Feeding patterns and performance of cows in controlled cow traffic in automatic milking systems.

Two groups of dairy cows monitored from 3 to 19 wk postpartum were subjected to 2 different cow traffic routines in an automatic milking system with control gates and an open waiting area. Using different time settings in the control gates, the groups of cows were separated by average milking frequency; cows in the high milking frequency routine had a minimum of 4 h between milkings (MF(4)) and were milked 3.2 +/- 0.1 times daily, whereas cows in the low milking frequency routine had at least 8 h between milkings (MF8) and were milked 2.1 +/- 0.1 times daily. Cows in the 2 groups were switched to the opposite milking frequency control for wk 18 and 19. The increased milking frequency resulted in a higher milk yield of about 9% through 16 wk of early lactation Although the higher milk yield was not significant when measured as energy-corrected milk, significant interactions of milking frequency and study period for milk yield and energy-corrected milk yield were consistent with a yield response when cows were milked more frequently. Meal criteria estimated for each individual cow were used to group feeding visits into meals. During MF4, cows fed in fewer meals per day and had longer meals than during MF8. The control gates were used efficiently, with only a few passages not resulting in actual meals. Although the voluntary meal intervals seemed to be short, the average milking frequency was far below that theoretically possible. This was explained by individual differences in milking frequency and long intervals from when a cow was redirected in a control gate until it arrived in the milking unit. A wide individual range in the voluntary interval between the first and the second meal in the milking cycle suggests that fixed time limits for control gates set on group level have no justifiable biological basis. It was also concluded that primiparous cows were well adapted to the automatic milking system after 2 wk in the barn.

Analysis of feeding and drinking patterns of dairy cows in two cow traffic situations in automatic milking systems.

With increasing possibilities for obtaining online information for individual cows, systems for individual management can be developed. Feeding and drinking patterns from automatically obtained records may be valuable input information in these systems. With the aim of evaluating appropriate mixed-distribution models for feeding and drinking events, records of 30 fresh cows from visits at feeding stations (n = 83,249) and water bowls (n = 67,525) were analyzed. Cows were either allowed a high-milking (HF) or a low-milking (LF) frequency by being subjected to controlled cow traffic with minimum milking intervals of 4 and 8 h, respectively. Milking frequency had significant effects on feeding patterns. The major part (84 to 98%) of the random variation in feeding patterns of the cows was due to individual differences between cows. It can be concluded that cows develop consistent feeding and drinking patterns over time that are characteristic for each individual cow. Based on this consistency, patterns of feeding and drinking activities have valuable potential for purposes of monitoring and decision making in individual control management systems. Use of a Weibull distribution to describe the population of intervals between meals increased the statistical fit, predicted biologically relevant starting probabilities, and estimated meal criteria that were closer to what has been published by others.

Effects of fresh cassava tops on rumen environment parameters, thyroid gland hormones and liver enzymes of local yellow cattle fed urea-treated fresh rice straw.

In a 4 x 4 Latin square design study, four rumen-cannulated local yellow cattle, average weight 330 kg, were fed urea-treated fresh rice straw (UFRS) ad libitum and given 1 kg cassava root meal daily as basal diet in each 30-day trial period. Four treatment levels of crude protein of fresh cassava tops (FCT) were supplied: 0 (FCT0), 50 (FCT50), 100 (FCT100) and 150 g (FCT150) crude protein per 100 kg body weight. The results showed a continuous decrease in dry matter intake (DMI) of UFRS with increasing level of FCT supplementation (p<0.001). Total DMI for treatments FCT150, FCT100, FCT50 and FCT0 were 2.66, 2.42, 2.23 and 2.05 kg dry matter per 100 kg live weight per day, respectively. Increasing levels of FCT supplementation increased the concentration of total volatile fatty acids (p<0.05) and ammonia (p<0.001) and resulted in a decrease in pH (p<0.05). Rumen protozoa population varied widely but was significantly lower with increasing FCT supplementation (p<0.001), while rumen bacteria population was higher (p<0.05). Overall, average plasma triiodothyronine and thyroxine concentrations in the four groups were respectively 1.36, 0.94, 0.91, 0.80 ng/ml (p<0.01) and 60.9, 48.7, 45.2, 42.5 ng/ml (p<0.001). There were non-significant differences in alanine aminotransferase and aspartate aminotransferase concentrations among the treatments.

Behaviour of Zebu and crossbed cows in restricted suckling groups.

