Banca de DEFESA: MARIANA MONTEIRO BOENG PELEGRINI

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIANA MONTEIRO BOENG PELEGRINI
DATE: 04/08/2023
TIME: 09:00
LOCAL: Web Conferência - Google Meet: https://meet.google.com/zhw-aiod-jfc
TITLE:

Subclinical hypocalcemia in Jersey dairy cows and its effects on peripartum metabolism and productive performance.

KEY WORDS:

milk production; calcium; Beta hydroxy butyrate; calving interval first heat

PAGES: 45
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

The objective of this work was to determine the influence of subclinical hypocalcemia in Jersey dairy cows on peripartum metabolism and productive performance. Samples of urine, milk, blood and productive data were collected from 40 Jersey cows kept in a semi-extensive system. Urine was collected seven days after the expected date of delivery to measure urinary pH and observe the efficiency of the prepartum diet. Blood samples were taken after the afternoon milking, by puncture of the coccygeal arteriovenous complex, seven days before the expected date of parturition and on days 1, 3, 7, 14 and 21 after parturition. In the serological samples, the concentrations of calcium (Ca), magnesium (Mg), phosphorus (P), beta hydroxy butyrate (BHBA), aspartate amino transferase (AST), gamma glutaryl transferase (GGT), albumin (ALB) and proteins were analyzed. total plasma concentrations (TPP). Formulas were used to estimate ionizable calcium and globulin. Milk samples were collected weekly from the use of the individual collection cup and adjusted for days 7, 14, 21, 28, 35, 42, 49, 56 after delivery and evaluated for somatic cell count (SCC) and chemical composition (fat, protein, lactose, total solids and casein). Zootechnical data on body condition score (BCS) and weight were obtained seven days before the expected date of parturition and on days 1, 3, 7, 14, 21, 30 and 60 days after parturition. Calving-first heat interval data (IPPCio) were obtained from the property's database. The animals were categorized into Normo (GNC; >8.84 mg/dL or 2.18 mmol/L) or hypocalcemic (GHC; ≤ 8.84 mg/dL or 2.18 mmol/L) groups based on calcemia 24 hours after delivery. Data from metabolic variables, milk quality and zootechnical data were submitted to analysis of variance using the SAS® program. GHC cows showed higher milk production up to 56 days after calving (GHC 27.06 ± 1.13 kg vs GNC 23.83 ± 0.85 kg; P= 0.0229) and had lower amounts of protein and casein (P<0.05) in milk up to day 28 postpartum. BHB levels were highest on day 3 postpartum in the GHC (GHC= 0.82; GNC= 0.48 mmol/L; P= 0.0060) and PPT concentrations were lowest 7 days after the expected date of parturition ( 7.50 mg/dl) and 1 day postpartum (7.23 mg/dl) in GHC (P= 0.0077). The GHC had a higher IPPCio (GHC 36.50 vs GNC 24.83 days; P=0.0529). GHC multiparous cows showed the highest lactation number (3.92 ± 0.13) compared to the GNC multiparous cows (2.79 ± 0.12) (P=0.0026). From the data obtained, we concluded that dairy cows of the Jersey breed with subclinical hypocalcemia have higher milk production, higher number of lactations and a longer calving interval for the first heat. In addition, hypocalcemic animals have a more pronounced negative energy balance on the third day after parturition, with lower concentrations of total plasmatic proteins until the first day after parturition.

COMMITTEE MEMBERS:
Externo à Instituição - URIEL SECCO LONDERO - UFPel
Interno - 1760760 - CARLOS EDUARDO NOGUEIRA MARTINS
Presidente - 1046884 - ELIZABETH SCHWEGLER