Diet effect on the daily feeding behaviour, frequency and characteristics of meals in dairy goats

Comparative study of feeding and rumination behaviour of goats and sheep fed mixed grass hay of different chop length

Rumination is reported to be more pronounced in sheep compared to goats. This study compared the feeding and rumination behaviour of small ruminants and consisted of two experiments (E1 and E2). In E1, four sheep and four goats were offered low-quality hay (NDFom: 692 g/kg dry matter [DM]), processed to two chop lengths (long hay [LH]: 35 mm; short hay [SH]: 7 mm) in a 2 × 2 factorial (2 species × 2 chop lengths), cross-over design. In E2, the same animals were offered moderate-quality hay (NDFom: 636 g/kg DM) processed as LH and SH. Hay was offered for ad libitum consumption. Feeding and rumination behaviour was evaluated using video recordings. Aspects of rumination like chewing frequency were evaluated for 30 min per day. Faecal samples were analysed for faecal-N and particle size. There was no species effect on feed intake and organic matter digestibility (faecal N as proxy); however, goats consumed more LH than SH in E1 and E2. There was an effect of species on rumination:eating duration (R:E) ratio (higher in sheep) in E1 but not in E2, where there was a tendency for a species effect on rumination duration. In E1 and E2, sheep had a higher R:E ratio for SH than for LH. For rumination behaviour, there was a species effect for number of daily boli, chewing frequency and chews per day (more in sheep) in E1 and E2. No effect of species was found for faecal particle size. Despite much concordance, feed comminution behaviour differed in some aspects between sheep and goats. In an evolutionary context, a shift of significance of rumination could be triggered by a higher amount of abrasives in natural diets of sheep, rendering a shift of chewing towards ruminally prewashed material a rewarding strategy.

Effect of Dietary Corn Stalk Inclusion on the Performance of Non-Nutritive Oral Behaviors of Drylot-Housed Beef Steers

Dietary forage levels contribute to the performance of non-nutritive oral behaviors (NNOB) in cattle, yet the impact of varying forage levels on these behaviors is unknown. To evaluate the impact of dietary corn stalk inclusion (CSI) levels on NNOB, rumination time, and activity, pre-dominantly British-continental crossbred drylot-housed steers (n=27) were blocked by weight and randomly assigned to one of three dietary treatments (5%, 10%, or 15%) of CSI on a DM basis. Animals were fitted with a rumination collar upon arrival that measured rumination time and activity and video recorded. Cattle that spent more time bar licking had greater DMI, tended to have greater ADG and be more active. CSI in this study did influence NNOB performance; however, the impacts observed were not as expected. Cattle fed the 10% CSI performed the most bar licking and tongue rolling. This pilot investigation suggest that these CSI were insufficient to have a meaningful impact on NNOBs. Cattle spending more time bar licking and bar licked more frequently may be more orally motivated as reflected in their increased DMI and activity levels.

Dairy sheep and goats prefer the single components over the mixed ration

Mixed rations provide ruminants with a balanced diet by aiming to prevent selective feeding. However, this is a natural behavior of sheep and goats based on their dietary needs and the nutritional properties of feedstuffs. Therefore, the present study investigates non-lactating dairy sheep's and goats' acceptance of a mixed ration when it is offered as choice next to its single components. Because all offered feeds were of comparable nutritional value, the animals were expected to not show a particular preference. Twelve pairs of sheep and goats each, were offered three different feeds simultaneously for 5 replicate days. Two feeds consisted of a single component, hay (H) or grass-silage (G) of similar nutritional value. The third feed was a mixed ration (M) including both single-feed components in a 50:50 dry matter (DM) ratio. Feeds were offered ad libitum twice daily. The animals' intake of each feed was recorded at six time points per day by weighing the leftovers. Feed preference was expressed as the natural logarithm of the ratio of the intake of the single component to the intake of M and analyzed using linear mixed-effects models. Additionally, the animals' first choices after gaining access to the feeds were recorded at each weighing event and analyzed using an item response tree generalized mixed-effects model. The sheep's average daily DM intake was 59 (±11)% G, 26 (±10)% H, and 15 (±10)% M (mean ± standard deviation). Goats consumed an average of 56 (±13)% G, 37 (±12)% H, and 7 (±6)% M daily. Both species preferred the single components to M in all observation periods. The proportions of the three feeds consumed differed throughout the day and between species. For both species, the estimated probability that an animal chooses a single component over M first was over 94% at all time points. These results show that, contrary to our expectations, non-lactating dairy sheep and goats prefer single components over a mixed ration of the same components and similar nutritional value. This might be caused by the animals seeking to diversify their feed throughout the day independent of apparent nutritional values and/or because sensory properties of the single components, indicating palatability, are relevantly reduced by mixing.

