Gastrointestinal structure and function of preweaning dairy calves fed a whole milk powder or a milk replacer high in fat.

The composition of milk replacer (MR) for calves greatly differs from that of bovine whole milk, which may affect gastrointestinal development of young calves. In this light, the objective of the current study was to compare gastrointestinal tract structure and function in response to feeding liquid diets having a same macronutrient profile (e.g., fat, lactose, protein) in calves in the first month of life. Eighteen male Holstein calves (46.6 ± 5.12 kg; 1.4 ± 0.50 d of age at arrival; mean ± standard deviation) were housed individually. Upon arrival, calves were blocked based on age and arrival day, and, within a block, calves were randomly assigned to either a whole milk powder (WP; 26% fat, DM basis, n = 9) or a MR high in fat (25% fat, n = 9) fed 3.0 L 3 times daily (9 L total per day) at 135 g/L through teat buckets. On d 21, gut permeability was assessed with indigestible permeability markers [chromium (Cr)-EDTA, lactulose, and d-mannitol]. On d 32 after arrival, calves were slaughtered. The weight of the total forestomach without contents was greater in WP-fed calves. Furthermore, duodenum and ileum weights were similar between treatment groups, but jejunum and total small intestine weights were greater in WP-fed calves. The surface area of the duodenum and ileum did not differ between treatment groups, but the surface area of the proximal jejunum was greater in calves fed WP. Urinary lactulose and Cr-EDTA recoveries were greater in calves fed WP in the first 6 h post marker administration. Tight junction protein gene expression in the proximal jejunum or ileum did not differ between treatments. The free fatty acid and phospholipid fatty acid profiles in the proximal jejunum and ileum differed between treatments and generally reflected the fatty acid profile of each liquid diet. Feeding WP or MR altered gut permeability and fatty acid composition of the gastrointestinal tract and further investigation are needed to understand the biological relevance of the observed differences.

Genome-based selection and application of food-grade microbes for chickpea milk fermentation towards increased L-lysine content, elimination of indigestible sugars, and improved flavour.

BACKGROUND: Plant-based milk alternatives are more popular than ever, and chickpea-based milks are among the most commercially relevant products. Unfortunately, limited nutritional value because of low levels of the essential amino acid L-lysine, low digestibility and unpleasant taste are challenges that must be addressed to improve product quality and meet consumer expectations. RESULTS: Using in-silico screening and food safety classifications, 31 strains were selected as potential L-lysine producers from approximately 2,500 potential candidates. Beneficially, 30% of the isolates significantly accumulated amino acids (up to 1.4 mM) during chickpea milk fermentation, increasing the natural level by up to 43%. The best-performing strains, B. amyloliquefaciens NCC 156 and L. paracasei subsp. paracasei NCC 2511, were tested further. De novo lysine biosynthesis was demonstrated in both strains by 13C metabolic pathway analysis. Spiking small amounts of citrate into the fermentation significantly activated L-lysine biosynthesis in NCC 156 and stimulated growth. Both microbes revealed additional benefits in eliminating indigestible sugars such as stachyose and raffinose and converting off-flavour aldehydes into the corresponding alcohols and acids with fruity and sweet notes. CONCLUSIONS: B. amyloliquefaciens NCC 156 and L. paracasei subsp. paracasei NCC 2511 emerged as multi-benefit microbes for chickpea milk fermentation with strong potential for industrial processing of the plant material. Given the high number of L-lysine-producing isolates identified in silico, this concept appears promising to support strain selection for food fermentation.

Advocacy, Strategy and Tactics Used to Confront Corporate Power: The Nestlé Boycott and International Code of Marketing of Breast-milk Substitutes.

Douglas A. Johnson began his career as a human rights activist while earning his undergraduate degree in philosophy (1975) at Macalester College in the United States. He lived at Gandhi's ashram in India to study nonviolent organizing (1969 to 1970). He served as the director of the Third World Institute in Minneapolis, MN, USA (1973-1979), which functioned as the international social justice program of the Archdiocese of Minneapolis and St. Paul. Johnson's work included creating and running a political collective; leading development study tours into villages in Guatemala and Honduras; and investigating how transnational companies (e.g., Nestlé) were penetrating the developing world. He was the co-founder of the Infant Formula Action Coalition (INFACT), elected national chairperson (1977-1985), and appointed as Executive Director (1978-1984). His role included representing INFACT before national and international organizations, the human milk substitute industry, the US Congress and Executive Branch, and the press. He initiated and coordinated the first international grass-roots consumer boycott (against Nestlé) in ten nations. He was also a co-founder of the International Nestlé Boycott Committee and the International Baby Food Action Network (IBFAN). He earned a Master's in Public and Private Management at Yale University (1988). Then he became the first Executive Director of the Center for Victims of Torture, in Minneapolis (1988-2012), the first treatment center for torture victims in the US. Since 2013, he has been teaching human rights theory and practice, and sharing lessons he has learned, as a Lecturer in Public Policy at the Harvard Kennedy School, Harvard University (US). (This interview was conducted via Zoom and transcribed verbatim. It has been edited for ease of readability. DJ refers to Doug Johnson and LD refers to Laura Duckett.).

