Effects of exchanging lactose for fat in milk replacer on ad libitum feed intake and growth performance in dairy calves

Abstract

The recent trend in the dairy industry toward ad libitum feeding of young calves merits reconsideration of calf milk replacer (CMR) formulations. Additionally, feed intake regulation in young calves provided with ad libitum milk and solid feeds is insufficiently understood. This study was designed to determine the effect of exchanging lactose for fat in CMR on voluntary feed intake and growth performance. Lactose was exchanged for fat on a weight/weight basis, resulting in different energy contents per kilogram of CMR. Thirty-two male calves (1.7 ± 0.12 d of age, 47.6 ± 0.83 kg of body weight) were assigned to 1 of 16 blocks based on arrival date. Within each block, calves were randomly assigned to 1 of 2 treatments. The experimental period was divided into 4 periods. In period 1, until 14 ± 1.7 d of age, calves were individually housed, restricted-fed their assigned CMR treatments at 2.5 to 3 L twice daily, and provided with unlimited access to water, chopped straw, and starter. In period 2, calves were group-housed with 8 calves per pen and received ad libitum access to their assigned CMR treatments, starter feed, chopped wheat straw, and water. During period 3, from 43 until 63 d of age, calves were weaned by restricting CMR allowance in 2 steps, maintaining access to all other feeds. All calves were completely weaned at d 64 of age and were monitored until 77 d of age (period 4). Measurements included the intake of all dietary components, body weight gain, and a selection of blood traits. Increasing fat content at the expense of lactose decreased CMR intake by 10%, whereas total calculated metabolizable energy intake and growth remained equal between treatments. Total solid feed (starter and straw) consumption was not affected by CMR composition. These data indicate that calves fed ad libitum regulate their CMR intake based on energy content. High-fat CMR increased plasma phosphate, nonesterified fatty acids, triglycerides, and bilirubin, whereas plasma glucose remained unchanged. Despite the limited animal numbers in the present experiment, there was a significant decrease in the total number of health events (mainly respiratory) requiring therapeutic intervention and in the total number of therapeutic interventions in calves fed high-fat CMR. Calves appeared to consume CMR based on energy content, with a difference in ad libitum intake proportional to the difference in energy content of the CMR, maintaining equal body weight gain and solid feed intake.

Effect of partial exchange of lactose with fat in milk replacer on ad libitum feed intake and performance in dairy calves

“…One of the most reliable parameters to consider in calf performance is growth (ADG). Based on the outcome of a previous study conducted at the same facility by Berends et al (2020) with 32 calves allocated into 2 treatments and fed ad libitum milk allowances, at 84 d of age, a standard deviation of 0.128 kg/d was assumed for ADG. The minimal meaningful difference in ADG was considered to be 0.125 kg/d.…”

“…Compared with Holstein whole milk, and even considering its natural variability, some conventional MR formulations provide high amounts of lactose (40-50% DM in MR vs. 33-38% DM in whole milk; Pantophlet et al, 2016), low concentrations of fat (16-22% vs. 30-40% DM; Berends et al, 2020), high amounts of ash (9-12% vs. 7-9% DM; Gaucheron, 2005), and comparable CP levels (20-26% vs. 25-27% DM; Morrison et al, 2017;Chapman et al, 2017). The high lactose content in MR may derive partly from historical availability of milk byproducts from cheese and butter production, which, combined with the traditional industry targets for lean growth and low feed costs, discourages fat inclusions in MR formulation (Berends et al, 2020). Consequently, MR provides a lower dietary energy density (~4.7 Mcal of ME/kg of DM) than whole milk (~5.4 Mcal of ME/kg of DM; Drackley, 2008).…”

“…Nevertheless, higher fat intake from the liquid diet has been linked to decreased mortality in calves (Urie et al, 2018). Additionally, higher fat inclusion in MR has been linked to improved health in terms of fecal consistency (23% vs. 17% fat inclusion; Amado et al, 2019) and reduced respiratory therapeutic interventions (31% vs. 21% fat inclusion; Berends et al, 2020). Furthermore, metabolic signals derived from glucose utilization and fatty acid oxidation have been suggested to play an important role in regulating feed intake (Langhans, 1996) and feeding behavior (Laviano et al, 2018).…”

Inclusão de lisolecitina ou β-glucanas na dieta líquida de bezerros leiteiros: efeitos no desempenho, saúde e metabolismo

“…Indeed, it is much more likely that simply MR fatty acid composition differs from whole milk, and emulsification may be more important when vegetable sources of fat are fed (Raven and Robinson, 1964). Recent research has shown that feeding high-fat content MR, at the expense of lactose, can improve performance in intensively fed calves (Berends et al, 2020). However, one limitation to Berends et al, (2020) was the lack of description on which emulsifiers were used in the milk replacer.…”

“…Recent research has shown that feeding high-fat content MR, at the expense of lactose, can improve performance in intensively fed calves (Berends et al, 2020). However, one limitation to Berends et al, (2020) was the lack of description on which emulsifiers were used in the milk replacer. According to Boerman et al (2015), for adult ruminants, FA digestibility is inversely correlated to intake and flow of FA, with FA profile being also a critical factor.…”