Physiological Indicators and Production Performance of Dairy Cows With Tongue Rolling Stereotyped Behavior

Non-nutritive oral behaviors, especially tongue rolling, are prevalent in the stabled cow population. These behaviors mean that the environment or management process might not suit the cows, suggesting low welfare. However, few researches have reported the physiological indicators or production performance of dairy cows with the stereotyped behavior. This study aimed to determine physical conditions, daily activity, rumen fermentation, and milk production of cows with tongue-rolling behavior. Three hundred and fifty nine Holstein cows in the same barn and lactation stage were subjected to scan sampling behavior observations 126 times for 7 days. Ten cows with high-frequency tongue-rolling behavior (TON) and 10 cows without abnormal oral behavior (CON) were selected for further study. Serum sample, ruminal fluid, milk sample, and behavior record video of TON and CON cows were collected. TON cows had more drinking behavior and more stable lying behavior than the CON cows during the daytime. The body condition score of the TON cows decreased, while the milk yield, yield of milk fat, protein, and lactose in the study period increased. The TON cows had lower ruminal fluid pH, acetate/propionate ratio, and total volatile acid. The bacterial diversity in the ruminal fluid was not different between the two groups. Compared to CON cows, the TON cows had a higher level of serum stress indicators, such as cortisol, thyroid hormone, and norepinephrine, which positively correlated to the frequency of tongue-rolling behavior. Meanwhile, the TON cows had a higher level of lactate dehydrogenase, serum glucose, total triglyceride, total cholesterol, and Interleukin 6. Overall, it means they suffer from higher levels of stress and have higher energy metabolism for a long time when cows show tongue-rolling behavior. TON cows had suffered a higher stress level and had higher energy metabolic status for a long time. The TON cows might have better heat tolerance to the thermal environment by more lying and drinking time. Our data revealed the changes in milk production, physiological stress indicators of dairy cows with high-frequency tongue rolling behavior, which will provide essential knowledge for the in-depth understanding of tongue rolling behavior in dairy cows.

Dairy goats adjust their meal patterns to the fibre content of the diet

Few studies have investigated how meal patterns of ruminants are affected by diet fibre content. Dairy goats (N = 32) in late lactation and early gestation were housed in eight groups of four goats, with all combinations of breed (Alpine and Saanen) and lactation number (1 and 2) represented in each group. Each goat had access to its own individual feed trough placed on a weigh scale with data logged automatically. All goats were fed the same total mixed ration (TMR; 30% concentrate and 44.6% NDF in DM) ad libitum for a control period of 22 days. Using the same feed ingredients, half of the groups were then offered a High fibre diet (20% concentrate; 47.3% NDF), and the other half a Low fibre diet (40% concentrate; 41.5% NDF) for a treatment period of 16 days. Daily meal patterns (meal frequency, duration and size, feeding rate, daily feed intake and daily feeding time) were computed for each animal using a meal criterion of 8 min. The last 10 days for each period (control and treatment) were used to calculate individual period means and individual differences between the two periods. During the control period, the goats ate on average 12.1 ± 0.49 meals/day, consuming 4.2 ± 0.10 kg fresh TMR daily. When the ration changed, all measures of feeding behaviour except meal size changed asymmetrically for the goats on the two diets. Goats fed the High fibre diet reduced their meal frequency by 10%, and the first meal after feed distribution lasted 11% longer, leading to a 9% reduction in feeding rate and no significant changes in daily feed intake and daily feeding time. Goats on the Low fibre diet did not significantly change their meal frequency or meal size, but the combined changes nevertheless led to a 9% increase in daily feed intake. On the Low fibre diet, goats were able to increase their feeding rate by a third, leading to a reduction in meal durations, thus reducing daily feeding time by 13%. Goats adapt their feeding behaviour to the fibre proportion of the offered diet, with more changes when fibre content is lowered, which needs to be taken into account when comparing phenotypes and adaptability of small ruminants to different diets.

Dietary Starch Concentration Affects Dairy Sheep and Goat Performances Differently during Mid-Lactation

Simple Summary

In order to favor milk production, this research suggests that the concentration of starch in the diet of dairy ewes in mid-lactation should be reduced, compared to early lactation, by introducing sources of highly digestible fiber. On the other hand, this type of diet is not adequate for dairy goats, which should maintain the use diets rich in starch, even in mid-lactation, to support milk yield, as well.