Influence of dietary fructose supplementation on visceral organ mass, carbohydrase activity, and mRNA expression of genes involved in small intestinal carbohydrate assimilation in neonatal calves.

The hypothesis of this experiment was that dietary fructose would influence visceral organ mass, carbohydrase activity, and mRNA expression of carbohydrases and nutrient transporters in the small intestine in neonatal calves. Therefore, our objective was to use the neonatal calf as a model to evaluate the effects of postruminal fructose supply on small intestinal carbohydrate assimilation. Ten calves (<7 d of age; 41.2 ± 1.46 kg of body weight) were fed milk replacer at 2.0% of body weight daily (816 ± 90.5 g/d; 272 ± 30.1 g/L; dry-matter basis) in 2 equal portions and assigned to the following dietary treatment groups: (1) milk replacer (control; n = 6) or (2) milk replacer + 2.2 g of fructose/kg of body weight (fructose; n = 4). Calves were fed dietary treatments for 28 d, with jugular blood sampled every 7 d before and after the morning feeding. Calves were slaughtered, and visceral weights were recorded. Postruminal carbohydrase activities were assayed. Quantitative real-time PCR was conducted for small intestinal mRNA expression of nutrient transporters [solute carrier family 2 member 5 (GLUT5), solute carrier family 2 member 2 (GLUT2), and solute carrier family 5 member 1 (SGLT1)], carbohydrases (lactase, maltase-glucoamylase, and sucrase-isomaltase), and ketohexokinase (KHK). Data were analyzed using MIXED procedures in SAS version 9.4 (SAS Institute Inc, Cary, NC). Dietary fructose supplementation decreased serum glucose concentration. Small intestinal mass was greater in calves supplemented with fructose. Dietary fructose supplementation did not influence pancreatic α-amylase, small intestinal isomaltase, or maltase activities. Sucrase activity was undetected in the small intestine. Dietary fructose supplementation increased small intestinal glucoamylase activity per gram of tissue by 30% and increased maltase-glucoamylase mRNA expression by 6.8-fold. Dietary fructose supplementation did not influence mRNA expression of GLUT5, SGLT1, GLUT2, or KHK. Dietary fructose supplementation increased small intestinal lactase mRNA expression by 3.1-fold. Sucrase-isomaltase mRNA expression in the small intestine decreased 5.1-fold with dietary fructose supplementation. Dietary fructose supplementation does not induce sucrase activity in neonatal calves; however, sucrase-isomaltase may be transcriptionally regulated by dietary fructose in neonatal calves. More research is needed to compare glucose and fructose at isocaloric intakes to examine effects of dietary fructose at equal metabolizable energy intake.

Technical note: Is fecal consistency scoring an accurate measure of fecal dry matter in dairy calves?

The objective of this cross-sectional study was to evaluate the accuracy of fecal consistency scoring as a measure of fecal dry matter (DM) in dairy calves. This study was conducted at a commercial grain-fed veal facility in southwestern Ontario. A total of 160 calves arrived at the facility in 2 groups of 80 calves each. Calves were fed milk replacer twice daily at 0700 and 1700 h and had ad libitum access from arrival onward to water through nipple drinkers and starter through a shared trough. Fecal consistency scores were evaluated once daily in the first 28 d after arrival before milk feeding. The fecal consistency scoring was conducted using a 4-level scoring scale: 0 = normal (firm but not hard); 1 = soft (does not hold form, piles but spreads slightly); 2 = runny (spreads readily); and 3 = watery (liquid consistency, splatters). Fecal samples were collected from all calves via rectal palpation on d 1, 7, 14, and 21 at 0900 h for determination of fecal DM. Mixed repeated measures linear regression models were built to assess the accuracy of fecal consistency scoring in predicting fecal DM. Over 4 selected time points (d 1, 7, 14, and 21) the 160 calves were observed, 382 (61.6%) had a fecal consistency score of 0, 121 (19.5%) had a score of 1, 85 (13.7%) had a score of 2, and 32 (5.2%) had a score of 3. A fecal score of 0 had a fecal DM of 25.1 ± 8.4%, whereas a fecal score of 1 had a DM of 21.8 ± 8.2%. With respect to calves that had a fecal score of 2 or 3, their fecal DM was 16.0 ± 11.1% and 10.7 ± 6.9%, respectively. In evaluating the pairwise comparisons generated in the repeated measures model that controlled for day of sampling, a fecal score of 0 had a 3.2%, 8.1%, and 12.0% higher fecal DM, respectively, when compared with those that had a fecal score of 1, 2, and 3. In addition, calves with a fecal score of 1 had a 5.0% and 8.8% higher fecal DM than calves with a fecal score of 2 and 3, respectively. Finally, calves with a fecal score of 2 had a 3.8% higher fecal DM than those with a fecal score of 3. This study confirms that using observational fecal consistency scoring can accurately predict diarrhea or a decline in fecal DM.

Effects of feeding frequency and protein source in milk replacer for Holstein calves.