The aim of this study was to investigate whether Zebu (Bos indicus) and crossbred (Bos indicusxBos taurus) cows differ in maternal related behaviour during restricted group suckling. The behaviours of 20 Zebu and 16 crossbred cows were recorded during two 30min sessions each day after milking when their calves were present for suckling, for a time period of 2 weeks per month for 6 months postpartum. The main activity in both breeds during the 0.5h observation sessions was suckling. However, the two breeds differed significantly in several behavioural aspects. The Zebu cows had longer total duration of suckling than the crossbred cows, per 30min session, 11.8 and 9.4min, respectively. The separate suckling bouts were longer in the Zebu cows (2.8min in Zebu and 2.3min in crossbred) and this breed also had more suckling bouts than the crossbred per session, 3.8 and 3.2, respectively. Zebu cows stayed in close contact with their calves for longer time and directed more agonistic actions against alien calves and cows than the crossbred cows.

Effect of age of calf on suckling behaviour and other behavioural activities of Zebu and crossbred calves during restricted suckling periods.

The objective of this study was to investigate the effect of age of calf on the behaviour of Zebu and crossbred calves during restricted suckling (RS) periods. The behaviours of 20 Zebu and 16 crossbred calves were recorded during two 30-min sessions each day after milking when the calves and their dams were brought together in a group for suckling. This was made for a time period of 2 weeks/month for 6 months postpartum.The total suckling duration was significantly longer in Zebu calves (11.8+/-0.19 min) compared to the crossbred calves (9.4+/-0.19 min), but decreased significantly in both breeds with increasing age from 1 to 6 months. The number of suckling bouts decreased from a mean of 3.8 at 1 month of age to 1.1 at 6 month (P<0.05). The duration of each suckling bout decreased significantly from a mean of 3.5+/-0.15 min at 1 month of age to 1.6+/-0.01 min at 6 months (<0.05). The frequency of crossbred calves cross-suckling (3.7%) was significantly higher than that of the Zebu calves (1.9%; P<0.05). The frequency of calves cross-suckling decreased significantly from 4.2% at 1 month of age to 2.3% at 6 months. The duration and number of bouts of cross-suckling was significantly higher in the crossbred calves (duration 0.9+/-0.06 min; bouts 3, 7) than in the Zebu calves (duration 0.5+/-0.06 min; bouts 2, 7) and decreased with increasing age of calf. The duration and number of bouts of inter-sucking was significantly higher in the crossbred calves (duration 0.6+/-0.07 min; bouts 1, 6) than in the Zebu calves (duration 0.1+/-0.04 min; bouts 0, 5) and decreased with increasing age of calf. Exploration increased in duration as the calves increased in age from 1 to 6 months (P<0.05). The duration of play increased significantly with the increase in age of calf from 1 to 6 months, and occurred mainly after nursing.

Influence of restricted suckling and level of feed supplementation on postpartum reproductive performance of zebu and crossbred cattle in the semi-arid tropics.

This study was carried out in central Tanzania on a group of 45 Zebu and 37 crossbred cows which were 4 to 10 years old. At calving time, the animals were allocated to one of the 4 treatment groups. In addition to free access to grazing for all cows in the study, in group H:AR (n = 18), cows were fed a high level of concentrate supplementation (4kg/day) and calves were artificially reared; in group H:RS (n = 24), cows were fed a high level of concentrate supplementation (4kg/day) and calves were only allowed restricted suckling up until the weaning age of 6 months. In group L:AR (n = 23) cows were fed a low level of concentrate supplementation (2kg/day) and calves were artificially reared; and in group L:RS (n = 17) cows were fed a low level of concentrate supplementation (2kg/day) and calves were only allowed restricted suckling up until the weaning age of 6 months. Milk progesterone was used as a means of determining the postpartum resumption interval (PRI) and the interval from parturition to conception (PCI). The overall PRI was 47.4 +/- 0.4 days and was significantly affected by breed but not by calving season, with crossbred cows exhibiting a shorter PRI than Zebu cows. The effect of the treatments was significant, with cows in the group H:AR displaying a significantly shorter PRI than those in the other groups, while cows in group L:RS showed a significantly longer PRI than those in the other groups. The overall PCI was 149.5 +/- 3.7 days, and was not significantly affected by breed or calving season. The effect of the treatments was significant, with cows in the group H:AR having a significantly shorter PCI than cows in the other groups, while cows in group L:RS showed a significantly longer PCI than those in the other groups. Crossbred cows had higher live weights at calving (299.4 kg) than Zebu cows (272.6 kg), while all cows gained weight during the first 3 months after calving. The treatments had a significant effect on weight gain, with cows in the group H:AR gaining significantly more weight than those in the other groups. Cows which had high live weights at calving exhibited significantly shorter PRI and PCI than the lighter cows. Animals which had gained more than 5 kg during the first month after calving, or which had gained more than 8 kg during the first 3 months after calving, showed significantly shorter PRI and PCI than cows which had gained less weight. The results show that the calf rearing system and the level of feed supplementation interact with each other and can influence the postpartum anoestrous period in Zebu and Zebu crossbred cattle. Increasing the level of nutrition in restricted suckling cows tended to improve the postpartum anoestrous period, but the positive effects of supplementation could not completely compensate for the negative effects of suckling.