Abstract

Evolution of milk production, body reserves and blood metabolites and their relationships with dietary carbohydrates were compared in 30 Sarda dairy ewes and 26 Saanen dairy goats in mid-lactation. From 92 to 152 ± 11 days in milk (DIM), each species was allocated to two dietary treatments: high-starch (HS: 20.0% starch, on DM basis) and low-starch (LS: 7.8% starch, on DM basis) diets. In mid-lactating goats, the HS diet increased fat-corrected milk yield (FCM (3.5%); 2.65 vs. 2.53 kg/d; p = 0.019) and daily milk net energy (NE_L; p = 0.025), compared to the LS diet. The body condition score (BCS) was not affected. In mid-lactating ewes, the LS diet increased FCM (6.5%) (1.47 vs. 1.36 kg/d; p = 0.008), and NE_L (p = 0.008), compared to the HS diet. In addition, BCS was greater in HS than in LS ewes (3.53 vs. 3.38; p = 0.008). Goats had a higher growth hormone (GH) and lower insulin concentration than ewes (GH: 2.62 vs. 1.37 ng/mL; p = 0.04; insulin: 0.14 vs. 0.38 µg/L; p < 0.001 in goats and ewes, respectively). In conclusion, in mid-lactation, the two species responded differently to dietary carbohydrates, probably due to differences in the concentration of GH and insulin. The HS diet favored milk yield in goats and body reserve accumulation in ewes. In ewes, the partial replacement of starch with highly digestible fiber increased energy partitioning in favor of milk production.

Sheep and goat feeding behavior profile in grazing systems

 Feeding behavior analysis provides information about the relationships between animals and pastures. Therefore, this review aims to describe some aspects of the feeding behavior profiles of both sheep and goats in grazing systems. The structure of the pasture is a key factor in the feeding behavior of grazing animals. The amount of feed consumed in a given period of time is affected by the number of meals, duration and velocity of swallowing, changes in grazing time, bite rate, bite weight, and quality of ingested forage. The different phenological stages of forage also influence the animals’ strategies to optimize their intake, which consequently changes their behavioral activities. Sheep and goats tend to be more selective than cattle, and young animals are more selective than older animals; this selectivity characteristic is one of the most important aspects to be observed in pasture management. According to the degree of selectivity, the animals will intake forages of higher or lower nutritive quality. In addition, the intensity and distribution of their daily activities (grazing, ruminating, and resting) are influenced by several factors, such as the availability and nutritive value of the pasture, its management, the animal activity in the group, and the predominant climatic conditions of the region.

The Effect of Behaviour and Diet on the Rumen Temperature of Holstein Bulls

Rumen temperature boluses are becoming increasingly used as a means of monitoring core body temperature for the detection of ill health. However, the effect of behavior on rumen temperature is largely unknown. This research investigates the impact of behaviour and diet on the rumen temperature of Holstein bulls, both at grass, and in a housed environment. Rumen temperature was recorded at five-minute intervals using a bolus. Direct observations were conducted on young bulls in two studies (i) at grass (n = 30) and (ii) while housed (n = 32). In addition, activity monitors were attached to bulls at grass (n = 24). Within each study, diet differed by the level of concentrate supplementation. There was no effect of diet on rumen temperature. Significant differences in rumen temperature were observed between behaviour groups for bulls at grass (p < 0.001) and housed (p < 0.001). Furthermore, drinking resulted in the lowest rumen temperature (grass 35.97 °C; housed 36.70 °C). Therefore, rumen temperature is affected by behavior; however, the temperatures recorded were not outside the normal temperature range for healthy cattle.

Seasonal variation in the foraging activity of desert argali (Ovis ammon) in Mongolia

Debate remains whether energy maximization or time minimization strategies best explain foraging in ungulates. It has also been hypothesized that the capacity of an animal to dissipate body heat regulates animal activity. We investigated these hypotheses while measuring the daily activity of desert argali (Ovis ammon (Linnaeus,1758)) for 12 months and relating the activity pattern to environmental seasonality. We found significant seasonal cycles in argali activity, with the greatest proportion of daytime in winter spent foraging and the greatest proportion of daytime in summer spent bedding. Consistent with an energy maximization strategy, argali reduced all behaviors during the winter in favor of foraging, compensating for the increased energy demands of winter at a time of low forage quality. Consistent with a time minimization strategy, argali in summer significantly reduced foraging and spent more time bedding in shaded areas to avoid hyperthermia due to high ambient temperatures. Both optimal foraging and heat dissipation can be used to explain the observed foraging pattern. Foraging behavior in argali is best described by the extent to which the animals schedule their activities to meet their physiological demands, the way these demands are affected by environmental variables, and the time that is available to accomplish them.