Whey proteins are a primary component of milk replacers (MR) and are considered the gold standard for calves. Alternative protein sources may decrease MR cost if calf performance is similar. A blend of bovine plasma protein and modified wheat protein might be a good partial replacement for whey protein. Usually MR is fed twice daily, but feeding 3 times daily might increase efficiency of nutrient use, especially with MR containing alternate proteins. Therefore, our objective was to determine the effects of 2 MR, containing either entirely whey protein (CON) or a combination of whey protein, bovine plasma protein, and modified wheat protein (WBP), when fed in either 2 or 3 meals daily on calf growth and health. Female and male Holstein calves (n = 103) housed in individual hutches were studied for the first 63 d of life, with additional measurements obtained at wk 12 of life in group housing. The MR contained 25% CP, 17% fat, and a Lys:Met ratio of 3.1:1. Individual treatments arose from the 2 × 2 factorial arrangement of MR formulation and frequency of feeding. After colostrum, calves were fed MR (12.5% solids) at daily rates of dry matter dependent on age. Amounts were as follows: d 3 to 10 = 0.52 kg/d (2× = 0.259 kg, 3× = 0.173 kg per feeding); d 11 to 20 = 0.68 kg/d (2× = 0.341 kg, 3× = 0.227 kg per feeding); d 21 to 42 = 0.84 kg/d (2× = 0.42 kg, 3× = 0.28 kg per feeding); d 43 to 46, 47, 49, and 51 = 0.42 kg/d, with both 2× and 3× changed to 1 feeding daily and skip days (d 48 and 50) between where calves were not given MR; and d 52 = calves weaned. Starter was fed and intake was measured from d 1 until d 63. Intakes, health scores, attitude scores, and fecal scores were measured daily. Body weight (BW) and growth measurements were obtained weekly until wk 8 and again at wk 12. Blood samples were obtained at 0, 24, and 48 h and then on d 5, 14, 28, and 42 of age. Starter intake was greater for calves fed WBP versus CON during wk 7 to 9. Final BW and hip width at wk 12 were greater for calves fed WBP than for calves fed CON. Calves fed 2× had greater mean and final BW to wk 6 and greater feed efficiency (gain:feed ratio) than calves fed 3×. Blood variables supported the generally similar growth outcomes. Health outcomes did not differ between diets or feeding frequencies. Overall, calves fed WBP had increased starter intake and greater BW gains during wk 7 to 12 than calves fed CON, and calves fed 2× had increased growth and feed efficiency compared with those fed 3×.

Postweaning response on growth and nutrient digestion to using different weaning strategies when feeding moderate and high amounts of milk replacer to Holstein calves.

Many changes occur in the rumen as calves transition from consuming a liquid diet to a completely solid diet. These changes can influence growth and calf health, being greatly affected by preweaning diet as well as the transitional steps used to wean calves. A 2 × 2 factorial design of moderate [MOD; 0.66 kg of dry matter (DM)] or high (HI; up to 1.1 kg of DM) feeding rates of milk replacer (MR) and abrupt (AB; 7-d step-down) or gradual weaning (GR; 21-d step-down) was used to study how preweaning program affects calf performance from 2 to 4 mo of age. Calves (n = 50) were randomly assigned to 1 of the 4 preweaning treatments. For the following 56-d grower portion of the experiment, calves were grouped into 12 pens based on MR program, with 4 to 5 calves per pen. Data were analyzed as a completely randomized design, with repeated measures when applicable, by PROC MIXED in SAS (version 9.4; SAS Institute Inc., Cary, NC). All calves received ad libitum access to water and a textured starter [42% starch and 20% crude protein (CP)] blended with 5% chopped grass hay. Overall, apparent digestibility coefficients (dC) of DM, neutral detergent fiber, and acid detergent fiber were greater for MOD compared with HI, and apparent dC of DM and ADF were greater for GR than for AB. No significant differences were detected between organic matter, CP, fat, starch, or sugar dC based on treatment, and no interactions were observed. However, by d 56 only starch dC differed by treatment. Weaning body weight (BW), hip width (HW), and hip height (HH) were greater for HI compared with MOD calves. Weaning HH was greater for AB than for GR calves. However, final BW, HW, HH, and body condition score, as well as average daily gain, did not differ among treatments. An interaction occurred where feed efficiency (gain/feed) was reduced with GR weaning in MOD, whereas the opposite occurred in the HI group. When feeding calves a moderate level of MR, a several-step gradual weaning is not necessary to ensure growth and development; however, calves should be gradually weaned when offered a high level of MR.

Effects of 2 colostrum and subsequent milk replacer feeding intensities on methane production, rumen development, and performance in young calves.

