How Does the Provision of Shade during Grazing Affect Heat Stress Experienced by Dairy Cows in Sweden?

Heat stress in dairy cows can cause an increase in body temperature and respiration rate, and a decreased feed intake leading to reduced production. Dairy cows are better at handling heat when they have access to shade. Therefore, this study aimed to determine the effects of providing shade to high-yielding dairy cattle during the summer in the Swedish climate. Twenty high-yielding Swedish Red dairy cows, held on pasture, were divided into two groups, one with access to shade (S) and one without (NS). Milk production was recorded daily and shade temperature and relative humidity were recorded at 10 min intervals at pasture. A major effect of heat stress was found in cows in early lactation in the NS group. In this group, a high mean temperature two days before and a high THI two days before affected the milk production negatively (p < 0.001), which was the same for the maximum temperature and maximum THI measured on the same day (p < 0.001). Increases in the mean temperature and THI two days before also affected milk production negatively (p < 0.05) for cows in early lactation in the S group, though to a lesser extent. This study suggests that dairy cows in early lactation benefit from access to shade during summer.

A systematic literature review of milk consumption and associated bacterial zoonoses in East Africa.

Consumption of unsafe animal-source foods is the major cause of foodborne disease outbreaks in low-income countries. Despite current knowledge of the threat posed by raw milk consumption to human health, people in many countries in East Africa still consume unboiled milk. This literature review explored the association between milk consumption and the occurrence of five milk-borne bacterial zoonoses: brucellosis, salmonellosis, campylobacteriosis, Escherichia coli infections, and tuberculosis. A search for literature published up to 1 October 2021 was conducted through the Web of Science, PubMed, and Scopus databases, using Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. The selection process yielded 65 articles describing studies conducted in East Africa 2010-2021, which were carefully scrutinized. The most investigated pathogen was Brucella spp. (54.5%), followed by E. coli (18.2%), Salmonella spp. (12.1%), Mycobacterium spp. (6.1%), and E. coli O157: H7 (6.1%). The most common predisposing factors for potential milk-borne disease outbreaks were consumption of contaminated raw milk, inadequate cold storage along the milk value chain, poor milk handling practices, and lack of awareness of the health risks of consuming unpasteurized milk. Thus, a tailor-made training program is needed for all milk value chain actors to enhance the safety of milk sold in informal markets, and a One Health approach should be applied. Future studies should employ more advanced diagnostic techniques and countries in East Africa should invest in modern diagnostic tools and equipment, both in hospitals and in local rural settings where most cases occur.

Feeding and Manual Brushing Influence the Release of Oxytocin, ACTH and Cortisol Differently During Milking in Dairy Cows.

Aim: This study aimed to examine the effects of feeding or abdominal brushing on the release of the hormones oxytocin, ACTH and cortisol during milking in dairy cows. Methods: Twelve cows in early lactation were used (2 × 2 factorial experimental design), testing the effects of two types of sensory stimulation during milking over a 3 day period; feeding concentrate or manual abdominal brushing (1 stroke/s). Blood samples for hormone analyses were collected at time at -15, -1, 0 (onset of cluster), every min for 8 min, at 10, 12, 14, 16, 30, and 60 min. Hormone levels were assayed and AUC was calculated. Results: Milking was associated with an immediate and significant rise of oxytocin. When milking was combined with feeding, significantly higher levels of oxytocin were observed at 2 and 4 mins (p < 0.05). No effect of brushing on oxytocin levels was observed. Milking alone was associated with a significant rise of ACTH levels. Feeding in connection with milking reduced the immediate rise of ACTH levels (p < 0.05) and AUC (p < 0.02), whereas no effects of brushing were found. Milking caused a progressive rise of cortisol levels. Concomitant feeding did not influence cortisol levels, whereas brushing significantly decreased cortisol levels at 1, 5 and 14 mins after onset of milking (p < 0.05). Conclusion: Feeding increases oxytocin release in response to milking and decreases ACTH levels. Abdominal brushing did not influence these variables, but decreased cortisol levels. These data demonstrate that activation of afferent vagal nerve fibres and of cutaneous sensory nerves originating from the abdominal skin in front of the udder influence milking related hormone release differently.

Effects of Replacing Grass with Foliage on Growth Rate and Feed Intake in Goats-A Systematic Review and Meta-Analysis.

