The objective of this study was to evaluate the effects of different liquid-feeding systems using a medium crude protein milk replacer on performance, rumen, and blood parameters. Thirty newborn Holstein calves were blocked according to birth weight and date of birth, and randomly distributed to different liquid-feeding systems: conventional (4 L/d), intensive (8 L/d), or step-up/step-down (wk 1, 4 L/d; wk 2 to 6, 8 L/d; wk 7 and 8, 4 L/d). The commercial milk replacer (12.5% solids, 20.2% crude protein, 15.6% fat) was fed twice daily (0700 and 1700 h) until calves were weaned, at 8 wk of age. Calves were individually housed in wood hutches, with free access to water and starter concentrate, and to hay only after weaning. They were followed through 10 wk of age. Milk replacer and starter intake were inversely affected by feeding system. After weaning, starter intake and hay intake were similar among feeding systems. Total dry matter intake was higher during the liquid-feeding period for calves on the intensive system compared to calves on the conventional system, but conventional feeding resulted in the highest dry matter intake after weaning. Feed efficiency was similar among feeding systems before and after weaning. Average body weight and daily gain were not affected by feeding system before or after weaning. During liquid feeding, diarrhea occurrence was lower for calves on the conventional system; however, when calves on the step-up/step-down system were fed lower volumes of liquid feed, diarrhea occurrence was similar to that of calves on the conventional system. Plasma concentrations of β-hydroxybutyrate were higher for calves on the conventional system, reflecting starter intake. Rumen pH, short-chain fatty acids, and N-NH were not affected by feeding system. Feeding higher volumes of milk replacer with a medium crude protein content had no beneficial effect on the performance of calves up to 10 wk of age.

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RESUMO Vinte bezerros mestiços da raça Holandês x Jersey, distribuídos em blocos completos casualizados, foram utilizados para determinar o efeito do fornecimento de probiótico de bactérias ruminais sobre o desempenho e os parâmetros sanguíneos de bezerros leiteiros em sistema de desaleitamento precoce. Os animais foram submetidos ao tratamento controle ou ao fornecimento via oral de 2g de probiótico/dia durante o aleitamento. Os bezerros receberam 6 litros de sucedâneo lácteo por dia divididos em duas refeições diárias e foram desaleitados de forma gradual na 6ª semana de vida, entretanto, as variáveis foram coletadas até a 10ª semana. O consumo de concentrado inicial e o escore fecal foram registrados diariamente. Semanalmente foram realizadas pesagens e medidas corporais como, altura de cernelha, largura de garupa e perímetro torácico. Foram realizadas colheitas de sangue nas semanas, 2, 4, 6, 8 e 10, 2h após o primeiro aleitamento, para determinação de concentrações plasmáticas de glicose, proteína total, albumina, β-hidroxibutirato e cortisol. A suplementação de probiótico não afetou o consumo de concentrado, o peso, o ganho de peso, e as medidas corporais dos animais. Não houve efeito sobre o escore fecal entre os tratamentos. Os parâmetros sanguíneos não foram alterados em resposta ao fornecimento do probiótico, apenas a concentração de cortisol, que foi maior nos animais suplementados. O fornecimento de probiótico de bactérias ruminais não favorece o desempenho e o metabolismo de bezerros leiteiros em sistema de desaleitamento precoce.

The aim of the present study was to evaluate the effect of replacing corn grain with citrus pulp (CSP) in the starter concentrate on performance and metabolism of dairy calves. Twenty-four individually housed Holstein calves were blocked according to birth date and weight and fed one of the following concentrates: (1) concentrate containing 64% corn and 0% CSP (0CSP); (2) concentrate containing 32% corn and 32% CSP (32CSP); and (3) concentrate containing 0% corn and 64% CSP (64CSP). Animals were fed 4 L of milk replacer daily (20% crude protein, 16% ether extract) divided in two meals (at 0700 hours and 1800 hours). The starter feed and water were provided ad libitum. Starter intake and faecal score were monitored daily. Bodyweight and measurements (withers height, hip width and heart girth) were recorded weekly. Blood samples were collected weekly, and ruminal fluid samples at 4, 6 and 8 weeks of age, 2 h after the morning feeding. After 8 weeks, animals were harvested to evaluate the development of the proximal digestive tract. Concentrate composition had no effect (P > 0.05) on concentrate intake, weight gain, bodyweight, body measurements, and faecal score. However, there was a lower concentration of ruminal butyrate (P < 0.05) in animals receiving 0CSP than in those fed the starter containing CSP. The 0CSP concentrate resulted in a lower (P < 0.05) total weight of the proximal digestive tract, weight of the reticulum–rumen and weight of the omasum than did the other concentrates. The length of the rumen papillae was the greatest (P < 0.05) in 32CSP-fed animals. However, papillae area in animals fed 32CSP concentrate was larger (P < 0.05) than that in 0CSP- and 64CSP-fed animals, with no difference observed between these latter two treatments. However, 0CSP-fed animals showed a higher proportion of abomasum than did the animals fed 32CSP and 64CSP concentrates. The replacement of 50% or 100% of corn by CSP in the starter feed of dairy calves did not affect performance and probably contributed to the better development of the proximal digestive tract.

