Effect of curd suppression of a calf milk replacer fed at increasing levels on nutrient digestibility and body mass-gain

Abstract

Two groups of eight Friesland bull calves each were used in the trial. Calves received a commercial, coagulable milk replacer in which casein coagulation either was normal (CM treatment), or was prevented by the precipitation of Ca⁺⁺ with an oxalic acid-sodium hydroxide buffer (NCM treatment). In both treatments, the daily milk replacer feeding level (percentage of birth mass) was increased from 9% (week 1), to 12% (week 2), 15% (week 3) and 18% (week 4). Calves were weighed at weekly intervals and occurrence of diarrhoea was monitored. At four weeks of age, five calves from each treatment were randomly selected for a digestibility trial of seven days. Body mass-gain and efficiency of feed conversion (kg dry matter/kg gain) were 10,4 kg and 1,7; and 10,7 kg and 1,6 for the CM and NCM treatments, respectively. Digestibility coefficients were 90,2 and 91,1 % (dry matter), 91,9 and 93,6% (organic matter), and 81,0 and 85,6% (crude protein), for CM and NCM respectively. It was concluded that prevention of abomasal curd formation had no effect on body mass-gain, occurrence of diarrhoea, or digestibility of dry matter, organic matter and crude protein. Digestibility coefficients remained high, even at a daily feeding level of 18% of birth mass.

Twee groepe van agt Friesbulkalwers elk is in die proef gebruik. Kalwers het 'n kommersiele, koaguleerbare melksurrogaat ontvang waarin koagulering of normaal was (CM-behandeling), of voorkom is deur die presipitering van Ca⁺⁺ met 'n oksaalsuur-natriumhidroksiedbuffer (NCM-behandeling). Daaglikse melksurrogaatvoedingspeil (persentasie van geboortemassa) het in albei behandelings toegeneem vanaf 9% (week 1), tot 12% (week 2), 15% (week 3) en 18% (week 4). Kalwers is weekliks geweeg en die voorkoms van diarree is gemonitor. Vyf kalwers uit elke groep is op vier-weke-ouderdom ewekansig geselekteer vir 'n verteringsproef van sewe dae. Massatoename en doeltreffendheid van voeromsetting (kg droemateriaal/kg toename) was 10,4 kg en 1,7; en 10,7 kg en 1,6 vir die CM- en NCMbehandelings onderskeidelik. Verteerbaarheidskoeffisiente was 90,2 en 91,1% (droemateriaal), 91,9 en 93,6% (organiese materiaal) en 81,0 en 85,6% (ruprotei'en) vir CM en NCM, onderskeidelik. Die gevolgtrekking is gemaak dat voorkoming van abomasale stolselvorming geen invloed op massatoename, voorkoms van diarree, of die verteerbaarheid van droemateriaal, organiese materiaal en ruprotei'en gehad het nie. Verteerbaarheidskoeffisiente het hoog gebly, selfs teen 'n daaglikse voedingspeil van 18% van geboortemassa.

Keywords: calves, milk replacers, casein, curd formation, digestibility, body mass-gain