One of the key elements of good milk cow nutrition is fat. Feeding dairy cows a high-fat diet has several benefits, including increased milk yield, lower milk protein concentration, and better fertility. It also improves body condition and fertility. Minerals, meanwhile, are classified as metal elements. They play various roles in our body, including enzyme and catalyst functions. This makes it crucial for milk cows’ overall health and performance.
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Table 9.4: Nutrient requirements of lactating Holstein cows
Nonstructural carbohydrates should comprise 35% of a lactating cow’s diet (DM). For far-off dry cows and postweaned growing heifers, this percentage should be much lower. In general, the milk yield of lactating Holstein cows should be at least as high as that of beef cattle. However, some feed additives may enhance milk yields and are useful in improving cow nutrition.
After calving, cows face numerous challenges. They must return to a fertile reproductive state and produce sufficient amounts of colostrum. These challenges depend on the age of the cow. The younger the cow, the higher the nutritional requirements. Table 9.4 lists the nutritional requirements for lactating Holstein cows. The diet should contain at least four percent of the recommended DM and 20% of the recommended energy from pasture.
The milk efficiency of the individual cow may influence the microbial community in the large intestine. This finding may help explain why cows with high milk efficiency are more efficient at extracting nutrients from dietary sources. Additionally, studies of the rumen microbiome revealed increased presence of CAZymes, which are associated with cellulose degradation. Pectin and hemicellulose are two major nutrient components in the lower gut of rumins. The rumen microbiome also reflects the ASVs associated with each efficiency group.
Effects of oilseeds on feed efficiency
The effects of oilseeds on the FA composition of milk in commercial herds have not been studied in detail. A study by Stergiadis et al. looked at the effects of full-fat rolled linseed and rapeseed supplements on milk production and FA content. The cows received 1.5 g oil per day. While this was a small amount of oil, the authors reported that the addition of this source of dietary fat resulted in higher milk yields. The results showed that fat supplementation reduced milk SFA but increased the yield of MUFA and PUFA.
The total dietary fat content in milk cow diets should not exceed 8% of the dry matter. For beef cattle, this level is acceptable. However, feeding oilseeds in excess of this amount may cause digestive problems in the cows, interfere with ruminal fermentation, and affect post-ruminal digestibility. The maximum levels of oilseed inclusion in the milk cow diet should not exceed three to four percentage points.
Effects of free water intake on milk production
The study looked at the effects of free water intake on milk production in dairy cows. They divided a group of cattle into two equal groups. One group had free access to water daily while the other received water only once a week for 30 minutes. Milk production was recorded daily and blood samples were taken at the end of each phase. Milk composition was also analysed. In the control group, milk yield was 80% higher than in the restricted group, indicating that the free water was not a factor in their milk production.
To study the effect of free water intake on milk production, researchers first looked at the amount of milk produced by dairy cows. In mid-lactation, cows were milked twice a day. Their milk yield was automatically recorded at each milking and summed for daily milk production. Mean temperatures were calculated by a station two kilometers from the farm. Rainfall events were taken into account. The study period was 65 days, or 655 cow-days, including two rainy days.
Effects of ration formulation on heifer growth
A better understanding of the diet composition of heifers is essential for maximizing their milk production. The NRC estimates can be used to formulate rations for British-type heifers. However, the actual requirements of a given animal may vary. Grazing activity, environmental temperature, breed, and compensatory gain can all influence ration requirements. Using the NRC estimates as a basis, you can calculate the ration requirements for your animal to reach its target weight at the start of the breeding season.
The relative feed value is based on estimates of nutrient content. It is often used as a quality benchmark for alfalfa hay. However, it is not considered in ration formulation. In addition, relative forage quality is not an accurate measure of forage quality. Relative forage quality is calculated based on estimates of forage intake and incubation with rumen microorganisms. A ration containing high ICP is usually discolored and has a sweet smell.