Feeding, Resting and Agonistic Behavior of Pregnant Boer Goats in Relation to Feeding Space Allowance

The aim of this study was to test the effect of the animal to feeding place ratio on behavior of meat goats during gestation. In one group (FP-1.0; n=10) every goat had a single feeding place while in the other group (FP-0.5; n=10) two goats had to share one feeding place. Behaviors were analyzed with the continuous sampling method for 24 h for each animal. Social dominance index was used by ranking individuals as low-, medium- and high-ranking according to withdrawal and displacement behaviors. Total daily feeding duration decreased (P=0.001) from 5.2 h to 4.2 h by reducing feeding place. Feeding duration was neither affected by social rank (P=0.362) nor its interaction with feeding place (P=0.159). Feeding frequency was higher in FP-0.5 than FP-1.0 (P=0.001). Low-ranking goats had a higher feeding frequency (P<0.001). Resting duration (lying and standing) decreased in medium- and low-ranking goats in FP-0.5 (P=0.001) while all rank categories were similar in FP-1.0. Competition behaviors increased (P=0.001) in medium- and low-ranked goats in FP-0.5 but were similar between rank categories in FP-1.0. Feeding place and social rank had an effect (P≤0.009) on some of the agonistic behaviors. Agonistic interactions such as displacement, butting and ignoring were affected by the interaction of feeding place and social rank (P≤0.005). In conclusion, the reduction of the number of feeding places from 1.0 to 0.5 per goat in pregnant hornless Boer goats negatively affected feeding, competition, resting and aggressive behaviors, whereas low-ranking animals suffered more from competition and aggression behaviors.

Interaction effect of ruminal undegradable protein level and rumen-protected conjugated linoleic acid (CLA) inclusion in the diet of growing goat kids on meat CLA content and quality traits

The aim of the present study was to determine the effects of dietary rumen undegradable protein (RUP) level and rumen-protected conjugated linoleic acid (rpCLA) on meat fatty acid (FA) profile, chemical compositions and colour parameters of growing kids. Thirty-two Kurdish goat kids (13·06 ± 1·08 kg body weight) were fed diets differing in RUP level (low = 250 v. high = 350 g/kg of dietary crude protein) supplemented either with 15 g/kg of rpCLA or 12 g/kg of hydrogenated soyabean oil (HSO) for 80 d. Interaction of dietary rpCLA and RUP level had no effect on hot carcass weight, dressing and cut percentage, and meat chemical composition and colour parameters. Meat total SFA, MUFA and PUFA concentrations were not influenced by experimental diets, whereas kids fed diets supplemented with rpCLA had lower meat total SFA and higher PUFA concentrations compared with those fed diets supplemented with HSO. The concentration of meat trans-11-8 : 1 was not influenced by rpCLA supplementation, RUP level and their interaction. Kids fed diets containing rpCLA supplementation had higher meat total CLA and cis-9, trans-11-CLA and trans-10, cis-12-CLA isomers compared with those fed diets containing HSO supplementation. Desaturase indexes of C14, C16 and C18 were not influenced by rpCLA supplementation, RUP level and their interaction. It is concluded that supplementing growing kids' diets with RUP and 15 g/kg of rpCLA not only decreased meat fat content but also increased some FA considered to be of potential benefit to human health.

Estimating optimal observational sampling frequency of behaviors for cattle fed high- and low-forage diets

Video recordings of behavioral activities including eating, ruminating, drinking, standing, and lying were monitored to determine the minimum number of sampling days and sampling frequency required to obtain reliable estimates of these behaviors. Eight continental crossbred heifers, individually housed in a tie-stall barn with total mixed ration provided once per day, were divided by BW into two blocks and assigned to each of the two dietary treatments in a crossover design: high-forage diet (HF, forage:concentrate ratio 70:30) and low-forage diet (LF, forage:concentrate ratio 30:70). The cows were monitored continuously using a digital video recording system for 6 d in each of the two periods and a trained observer manually recorded the behavioral activities by minute. Mean time spent performing each behavior for 6 d with instantaneous samples of 1 min was compared with those obtained using fewer sampling days (1, 2, 3, 4, and 5 d) and less frequent scanning (2, 3, 4, 5, 10, 15, 30, and 60 min) using linear regression analysis, and the minimum number of sampling days or frequency was determined. Diet did not affect the accuracy and precision of predicting behavior from video recordings of the cows. When sampling days and scanning intervals were combined, the minimum recommended sampling frequency for accurately estimating a specific set of behaviors of beef heifers in tie stalls was: eating, 2 d with 4-min intervals; ruminating, 3 d with 4-min intervals; drinking, 2 d with 3-min intervals; and standing and lying, 2 d with 15-min intervals. Increasing sampling frequency beyond these minimums further enhanced the accuracy and precision of predictions. The total time of each behavioral activity was different between cows fed HF and LF diets with eating, ruminating, total chewing, and standing of heifers fed the HF diet greater (P < 0.01), but the lying (P < 0.01) and drinking time (P = 0.028) of heifers fed the LF diet greater. Meal patterns were different (P < 0.05) between the treatments except when meal size (kg) was expressed as DM or OM intake. For rumination patterns, the mean or maximum bout length (min/bout) was greater, but the maximum or minimum length of time heifers took to ruminate after eating was lower for the HF diet. From a practical standpoint, it is recommended to use 3 days of observations scanned at an interval of 4 min to reliably estimate the behavior of cows. If the focus is only lying and standing time, then 2 days with 15 min intervals can be used.

