Preweaning intake and postweaning dietary energy effects on intake and metabolism of calves weaned at 26 days of age

A 100-Year Review: Calf nutrition and management

The first calf paper, published in the May 1919 issue of the Journal of Dairy Science (JDS), described factors affecting birth body weight of different breeds of calves. Other studies were done on nonmilk ingredients, growth charts were developed, and early weaning was followed to conserve milk fed to calves. Calf papers did not report use of statistics to control or record variation or to determine whether treatment means were different. Many experiments were more observational than comparative. Typically fewer than 5 calves, and sometimes 1 or 2 calves, were used per treatment. During the next 20 yr, calf studies increased and included colostrum feeding, milk and milk replacer feeding, minerals and vitamins, and fats and oils. Many concepts fundamental to current knowledge and understanding of digestion, rumen development, and milk replacer formulation were developed during this period. In addition, the concept of using antibiotic growth promoters in dairy calf diets was first evaluated and developed during the 1950s. During the 20-yr period of January 1957 through December 1976, a large number of universities in the United States and 1 in Canada contributed almost 150 papers on a variety of calf-related topics. These topics included genetics, physiology of the calf, review of calf immunity, antibiotic feeding, and milk replacer ingredients. This became the golden era of calf rumen development studies, which also engendered studies of calf starter rations and ingredients. A classic review of management, feeding, and housing studies summarized research related to calf feeding and management systems up to that point with an emphasis on maintaining calf growth and health while reducing labor and feed costs. It was also during this period that metric measurements replaced English units. In the 20-yr period from 1977 to 1996, more than 400 articles on calf nutrition and management were published in JDS. With the growing research interest in calves, a paper outlining standardized procedures for conducting and reporting data from calf experiments was first published. A very active area of calf nutrition research from the late 1970s to the mid 1980s was colostrum quality, feeding, and preservation; more than 60 such research articles were published in the journal during this time. Various nonmilk protein sources were evaluated. Extensive studies were done evaluating trace and major mineral requirements in calves along with some vitamin studies. Throughout the 1970s, 1980s, and 1990s, the primary objective of most calf research was how to wean healthy, adequately grown calves at an early age-generally less than 30 d of age. This program was reviewed in a 1979 publication. Research on calf starter ingredients, nutrient composition, and additives was minimal in the 1980s and 1990s given the importance of starter intake to the success of early weaning, but the role of water intake in starter intake and growth was established. Research on issues with calves continued to increase during the last 20-yr period as evidenced by publication of more than 580 articles in JDS as well as many more in other refereed journals. In addition to papers contributed by several universities in the United States and Canada, the number of papers authored by scientists at universities and institutes in other countries increased dramatically during this period. Factors influencing colostral antibody absorption, heat treatment of colostrum, and efficacy of colostrum supplements and replacers were reported. Most studies in this period related to nutrition. Studies were published supporting greater neonatal growth rates from feeding more milk replacer but with a higher crude protein content than traditional. Protein energy effects on growth and body composition were evaluated in concert with greater growth rates. Milk and nonmilk protein sources in milk replacers along with AA supplementation were evaluated. Limited studies were done with fat sources and fatty acid supplementation along with trace minerals and fat-soluble vitamins. Waste milk feeding and heat treatment became more prevalent. Studies established starter ingredient palatability and use of forage when fed with pelleted starters. With the advent of automatic milk and milk replacer feeders, factors influencing how and when to wean were established. Research programs established factors affecting calf behavior and welfare. Several databases were evaluated along with various published studies, and established calf growth during the first 2 mo was subsequently reflected in first- and later-lactation milk production of those calves. A new area of calf research that emerged from 1997 on was the effects of maternal environment and nutrition on calf health, growth, and future productivity. From a mechanistic standpoint, the field of epigenetics seems likely to explain many of these phenomena. Some possibilities for future calf nutrition and management were elaborated.

Effect of weaning age on feed intake and ruminal fermentation patterns of calves fed a dry total mixed ration with ad libitum access to grass hay

To study the effect of weaning age on average daily gain (ADG), dry matter intake (DMI) and ruminal fermentation, 10 rumen-cannulated male Holstein calves were randomly assigned to one of two treatments: (i) early weaned at 8 weeks of age (235 l milk); (ii) conventionally weaned at 12 weeks of age (347 l milk). Twice daily grass hay (9.0 MJ ME x kg(-1) DM) and a dry total mixed ration (TMR) (11.6 MJ ME x kg(-1) DM) containing 15% alfalfa hay and 85% concentrates were offered separately. Water was available ad libitum. Ruminal fluid was collected via cannulas at weeks 9, 11, 13 and 15, twice weekly just prior to as well as 1, 3, 5 and 7 h after morning feeding. Calves of both treatments achieved adequate ADG (947 vs. 959 g; p > 0.05). Just-weaned calves rapidly increased DMI (1.1-2.5 kg TMR and 2.4-3.6 kg TMR for early- and conventionally-weaned calves, respectively). From weeks 10-12 early-weaned calves consumed significantly more dry feed than conventionally-weaned calves (week 10: 2.5 vs. 1.6 kg/d; week 12: 3.4 vs. 2.4 kg/d). Early weaning stimulates DMI supporting ruminal fermentation intensity, indicated by lower ruminal pH. After weaning, only early-weaned calves achieved critical average ruminal pH (week 9: 5.7 vs. 6.0, p = 0.017; week 11: 5.9 vs. 6.2, p = 0.007). Experimental treatment did not affect the concentration of ruminal short-chain fatty acids (SCFA). For all calves, the effects of the concentrate-rich TMR were shown by a high SCFA level (daily average: 137-152 mmol x l(-1)) and an acetate to propionate to butyrate ratio between 51:36:9 and 54:33:10.