Small ruminants such as goats have a higher preference for browse species than cattle and sheep. In a meta-analysis of 42 papers describing 117 experimental treatments found by a search performed in June 2021 in PubMed and Web of Knowledge, we examined the general effect of including foliage in the diet of goats, replacing grasses, on dry matter intake and average daily weight gain. The inclusion requirement for a paper was that it described a controlled trial with a control diet of grass and with grass replaced by foliage in the experimental diet. Publication bias was estimated by calculating the Fail-safe n. Random effects analyses were conducted, using effect size calculated as Hedges' d. The results showed that inclusion of foliage increased feed intake (Hedges' d = 1.350, SE = 0.388) and average daily weight gain (Hedges' d = 1.417, SE = 0.444) compared with a grass-based control. The positive effect of foliage inclusion on dry matter intake was associated with lower neutral detergent fiber (NDF) and higher crude protein (CP) in the foliage than in the grass it replaced. The positive effect on average daily weight gain was associated with higher CP concentration in the foliage than in grass. Foliage inclusion level showed a quadratic relationship with dry matter intake, with maximum dry matter intake achieved at a level of 50-60%. There was wide variation between the studies reviewed, and this variation was not reduced by subgroup analysis based on different kinds of foliage. In conclusion, the addition of foliage to goat diets can increase feed intake and daily weight gain, as an effect of the dietary preferences of goats and of generally higher nutritional value in foliage species compared with natural/semi-natural grass species.

Evaluation of rangeland condition in miombo woodlands in eastern Tanzania in relation to season and distance from settlements.

Miombo woodlands sustainability in east and south-central Africa is threatened by human activities, including overgrazing. This study investigated seasonal variations in rangeland condition in three grazed areas in miombo woodlands in eastern Tanzania. Transect lines were established across the grazing areas, sampling points were identified and marked at every 10% of the length of transect line. Sampling points were categorised in different distances with respect to settlement. The line intercept method was used to collect data on vegetation cover and forage distribution, while herbaceous forage biomass was estimated using a disc pasture meter. A total of 118 different plant species were observed and grasses comprised 40.6% of all herbaceous species. Bothriochloa pertusa, Cynodon plectostachyus, Hyparrhenia rufa and Urochloa mosambicensis grass species dominated miombo grazed areas in various seasons and distances. These perennial grass species are desirable and indicated moderate grazing activities in miombo. Season affected grass cover, herbaceous forage biomass and nutritional composition. Grass cover and forage biomass were at the lowest during late dry season while forage nutritional quality was best during early dry season. Distance from settlement had no effect on grass cover and herbaceous forage biomass. Rangeland condition was generally fair, livestock stocking rate in continuously grazed drylands should be set at the lowest monthly forage biomass in order to ensure grazing land sustainability.

Analysis of the developing gut microbiota in young dairy calves-impact of colostrum microbiota and gut disturbances.

The aim of this study was to characterize the colostrum and fecal microbiota in calves and to investigate whether fecal microbiota composition was related to colostrum microbiota or factors associated with calf health. Colostrum samples were collected in buckets after hand milking of 76 calving cows from 38 smallholder dairy farms. Fecal samples were taken directly from the rectum of 76 calves at birth and at 14 days age. The bacterial community structure in colostrum and feces was analyzed by terminal restriction fragment length polymorphism for all samples, and the microbial composition was determined by 16S rRNA gene amplicon sequencing for a subset of the samples (8 colostrum, 40 fecal samples). There was a significant difference in fecal microbiota composition between day 0 and day 14 samples, but no associations between the microbiota and average daily gain, birth weight, or transfer of passive immunity. At 14 days of age, Faecalibacterium and Butyricicoccus were prevalent in higher relative abundances in the gut of healthy calves compared to calves with diarrhea that had been treated with antimicrobials. Colostrum showed great variation in composition of microbiota but no association to fecal microbiota. This study provides the first insights into the composition of colostrum and fecal microbiota of young dairy calves in southern Vietnam and can form the basis for future more detailed studies.

High level of multidrug-resistant Escherichia coli in young dairy calves in southern Vietnam.