Effects of diet and roughage quality, and period of the day on diurnal feeding behaviour patterns of sheep and goats under subtropical conditions

Objective

This study investigated the effect of diet and roughage quality (RQ) on dry matter intake, duration and number of daytime and night-time eating bouts, idling sessions and ruminating activities in small ruminants.

Methods

In Exp 1 and 2, RQ was improved by urea treatment of veld hay, while diet quality was improved by supplementing with Lucerne hay (Exp 3), sunflower meal and lespedeza (Exp 4), fish meal (Exp 5a), and sunflower meal (Exp 5b). In all experiments goats and sheep were blocked by weight and randomly allocated to experimental diets. Day-time (06:00 to 18:00 h) and night time (18:00 to 06:00 h) feeding behaviour activities were recorded.

Results

RQ affected rumination index in Exp 1, but not in Exp 2, 3, and 5. Time spent eating and ruminating was affected by RQ (Exp 1, 3, and 4), period of day (all experiments) and their interaction (Exp 1). Intake rates (g/bout and g/min) were similar across diets. Period of day affected the duration of rumination sessions (Exp 1, 2, and 3); diet or RQ affected the duration of eating bouts (Exp 3) and rumination sessions (Exp 1 and 2). RQ had a significant effect on the duration of eating sessions in Exp 3 only, whilst period of day affected this same behaviour in Exp 2 and 3. Generally, goats and sheep fed on roughage alone ruminate at night and eat more during the day but those fed a roughage and supplemented with Lucerne hay spent more time ruminating than eating. Time spent eating and ruminating had positive correlations to crude protein and feed intake. Intake rates had strong positive correlations to intake.

Conclusion

Chewing time, number of eating and ruminating sessions, and duration of eating bouts are physiologically controlled in small ruminants, though chewing time requires isometric scaling during modelling of intake.

Determining suitable dimensions for dairy goat feeding places by evaluating body posture and feeding reach

Confined goats spend a substantial part of the day feeding. A poorly designed feeding place increases the risk of feeding in nonphysiological body postures, and even injury. Scientifically validated information on suitable dimensions of feeding places for loose-housed goats is almost absent from the literature. The aim of the present study was, therefore, to determine feeding place dimensions that would allow goats to feed in a species-appropriate, relaxed body posture. A total of 27 goats with a height at the withers of 62 to 80 cm were included in the study. Goats were tested individually in an experimental feeding stall that allowed the height difference between the feed table, the standing area of the forelegs, and a feeding area step (difference in height between forelegs and hind legs) to be varied. The goats accessed the feed table via a palisade feeding barrier. The feed table was equipped with recesses at varying distances to the feeding barrier (5-55 cm in 5-cm steps) at angles of 30°, 60°, 90°, 120°, or 150° (feeding angle), which were filled with the goats' preferred food. In 18 trials, balanced for order across animals, each animal underwent all possible combinations of feeding area step (3 levels: 0, 10, and 20 cm) and of difference in height between feed table and standing area of forelegs (6 levels: 0, 5, 10, 15, 20, and 25 cm). The minimum and maximum reach at which the animals could reach feed on the table with a relaxed body posture was determined for each combination. Statistical analysis was performed using mixed-effects models. The animals were able to feed with a relaxed posture when the feed table was at least 10 cm higher than the standing height of the goats' forelegs. Larger goats achieved smaller minimum reaches and minimum reach increased if the goats' head and neck were angled. Maximum reach increased with increasing height at withers and height of the feed table. The presence of a feeding area step had no influence on minimum and maximum reach. Based on these results, the goats' feeding place can be designed to ensure that the animals are able to reach all of the feed in the manger or on the feed table with a relaxed posture, thus avoiding injuries and nonphysiological stress on joints and hooves. A feeding area step up to a maximum of 20 cm need not be taken into account in terms of feeding reach. However, the feed table must be raised at least 10 cm above the standing area to allow the goats to feed in a species-appropriate, relaxed posture.

