Effect of Adding Choline Chloride to the Diet in Milk Production of Holstein Cows

This study aimed to show the effect of adding choline chloride to the feed on milk production during the summer in central Iraq. This study was conducted at Al-Khalis cows station in Diyala Governorate during the period from 21/6 to 21/9/2022, where 25 Holstein cows between the ages of 3-5 years used, the cows were divided into five treatments, so that treatment T1 represents the control treatment (without adding Choline chloride), while treatments T2 and T3 add untreated and formaldehyde-treated choline chloride, respectively, to the concentrated feed with an amount of 35 g /cow /day, T4 and T5 add untreated and formaldehyde-treated Choline chloride, respectively, with an amount of 70 g /cow /day, It is noted from the results that there is a significant effect of the treatment of adding Choline chloride treated with formaldehyde T3 during the ninth and thirteenth weeks in the daily milk. In the ninth week, the average milk production was 14.50 kg / cow/day compared to 9.88 kg/cow/day in the control treatment, and the rest of the treatments were T4 and T5 were 11.25 and 10.00 kg/cow/ day respectively. In the thirteenth week milk yield was 12.50 kg/cow/day compared to 7.20 kg/cow/day in the comparison treatment, and the rest of the treatments T2, T4, and T5 were 8.75, 8.50, and 8.60 kg/cow/day, respectively. While the monthly and total milk production and the amount of fat and protein in milk for cows, there were no significant differences between the treatments, we conclude from the current experiment that adding Choline chloride treated with formaldehyde in an amount of 35 g / cow/day to the feed increases the daily milk production in some weeks for this experiment in the season Summer when the average Temperature Humidity Index for this season is 79 and cows are under heat stress.


Introduction
Milk is an essential component of the diet of eight billion people around the world, and it contains nutrients needed by the human body, such as calcium, vitamin D and potassium, in addition to energy, protein and fat.According to a 2021 FAO/OECD estimate, global milk production will reach 1020 million tons in 2030, and dairy cows will produce 80% or more of the milk consumed globally [1].
Many studies have been conducted to increase milk production for animals such as adding medicinal plants (Awwad , Shwayel ,2020) and spraying water on the body cows (Al-Qudsi, and Shwayel 2015 ; Shwayel and Al Mafragi, 2019)Living organisms vary in their ability to withstand heat stress, especially dairy cattle, as the sharp rise in ocean temperature causes a significant decrease in their production performance(Ahmad, Al-Khazraji , 1259 (2023) 012076 IOP Publishing doi:10.1088/1755-1315/1259/1/012076 2 2021 ).Genetic selection for important traits such as milk yield, fat rate, protein in milk, as well as reproductive traits in dairy cows has transformed and advanced the dairy cattle industry, but in turn decreased resistance to heat stress.Researchers have conducted several studies to reduce the negative effects of heat stress on cows, including Feed additives, including adding choline chloride to the feed, which is a multifunctional substance in the body, including that it reduces the risk of fatty liver and reduces the level of ketone bodies in the blood.It also acts to reduce the level of non-citric fatty acids and increase liver glycogen content [2].[3], reported that the addition of choline chloride to the feed of cows during pregnancy and after calving significantly improved milk production and reduced placental retention and mastitis.[4], showed that the addition of choline chloride to the diet of dairy cows resulted in an increase in milk production compared to the control treatment.[5], found that the addition of protected choline significantly increased the quantity and quality of milk production by increasing its protein and fat content.The aim of the current study is to demonstrate the effect of adding formaldehyde-treated choline chloride to reduce its degradation in the rumen and untreated to the forage in the milk production of Holstein cows.

Materials and Methods
The study was conducted at Al-Khalis cows station in Diyala Governorate under conditions of heat stress in central Iraq, as 25 Holstein cows were randomly selected and Ethical standards were considered in all steps of performing procedures and animal handling and the study was approved by the Ethical Committee [Approval letter No. UoM.Dent/A.L.66/21].No. Um.VET.2021.5.during the period from 6/21 to 9/21/2022 summer between the ages of 3-5 years.The cows were divided into five treatments, each treatment Five cows, treatment T1 represents the control treatment (without adding choline chloride) and treatments T2 and T3 in which untreated and formaldehyde-treated choline chloride were added to the concentrated feed at an amount of 35 g / cow / day, respectively, and treatments T4 and T5 in which untreated choline chloride was added and treated with formaldehyde to concentrated feed with an amount of 35 g / cow / day, respectively.The chemical composition of concentrated feed for cows contained 20.21% crude protein, 11.5% crude fiber, 6.20% fat and 47.0% carbohydrates in addition to hay, alfalfa and alfalfa as rough feed.Water was Always available at all times, the daily milk production of dairy cows was recorded during the experiment in the morning (5 am) and evening (4 pm) for each cow, and the cows were milked with automatic milking machines inside the station, and the total milk and the amount of fat and protein in the milk after calculating the percentage of fat and Protein in Milk by Milk Components Analyzer, A randomized complete block design (RCBD) was used using the ready-made program (SPSS) (2011) for the calculator in analyzing the results for the purpose of excluding the effect of the milk season and its overlap with the effect of the coefficients