This study investigated the occurrence of antimicrobial-resistant Escherichia coli in dairy calves in southern Vietnam. Fecal samples were taken directly from the rectum of 84 calves from 41 smallholder dairy farms, when newborn and at 14 days of age for isolation of E. coli. Escherichia coli strains were isolated from 144 of the 168 fecal samples tested. Of the 144 E. coli isolates, 40% were found to be susceptible to all 12 antimicrobial drugs tested and 53% of the E. coli isolates were resistant to at least three antimicrobials. Calves were colonized with antimicrobial-resistant E. coli already on the day of birth. Resistance to tetracycline was most common, followed by resistance to sulfamethoxazole, ampicillin, trimethoprim, and ciprofloxacin. Four isolates carried a gene encoding for extended-spectrum cephalosporinases (ESC), and these genes belonged to blaCTX-M group 1 (2 isolates), blaCTX-M group 9 (1 isolate), and blaCMY-2 (1 isolate). Thirty-three isolates had a plasmid-mediated quinolone resistance (PMQR) phenotype, and 30 of these carried the qnrS gene. These results are of importance for management routines of dairy cattle to prevent the spread of antimicrobial resistance.

Colostrum quality, IgG absorption and daily weight gain of calves in small-scale dairy production systems in Southern Vietnam.

Dairy production is expanding rapidly in Vietnam, but still, the smallholder farms are most common. The aim of this study was therefore to get improved knowledge about colostrum quality in dairy cows, immunoglobulin G (IgG) absorption, daily weight gain in dairy calves and calf management in small-scale dairy production systems in Southern Vietnam. A field survey was conducted on 40 farms, with two calves on each farm being intensively studied. It was observed that newborn calves were separated from their dams immediately after birth and offered 2-4 L first colostrum within 4 h by bucket feeding. The first colostrum IgG level, fat and protein content were on average 35.6, 4.8 and 21.4%, respectively, and 91% of the cows produced colostrum of good quality (Brix value >22%). The IgG level in serum of calves, measured as Brix value, was on average 9.3%. Colostrum in the samples studied was of quite high quality and on-farm observations showed that colostrum was offered on the first day of calf life, so passive transfer of immunity to the calves was high. In total, 10% of the calves had a Brix value for IgG in serum lower than 8.3%, indicating that those calves had suffered from failure of passive immune transfer (FPT). The daily weight gain of female and male calves was 0.75 and 0.54 kg, respectively. Serum IgG was positively correlated with colostrum protein (P = 0.002). Daily weight gain and diarrhoea was negatively correlated (P = 0.001).

Whole lactation production responses in high-yielding dairy cows using high-quality grass/clover silage.

BACKGROUND: Limiting the use of purchased concentrate for livestock and replacing it with home-grown forage without compromising milk production can offer benefits in both organic and conventional dairy systems. A full lactation trial was conducted with 92 cows over two years comparing three diets, each differing in the mean forage proportion over the lactation, 500 (500F), 600 (600F) and 700 (700F) g kg-1 dry matter (DM) respectively. The diets were designed to represent common conventional feeding, current regulations for organic production and more extreme high-forage-based production respectively. The aims were to determine the effects of forage proportion in the diet on milk production and feed utilisation. RESULTS: Compared with 500F, daily milk yield did not differ in 600F but was lower in 700F (31.3, 31.1 and 29.2 kg energy-corrected milk respectively). Daily dry matter intake (DMI) was similar between treatments (20.3, 20.4 and 19.9 kg in 500F, 600F and 700F respectively). CONCLUSION: Increasing the forage proportion from 500 to 600 g kg-1 DM did not have any adverse effects on milk production or DMI. Thus it is possible to produce the same quantity of milk with less concentrate and reduce the use of potential human feeds in dairy production. © 2016 Society of Chemical Industry.

Effects of calving month, pasture conditions and management on the growth of Holstein-Friesian × Ankole crossbred calves in a semi-arid rangeland.

Daily weight gain of crossbred calves was studied in relation to seasonal changes in pasture quality and quantity, and management routines. A total of 171 and 56 calves were monitored up to the ages of 6 and 9 months, respectively, on ten farms in a semi-arid region of Uganda. Daily weight gains of calves were 288, 315 and 442 g/day at ages 0-2, 2-6 and 6-9 months, respectively. Average live weights of calves at ages 6 and 9 months were around 90 and 120 kg, respectively. Daily weight gain of calves at ages 6-9 months increased by 81 g for each additional percentage of crude protein in pasture (p < 0.05). At ages 0-2 (p < 0.05) and 0-6 (p < 0.05) months, crosses with >75 % Holstein-Friesian (HF) had 30 and 60 g lower daily weight gain, respectively, than crosses with 75 % HF and 25 % Ankole. Birth month (August-January) and the number of days with low pasture quantity (<800 kg dry matter (DM)/ha) had no significant effect on calf weight gain. A significantly higher weight gain was obtained for calves with the opportunity to suckle twice daily, compared with once. This indicates that suckling is beneficial for calves in semi-arid environments where seasonal pasture shortage regularly occurs.

