جستجوی مقالات مرتبط با کلیدواژه « خوراک آغازین » در نشریات گروه « علوم دام »

Breeding quality calves with a desirable genetic potential is one of the important criteria in dairy herds. In recent years, particular attention had been paid to calf breeding, especially to the composition of starter. Early weaning and encouraging the calf to consume solid feed reduces the incidence of various diseases, including diarrhea. It was important to transfer the calf from the non-ruminant state to the active ruminant state as soon as possible for the improved health and growth of the dairy calf. To transition from a liquid feed to a solid feed containing grains and forage, it was necessary to address several challenges. These included adapting the digestive system, enabling ruminal fermentation, and improving the digestion of nutrients through the intestine. Grains, which are full of carbohydrates, were considered to be the main source of energy in ruminants, leading to an excess in the growth of rumen epithelium. Corn grain was a major source of energy in ruminants as a digestible source. In comparison with other grains, the starch available in the corn grains was digested more slowly in the rumen. To use it to its full potential, its bio-availability should be increased so that a higher level of energy was released from the starch.

This experiment was performed in the Astan Qods Razavi dairy farm, Mashhad, Iran. Forty Holstein calves, consisting of 20 male and 20 female, with an average birth weight of 42.4 Kg (± 4.3) were used from birth to 70 days. Calves were birth and immediately separated from their dam and weighting, then they were transferring to individual pen. On the third day, the calves were randomly assigned to one of two treatments. The experimental treatment included: 1) low starch, and 2) high starch. All calves received colostrum for 3 d and then whole milk at 15% of body weight in the two equal meals, morning (5:00 A.M) and evening (15:00 P.M), until weaning. Calves’ accesses to water and starter ad libitum and starter was mixed with 5% of alfalfa hay chopped (% of DM). Composition of starter did not change throughout the experiment. Starter intake was record daily. Body weight determine every two weeks until the end of experiment. Fecal consistence was scored daily. Blood sample was harvested from jugular vein for collection of blood serum. Blood metabolites including: glucose, cholesterol, triglyceride, albumin, total protein, ALT, AST, and urea were analyzed. Skeletal development was measured and recorded using special instruments on the 3, 56 and 70 days. Data were analyzed using SAS version 9.4 as a randomized completely design with GLM method and tendencies were reported at 0.05<P<0.10. Least square means for each treatment are reported in the tables and were separated using Tukeys test.

The results of this study showed that the use of the different level of starch had no significant effect on the starter feed intake, average daily gain, feed efficiency, fecal score and skeletal growth parameters of calves. Serum concentration of total protein, triglyceride, albumin, cholesterol, urea. ALT, and AST not affected by experimental treatments. ADG was not influenced by treatment in experiment. Our results are consistent with the observations of Zhang et al. (2010). There were no treatment effects on the blood parameters measured over time, which aligns with the findings of Soltani et al. (2020).The treatments did not affect fecal scores, as reported in the studies by Soltani et al. (2020). There were no significant differences in the initial, daily change, and final parameters, which is similar to the findings of Soltani et al. (2020). Additionally, starter intake, total dry matter intake (DMI), and weaning body weight (BW) were not affected by the experimental diets. This result is consistent with the observations of Lesmeister and Heinrichs (2004).

The result of this study showed that different levels of starch had no marked effects on body weight, daily feed intake, feed efficiency, fecal score, skeletal growth and blood metabolites.

In Suckling calves, due to the low development of rumen, the digestibility of food may decrease, so the energy of the diet can be increased by adding fat sources. The present experiment was conducted to investigate the effect of omega-3 and omega-6 fatty acids on feed intake and growth parameters of Holstein calves.

A total of 40 newborn calves (average age 3 days), for 60 days, in the form of a repeated design to 4 treatments including: (1) no supplemented fat source (control; CON), (2) 3% calcium-salts of soybean oil (Ca-SBO), (3) 3% calcium-salts of flaxseed oil (Ca-CO), and (4) 3% mixture of Ca-SBO and Ca-CO (1.5% each, DM basis; MIX). The study continued 66 days and the calves were gradually weaned during 61-65 days of age.