A multi-population survey on swine feeding behavior with electronic feeding devices

Abstract. In this study, we used electronic feeding station observations of pigs to investigate their growth performance and feeding behavior. These pigs were raised in Xinda Livestock Company Ltd. in Henan, China, and followed the Chinese directive for the protection of farm animals. Electronic feeding stations are often used in pig breeding and for identifying loci associated with feed consumption. Moreover, they can also provide much valuable information on pig behavior that could be directly used to improve production efficiency. This study involves three different pig population feeding-intake data from 383 Yorkshire, 243 Landrace and 197 Duroc breeds to investigate their growth performance and feeding behavior. Similar patterns of growth performance (slow–fast–slow) were observed in the three breeds, while the Duroc have a slightly faster average growth rate throughout the whole test period. Study of the number of visits to the feeding station over 24 h detected two peaks of feeding intake activity at 08:00–09:00 and 14:00–15:00. During these two peak feeding times, lower feed intake and less occupation time were observed, implicating fiercer competition at these time periods. The effective intake time for Duroc, Landrace and Yorkshire populations was 19, 16 and 19 min, respectively, suggesting that the ultimate feed intake time for each individual can be set up to 20 min for each visit. Studies on the ADFI (average daily feed intake) showed a significant difference (P value  =  0.000009) between seasons and consistent patterns for these three breeds. The present study provides a detailed survey on pig feed intake behaviors across different populations and feeding seasons.

Influence of forage: concentrate ratio and type of starch in the diet on feeding behaviour, dietary preferences, digestion, metabolism and performance of dairy goats in mid lactation

In a 12-week trial, 12 Alpine and 12 Saanen dairy goats in mid lactation were housed in individual stalls for behavioural, digestive and metabolic studies. Eight of them were fitted with ruminal cannulae. They were offered ad libitum four complete diets CR, CS, FR and FS (450 g dry matter (DM) per kg) in a 4✕4 Latin-square design. Forage: concentrate ratio was either low (C = 30: 70) or high (F = 55: 45) and starch source either rapidly (R, barley) or slowly (S, maize) degraded in the rumen.

Diet preferences were tested. DM intake, chewing activities and performance were determined. Ruminal pH and ammonia-nitrogen (NH3-N) concentrations were measured. Goats were also challenged intravenously with glucose (0·2 g/kg live weight) to assess glucose homeostasis.

CR was the most preferred diet. The level of intake differed according to the type of starch (2·2 kg DM per day of CR and FR and 2·0 kg DM per day of CS and FS). FS lowered ruminal pH significantly less than the other diets after the meal. Ruminal NH3-N concentrations were lower in goats given CR and CS than FR and FS. Goats’ resistance to a glucose challenge was not different among diets. Milk yield was 2·00, 1·85, 2·01, 1·85 kg/day on CR, CS, FR and FS respectively. Milk fat content decreased significantly with diets rich in concentrate (24 v. 26 g/kg milk) but milk protein content varied only a little.

In conclusion it appears that (1) higher forage: concentrate ratios were less preferred and decreased ruminal acidity but increased daily chewing, ruminal NH3-N and milk fat content; and (2) rapidly degraded starch increased intake, ruminal acidity and milk yield.

Posidonia oceanica banquettes as a substitute for straw in dairy goat rations: metabolic and productive effects

BACKGROUND

The marine plant Posidonia oceanica (L.) Delile can be a source of fibre to increase the efficiency of product costs. The aim of the present study was to assess the productive (milk production and performance) and metabolic (blood metabolites) effects of P. oceanica in the ration of dairy goats as a substitute for straw. Posidonia oceanica was used at 225 and 450 g day(-1) per goat in lieu of barley straw.

RESULT

Supplementation with P. oceanica had no detrimental effects on the body weight, milk production and metabolic status of goats. Goats fed P. oceanica produced more milk fat, had a lower somatic cell count in their milk and showed a decreased risk of oxidative stress.

CONCLUSION

Goats can be fed P oceanica at levels of up to 450 g day(-1) without detrimental effects on milk production and health, therefore P. oceanica can be a substitute for barley straw in the nutrition of goats.

Diet choice by goats as effect of milk production level during late lactation

The diet self-regulation ability of goats during late lactation has been studied with regard to their production level. Two groups of seven Girgentana goats producing 1100 ± 157 g/day (H group) and 613 ± 138 g/day (L group) were housed in individual pens and were given alfalfa pelleted hay (1.5 kg), whole grains of maize (0.5 kg), barley (0.5 kg), faba bean (0.5 kg) and pelleted sunflower cake (0.5 kg) on a daily basis. During a 7-day pre-experimental period, goats received a mixed ration based on the same feeds used during the experimental period (1.5 kg of hay and 0.4 kg of each concentrate). Individual choice of feeds was continuously recorded for 7 days using a 24-h IR video surveillance system equipped with four video cameras. The nutrient intake in both groups was much higher than needed. Goats in the H group ate more (2016.3 v. 1744.3 g dry matter (DM)/day) and selected less hay (26.9% v. 34.6% DM), more high-protein feeds (faba bean and sunflower cake: 14.0% and 15.9% v. 8.8% and 7.9% DM, respectively) and less maize (21.5% v. 25.0% DM), reaching a higher CP concentration in the diet (17.3% v. 15.0% DM) compared with the goats in the L group. During the 24-h trial period, hay was more constantly selected (on average never reaching <20% of the total hourly basis feeding time, apart from the first hour after feed administration) compared with concentrate feeds. This feeding behaviour has probably exercised a 'curative' effect that enabled the goats to continue to take in very high levels of starch and protein, without manifesting any symptom of metabolic disease. Shifting goats from the pre-experimental diet, based on a mixture of the same feeds used during the experimental period, to the free-choice feeding caused more than 20% increase in milk production in both groups. From the results of the intake, we are unable to conclude that the goats can select their diet to meet their requirements, as goats consumed much more than needed. However, when free to choose their diet, the animals improved milk performance, despite the late-lactation stage.

