Abstract
Simple SummaryThe excessive mobilization of fatty acids from dairy cows’ adipose tissue increases blood non-esterified fatty acid concentrations and could have a negative effect on the fertility parameters and milk yield, as well as increase the risk of metabolic disorders and also result in early-lactation culling risk. Propylene glycol and rumen-protected starch from maize grain are commonly used as glucose precursors reducing nonesterified fatty acid levels; however, no such comparisons are available, thus it was decided to assume it as the aim of this study. Propylene glycol had a positive effect on shortening the period to first ovulation. Propylene glycol and maize grain improved the first service conception rate and decreased the number of services per conception in cows. In conclusion, both treatments with propylene glycol and maize grain had a slight effect on the metabolic profile and no effect on milking performance, yet they improved fertility parameters, which could indirectly enhance milk production economics.The aim of the study was to determine the effect of propylene glycol and maize grain content by-pass starch supplementation during the transition period and the first 56 days of lactation on blood metabolic indices, milk production and fertility parameters in dairy cows. Seventy-five Polish Holstein-Friesian dairy cows were assigned to treatment 21 days before calving. The treatments included: TG—2.5 kg triticale grain/cow per day supplemented from 14 days prepartum to day 56 postpartum, PG—2.5 kg triticale grain/cow per day supplemented from day 14 before parturition to day 56 postpartum, and 400 g propylene glycol/cow per day from 14 days prepartum to 14 days of lactation and MG—2.5 kg maize grain/cow per day supplemented from day 14 before parturition to day 56 postpartum. PG and MG had an effect resulting in the highest glucose concentration at 28 d of lactation. Cows assigned to the PG and MG groups had significantly higher cholesterol levels confronted with TG group at day 14 of lactation, while at days 28 and 56 the same difference was observed only between the MG and TG groups. PG had an effect on shortening the period to first ovulation. PG and MG improved the first service conception rate and decreased the number of services per conception in cows. In conclusion, both treatments of dairy cows with PG and MG improved their fertility parameters, while they had a slight effect on their metabolic profile and no effect on their milking performance.
Highlights
During the past decades intensive genetic selection of dairy cows, which main goal was to increase milk yield, has brought about a level of production in which nutrition allowances are difficult to supply [1]
Propylene glycol and maize grain had no effect on body condition score (BCS) and condition changes during the last 21 d of the dry period as well as during the first 2 months of lactation (p > 0.05, Table 2)
TG—2.5 kg triticale grain/cow per day supplemented from 14 days prepartum to day 56 postpartum, Propylene glycol (PG)—2.5 kg triticale grain/cow per day supplemented from day 14 before parturition to day 56 postpartum, and 400 g propylene glycol/cow per day from 14 days prepartum to 14 days of lactation, MG—2.5 kg maize grain/cow per day supplemented from day 14 before parturition to day 56 postpartum
Summary
During the past decades intensive genetic selection of dairy cows, which main goal was to increase milk yield, has brought about a level of production in which nutrition allowances are difficult to supply [1]. Nutritional requirements rise rapidly during the last week of pregnancy, as it is the case at increasing milk production after calving, resulting in the energy deficit postpartum [2]. A higher frequency of metabolic disorders, as well as lower milk yields and inferior reproductive performance are increasingly common [3,4,5] and may result in early lactation culling risk [6]. In effect cows are affected by excessive lipid mobilization from the adipose tissue, lower appetite and glucose concentration, the risk of ketosis and fatty liver frequency is higher. Incidence of subclinical ketosis can range from 6.9 to
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