Effects of different energy levels, concentrate/forage ratios and lipid supplementation to the diet on the adaptation of the energy metabolism at calving in dairy cows.

A low level of energy (110 MJ ME) and a low concentrate/forage ratio (10/90) at calving resulted in low basal concentrations of glucose and insulin, but the cows had the capacity to increase the glucose level after glucagon injections. No signs of disturbances in the metabolic adaptation were observed. High intensity feeding (200 MJ ME and 50% concentrates) resulted in high basal serum insulin levels. The increase in the insulin concentrations after glucagon injections and the changes in insulin levels around calving varied widely between individual cows. The metabolic adaptation period was longer than in cows in the former group. An energy level of 170 MJ ME and variations of concentrate/forage ratios (5/95, 30/70 and 60/40) resulted in small differences in basal glucose and insulin concentrations and in response to glucagon injections. But the cows fed 60% concentrates showed signs of prolonged metabolic adaptation. Increased lipid concentrations in diets containing equal levels of energy and protein resulted in a fall in basal glucose and insulin levels and the metabolism seemed to be directed towards catabolism. Because of these metabolic effects, more needs to be known on fat supplementation if it is used in practical feeding. It is also necessary to take more interest in the effects of protein feeding on the periparturient metabolism.

Rapeseed products from double-low cultivars as feed for dairy cows: effects of long-term feeding on thyroid function, fertility and animal health.

Eighty-five dairy cows of the Swedish Red and White Breed (SRB) were included in a long-term experiment during 3 consecutive lactations. The cows were divided into 3 different dietary groups that received no rapeseed (NR), up to 1.2 kg dry matter (DM) 00-rapeseed meal plus 0.2 kg DM full-fat 00-rapeseed (MR), and up to 2.5 kg DM 00-rapeseed meal plus 0.9 kg DM full-fat 00-rapeseed (HR) per day. No significant differences in culling rates or disease rates were found between the feeding groups at any time during the experiment. The interval from calving to conception among the primiparous cows was longer for the HR-group (125 days) than for the NR-group (100 days). The response to a thyrotroph releasing hormone around 90 days postpartum during the first lactation was significantly higher for the HR-group (86.7 mu/L/h) than for the NR-group (55.2 micrograms/L/h). This indicates that at the highest level of rapeseed feeding, glucosinolates had a very mild, suppressive influence on thyroid hormone release, apparently compensated for by an increased activity along the hypothalamic-pituitary-thyroid axis. No significant differences in fertility or thyroid function were found among the pluriparous cows. During 2nd lactation the concentration of serum urea was higher in the NR-group (7.31 mmol/L) than in the HR-group (6.83 mol/L). The effects of independent environmental factors influenced fertility and thyroid function to a much greater extent than the rapeseed feeding. It was concluded that the feeding of rapeseed products from certified double low varieties of B. napus to adult dairy cows in amounts up to 3 kg rapeseed meal per cow and day would not have any negative effects on animal health or fertility.

A comparative study of arterial and venous blood acetate concentration in cows fed different diets close to parturition.

Blood samples were collected from the coccygeal artery and a jugular vein two weeks before expected calving, one to five days after calving and three weeks after calving of cows which were fed either a high roughage or a low roughage diet from four weeks before to 14 weeks after calving. The mean venous acetate concentration ranged from about half to three-quarters of the arterial concentration. No differences were observed at any time between concentrations of acetate in either the arterial or venous blood of the cows on the different diets.

Rumen and total diet digestibilities in lactating cows fed diets containing full-fat rapeseed.

Effects of full-fat crushed rapeseed (0, 1, or 2 kg/d) on rumen and total digestion, rumen biohydrogenation, and rumen microbial protein synthesis were studied in lactating cows. Rumen digestibilities (%) of DM, NDF, and cellulose were 52.1, 46.1, and 51.8, respectively, for control. Rapeseed decreased rumen and total DM digestibilities and proportion of DM digested in the rumen. Rumen digestibility of cellulose was decreased by rapeseed, but this was apparently compensated by hindgut fermentation. Dry matter, NDF, and hemicellulose digestibilities were compensated at 1 kg but not at 2 kg/d. Biohydrogenation of 18:1 fatty acids increased with increasing dietary fat, whereas that of 18:2 and 18:3 was 85% on all diets. Fatty acid digestibility was not different among diets. Microbial nitrogen in the duodenum increased from 142 g/d for control to 191 g/d for 1 and 2 kg/d. Efficiency of microbial protein synthesis (grams of microbial nitrogen per kilogram organic matter apparently digested in the rumen) was 17.3, 24.8, and 26.6 for 0, 1, and 2 kg/d. Slow release of fat from crushed rapeseed minimized negative effects on rumen metabolism; 1 to 2 kg/d of full-fat crushed rapeseed may be fed to lactating cows without detrimental metabolic effects.