A growing need exists for the development of practical feeding strategies to mitigate methane (CH4) emissions from cattle. Therefore, the objective of this study was to evaluate the influence of milk replacer feeding intensity (MFI) in calves on CH4 emission, rumen development, and performance. Twenty-eight female newborn Holstein calves were randomly assigned to 2 feeding groups, offered daily either 10% of the body weight (BW) in colostrum and subsequently 10% of the BW in milk replacer (MR; 10%-MR), or 12% of the BW in colostrum followed by 20% of the BW in MR (20%-MR). In wk 3, half of each feeding group was equipped with a permanent rumen cannula. Both groups were weaned at the end of wk 12. Hay and calf starter (mixture of pelleted grains) were offered from d 1 until wk 14 and 16, respectively. A total mixed ration was offered from wk 11 onward. Feed intake was measured daily and BW, anatomical measures, and rumen size weekly. Methane production and gastrointestinal passage rate were measured pre-weaning in wk 6 and 9 and post-weaning in wk 14 and 22, with additional estimation of organic matter digestibility. Rumen fluid, collected in wk 1, 2, 3, 6, 9, 14, 18, and 22, was analyzed for volatile fatty acid concentrations. Although the experimental period ended in wk 23, rumen volume of 17 calves was determined after slaughter in wk 34. Data was analyzed using ANOVA for the effects of feeding group, cannulation, and time, if applicable. Dry matter intake (DMI) of solid feed (SF) in 20%-MR animals was lower pre-weaning in wk 6 to 10 but mostly higher post-weaning. From wk 6 onward, anatomical measures and BW were greater in 20%-MR animals, and only the differences in body condition score gradually ceased post-weaning. Following the amount of SF intake, 10%-MR calves emitted more CH4 pre-weaning in wk 9, whereas post-weaning the 20%-MR group tended to have higher levels. Methane emission intensity (CH4/BW) was lower pre-weaning in 20%-MR animals but was comparable to the 10%-MR group post-weaning. Methane yield (CH4/DMI of SF) and estimated post-weaning organic matter digestibility were not affected by MFI. Rumen size normalized to heart girth was greater in 10%-MR calves from wk 5 to 10, but differences did not persist thereafter. In wk 34, rumen volume was higher in 20%-MR calves, but normalization to BW revealed no difference between feeding groups. In conclusion, high MFI reduces CH4 emission from calves pre-weaning, although this effect ceases post-weaning.

Gradual weaning does not improve performance for calves with low starter intake at the beginning of the weaning process.

The weaning process may cause intense stress for dairy calves, even when low volumes of liquid diet are fed. Management tools that increase the intake of solid feeds, such as gradual weaning, can provide better physiological and metabolic conditions through better ruminal development, leading to better adaptation to ruminant metabolism and aiding in stress mitigation. The objective of this study was to evaluate the effects of 2 weaning protocols and 2 levels of concentrate intake on the performance and physiological and behavioral variables related to stress in dairy calves. Thirty-six newborn male Holstein calves were used in a randomized block design with a 2 × 2 factorial arrangement: 2 weaning strategies, abrupt or gradual, and 2 levels of concentrate intake at 5 wk of age, high (>350 g/d) or low (≤350 g/d). Calves were equally managed until they were 5 wk of age and then grouped according to concentrate intake. Statistical analyzes were performed using the MIXED procedure of SAS software (SAS Institute Inc., Cary, NC), and no significant interaction was observed between studied factors (weaning method and starter intake level); therefore, we considered each factor separately and their interactions with age. The highest dry matter intake and concentration of ß-hydroxybutyrate were recorded for animals with a high level of starter intake independent of the weaning method. Structural growth (cm/wk) and average daily gain were superior for calves with high starter intake, but weaning method had no effect. The gradual weaning protocol increased the time eating starter, regardless of the level of concentrate intake. Even animals with low concentrate intake that were weaned abruptly showed levels of cortisol and acid-soluble glycoprotein within normal physiological levels. Apparently, other factors besides the milk supply affect the starter intake level of calves in a conventional feeding program. The adoption of gradual weaning is not effective in improving performance when a calf has low intake 3 wk before weaning is complete, but it reduced vocalization on d 2 postweaning.

A virtual dairy herd as a tool to teach dairy production and management.

The objective of this project was to develop and test a web-based virtual dairy herd to help students understand the structure and functioning of a dairy herd, and to promote active learning. At the beginning of the course, the instructor defines the profiles of herds to be assigned to students (e.g., herd size, production, diets, fertility). Each student has a unique herd and engages in decision-making for desired management practices in the herd. Modeled events are based on cow physiology and normal dairy herd management practices. Students' activities and decisions include heat detection, insemination, pregnancy diagnosis, dry-off, diet specifications, feeding groups, colostrum and milk-replacer feeding, weaning, treatment of diseases, and milk withdrawal from the tank if antibiotics are used, among others. The daily output provides information on technical indexes, economic performance, counters of incorrect decisions as feedback for students, and score. Time in class can be devoted to discussions of dairy management issues. Additional exercises based on students' own herds (e.g., calculating required space for cows, land for forage production, manure management) can also be implemented. Students' performance in the virtual dairy farm was monitored over 3 years. The average score (n = 326) was 87.8 ± 1.1 over 100 points, suggesting that self-learning with the virtual dairy farm was highly successful. At the end of each semester, students (n = 277) responded to a survey on the experience of working with the virtual dairy herd. Most students (>87%) agreed that the virtual dairy herd was more effective and motivating than traditional lectures and helped them understand dairy production better. In an unannounced test conducted at least 2 wk before the final exam, students (n = 207) were asked 14 questions on dairy cattle and 14 similar questions on other species taught in the same class through traditional lectures. A similar test on the same students (n = 142) was conducted in their fifth semester (2 years later). Results were better in dairy compared with other species questions in the first (9.6 vs. 3.7) and fifth (8.0 vs. 3.8) semesters. The virtual dairy herd is an effective tool for teaching introductory courses in dairy production. The program can be accessed at www.virtualdairyfarm.org, and a manual and videos with instructions for instructors and students are available online.