Prevalence of subclinical mastitis and isolated udder pathogens in dairy cows in Southern Vietnam.

Dairy production is not traditional in Vietnam. The farmers have little practical knowledge and udder health control is generally lacking. In order to give the farmers appropriate advice, knowledge about the distribution of udder pathogens is crucial. The aim of the study was to investigate the prevalence of sub-clinical mastitis and to identify udder pathogens isolated from smallholder dairy herds in Southern Vietnam. Twenty farms with a herd somatic cell count (SCC) ranging from low (≤ 400 × 10(3)cells/mL) to high (>400 × 10(3)cells/mL) were randomly selected. Milk samples were collected from 458 quarters of 115 clinically healthy cows. SCC was analyzed on farm by a portable cell counter. Bacteriological samples were taken using Mastistrip(©) cassettes and sent to Sweden for examination. For all herds the mean herd SCC was 632 × 10(3)/mL milk. The prevalence of subclinical mastitis at quarter SCC basis was 63.2 % and at cow basis 88.6 %. Only 40 % of all cows were bacteriologically negative in all quarters. Streptococcus agalactiae was the most commonly found bacteria species, isolated from 96 of the 458 quarter samples, in 13 of the 20 farms. The results indicate pronounced subclinical mastitis problems among the dairy cows in this region mainly due to infections with S. agalactiae. The high prevalence of this highly contagious pathogen is probably attributable to the generally poor milking hygiene and low awareness of proper measures to prevent occurrence and spread of udder infections. A strict, targeted action program for the herds in this area is required in order to lower the prevalence of subclinical mastitis.

Protein degradation in bovine milk caused by Streptococcus agalactiae.

Streptococcus (Str.) agalactiae is a contagious mastitis bacterium, often associated with cases of subclinical mastitis. Different mastitis bacteria have been evaluated previously from a diagnostic point of view, but there is a lack of knowledge concerning their effect on milk composition. Protein composition is important in achieving optimal yield and texture when milk is processed to fermented products, such as cheese and yoghurt, and is thus of great economic value. The aim of this in vitro study was to evaluate protein degradation mainly caused by exogenous proteases originating from naturally occurring Str. agalactiae. The samples were incubated at 37°C to imitate degradation caused by the bacteria in the udder. Protein degradation caused by different strains of Str. agalactiae was also investigated. Protein degradation was observed to occur when Str. agalactiae was added to milk, but there were variations between strains of the bacteria. Caseins, the most economically important proteins in milk, were degraded up to 75% in milk inoculated with Str. agalactiae in relation to sterile ultra-high temperature (UHT) milk, used as control milk. The major whey proteins, α-lactalbumin and ß-lactoglobulin, were degraded up to 21% in relation to the sterile control milk. These results suggest that different mastitis bacteria but also different strains of mastitis bacteria should be evaluated from a milk quality perspective to gain knowledge about their ability to degrade the economically important proteins in milk.

Effect of feeding different levels of foliage from Erythrina variegata on the performance of growing goats.

The effect of feeding different levels of foliage from Erythrina variegata on the performance of growing goats was studied using a local breed (Ma T'ou) with an average initial body weight of 11.2 kg (SD = 0.9). Twenty-four animals were allocated to a randomized design, with six animals (three males and three females) per treatment. The treatments were four different levels of replacement of the diet crude protein (CP) with CP from Erythrina foliage (EF) at 0 % (E-0), 20 % (E-20), 40 % (E-40), and 60 % (E-60). There were no significant differences in the dry matter (DM) intake between treatments, but total CP intake was significantly higher in the goats fed the diet E-60 compared to E-20 (61.1 and 51.4 g/day, respectively). The average daily liveweight gain of the goats did not differ between treatments and ranged from 51 to 63 g/day. Sixteen animals were kept in metabolism cages for a digestibility study and given with the same four diets as in the main experiment. The digestibility of DM, organic matter, neutral detergent fiber, and acid detergent fiber was significantly higher for diet E-60 than for E-0. Neither the apparent digestibility of CP and N retention nor carcass characteristics (16 animals) differed with an increase in the level of CP from EF in the diets. In conclusion, CP from EF can replace up to 60 % of CP from a mixed diet with soybean meal without any negative effect on the growth in goats.

Effect of harvesting frequency, variety and leaf maturity on nutrient composition, hydrogen cyanide content and cassava foliage yield.

