Reduction of phosphorus concentration in mineral supplement on fertility rate, maternal ability and costs of beef cows reared in pastures of Urochloa decumbens

Abstract

Manufacturing and marketing of mineral mixtures with less than 40 g kg(-1) phosphorus (P) is prohibited under Brazilian regulations, although scientific evidence rejects this recommendation. Considering the hypothesis that P levels in commercial mineral supplements can be reduced without affecting animal performance and health, the objective of this experiment was to evaluate the effects of reducing the concentration of P in the mineral supplement (from 40 to 18 g kg(-1)) of a herd of beef cows grazing tropical pastures of signal grass (Urochloa decumbens). The experiment was carried out in the savanna region of Mato Grosso do Sul, Brazil, during the years 2011 to 2013. Variables analyzed included pregnancy rate, calving interval, weight of calves at weaning, and cost of mineral supplementation. There were no changes in the reproductive parameters of the herd and the weight at weaning of the calves. However, the cost of mineral supplementation was significantly lower when the herd was supplemented with the mineral mix containing only 18 g kg(-1) P. Phosphorus concentration of the forage was analyzed monthly during 1 year and averaged 1.9 ± 0.45 g kg(-1) DM. Thus, it appears possible to reduce P content and cost of mineral supplementation without any adverse effects on the health and productivity of beef cattle herds in the State of Mato Grosso do Sul. However, the final decision should be made based on the clinical-nutritional examination and by constant technical assistance to the farm.

Bio-economic evaluation of a reduced phosphorus supplementation strategy for a cow-calf system in Brazil: a case study

“…Similar results were found in Brazil by Peixoto et al (2003) that evaluated the reproductive performance of about 1200 breeders, for 5 years, and found no differences in FR when cows were fed SMS or a CMS. Costa et al (2016) supplemented Nellore cows with CMS (40 g P/kg) or a SMS (18 g P/kg) and obtained similar results on FR.…”

“…Alternatively, the selective mineral supplementation (SMS) is based on a previous clinical-nutritional examination of the herd, indentification of minerals that are deficient, and the supplying adequate amounts of specific minerals, in particular P. The use of SMS allows significant economy with MS in comparison to a CMS (Costa et al 2016).…”

Influence of organic phosphorus on reproductive performance and metabolic profiles of anoestrous Farafra ewes in subtropics at the end of breeding season

“…Our results concerning the improvement of ewes’ reproduction and health are in agreement with studies in other species (Orden et al., ; Phiri et al., ). Decreased phosphorus concentration as a mineral supplement did not modify the reproductive parameters in beef cows (Costa, Ponsano, de Souza, & Malafaia, ) while others reported that phosphorus in mineral supplements was associated with good reproductive performance in ruminants (McDowell, Conrad, Ellis, & Loosli, ). It is well known that phosphorous is an important element for normal reproduction (Kumar, ).…”

In situ and in vitro estimation of mineral release from common feedstuffs fed to cattle

“…Despite this, two points may be considered in this context for reducing mineral input for cattle. First, in most tropical areas, cattle depend exclusively on forages to meet their mineral requirements (Perdomo et al 1977; Ibrahim et al 1998; Costa e Silva et al 2015; Costa et al 2016). Second, when mineral supply in a production system is reduced, environmental excretion and costs are reduced (Khorasani et al 1997; Humer & Zebeli 2015).…”