Results and Discussion
The following table (Table 1) shows the effect of adding choline chloride to the feed on the daily milk production during the weeks of the experiment.g/cow/day of formaldehyde-treated choline chloride.Significant differences were observed in the ninth and thirteenth weeks of the same treatment if the daily milk production in the treatment was 14.5 kg / cow / day over the treatments T1, T4 and T5, which were 9.80, 11.25 and 10.00 kg / cow / day respectively.And in the thirteenth week of the T3 treatment experiment, it amounted to 12.50 kg / cow / day, compared to the rest of the treatments, which were 7.20, 8.75, 8.50, and 8.60 kg / cow / day for the treatments T1, T2, T4, and T5, respectively.These results are consistent with the research conducted by the two researchers, [5], who found that adding choline chloride to milk cows in the feed at an amount of 55 g/cow/day led to an improvement in milk production, as the average daily milk production in the control treatment was 12.96 kg./cow versus 14.93 kg/cow/day in the choline treatment.Choline supplementation increases volatile fatty acid (VFA) production and rumen pH tends to increase the rumen coefficient of digestibility of nutrients [6], and increased focus and prevention of metabolic disorders such as ketosis and fatty liver syndrome, and increased feed digestion and absorption efficiency led to an increase in the availability of nutrients for the body, which was reflected in the improvement of milk production [6], as researchers found that choline supplementation increases utilization of the forage material in milk cows [7], while some researchers also found that choline supplementation did not affect the forage material, but when added to the feed after calving tended to increase the feed material without knowing the mechanism by which choline might affect the feed material [8].
Table 1.Effect of adding choline chloride to the feed on the daily milk production during the experimental weeks (kg/cow day) for Holstein cows in the summer season(SE± mean).

Transactions The first week
The third week The In the second table, there were no significant differences between the treatments, but we notice an arithmetic increase in milk production in the first month in treatment T3 and it amounted to 414.6 kg compared to the rest of the treatments, as it was 381.30, 348.75, 352.62, 328.60 kg / cow / day for treatments T1, T2 and T4 and T5, respectively, and total milk production we also notice an increase, but arithmetic, in the T3 treatment, as it amounted to 1142.25 kg / cow and the rest of the treatments were 961.30, 985.50, 955.50, 933.30kg / cow / day for the treatments T1, T2, T4, T5, respectively .
Table 2. Effect of adding choline chloride to the feed on the monthly and total milk production of Holstein cows during the summer season for the period from 6/21/2022 to 9/21/2022 (mean ± SE).It is noted in table 3 that there are no significant differences between the treatments in the amount of fat in milk, but an arithmetic increase was observed for the T3 treatment for the first, second and third months over the rest of the treatments.This study did not agree with previous studies, as in a study conducted by [5], it was found that the addition of choline chloride to the feed of milk cows after calving at an amount of 12.9 grams per day/cow led to an increase in the amount of fat in milk, reaching 1.29 and 1.36.kilograms per day in the control and choline-treated groups, respectively.NS= indicates no significant differences.It is also noted in Table 4 that there are no differences between the treatments in the amount of protein in milk, but an arithmetic increase was observed in the third month of the experiment for the two treatments T2 (adding 35 g / cow / day of choline chloride) and T3 (adding 35 g / cow / day of choline chloride choline treated with formaldehyde) on the rest of the treatments if it recorded 10.08, 10.52 kg / cow compared to 8.79, 9.36, 8.22 for T1, T4 and T5, respectively.These results did not agree with previous studies by [5], which found that the addition of choline chloride to the feed for postpartum milk cows at a rate of 12.9 grams / day led to an improvement in the amount of protein in milk, as it was 1.06 and 1.11 kg / day in the treatment of control and choline, respectively.The use of formaldehyde treatment can give a positive result in reducing the decomposition of feed materials in the rumen to reach the required state of the degree of decomposition of protein and other compounds in the treated materials to balance the diet.This method is easy to apply and highly effective in reducing the degree of decomposition [9].The reason for the fact that choline treatment 35 g / cow / day formaldehyde treatment is the best is due to the reason that this treatment is the most appropriate in cows and production and the best for them is that the treatment with formaldehyde reduced the decomposition of choline chloride in the rumen by microorganisms, which increased the Absorption and availability of this substance in the intestine and thus led to a better result [10].

Table 3 .
Effect of adding choline chloride to the feed on the amount of fat in the milk of Holstein cows during the summer season for the period from 6/21/2022 to 9/21/2022 (mean ± SE).

Table 4 .
Effect of adding choline chloride to the feed on the amount of protein in the milk of Holstein cows during the summer season for the period from 6/21/2022 to 9/21/2022 (mean ± SE).