Effective disease control

In South-Africa, communicable diseases are a major cause of livestock losses and it is disconcerting that so many preventable diseases still frequently result in substantial financial losses.http://www.dairyconnect.co.za/dairyMail

The effect of unrestricted milk feeding on the growth and health of Jersey calves

This study was conducted to determine the effect of feeding high milk volumes on the growth rate, health and cross-sucking behaviour in group-fed Jersey calves. Three-day-old heifers (n = 120) in a seasonal calving dairy herd were randomly assigned to one of 6 treatment groups. Three groups received high milk volumes (HMV), consisting of ad libitum milk or milk replacer feeding twice a day, while 3 groups received restricted milk volumes (RMV), consisting of 2 twice daily, during the pre-weaning period. After a pre-weaning period during which feeding was reduced to once daily, all calves were weaned at 42 days and monitored until 60 days of age.Adjusting for birth mass, birth date,damparity and sire, average daily mass gain (ADG), both pre-weaning (days 0–42) and overall (days 0–60), was higher inHMVthan inRMVcalves (P<0.001).After weaning, growth rates showed no differences and at 60 days of age the HMV calves maintained a 6.74 kg advantage in mean body mass (P < 0.001). The mean intake of dry starter feed was higher in RMV than in HMVcalves. Overall feed conversion rate ofHMVcalves was 9.6%better thanRMVcalves. However, the variable cost per kg mass gain was 12 % higher for HMV calves. In the RMV groups 75 % of calves showed cross-sucking behaviour pre-weaning and 18 % post-weaning, whereas in HMV calves the proportions were 2 % and 7 %, respectively. There was no significant effect of milk volume on the incidence of diarrhoea.We conclude that the feeding of high volumes of milk to Jersey calves has a positive effect on growth rate, without compromising health or reducing solid feed intake after weaning. However, the higher cost of such a feeding system may limit its implementation.http://www.journals.co.za/ej/ejour_savet.htm

The effect of cow-level factors on colostrum quality, passive immunity and health of neonatal calves in a pasture-based dairy operation

A study of 95 cows (19 primiparous and 76 multiparous) and their offspring was performed on a pasture-based dairy in the coastal region of South Africa. Collected data included weight changes during the dry period, colostrum immunoglobulin G (IgG) and calf serum IgG at 24–48 h after birth. Colostrum and serum IgG concentrations were measured using radial immunodiffusion and colostrum was regarded as having adequate IgG concentration if the amount was 50 g/L. Calf serum IgG concentration of 10 g/L was considered an adequate transfer of passive immunity. The median (range in parentheses) colostrum quality for cows with weight loss during the dry period was 23.1 g/L (9.0, 108.1) compared with 61.9 g/L (10.9, 200.0) in cows without weight loss. The median serum IgG of calves from cows with weight loss was 9.9 g/L (0.5, 44.6) compared with 14.0 g/L (0.5, 76.3) in calves from cows that did not lose weight during the dry period. Cows experiencing weight loss were four times more likely to have colostrum with lower concentrations of IgG (OR = 0.25; 95% CI, 0.07–0.88; P = 0.030). Lactation number was also significantly associated with colostrum IgG concentration (P < 0.001), with younger cows tending to have higher IgG concentrations. Failure of passive transfer did not have a significant effect on any calf-health or production variables measured in the study. The effect of dry-cow feeding on colostrum IgG concentration is poorly understood and inadequate pasture management could have an impact on colostrum quality in pasture-based dairy herds.The University of Pretoria and the National Research Foundation (NRF) of South Africa (Grant No. 76734).http://www.publish.csiro.au/anhj2018Production Animal Studie

Pre-breeding blood urea nitrogen concentration and reproductive performance of Bonsmara heifers within different management systems

This study investigated the association between pre-breeding blood urea nitrogen (BUN) concentration and reproductive performance of beef heifers within different management systems in South Africa. Bonsmara heifers (n= 369) from five herds with different estimated levels of nitrogen intake during the month prior to the commencement of the breeding season were sampled in November and December 2010 to determine BUN concentrations. Body mass, age, body condition score (BCS) and reproductive tract score (RTS) were recorded at study enrolment. Trans-rectal ultrasound and/or palpation was performed 4–8 weeks after a 3- month breeding season to estimate the stage of pregnancy. Days to pregnancy (DTP) was defined as the number of days from the start of the breeding season until the estimated conception date. Logistic regression and Cox proportional hazards survival analysis were performed to estimate the association of pre-breeding BUN concentration with subsequent pregnancy and DTP, respectively. After stratifying for herd and adjusting for age, heifers with relatively higher prebreeding BUN concentration took longer to become pregnant when compared to those with relatively lower BUN concentration (P=0.011). In the herd with the highest estimated nitrogen intake (n=143), heifers with relatively higher BUN were less likely to become pregnant (P=0.013) and if they did, it was only later during the breeding season (P=0.017), after adjusting for body mass. These associations were not present in the herd (n=106) with the lowest estimated nitrogen intake (P>0.500). It is concluded that Bonsmara heifers with relatively higher pre-breeding BUN concentration, might be at a disadvantage because of this negative impact on reproductive performance, particularly when the production system includes high levels of nitrogen intake.Faculty of Veterinary Science, University of Pretoriahttp://link.springer.com/journal/112502015-08-31hb201

Japanese radish

Bulb is large, cylindrical and very prominent. Japanese Radish is a well known and proven frost-tolerant winter forage suited to the cooler, higher rainfall crop growing regions of South Africa. Greater yields can be achieved when the radish is lifted from the land and fed to the animals, either as a supplement or as a winter feed. Bulb is high in NO3Color photograph of a Japanese radish plan

Babala

Babala planted at Groblersdal for summer forage.Color photo taken on a farm at Groblersdal, South Africa

Wheat

Wheat planted at Onderstepoort for winter forage. Wheat is classified as a small grain. Acidosis can occur when cattle consume too much carbohydrates (primarily grain) in a short period of time.Color phot

Dairy farm in Belgium

Free-stall barn on dairy farm in Belgium. Dairy cattle feeds on green chop and dry silage.Color phot

Oats

Oats planted at Onderstepoort, South Africa as winter forage for dairy cattle. Oats is classified as a small grain. Acidosis can occur when cattle consume too much in a short period of time.Color phot

Nguni cattle on a sorghum pasture

Nguni cattle grazing on a sorghum field in Doornpoort, Pretoria area, South Africa