Efeito da substituição do feno de Tifton 85 pelo caroço de algodão como fonte de fibra na dieta de bezerros

Para avaliar a substituição do feno Tifton 85 pelo caroço de algodão como fonte de fibra na dieta foram utilizados 24 bezerros da raça Holandesa, distribuídos em dois grupos. O grupo-feno recebeu feno e concentrado separados, fornecidos à vontade, e o grupo- algodão recebeu caroço de algodão incorporado ao concentrado (13,5%), à vontade. O consumo de alimentos, o peso, as alturas da cernelha e do íleo, as circunferências torácica e abdominal, a concentração de glicose sangüínea, as concentrações de acetato, propionato e butirato, o pH do fluido ruminal e os pesos dos compartimentos do estômago foram mensurados. O consumo de alimentos, o desenvolvimento ponderal dos animais, as concentrações de acetato, propionato e butirato, o pH do fluido ruminal, as concentrações de glicose sangüíneas e o peso dos compartimentos do estômago foram semelhantes entre os tratamentos (P>0,05). À necropsia, não foram observadas alterações sugestivas de intoxicação por gossipol. Concluiu-se que o caroço de algodão substituiu, sem prejuízos, o feno como fonte de fibra na dieta de bezerros.

Pre- and postweaning attributes in faunated and ciliate-free calves fed calf starter with or without fish meal

In a 2 x 2 factorial design, 24 newborn, crossbred (Bos indicus x Bos taurus) calves were distributed in 4 equal groups involving dietary treatments of prestarter diets with (FM) or without fish meal (NFM) in a faunated (F) or ciliate-free (D) ruminal environment to study the ruminal fermentative development in pre-and postweaning periods. Defaunation was achieved by rearing calves in isolation and its effect was studied after first appearance of ciliate protozoa (observed after 8 wk of age) in the faunated animals. Calves were fed colostrum for 24 h and whole milk until weaning at 8 wk of age. Ruminal content samples were collected on d 4, 1 wk, weekly to 8 wk, and then biweekly at 9, 11, and 13 wk of age. The samples were analyzed for fermentation products [pH, total volatile fatty acids (VFA) and ammonia N] and enzyme [carboxymethyl (CM) cellulase, xylanase, beta-glucosidase, alpha-amylase, beta-galactosidase, proteases, and urease] activities. Weekly feed intake increased with age, but was similar in both groups. Ruminal pH declined steadily during 0 to 4 wk of age and then stabilized. The total VFA concentration increased with the age. The ammonia N (mg/dL) concentration increased from 14.9 on d 4 to 32.4 at 4 wk, decreased to 17.6 at 8 wk, and then steadied during the postweaning period. Samples collected on d 4 had no fibrolytic activity. Xylanase (U/dL) appeared first (1 wk) followed by beta-glucosidase (U/dL) and CM cellulase (U/dL), which increased steadily from a low of 4.69, 0.08, and 2.95 to 31.8 (6 wk), 5.92 (7 wk), and 19.8 (8 wk), respectively, and the concentrations showed nonsignificant alterations during postweaning periods. The concentration of alpha-amylase (U/dL) increased from 34.3 on d 4 to 87.2 at 8 wk, and then decreased to 56.6 (13 wk). beta-Galactosidase increased up to 6 wk then decreased to trace level (0.20 U/dL) at 13 wk of age. The concentrations of proteases and urease reached a steady state after 1 wk of age. The effect of diet type on ruminal fermentation products and enzyme parameters was nonsignificant. However, a steady and proportional alteration in both parameters in response to dry feed intake with the advancement of age was seen in all calves. Defaunation increased total VFA (97.3 vs. 75.8 mM/L) and alpha-amylase activity (80.3 vs. 61.4 U/dL) and decreased ammonia N (16.4 vs. 21.1 mg/dL), whereas the effect on other parameters was nonsignificant. Ruminal fermentative changes responded to dry feed intake, but did not differ in response to animal protein in prestarter diet.

Influence of weaning method on growth, intake, and selected blood metabolites in Jersey calves

Forty-three Jersey calves were assigned randomly at birth to treatments that evaluated the method of weaning on growth, intake, and concentrations of blood metabolites that were indicative of ruminal development. The three experimental treatments were 1) milk replacer fed at 10% of BW until abrupt weaning at 35 d of age, 2) milk replacer fed at 10% of BW until 28 d and then at 5% of BW until weaning at 35 d of age, or 3) milk replacer fed at 10% of BW until intake of calf starter reached 454 g/d for 2 consecutive d, at which time calves were weaned. Commercial milk replacer was reconstituted to 12.5% DM and fed twice daily. Commercial calf starter was offered from 3 d of age. When milk replacer was fed at 5% of BW from 29 to 35 d, BW gain was reduced compared with that of calves on the other treatments; however, BW at 56 d was unaffected by treatment. Concentrations of NEFA and blood urea N were higher from 29 to 56 d than when calves were fed milk replacer at 5% of BW from 29 to 35 d. Blood BHBA increased as starter DMI increased and was unaffected by treatment. Intake of milk replacer and feed cost were greater for calves that were weaned when calf starter intake reached 454 g/d for 2 consecutive d. For calves that were weaned according to intake, mean age at weaning was 40 d.