Development of equations, based on milk intake, to predict starter feed intake of preweaned dairy calves

Abstract

There is a lack of studies that provide models or equations capable of predicting starter feed intake (SFI) for milk-fed dairy calves. Therefore, a multi-study analysis was conducted to identify variables that influence SFI, and to develop equations to predict SFI in milk-fed dairy calves up to 64 days of age. The database was composed of individual data of 176 calves from eight experiments, totaling 6426 daily observations of intake. The information collected from the studies were: birth BW (kg), SFI (kg/day), fluid milk or milk replacer intake (MI; l/day), sex (male or female), breed (Holstein or Holstein×Gyr crossbred) and age (days). Correlations between SFI and the quantitative variables MI, birth BW, metabolic birth BW, fat intake, CP intake, metabolizable energy intake, and age were calculated. Subsequently, data were graphed, and based on a visual appraisal of the pattern of the data, an exponential function was chosen. Data were evaluated using a meta-analysis approach to estimate fixed and random effects of the experiments using nonlinear mixed coefficient statistical models. A negative correlation between SFI and MI was observed (r=-0.39), but age was positively correlated with SFI (r=0.66). No effect of liquid feed source (milk or milk replacer) was observed in developing the equation. Two equations, significantly different for all parameters, were fit to predict SFI for calves that consume less than 5 (SFI5) l/day of milk or milk replacer: ${\rm SFI}_{{\,\lt\,5}} {\equals}0.1839_{{\,\pm\,0.0581}} {\times}{\rm MI}{\times}{\rm exp}^{{\left( {\left( {0.0333_{{\,\pm\,0.0021 }} {\minus}0.0040_{{\,\pm\,0.0011}} {\times}{\rm MI}} \right){\times}\left( {{\rm A}{\minus}{\rm }\left( {0.8302_{{\,\pm\,0.5092}} {\plus}6.0332_{{\,\pm\,0.3583}} {\times}{\rm MI}} \right)} \right)} \right)}} {\minus}\left( {0.12{\times}{\rm MI}} \right)$ ; ${\rm SFI}_{{\,\gt\,5}} {\equals}0.1225_{{\,\pm\,0.0005 }} {\times}{\rm MI}{\times}{\rm exp}^{{\left( {\left( {0.0217_{{\,\pm\,0.0006 }} {\minus}0.0015_{{\,\pm\,0.0001}} {\times}{\rm MI}} \right){\times}\left( {{\rm A}{\minus}\left( {3.5382_{{\,\pm\,1.3140 }} {\plus}1.9508_{{\,\pm\,0.1710}} {\times}{\rm MI}} \right)} \right)} \right)}} {\minus}\left( {0.12{\times}{\rm MI}} \right)$ where MI is the milk or milk replacer intake (l/day) and A the age (days). Cross-validation and bootstrap analyses demonstrated that these equations had high accuracy and moderate precision. In conclusion, the use of milk or milk replacer as liquid feed did not affect SFI, or development of SFI over time, which increased exponentially with calf age. Because SFI of calves receiving more than 5 l/day of milk/milk replacer had a different pattern over time than those receiving <5 l/day, separate prediction equations are recommended.

ADSA Foundation Scholar Award: New frontiers in calf and heifer nutrition—From conception to puberty

“…However, regardless of WM or MR feeding level, solid feed consumption is low during the first 3 wk of life (Quigley et al, 2018). After the initial weeks of life, preweaning starter intake and liquid feed intake are inversely correlated, which may negatively affect preweaning growth (Gelsinger et al, 2016;Silva et al, 2019). Specifically, for each 100 g of MR DMI, starter DMI decreased by 13 g/d at 30 d of age and by ~93 g/d at 60 d of age (Silva et al, 2019).…”

“…After the initial weeks of life, preweaning starter intake and liquid feed intake are inversely correlated, which may negatively affect preweaning growth (Gelsinger et al, 2016;Silva et al, 2019). Specifically, for each 100 g of MR DMI, starter DMI decreased by 13 g/d at 30 d of age and by ~93 g/d at 60 d of age (Silva et al, 2019). Thus, it is thought that feeding a high plane of WM or MR nutrition preweaning causes a decrease in growth rate postweaning, largely due to an inability to consume and digest sufficient quantities of starter for growth (Dennis et al, 2018;Quigley et al, 2018).…”

Effects of 2 liquid feeding rates over the first 3 months of life on whole-body energy metabolism and energy use efficiency of dairy calves up to 5 months

“…The lower MR intake in the 10%-MR group lead to higher DMI of SF (hay, concentrate, and TMR) preweaning in wk 6 to 10, whereas postweaning DMI levels of SF were mostly higher in the 20%-MR group (Tümmler et al, 2020). Although the 10%-MR fed group revealed higher DMI of SF preweaning, which was similarly observed as a linear increase of forage intake with MR reduction (Broesder et al, 1990) or in a model for starter intake (Silva et al, 2019), this effect was not sufficient to compensate for the lower energy intake with MR in this group. Consideration must also be given to the fact that ME of SF might be overestimated because digestibility is lower in young calves and energy from starter is less metabolically available as predicted by NRC ( 2001) models (Quigley et al, 2019).…”

Short communication: Development and evaluation of equations to predict growth of Holstein dairy heifers in a tropical climate

“…The lower precision of the BW~A and BW: H ~A models, when compared with the other equations, was likely due to the dispersion of these measures in older animals, as described above and reported by Cue et al (2012). For all equations, the majority of the MSEP was associated with random effects (>99%; Table 2); this, in association with their high accuracy, demonstrates the models' abilities to predict both actual and precise values (Tedeschi, 2006;Silva et al, 2019).…”

“…The first subset (training subset) was used to obtain the equation parameters, and the second subset (testing subset) was used to test the obtained parameters. After each simulation, the data set was reorganized, and the process was repeated 1,000 times to generate the average of the sensitivity statistics (Silva et al, 2019).…”