Physiological effects of starter-induced ruminal acidosis in calves before, during, and after weaning.

The objectives were to nutritionally induce or blunt ruminal acidosis in young calves and to compare indicators of rumen and systemic health. Ten bull calves (n = 5/diet) were ruminally cannulated at 3 wk of age and received milk replacer and 1 of 2 calf starter diets that were designed to cause (AC; pelleted, 42.7% starch, 15.1% neutral detergent fiber, 57.8% nonfiber carbohydrates) or blunt (BL; texturized, 35.3% starch, 25.3% neutral detergent fiber, 48.1% nonfiber carbohydrates) ruminal acidosis. Mean birth weight was 38.7 ± 1.3 kg. Body weight and calf starter intake were measured weekly. Rumen contents were sampled at -8, -4, 0, 2, 4, 8, 12, and 24 h relative to starter feeding during wk 6, 8, 10, 12, 14, and 16 of age. Blood was collected from the jugular vein during the same weeks for complete blood cell count, blood pH, and partial pressures of oxygen and carbon dioxide. Rate of starter consumption was assessed during wk 16. Marker systems were used to estimate liquid passage and volatile fatty acid absorption rates. Calves were slaughtered at 17 wk, and rumen tissue was collected and assessed for papillae length, width, and degree of tissue degradation. Mean ruminal pH ± standard error was 5.37 ± 0.24 and 5.63 ± 0.24 for AC and BL calves, respectively. Lowest pH values were observed the week after weaning. Total ruminal volatile fatty acid concentrations were 131.5 and 124.8 ± 2.4 mM in AC and BL calves, respectively, and increased with age and time after feeding. Dry matter intake was lower in AC calves at wk 4 and remained lower through wk 16. Rate of starter consumption was also lower in AC calves at wk 16. Body weight also was also lower for AC calves from wk 5 through 16. Blood hemoglobin and hematocrit were lower in AC calves, but other blood characteristics were not different. Rumen volume increased with age and tended to be greater in BL calves. Passage rate and papillae length and width were not different between diets, but AC calves experienced a greater degree of tissue degradation. Ruminal acidosis symptoms in calves appear similar to those in adult cattle, and the etiology of the disease seems to follow similar mechanisms. It is clear from this study that symptoms can be moderated by diet, but further research is needed to determine whether symptoms can be nutritionally prevented or whether calves that experience ruminal acidosis are more susceptible to the disease as adults.

Effects of feeding a high- or moderate-starch prepartum diet to cows on newborn dairy heifer calf responses to intravenous glucose tolerance tests early in life.

The objective of this study was to evaluate the effect of feeding a prepartum diet with a high or moderate starch content on growth and insulin sensitivity of female offspring early in life. Thirty-eight Holstein heifer calves were born to dams fed either a high-starch (26% starch on a DM basis, HI; n = 20) or moderate-starch (14% starch on a DM basis, MOD; n = 18) prepartum diet commencing at 28 ± 3 d before expected parturition date. Following birth, all calves were housed individually and fed three 2-L meals of colostrum within the first 24 h of life and offered 10 L/d of milk replacer (26% CP, 18% fat, mixed to 130 g/L). Body weight of calves was measured at birth and on d 2 (after colostrum feeding but before milk feeding), 10 ± 2, and 20 ± 2. A glucose tolerance test was performed at a minimum of 6 h after their last colostrum or milk meal to evaluate insulin sensitivity on d 2, 10 ± 2 and 20 ± 2. Body weight did not differ throughout between HI and MOD calves; however, calves born to primiparous dams were smaller compared with those born to multiparous dams. Glucose or insulin concentrations were not different before the glucose tolerance test. Following the glucose tolerance test, maximum glucose concentrations were not different between treatments at any time point. However, HI calves had greater insulin area under the curve, and HI calves had greater maximum insulin concentrations on d 2. Glucose or insulin clearance rates were not different nor was the calculated insulin sensitivity index between treatments. These findings suggest that feeding a HI prepartum diet may reduce some insulin sensitivity indicators of female offspring early in life.

Intake, nutrient digestibility, and growth performance of Holstein dairy calves consuming a milk replacer at moderate or high feeding rates.