Effects of the forage-to-concentrate ratio of the diet on feeding behaviour in young Blond d'Aquitaine bulls

The activities of bulls, their feeding behaviour and their ruminal pH were examined at several stages during the finishing period, according to the forage-to-concentrate ratio of their diet. Twenty-four bulls of the Blond d'Aquitaine breed (initial body weight = 326 ± 21 kg) were assigned to six balanced pens with a space allowance of 9.4 m2 per bull during the finishing period. They were fed three different diets with achieved forage-to-concentrate ratios of (i) 8% straw and 92% concentrate, (ii) 44% hay and 56% concentrate and (iii) 57% maize silage and 43% concentrate. Bulls had ad libitum access to feed dispensed once daily. Offered and refusals were weighed on 5 consecutive days per week. The bulls were slaughtered at the common final live weight of 650 kg and the finishing period lasted 138, 181 and 155 days for straw-concentrate, hay-concentrate and maize silage-concentrate diets, respectively. The time budget was estimated four times by scan sampling with a 10-min interval. Feeding behaviour was appraised using data from electronic feeding gates. Ruminal pH was measured from a ruminal fluid sample collected by rumenocentesis. On average, the bulls spent 78% of the time lying or standing still, and 11% of the time eating. The forage-to-concentrate ratio of the diet influenced only those activities directly linked to feeding, i.e. eating and drinking. Bulls fed a high-concentrate diet spent less time eating than the other bulls (47 min v. >2 h) and took shorter meals (7 min v. 17 min). The bulls fed the straw-concentrate diet spread their meals over the entire day, whereas the others maintained two major peaks of eating activity, the main one in the morning after feed dispensing, the other one at the end of the diurnal period. Intake rate ranged widely between diets, from 58 g/min on average for the diets based on hay or maize silage up to 173 g/min for the high-concentrate diet. The concentrate-diet bulls also had a lower ruminal pH during the first 2 months of the finishing period. The dispersion of meals based on a high-acidosis-risk diet may be a way to limit the decrease in ruminal pH.

Selection for nutrients by pregnant goats on a microphyll desert scrub

The behavioral consequences of pregnancy in goats were studied to test the hypothesis that pregnant females on rangeland select a diet richer in nutrients once the demands of gestation increase, and that nutrient content in goat diets changes with the grazing season. A total of 12 mature mixed breed goats either pregnant (n = 6) or non-pregnant (n = 6) were used during the dry period (February to May). Dietary samples obtained from the oral cavity of grazing goats (restrained with a short light rope permanently tightened around their neck) were used for chemical analyses. Across months, pregnant goats selected diets higher (P < 0.01) in crude protein (CP) than non-pregnant goats; this nutrient did not meet the requirements of late gestating goats. Pregnant goats made use of less (P < 0.01) fibrous feeds than non-pregnant goats. In order to cope with changing nutrient demands for pregnancy, goats adjusted their diet by increasing the selection of plants with 32% higher calcium content compared to forages selected by non-pregnant goats. The physiological state of goats did not alter the levels of phosphorus (P), magnesium (Mg) and sodium (Na) in their diets; these minerals were adequate to meet the demands of pregnancy. There were no effects of physiological state on concentrations of copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) in the goat diets during the dry season, with levels adequate for sustainability of pregnancy. Pregnant goats did not seek forages lower in tannins, alkaloids, saponins and terpenes. It was concluded that to cope with increasing pregnancy costs, goats adjusted their diets increasing selection of forages or plant parts with high nutritional value to maximize their net nutrient budget.

