroxide buffer (NCM). Apparent digestibility of dry matter, organic matter, crude protein and fat was 87 and 91 %, 88 and 92%, 75 and 84% and 83 and 87% for the NCM and CM treatments, respectively. Treatment means did not differ statistically, although there was a tendency towards lower crude protein  digestibility for the NCM treatment. Owing to Ca++ precipitation in the one treatment, apparent ash and calcium digestibility (availability) coefficients were significantly lower for the NCM treatment than for the CM treatment, viz. 65 vs. 83% and 29 vs. 78%, respectively. In Experiment 2 (growth trial), four groups of seven Friesian bull calves, two to four days of age, were used. Whole milk (WM) and a commercial coagulable milk replacer (CM), were used either directly, or after treatment with oxalic acid (NWM and NCM). Body mass-gain (kg) and efficiency of feed conversion (kg dry matter intake/kg gain) over the 28-day  experimental period were respectively 7,3 and 1,8 (WM); 7,3 and 1,8 (NWM); 4,3 and 3,9 (CM) and 4,9 and 2,9 (NCM). Both whole milk treatments were superior to milk replacer treatments, but prevention of coagulation per se had no significant effect on calf performance and on the occurrence of diarrhoea.

Twee pro ewe is uitgevoer om die invloed van voorkoming van koagulering van melk en melksurrogate op skynbare verteerbaarheidskoeffisiente en massatoename van kalwers te bepaal. Twee groepe van vyf Holsteinbulkalwers, tussen twee- en vier-dae-ouderdom, is in Eksperiment 1 gebruik. Een melksurrogaat is geformuleer en kaseienkoagulering is in die een behandeling (NCM) voorkom deur die presipitering van Ca++ met 'n oksaalsuur-natriumhidroksiedbuffer. Die ander groep kalwers (CM) het onbehandelde (koaguleerbare) melksurrogaat ontvang. Skynbare verteerbaarheid van droemateriaal, organiese materiaal, ruproteien en vet was 87 en 91 %, 88 en 92%, 75 en 84% en 83 en 87% vir die NCM- en  CM-behandelings, onderskeidelik. Verskille tussen behandelingsgemiddeldes was nie statisties betekenisvol nie, hoewel daar 'n neiging tot laer ruproteienverteerbaarheid by die NCM-behandeling was. As gevolg van Ca ++ presipitering in die een behandeling, was skynbare as- en kalsiumverteerbaarheid (-beskikbaarheid) betekenisvol laer vir die NCM-behandeling as vir die CM-behandeling, naamlik 65 vs. 83% en 29 vs. 78%, onderskeidelik. In Eksperiment 2 (groeistudie), is vier groepe van sewe Friesbulkalwers, tussen twee- en vier-dae-ouderdom, gebruik. Die behandeling was volmelk (WM), nie-koaguleerbare volmelk (NWM), 'n kommersiele koaguleerbare melksurrogaat (CM) en oksaalsuurbehandelde melksurrogaat (NCM).  Massatoename (kg) oor die 28-dae-proefperiode en doeltreffendheid van voeromsetting (kg droemateriaalinname/kg  massatoename) was onderskeidelik 7,3 en 1,8 (WM); 7,3 en 1,8 (NWM); 4,3 en 3,9 (CM) en 4,9 en 2,9 (NCM). Hoewel albei volmelkbehandelings betekenisvol beter resultate gelewer het as die  melksurrogaatbehandelings, het die voorkoming van koagulering per se geen invloed op kalfprestasie en op die voorkoms van diarree gehad nie.