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The aim of this study was to evaluate the effect of replacing corn grain for sugar cane molasses (MO) or glucose syrup (GS) in the starter concentrate on performance and metabolism of dairy calves. Thirty-six individually housed Holstein male calves were blocked according to weight and date of birth and assigned to one of the starter feed treatments, during an 8 week study: i) starter containing 65% corn with no MO or GS (0MO); ii) starter containing 60% corn and 5% MO (5MO); iii) starter containing 55% corn and 10% MO (10MO); and iv) starter containing 60% corn and 5% GS (5GS). Animals received 4 L of milk replacer daily (20 crude protein, 16 ether extract, 12.5% solids), divided in two meals (0700 and 1700 h). Starter and water were provided ad libitum. Starter intake and fecal score were monitored daily until animals were eight weeks old. Body weight and measurements (withers height, hip width and heart girth) were measured weekly before the morning feeding. From the second week of age, blood samples were collected weekly, 2 h after the morning feeding, for glucose, β-hydroxybutyrate and lactate determination. Ruminal fluid was collected at 4, 6, and 8 weeks of age using an oro-ruminal probe and a suction pump for determination of pH and short-chain fatty acids (SCFA). At the end of the eighth week, animals were harvested to evaluate development of the proximal digestive tract. The composition of the starter did not affect (p>0.05) concentrate intake, weight gain, fecal score, blood parameters, and rumen development. However, treatment 5MO showed higher (p<0.05) total concentration of SCFAs, acetate and propionate than 0MO, and these treatments did not differ from 10MO and 5GS (p>0.05). Thus, it can be concluded that the replacement of corn by 5% or 10% sugar cane molasses or 5% GS on starter concentrate did not impact performance, however it has some positive effects on rumen fermentation which may be beneficial for calves with a developing rumen.

The purpose of this study was to evaluate the effect of partial replacement of corn in the starter feed with crude glycerin on performance and energy metabolism of liquid-fed dairy calves. Twenty-four newborn individually housed Holstein calves were blocked according to weight and date of birth and randomly assigned to different starter feed treatments during 8 weeks: no crude glycerin; 5% crude glycerin; 10% crude glycerin on dry matter basis. All calves were individually fed daily 4 L of a commercial milk replacer (22.3% crude protein and 19.3% fat). Calves had individual access to starter diet and ad libitum access to water daily. Individual feed intake and faecal scores were recorded daily. Bodyweight and corporal measurements (heart girth, hip width, and withers height) were weekly recorded. From the second week of age, blood samples were collected weekly, 2 h after morning feeding, for determination of plasma glucose and β-hydroxybutyrate concentrations. Ruminal fluid was collected at 4, 6 and 8 weeks of age for determination of pH and short-chain fatty acids. At the end of the eighth week, animals were harvested to evaluate development of the proximal digestive tract. Feed intake, average daily gain, bodyweight or body measurements were not affected (P > 0.05) by the inclusion of crude glycerin in the starter feed. Faecal scores indicated that most of the calves had mild diarrhoea, with no treatment effect. Total short-chain fatty acids and the concentration of individual acids, as well as blood parameters, were not affected (P > 0.05) by the feed treatments. The total forestomach weight, the average weight of each compartment, the maximum capacity of reticulum-rumen, and papillae number, height and width were not affected (P > 0.05). In conclusion, crude glycerin can be used as an alternative energy source, replacing corn up to 10% in the starter feed for liquid-fed dairy calves without affecting growth, rumen development or metabolism.