Effects of the percentage of concentrate on rumen fermentation, nutrient digestibility, plasma metabolites, and milk composition in mid-lactation goats

The aim of this work was to study the effects of the dietary percentage of concentrate on patterns of intake, the evolution of rumen fermentation characteristics and plasma metabolites after a meal, nutrient digestibility, and milk production and composition in a medium-term trial in dairy goats. These effects have been well studied in dairy cattle but seldom in goats. Thirteen ruminally and duodenally cannulated dairy goats (95±4 d in milk) fed ad libitum were used in this study. Goats were assigned to 1 of 2 dietary treatments: high-concentrate (70% concentrate on dry matter basis) or a low-concentrate (35%) total mixed rations. The experiment was conducted over a period of 10 wk, including 3 wk of adaption to the diets. Patterns of intake, rumen fermentation characteristics, and plasma metabolites after a meal and fatty acids profile of milk fat were compared at the onset and at the end of the experiment. The increase in dietary percentage of concentrate decreased rumen pH, acetate to propionate ratio, ammonia-N concentration, and plasma urea concentration. The percentage of concentrate did not affect total volatile fatty acid concentrations. The high-concentrate diet increased the rate of intake during the morning meal at the onset of the experiment, whereas it decreased total dry matter intake and the rate of intake during the morning meal at the end of the experiment. The high-concentrate diet resulted in greater organic matter digestibility. Raw milk yield and protein yield were greater in goats fed the high-concentrate diet, whereas fat yield was not affected by dietary treatments. The milk fat content was lower in goats fed the high-concentrate diet. Proportions of the trans-C18:1 isomer relative to total fatty acids in milk were higher with the high-concentrate diet, but no modification of the proportion of total trans-C18:1 was detected, in particular no shift from trans-11 C18:1 to trans-10 C18:1 was observed. Further, the isomer trans-10,cis-12 C18:2 was not detected. Data from this study could be used for a new modeling approach or to improve existing models.

Diet selection and milk production and composition in Girgentana goats with different alpha s1-casein genotype

In goats, alpha s1-casein polymorphism is related to different rates of protein synthesis. Two genetic variants, A and F, have been identified as strong and weak alleles based on a production of 3.5 and 0.45 g/l of alpha s1-casein per allele. The aim of the trial was to test whether goats can select their diet as a function of their genetic aptitude to produce milk at different casein levels and whether this selection can influence milk production or composition. Two groups of 8 animals, homozygous for strong (AA) or weak (FF) alleles were housed in individual pens. Using a manger subdivided into five separate containers, the goats were offered daily for 3 weeks: 1.5 kg of alfalfa pelleted hay, 0.7 kg of whole barley, 0.7 kg of whole maize, 0.7 kg of whole faba bean and 0.7 kg of pelleted sunflower cake. Total dry matter intake was similar between groups and resulted in nutrient inputs much higher than requirements. On average, goats selected 86% of maize plus barley and only 46% of faba bean plus sunflower. Indeed, AA goats selected less faba bean compared with FF goats (37.2 v. 56.7% of the available amount; P=0.01); during week 2 and week 3 they significantly increased maize selection (respectively for week 2 and week 3: 94.9 and 99.1% v. 85.3 and 87.3%) thus increasing the ratio between the high-energy feeds and the high-protein feeds (2.41 v. 1.81, P=0.023). As for true protein, the high soluble fraction (B1) and the indigestible fraction (C) were lower in the diet selected by AA goats (respectively in AA and FF groups: B1, 7.85 v. 9.23% CP, P<0.01; C, 6.07 v. 6.30% CP, P<0.001); these diet characteristics can be associated with lower losses of protein. Milk production, being similar in AA and FF groups when goats were fed with a mixed diet, significantly increased in AA group, when free-choice feeding was given (mean productions: 1198 v. 800 g/d, P<0.01). Casein content was higher in AA group than in FF group (2.70 v. 2.40%, P<0.01) whereas milk urea was higher in FF group (59.7 v. 48.8 mg/dl, P<0.01). In conclusion, when the animals were free to select their diet, their higher genetic aptitude to produce casein seemed to adjust their energy and protein dietary input in qualitative terms, thus leading to an increase in milk production and a decrease in milk urea. These results seem to demonstrate that interactions probably occurred between genetic polymorphism at the alpha s1-casein locus, diet selection and the efficiency of nutrient transformation into milk.

Determinants of seasonal variation in activity patterns of mouflon

Balancing energetic requirements is a complex process governed by the current condition of the animal, its physiological state, and by the local environment. In response to these factors, animals are expected to adapt their activity patterns. Based on continuous monitoring of 14 GPS-collared animals in southern France, we studied how environmental conditions and reproductive life-cycle periods shape the monthly activity patterns of free-ranging female mouflon ( Ovis gmelini musimon  × Ovis sp. (Blyth, 1841)). More specifically, we analyzed total daily activity, diurnal activity, length of activity bouts, and number of activity bouts. We performed multivariate analyses to account for the relationship between several intercorrelated explanatory variables and monthly activity variables. Mouflon decreased their daily activity, diurnal activity, and length of activity bouts during the hot summer months. Such changes might allow animals to reduce thermoregulation costs. The resulting higher activity in winter compared with summer indicates that summer is the most limiting period for large herbivores in Mediterranean area. Both the number of active bouts and the daily activity increased during spring, when females have access to increased food quality, which ensures a faster digestion, and when they may face high energetic requirements owing to reproduction.