No abstract

Social pressure is increasing to adopt alternative housing and management practices that allow farm animals more opportunity to exercise and demonstrate social behavior. The present study investigated the effect of pair housing on the behavior and growth performance of Jersey heifer calves. Forty female Jersey calves were allocated to individual or pair housing at birth and monitored for 9 wk. Calves were provided with a single hutch, and those allocated to the pair housing treatment were provided a pen enclosure twice the size of individually housed calves and only one hutch was provided per pair. All calves were fed milk replacer via bucket twice per day (1.89 L/feeding first 7 d; 2.27 L/feeding until weaned) and had ad libitum access to grain and water. Gradual weaning commenced on d 49 by reducing the calves' milk allowance to one feeding per day, and weaning occurred on d 56. Grain consumption was monitored daily and calves were weighed weekly. Direct behavioral observations were conducted twice per week. Calves housed in pairs tended to have greater average daily gain compared with calves housed individually (0.63 vs. 0.59 ± 0.02 kg/d, respectively). Pair housing also increased final body weight compared with individual housing (64.9 vs. 61.7 ± 0.59 kg, respectively). During observation periods, calves housed individually spent more time engaging in nonnutritive sucking than calves housed in pairs (21.5 vs. 8.15 ± 0.03% of total observations). Calves housed in pairs were observed cross sucking 13.5% of the time during observational periods. Although housing Jersey calves in pairs may increase measures of growth performance, future research should aim to reduce cross-sucking behavior within the Jersey breed through alternative feeding systems or environmental enrichment.

Intramammary infections (IMI) are prevalent in non-lactating dairy cattle and their occurrence during periods of significant mammary growth and development (i.e. pregnant heifers and dry cows) is believed to interfere with growth, development, and subsequent milk production. However, direct study of IMI impacts on non-lactating but developing mammary glands is lacking. The objectives of this study were to (1) define how IMI affected total and differential mammary secretion somatic cell counts in mammary glands stimulated to rapidly grow using estradiol and progesterone, and (2) characterize changes in mammary morphology in response to IMI. Mammary growth was stimulated in 19 non-pregnant, non-lactating cows and 2 quarters of each cow were subsequently infused with either saline (n = 19) or Staphylococcus aureus (n = 19). Mammary secretions were taken daily until mammary tissues were collected at either 5 or 10 days post-challenge. Staph. aureus quarter secretions yielded greater concentrations of somatic cells than saline quarters and contained a greater proportion of neutrophils. Staph. aureus mammary tissues exhibited higher degrees of immune cell infiltration in luminal and intralobular stroma compartments than saline quarters. Infected tissues also contained reduced areas of epithelium and tended to have greater amounts of intralobular stroma. Results indicate that IMI in non-lactating glands that were stimulated to grow, produced immune cell infiltration into mammary tissues and secretions, which was associated with changes in mammary tissue structure. The observed reduction of mammary epithelium indicates that IMI impair mammary development in rapidly growing mammary glands, which may reduce future reduced milk yields.

publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active. ABSTRACTPurpose: Published literature regarding calf nutrition was reviewed to create an information base for the implementation of proper nutritional management to maximize health and productivity.Sources: The main source of data and information for this review was peer-reviewed literature.Synthesis: Feeding a sufficient volume of colostrum during the first hours of life is crucial to calf health and survival; however, less is known about transition milk feeding and the potential benefits of the myriad of bioactive compounds it contains. After feeding colostrum and transition milk, calves are susceptible to diarrhea when moved onto high amounts of milk, and antibiotic use is often necessary to decrease disease. Feeding an elevated plane of milk nutrition results in increased ADG and, in some studies, increased future milk production. Thus, this nutritional strategy is recommended; however, weaning calves from high volumes of milk represents massive changes in the structure and microbiology of the gastrointestinal tract.Conclusions and Applications: Colostrum and transition milk contain an abundance of bioactive molecules that can positively affect gut development and microbiota. There is significant potential for the use of novel feeding strategies and microbial-based products as alternatives to antibiotics. Calves fed an elevated plane of nutrition in the first month of life have greater productivity and growth. However, weaning should take place later in life. Moreover, applying a proper step-down feeding protocol is recommended, as it allows calves to intake and digest sufficient solid feed for growth and minimize distress at weaning.

A fermentation extract of the fungus Aspergillus oryzae can be used as a prebiotic. The objective was to determine if dietary inclusion of a fermentation extract of A. oryzae as well as calf age would alter growth, health, performance parameters, and the growth and development of the rumen in Holstein calves from birth thru 1 wk postweaning; it was hypothesized that it would. Purchased bull calves (n=52) that originated from 1 of 13 farms were used in this experiment. All calves had serum IgG greater than 10 mg/mL. Calves were randomly assigned to a slaughter age, 4 (n=16) or 8 wk (n=36), and treatment, control (n=27) or fermentation extract of A. oryzae (AMF; n=25). Calves were housed and fed individually; no bedding was used and no forage was fed. Calves assigned to AMF were fed 2 g of AMF daily. Liquid AMF was delivered in milk replacer for the first 4 wk of the study; solid AMF was top-dressed on texturized starter thereafter. Calves were fed nonmedicated milk replacer twice daily (22.0% crude protein, 20.0% fat, dry matter basis; 680 g/d) and were weaned upon consumption of 0.91 kg of starter (20% crude protein, 2.0% fat; medicated with decoquinate) for 3 consecutive days or on d 45 of the study, whichever came first. Calves had ad libitum access to starter and water throughout the study. Feed intake as well as fecal and respiratory scores were recorded daily; body weight, withers height, and hip height were recorded weekly. Gross rumen measurements and rumen samples for future gross and histological analyses were taken at 4 and 8 wk. All calves grew similarly; weaning age averaged 40.39±0.77 d. Lifetime average daily gain was 0.60±0.05 kg/d and lifetime gain-to-feed ratio was 0.56±0.05. Milk replacer, starter, total dry matter intake, gross and histological rumen measurements, rumen pH, fecal and respiratory scores, and total medical costs were not affected by treatment. Despite total medical costs not differing by treatment, a lower percentage of AMF calves were treated for respiratory ailments and respiratory treatment cost was lower for AMF compared with control. Several factors may have contributed to an overall lack of observed treatment effect in this study, including include the use of a low-forage (compared with concentrate) diet, immunocompetent calves, and the selected product dose and routes of delivery. Dietary inclusion (2 g/d) of an extract of A. oryzae did not affect calf growth, intake, and ruminal or health measurements.