The objective of this study was to evaluate nutrient intake and digestibility, and growth performance of calves when fed a milk replacer (MR) at 2 feeding rates. Male Holstein calves [n = 49; 45.0 ± 5.2 (mean ± SD) kg of body weight (BW); 3 to 4 d of age] were randomly assigned to 1 of 2 MR [27% crude protein (CP), 18% fat, dry matter (DM) basis; 14% solid] feeding programs: (1) 0.66 kg of DM/d for first 39 d divided into 2 equal a.m. and p.m. meals followed by one-half of the allotment per day for 3 d fed in the a.m. feeding only (moderate); (2) 0.96 kg of DM/d for the first 42 d divided into 2 equal a.m. and p.m. meals followed by one-half of the allotment per day for 7 d fed in the a.m. feeding only (high). A textured starter fed to calves contained whole grains with 20% CP and 44% starch (DM basis). At d 56, calves were moved into groups by treatment (4 calves/pen) and fed the same starter blended with 5% hay until d 112. Data were analyzed as a completely randomized design, or as a completely randomized design with repeated measures when applicable. Over the entire nursery period (d 0-56), there were no differences in average daily gain (0.63 vs. 0.64 kg/d) and hip width change (4.44 vs. 4.57 cm) for moderate- versus high-fed calves. Apparent digestibility of DM (76.5 vs. 70.3%), organic matter (77.4 vs. 71.2%), CP (78.8 vs. 72.6%), and neutral detergent fiber (37.2 vs. 22.7%) differed between moderate- and high-fed calves when estimated at d 51 to 55. From d 56 to 112, average daily gain (0.99 vs. 0.91 kg/d), hip width change (5.32 vs. 4.68 cm), and gain/DM intake (0.335 vs. 0.307 kg/kg) were greater, but DM intake per kg of BW (0.028 vs. 0.028 kg/kg) did not differ for calves previously fed moderate versus high. Feeding calves more than 0.66 kg of DM/d from a 27% CP, 18% fat MR did not improve BW gain and structural growth in the nursery period (d 0-56), and decreased these in the grower period (d 56-112) partially through reduction in digestibility of the starter.

Ruminal in situ disappearance and whole-tract digestion of starter feeds in calves before, during, and after weaning.

Ten bull calves (n = 5/diet) were cannulated at 3 wk of age and used in a 2 × 2 factorial design with repeated measures over time to compare rumen and whole-tract degradability of 2 calf starter diets and to describe an in situ technique for estimating ruminal degradability of diets in calves at different ages. Calves received milk replacer and 1 of 2 starter diets through wk 7. Mean birth weight was 38.7 ± 1.3 kg. Weaning occurred in wk 8, and calves received only starter (up to 4,500 g/d) through wk 15. Starter diets were a complete pellet (PEL; 42% starch, 13% neutral detergent fiber, NDF) or texturized feed (TEX; 31% starch, 22% NDF). Portions of each diet were dried and ground through a 2-mm screen, and 1.25 g was inserted into concentrate in situ bags (5 cm × 10 cm, 50-µm porosity). Each calf received duplicate bags of each diet for a total of 8 bags/calf (2 diets × 2 time points). All bags were inserted at the time of starter feeding. Half of the bags were removed at 9 h, and the other half were removed at 24 h. After removal from the rumen, bags were rinsed, dried (55°C), and composited by diet and by calf within week for NDF, nitrogen (N), and starch analyses. This process was repeated over 3 d during wk 5, 7, 9, 11, 13, and 15. Daily starter intake and total fecal excretion were recorded during the same 3-d periods. Diets, refusals, and feces were subsampled, dried, ground, composited by calf by week, and analyzed for NDF, N, and starch content. Apparent digestibility coefficients, total intake, and fecal excretion were calculated and analyzed with a mixed models procedure. Intake and fecal excretion of all measured nutrients increased from wk 5 through wk 15 of age and were greater for calves fed TEX, whereas the proportion of dry matter (DM), N, and starch apparently digested through the total tract decreased from wk 5 to 15 and was greater in calves fed PEL. Ruminal disappearance of DM, N, and starch after 9-h incubations increased linearly with age. Likewise, DM, NDF, and N disappearance after 24-h incubations also increased. Ruminal disappearance of DM and NDF was greater for PEL than for TEX. Ruminal disappearance was estimable for DM, NDF, N, and starch. In addition, changes over time and changes due to rumen environment were clearly demonstrated. Based on these data, there is potential to design specific rations and feed processing methods for calves based on their ability to utilize nutrients.

Relationships between protein and energy consumed from milk replacer and starter and calf growth and first-lactation production of Holstein dairy cows.