The starter intake during the period of 31 to 60 days for the control treatment was higher than the other treatments (p=0.05), but no differences were observed among the treatments in the entire experimental period. The daily weight gain in the periods of 31 to 60 days and the whole period for the treatment containing soybean oil supplement was better than the control treatment (p<0.05). Regarding body weight, soybean oil treatment had the highest weight at the end of the experiment. In terms of feed efficiency, mixed oil treatment had better performance than the control and flaxseed oil treatment, and it was not significantly difference with soybean oil treatment (p<0.05). Regarding blood metabolites, a significant differences were observed between experimental treatments in terms of glucose, total protein, cholesterol and other metabolites. Also, the liver enzyme concentration of aspartate aminotransferase for the treatment containing soybean oil on the 60th day of the experiment was the lowest compared to other treatments (p<0.01).

In general, the results showed that the use of soybean oil as a source of omega-3 fatty acids has more positive effects on the growth performance of Holstein suckling calves than flaxseed oil.

Introduction:

Ingestion of solid feed is necessary to stimulate rumen development in the young calf and facilitate the transition from a pre-ruminant to a functioning ruminant. Lipogenic nutrients in ruminants originate from fermentation of fiber to acetate and butyrate, dietary fat or are derived from body reserves. Glucogenic nutrients originate from starch that has escaped rumen degradation or gluconeogenesis. The use of low-starch starters is prevalent in dairy calf industry worldwide. These starters differ greatly in their composition of both fiber and fat. The NRC (2001) suggested that adequate digestible fiber should be included in starter diets but limited data exist to substantiate this statement. Digestible fiber sources such as sugar beet pulp, soybean hulls, and wheat bran have a lower ME value than corn and barley grains which are starch rich. A meta-analysis of 6 studies showed positive linear relationships between starch concentration of starter feed with ADG. However meta-regression analysis indicated that growth responses to starch concentration were influenced by ME concentration in dry feed fed to the calves. One possible way to enhance energy intake is to increase the energy density of the diet with fat. Convenient starter diets are typically low in fat. Most previous studies have either compared high-starch to high-fiber starter diets or investigated effects of fat supplementation on rumen environment and growth performance whereas our interest is in growth responses to diets differing in starch, NDF, and fat in calves. We hypothesize that a low-starch starter feed in which starch is substituted by fiber and fat will support growth performance similar to a traditional high-starch starter concentrate and high-fiber, high-fat diet might also improve ruminal environment in calves. We also hypothesized that preference for certain type of starter would become apparent, providing an indication of which type of energy sources may be considered more palatable for calves and therefore recommended to formulate starter feed mixture. The objectives of our study was to investigate the effects of lipogenic starter (low-starch with high-fiber and high-fat content) in comparison with a glucogenic (high-starch) or mixture of glucogenic and lipogenic starters on growth performance, ruminal fermentation, as well as blood metabolites of dairy calves during the first 70 d of life.

Materials and Methods:

 In first experiment, thirty Holstein female calves (4 d of age; 41.0 ± 4.0 kg of BW), randomly assigned by BW to one of the three dietary treatments. Treatments consisted of (1) a high starch starter feed containing corn and barley grain (glucogenic); (2) a high fiber and fat starter feed containing soybean hulls, corn germ meal, sugar beet pulp, wheat bran, full fat soybean, and vegetable oil (lipogenic); and (3) a starter feed containing mixture of diets 1 and 2 (MIX). Starter intakes were measured daily and all the calves were weighed at birth and subsequently every 7 d until the end of the experiment. Feed efficiency was calculated as the weight gain to feed intake ratio (kg/kg). In addition, the structural growth indices were measured on d 4, at weaning and at the end of the study. Blood samples from each calf were collected at 35 and 70 d to determine glucose, BUN, and β-hydroxybutyrate. Ruminal fluid was obtained 2 h after offering the morning feed at 35 and 70 d to determine the rumen pH and concentration of volatile fatty acids. Data were analyzed as a completely randomized design using a repeated-measures mixed model (PROC MIXED) of SAS software. In second experiment, 20 Holstein female calves fed a standard ration until 70 days of age. Three days after weaning, each calf was involved in a pairwise preference test between glucogenic and lipogenic diets. For each calf in each pairwise preference test, preference ratio was calculated as the consumption of one feed as a percentage of the consumption of both feeds in the test. Preference ratios were compared for a difference from 0.5 (lack of preference) using t-tests. The feed type was assigned +1 if it was preferred, −1 if it was not preferred, and 0 if the preference ratio in a pairwise preference test did not differ from 0.5. Total preference scores were used as an indicator of overall preference rank of individual feed type.