The experiment studied the effect of harvesting frequencies and varieties on yield, chemical composition and hydrogen cyanide content in cassava foliage. Foliage from three cassava varieties, K94 (very bitter), K98-7 (medium bitter) and a local (sweet), were harvested in three different cutting cycles, at 3, 6 and 9 months; 6 and 9 months and 9 months after planting, in a 2-yr experiment carried out in Hanoi, Vietnam. Increasing the harvesting frequency increased dry matter (DM) and crude protein (CP) production in cassava foliage. The K94 variety produced higher foliage yields than the other two varieties. Dry matter, neutral detergent fibre (NDF), acid detergent fibre (ADF) and total tannin content increased with months to the first harvest, whereas CP content decreased. Hydrogen cyanide (HCN) content was lower at the first harvest than at later harvests for all cutting cycles. At subsequent harvests the content of total tannins tended to decline, while HCN content increased (p<0.05). Chemical composition differed somewhat across varieties except for total tannins and ash. Dry matter, NDF, ADF and total tannins were higher in fully matured leaves, while CP and HCN were lower in developing leaves.

Effect of adaptation strategies when feeding fresh cassava foliage on intake and physiological responses of lambs.

The objective of the experiment was to study different adaptation strategies to avoid HCN intoxication when feeding fresh cassava foliage to sheep. Twenty-four Phan Rang lambs (initial weight = 19.6 kg at 5.5 months of age) were used in the study. The four experimental diets contained guinea grass (Panicum maximum) supplemented with concentrate at 1.5% of body weight (BW) as dry matter (DM) (control) or supplemented with fresh cassava foliage (FCF) that was introduced into the diet with an adaptation period of 0 (FCF-0), 7 (FCF-7) or 21 (FCF-21) days before reaching the target feeding level of 2% of BW. The average intake of FCF expressed as DM was not different amongst the supplemented treatments and ranged from 1.4 to 1.5% of BW but gradually increased during the first 7 days without any adaptation. The hydrogen cyanide consumed varied from 5.1 to 5.4 mg/kg BW and no difference between treatments with cassava foliage in the diet was found. The live weight gain was significantly higher in the treatments control and FCF-7 compared to FCF-21. No significant differences in heart rate, respiration rate and rumen movement were found between diets. The thiocyanate concentration in the urine of the lambs increased concomitantly with the increase in fresh cassava foliage offered during the first part of the experiment. In conclusion, an adaptation period of approximately 7 days seems to be favourable in combined diets where cassava foliage is offered in quantities up to 2% of BW. This level of intake could enhance the intake and LWG of the lambs without any documented effects on heart rate, respiration rate or rumen movements.

Is there a special mechanism behind the changes in somatic cell and polymorphonuclear leukocyte counts, and composition of milk after a single prolonged milking interval in cows?

BACKGROUND: A single prolonged milking interval (PMI) e.g. after a technical stop in an automated milking system is of concern for the producer since it is associated with a short-lasting increase in milk somatic cell count (SCC), which is a major quality criterion used at the dairy plants. The content of polymorphonuclear leukocytes (PMN) and how the milk quality is influenced has not been much investigated. The SCC peak occurs without any obvious antigen challenge, possibly indicating a different leukocyte attraction mechanism after a PMI than we see during mastitis. METHODS: Composite cow milk samples were taken at the milkings twice daily during 7 days before and 5 days after a PMI of 24 h. Milk was analyzed for SCC, PMN, fat, protein and lactose, and at some occasions also casein and free fatty acids (FFA). RESULTS: During the PMI the proportion of milk PMN increased sharply in spite of marginally increased SCC. The peak SCC was not observed until the second milking after the PMI, in the afternoon day 1. However, the peak SCC value in morning milk did not occur until one day later, concomitantly with a decrease in the proportion of PMN. After declining, SCC still remained elevated while PMN proportion was decreased throughout the study as was also the milk yield, after the first accumulation of milk during the PMI. Milk composition was changed the day after the PMI, (increased fat and protein content; decreased lactose, whey protein and FFA content) but the changes in the following days were not consistent except for lactose that remained decreased the rest of the study. CONCLUSION: The PMI resulted in increased SCC and proportion of PMN. Additionally, it gave rise to minor alterations in the milk composition in the following milkings but no adverse effect on milk quality was observed. The recruitment of PMN, which was further enhanced the first day after the PMI, appeared to be independent of milk volume or accumulation of milk per se. Hence, we suggest that there is a special immunophysiological/chemoattractant background to the increased migration of leukocytes into the milk compartment observed during and after the PMI.