Thirty calves were randomly assigned to two treatments and fed until weaning [42 days (d) of age]. Treatments were a control group (n = 15), which did not receive Megasphaera elsdenii (Me0) and a M. elsdenii group, which received a 50-ml oral dose of M. elsdenii NCIMB 41125 (10(8) CFU/ml) at day 14 day of age (Me14). Calves were given colostrum for the first 3 day followed by limited whole milk feeding. A commercial calf starter was offered ad libitum starting at day 4 until the end of the study. Fresh water was available throughout the study. Feed intake and growth were measured. Blood samples were collected via jugular venipuncture to determine β-hydroxybutyrate (BHBA) concentrations. Fourteen male calves (seven per group) were euthanised on day 42 and digestive tracts harvested. Reticulo-rumen weight was determined and rumen tissue samples collected from the cranial and caudal sacs of the ventral and dorsal portions of the rumen for measurements of papillae length, papillae width and rumen wall thickness. Dosing with M. elsdenii NCIMB 41125 improved starter dry matter intake (DMI), weaning body weight (BW) and tended to improve average daily gain. Calves in Me14 group had greater plasma BHBA concentration than Me0-calves during the last 3 weeks of the trial and had at day 42 greater reticulo-rumen weight, papillae width and papillae density compared to Me0. No differences in rumen wall thickness or papillae length were observed between the two groups. Total volatile fatty acids, acetate and propionate production did not differ between treatments, but butyrate production was greater in Me14 than Me0. Dosing M. elsdenii NCIMB 41125 showed benefit for calves with improved feed intake and rumen development suggesting increased epithelium metabolism and improved absorption of digestive end products.

No abstract

The effects of high thermal stress on serum protein metabolites, milk production of transition dairy cows in semi-arid areas in South Africa were evaluated. Forty, ± 8 months pregnant, Jersey heifers (± 26 months) in zero grazing management were selected during summer from two semi-arid communal areas. Summer thermal-humidity index (THI) of the areas were THI-1 (72–83: extreme caution) and THI-2 (75–87: danger). Blood samples were collected (21 days pre-partum, and 21 and 75 days post-partum) and analysed for serum protein metabolites. Milk yield was recorded daily and samples collected for milk fat, protein, lactose and urea nitrogen analysis. Heifers in THI-2 had lower (P < 0.05) total serum proteins, albumin and blood urea nitrogen than THI-1. Post-calving, cows in THI-1 had higher (P < 0.05) TP (73.4 vs 67.9 g/l) and BUN (4.61 vs 3.77 mmol/l) at 21 DIM, and lower (P creatinine at 21 and 75 DIM than THI-2 group. Milk yield, fat and protein in THI-2 were all lower (P < 0.05) than THI-1 21DIM. The results confirm that heat stress affects utilisation of nutrients in transition dairy cows.

No abstract

New born (male and female) calves (n = 26) weighing 33.3 ± 0.71 kg were used to evaluate effects of restricting frequency of free access to milk before and 2 weeks after weaning. Calves were randomly assigned at birth to 1 of 2 treatments being free access to whole milk twice daily (2X) or free access to whole milk once a day (1X). Milk and starter intakes were recorded daily, body weight (BW) was recorded weekly and metabolisable energy intake estimated. Before weaning, 2X calves had greater milk intake (8.76 L/d) and lower starter intake dry matter intake (DMI); 0.11 kg DM/d) compared to 1X calves (7.11 L/d and 0.21 kg DM/d, respectively; P < 0.01). Pre-weaning body weight (54.21 kg) and BW gain average daily gain (ADG) 0.74 kg/d were greater (P < 0.01) for 2X calves compared to 1X (45.30 kg and 0.58 kg/d, respectively). Feed and energy conversion ratio did not differ (P > 0.05) between treatments before weaning, but were greater (P < 0.03) in 1X calves compared to 2X calves after weaning. Calves fed 2X lost weight a week after weaning, while calves fed 1X maintained growth. Limiting frequency of free access to milk improved solid feed intake and helped calves maintaining apparent growth after weaning.