The objective was to determine relationships between protein and energy consumed from milk replacer and starter and calf growth and first-lactation production of Holstein heifer calves. Milk replacer and starter protein intake and metabolizable energy (ME) intake data were collected from 4,534 Holstein heifer calves for growth and 3,627 Holstein cows for production from birth year of 2004 through 2014. Calves from 3 commercial dairy farms were assigned to 45 different calf research trials at the University of Minnesota Southern Research and Outreach Center, Waseca, Minnesota, from 3 to 195 d of life. Calves were moved to heifer growers at 6 mo of age, and calves were returned to their farm of birth a few weeks before calving. Most calves (85%) were fed a 20% crude protein and 20% fat milk replacer at a rate of 0.57 kg/calf daily. Metabolizable energy and protein consumed from milk replacer and starter were calculated for each individual calf for 6 and 8 wk of age. Mixed model analyses were conducted to determine the effect of protein and energy consumed from both milk replacer and starter on calf growth and first-lactation 305-d production of milk, fat, and protein, adjusting for herd, season of birth, year, average daily gain (ADG), and calf trial. Calves with ADG >0.80 kg/d consumed more combined protein and ME than calves with lower ADG. Protein and ME intake from calf starter affected growth more than protein and ME intake from milk replacer because most calves were fed the same fixed amount of milk replacer. Calves born during the fall and winter had greater combined protein and ME intake than calves born during the spring and summer. Milk replacer protein and ME intake did not have a relationship with first-lactation 305-d milk, fat, and protein production. However, starter protein and ME intake during the first 6 and 8 wk of age had a significant positive relationship with first-lactation 305-d milk, fat, and protein production. Consequently, combined protein and combined ME intake had a positive effect on 305-d milk, fat, and protein production. Variance in protein and ME intake was high, suggesting that additional factors affect calf growth during the first 8 wk of life and milk production in first lactation.

Hypertonic milk replacers increase gastrointestinal permeability in healthy dairy calves.

Hypertonic milk replacers are commonly used in animal production systems and their effect on the gastrointestinal system of young animals is insufficiently studied. Total lactose inclusion or its partial replacement with dextrose increases intestinal osmotic pressure, which may compromise gastrointestinal barrier function. In this experiment, we investigated the effect of increased osmolality of calf milk replacer (CMR) on gastrointestinal permeability in 30 Holstein Friesian (n = 17) or crossbred (n = 13) bull calves. The osmolality of CMR increased as result of a gradual replacement of lactose by monosaccharides (dextrose and galactose). Calves were acquired from dairy farms that followed a standardized protocol for colostrum management, including 3 feedings of colostrum in the first 24 h. Calves were then transported to the research facility between 0 and 3 d of age, fed a milk replacer with 0% dextrose twice daily for the first 2 wk of age, and subsequently exposed to their respective treatments from 3 until 7 wk of age. Meal size was 3.2 L at 3 wk of age and increased to 3.5 L at 7 wk of age. No solids were provided throughout the study and calves had ad libitum access to water. Treatments included 4 levels of dextrose inclusion (replacing lactose): 0% (L1, n = 5), 13.3% (L2, n = 5), 26.7% (L3, n = 5), and 40% (L4, n = 5) and an additional treatment (G+D, n = 10) that included 20% galactose and 20% dextrose and matched the galactose supply of L1 and the osmolality of L4. Carbohydrates were exchanged based on hexose equivalents. Across treatments, the estimated osmolality ranged from 439 (L1) to 611 mOsm/kg (L4 and G+D). Gastrointestinal permeability was assessed by fractional urinary recovery of indigestible markers (lactulose, d-mannitol, and Cr-EDTA) delivered as a single dose at 3 and 7 wk of age. Marker recoveries were expressed as percentage of oral dose and assessed in 6-h and 24-h quantitative urinary collections. Increasing the osmolality of the CMR linearly increased urinary Cr-EDTA and lactulose recoveries at 3 and 7 wk of age. Lactulose and Cr-EDTA recoveries did not differ between G+D and L4, suggesting that the source of monosaccharide (dextrose and galactose) in CMR had no effect on gastrointestinal permeability. The observed increase in gastrointestinal permeability to large molecules (Cr-EDTA and lactulose) with increased osmolality suggests that hypertonic CMR may compromise gastrointestinal barrier function.

Liver transcriptomic and proteomic profiles of preweaning lambs are modified by milk replacer restriction.

Prenatal and early postnatal nutrition may promote long-term effects on both feed efficiency and health of animals. Therefore, moderated milk replacer restriction during the artificial rearing period might negatively affect feed efficiency during the postweaning phases in dairy ewes. The aim of this work was to identify differentially expressed (DE) genes by RNA sequencing and differentially accumulated proteins using MALDI-TOF mass spectrometry in the liver of artificially reared Assaf lambs to identify modified metabolic pathways as a consequence of milk replacer restriction in order to find possible solutions to correct any detrimental effect caused by this factor. Forty female Assaf lambs were used in this experiment. The animals were penned individually and assigned randomly to 1 of 2 treatments groups (n = 20 per treatment). The first group of lambs was fed ad libitum (AL), whereas the second (restricted, RES) only received approximately 62.5% of the level of intake measured in the AL group. Eight 35-d-old lambs from each group (16 lambs in total) were harvested and a piece of liver of 8 lambs (4 AL and 4 RES lambs) was excised for transcriptomic and proteomic analysis. Differential gene expression analysis identified 386 DE genes [198 of them being annotated genes in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway], with 176 downregulated and 210 upregulated in the early feed-restricted group relative to the AL group. A total of 26 spots were also differentially accumulated proteins in the liver of the 2 groups of lambs, 10 of them being down-accumulated whereas the other 16 evolved in the opposite way in the liver of RES relative to AL lambs. Collectively, both the transcriptomic and proteomic approaches revealed an upregulation of genes participating in oxidation of fatty acids in the early feed-restricted lambs. The expression of many genes involved in the degradation of several AA (e.g. alanine, valine, isoleucine, tyrosine) was also modified in the RES lambs, probably to render substrates for gluconeogenesis. Moreover, other genes involved in apoptosis, inflammation, or hepatic oxidative pathways were upregulated in these lambs. Finally, the expression of genes implicated in oxidative phosphorylation was modified in RES animals. Altogether all these modifications suggest that the partitioning and utilization of nutrients in the early feed-restricted lambs might have been modified, being partially responsible for changes during the replacement phase later in life.