Results and Discussion:

 Results of the first experiment showed that dry matter intake was higher in the MIX diet group in the post weaning period than the other groups and a tendency to increase dry matter intake was observed throughout the study period. Average daily gain, feed efficiency, body weight, and skeletal growth were not different between treatments. Blood glucose (day 35 and 70) and plasma β-hydroxybutyric acid concentration (day 70) were higher in calves fed the glucogenic and lipogenic diet, respectively, compared to the other treatments. Rumen fluid pH and acetate concentration in calves fed the lipogenic diet were higher than those fed the glucogenic and MIX diets. The second experiment showed that calves preferred the lipogenic diet over the glucogenic diet.

Conclusion :

The results from this study showed that providing MIX diet rather than glucogenic and lipogenic diets increased post weaning intakes of starter without improving ADG and final BW. The results of the preference test clearly indicate that lipogenic diet is a highly palatable feed for recently weaned dairy calves, whereas glucogenic diet is less preferred. Given the positive trend observed in MIX feed diet, this diet seems to be recommendable for farm application. Whether the effects of energy source in early life could have long-term consequences on growth and milk yield are not known and warrant further research.

This study was aimed to investigate the effect of adding dried dairy wastes to the starter diet on growth performance in Holstein dairy calves. A total of 28 female newborn Holstein dairy calves were randomly allocated to four groups (n=7/group) and after two weeks of habituation to experimental conditions and diet, in a completely randomized design, individually fed starter diets containing 0 (control), 10, 20, or 30% dried dairy waste up to eight weeks of age. Feed intake, weight gain, and feed efficiency (gained weight/consumed feed) were measured weekly, during the experimental period. Results showed that body weight, weight gain, feed intake, and feed efficiency were not affected by the treatments. Interactive effect of treatments by week showed that the highest weight gain was for calves fed by the diet containing 10% dairy waste or control group at first week. However, the highest gain was recorded for those that received 30% dairy waste at week five of the experiment (P<0.05). In conclusion, the results of the present study revealed that the inclusion of dried dairy products up to 30% of calves’ starter diet had no adverse effect on performance, and therefore can be used as an affordable and valuable nutritional by-product of the dairy industry in the nutrition of calves.

This study was carried out to assess the effects of alfalfa hay level and replacing corn grain by other grains in starter on daily feed intake, average daily gain (ADG) and feed efficiency (FE) of pre and post-weaning dairy calves during the pre and post-weaning periods. For this purpose, a database Meta-analysis used in the present study. Statistical analyses were performed using PROC MIXED in SAS software. Starter intake and ADG were not affected by alfalfa hay feeding level during the pre-weaning period. However, alfalfa hay feeding tended to increase starter intake during the post-weaning and entire periods (P = 0.07 and P = 0.09, respectively). Further, ADG increased during the post-weaning and entire periods with alfalfa hay supplementation. Starter intake and ADG quadratically affected by the level of alfalfa hay supplementation. At pre-weaning period, feed efficiency tended to decrease (P = 0.06) with alfalfa hay supplementation, but was not different with control group during the post-weaning and entire periods. In addition, partial replacement of corn with other grains increased (P

In order to survey the inclusion effects of different levels of barley and/or corn grain in diet on growth and performance of Holstein calves 40 newborn calves were taken in 5 experimental groups with 4 female and 4 male calves in each group for a duration of105 days. The experimental group was comprised of: group 1; no barley (only consisting of corn grain) and other experimental groups 2, 3, 4 and 5 which contained 5, 10, 15 and 20 percent respectively of barley grain in total diet. The values of dry matter intake (DMI), body weight changes and feed efficiency ratio were evaluated periodically. The obtained data were statistically analyzed using repeated measurements of mixed procedures. The least square means of final weight, gain, total DMI and feed conversion ratio of calves, fed diets with no barley grain, were respectively, 138.5, 97.3 and 125.3 kg and 1.29. Increasing barley grain ratio in the diet resulted in reduction of DMI (P<0.05). Body weights in calves which consumed diets containing barley were lower as compared with the control (P<0.05), but there were no differences observed between the groups consuming diets containing barley. Increasing the barley content in the diets had no effect on feed efficiency ratio. DMI was improved with increasing calves age (P<0.05), but was not affected by the sex. Body weight, weight gain during the period as well as feed conversion ratio in male calves was more pronounced than those in females. All in all, replacement of barley up to 20 percent in Holstein calves, diets is possible with no arisal of any negative effect on their feed efficiency ratios.