Effects of methionine plus cysteine inclusion on performance and body composition of liquid-fed crossbred calves fed a commercial milk replacer and no starter feed.

This experiment aimed to evaluate the effects of supplying 4 different inclusion levels of Met + Cys to crossbred liquid-fed calves on animal performance and body composition. Thirty-six Holstein-Gyr male calves were separated into 2 age groups: 16 calves, slaughtered at an age of 30 d, representing the physiological phase from 8 to 30 d, and 20 calves, slaughtered at an age of 60 d, representing the physiological phase from 30 to 60 d. At 8 d of age, the animals were randomly distributed among the experimental treatments: 4 Met + Cys inclusion levels (Met + Cys: 8.0, 8.7, 9.4, and 10.2 g/d), provided by an AA supplement added to 1.0 kg (as fed) of commercial milk replacer containing soy protein concentrate and wheat protein isolate reconstituted at 13.8% (dry matter basis). The diet was supplied without allowing leftovers and no starter feed was provided. The experimental diets were supplied without allowing orts, so that the dry matter, crude protein, and ether extract intakes were the same for all animals, independent of Met + Cys level. Total weight gain, average daily gain, gain composition, and body composition were evaluated for both age groups separately. Digestibility of organic matter, crude protein, and ether extract was lower for 8 to 30 d than for 30 to 60 d. The effect of Met + Cys levels on the digestibility of nutrients was not observed; there also was no significant interaction between physiological phase and Met + Cys levels. For the 8 to 30 d group, no responses in performance were observed according to the different Met + Cys levels, which indicates that 8.0 g/d of Met + Cys met the requirements for this physiological phase. The 30 to 60 d group responded positively to higher Met + Cys inclusion in the diet. In conclusion, an optimal Met + Cys dietary level to ensure best performance and protein gain ranges from 8.41 to 9.81 g/d.

Influence of ad libitum milk replacer feeding and butyrate supplementation on the systemic and hepatic insulin-like growth factor I and its binding proteins in Holstein calves.

Ad libitum milk feeding and butyrate (B) supplementation have the potential to stimulate postnatal growth and development in calves. The somatotropic axis is the main endocrine regulator of postnatal growth and may be affected by both ad libitum milk replacer (MR) feeding and B supplementation in calves. We hypothesized that ad libitum MR feeding and B supplementation stimulate systemic and hepatic insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBP) in preweaning calves. Sixty-four (32 male, 32 female) Holstein calves were examined from birth until wk 11 of life. Calves received MR either ad libitum (Adl) or restrictively (6 L/d; Res). In each feeding group half of the calves received a MR with 0.24% butyrate and the other half received same MR without butyrate. Ad libitum MR feeding was performed from d 4 until wk 8 of age. From wk 9 to 10, Adl and Res calves were gradually weaned and were fed 2 L/d until the end of the trial. Concentrate, hay, and water were freely available. Feed intake was measured daily and body weight weekly. Blood samples for analyzing plasma concentrations of glucose, insulin, IGF-I, and IGFBP-2, -3, and -4 were taken on d 1, 2, 4, and 7, then weekly or every other week (IGFBP) until wk 11 of life. Liver samples were taken on d 50 and at the end of the study (d 80) to measure gene expression of the growth hormone receptor 1A (GHR1A), IGF1, IGFBP1 to 4, and of the IGF Type 1 and insulin receptor in the liver. Intake of MR and body weight were greater, but concentrate intake was lower in Adl than in Res. Plasma concentrations of IGF-I and IGFBP-3 were greater and plasma concentration of IGFBP-2 was lower in Adl than in Res during the ad libitum milk feeding period. After reduction of MR in both groups to 2 L/d plasma concentrations of IGF-I and IGFBP-4 were lower and plasma concentration of IGFBP-2 was higher in Adl than in Res. Supplementation of B depressed plasma IGF-I from wk 1 to 4 and in wk 9. On d 50, mRNA abundance of the GHR1A and IGF1 was greater and of IGFBP2 mRNA was lower in Adl than in Res. At d 80, IGFBP2 mRNA was greater in Adl than in Res, and IGFBP2 mRNA increased with B supplementation. Ad libitum MR feeding stimulated the systemic and hepatic IGF system and mirrored the greater growth rate during the ad libitum MR feeding, whereas butyrate supplementation partly reduced the systemic and hepatic IGF system.